46 results on '"Abu-Lafi S"'
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2. Phenolic and Flavonoids Analysis of Pomegranate Peel Extracts and their Antiniflammatory and Antioxidant Activities
- Author
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Qabaha K., Al-Rimawi F, Nusseibeh S., Abbadi J J., and Abu-Lafi S.
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chemistry.chemical_classification ,Antioxidant ,ABTS ,medicine.drug_class ,DPPH ,medicine.medical_treatment ,Flavonoid ,High-performance liquid chromatography ,Anti-inflammatory ,chemistry.chemical_compound ,chemistry ,Polymorphonuclear cells ,medicine ,Palestine ,Food science ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) - Abstract
An in-vitro evaluation of the anti-inflammatory and antioxidant activities of pomegranate peel extract from Palestine were investigated. In parallel, the total phenolic content (TPC) and the total flavonoids content (TFC) were measured. The antioxidant activities were determined spectrophotometrically by DPPH, FRAP, CUPRAC and the ABTS methods. The phenolic and flavonoid contents were separated and partially identified using HPLC and LC-MS. In-vitro inhibitory effect of the extract on production of Interlukin-6 (Il-6) and Tumor Necrosis Factor-α (TNF-α) by Lipopolysacaride (LPS)-induced polymorphonuclear Cells (PMNCs) was evaluated. Pomegranate peel extract was found to have strong antiinflamatory activity as revealed by the reduction in the levels of IL-6 and TNF-alfa. It was also found that it is rich in phenoloic and flavonoids that enhanced its reducing activity and free radical scavenging ability.
- Published
- 2019
3. Isolation, Identification, and Characterization of the Novel Antibacterial Agent Methoxyphenyl-Oxime from Streptomyces pratensis QUBC97 Isolate
- Author
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Abu-Lafi S, Ayesh M, Ayyad I, and Sameer A. Barghouthi
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chemistry.chemical_compound ,Streptomyces pratensis ,chemistry ,Biochemistry ,Identification (biology) ,Oxime ,Isolation (microbiology) ,Microbiology ,Antibacterial agent - Published
- 2017
4. Effects of a saponin fraction extracted from Trigonella foenum-graecum L. and two commercially available saponins on sex ratio and gonad histology of Nile tilapa fry, Oreochromis niloticus (L.)
- Author
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Stadtlander, T., Levavi-Sivan, B., Kerem, Z., Dweik, H., Qutob, M., Abu-Lafi, S., Francis, G., Focken, U., and Becker, K.
- Subjects
Aquaculture - Abstract
Over three million tonnes (t) of tilapia, mostly Nile tilapia (Oreochromis niloticus, L.), are produced annually making it the second most abundantly produced freshwater fish (FAO, 2010). Tilapia are mouthbreeders that often produce stunted populations under pond conditions; one means of prevention is to produce all-male fish with the additional advantage that males usually grow faster than females. All-male populations can be achieved by supplementing feed with androgens such as 17-α-Methyltestosterone (MT) during days 10–25 post-hatch (Pandian and Sheela, 1995). However, MT is considered to be carcinogenic (Velazquez and Alter, 2004), and Hulak et al. (2008) also showed that effluents of systems in which carp were fed diets containing MT caused masculinization of female fish. Furthermore, in aquaculture the application of hormones to fish destined for human consumption is prohibited in the European Union under directive 96/22/EC, article 5, which also prohibits import of animal products produced with hormones. Kwon et al. (2000) showed that Fadrozole, a non-steroidal compound, caused masculinization in tilapia by inhibiting aromatase, which is the enzyme responsible for the conversion of endogenous androgens to estrogens. Steinbronn et al. (2004) were able to show that a dose of 2000 ppm Quillaja saponins (Sigma S-2149) inhibited reproduction of tilapia after dietary application for 32 days to first-feeding fry, suggesting saponins as a possible alternative to MT. These secondary plant compounds consist of either a steroid or triterpenoid basic structure (aglycone or sapogenin) plus one or more sugar side chains (Francis et al., 2002a). In a previous experiment a saponin fraction from the soapbark tree (Quillaja saponaria M.) inhibited aromatase in vitro (Golan et al., 2008). The fenugreek plant (Trigonella foenum-graecum L), widely cultivated in the Middle East and Asia, also has a high saponin content. The experiment was therefore conducted to test whether saponin fractions from Q. saponaria and from T. foenum-graecum were able to influence the sex ratio and gonad histology of Nile tilapia.
- Published
- 2013
5. Diversity of the terpenoids and phenolic compounds in Majorana syriaca (Labiatae) leaves growing wild in Palestine
- Author
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Abu-lafi, S., Odeh, I., Dewik, H., Qqabajah, M., Iimam, A., Dembitsky, V., and Hanuš, L.
- Abstract
Essential oils, which including terpenoids, phenolic compounds, and other volatiles of Majorana syriaca leaves growing wild in Palestine were analyzed using static headspace gas chromatography mass spectrometry technique (HS-GCMS) to check for their chemical variability. The samples were collected from thirty-four individual plants naturally growing in different locations from Palestine. In such a small-restricted area, a wide range of variation in oil characteristics was observed indicating that the Palestinian region is an important center of diversity. The essential oil yield, based on air-dried weight, ranged from 10.5-mg g-1 to 54-mg g-1. The major constituents identified throughout all the harvesting periods were varied greatly among the samples examined. HS revealed major volatiles and semi-volatiles of α-phellandrene (1.62-8.13%), α-pinene (1.22-4.61%), β-myrecene (0.5-11%), m-cymene (1.86-8.61%), p-cymene (8.44-48.6%), γ-terpinene (11.96-30.8%), thymol (0.26-11.6%), and carvacrol (0.65-21.7%). As for the phenolic compounds, the results revealed that the wild growing Majorana syriaca could be characterized by the dominant presence of carvacrol. Conversely, water irrigation has showed a prominent effect on the thymol isomer production. Therefore, we suggest using isomeric distribution ratios of these isomers as a marker to distinguish wild from cultivated Majorana syriaca.
- Published
- 2008
6. Determination of unifloral honey volatiles fromCentaurea ibericaandZizyphus spinachristiby solid-phase microextraction and gas chromatography-mass spectrometry
- Author
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Odeh, I., primary, Abu-Lafi, S., additional, and Al-Najjar, I., additional
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- 2014
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7. Effects of saponin fractions from fenugreek and the soap bark tree in the diet on performance of Nile tilapia, Oreochromis niloticus (L.)
- Author
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Stadtlander, T., Khalil, W.K., Levavi-Sivan, B., Kerem, Z., Dweik, H., Qutob, M., Abu-Lafi, S., Focken, U., Becker, K., Stadtlander, T., Khalil, W.K., Levavi-Sivan, B., Kerem, Z., Dweik, H., Qutob, M., Abu-Lafi, S., Focken, U., and Becker, K.
- Abstract
Saponins are generally regarded as anti-nutritional factors in aquaculture diets. However, previous experiments have shown that low dietary levels of saponins derived from Quillaja saponaria Molina do have growth promoting effects on common carp and Nile tilapia. Based on these experiments, we conducted an experiment in which we fed eluated saponin fractions from Q. saponaria and Trigonella foenum-graecum L. (fenugreek) to Nile tilapia in a respirometric system allowing for continuous measurement of oxygen consumption. Saponins were eluated with consecutive methanol/water concentrations (v/v, 40/60, 60/40, 80/20) resulting in three different eluates for each plant. Fractions chosen were the 80% methanol eluate from Q. saponaria (80QS) and all three eluates from T. foenum-graecum (40TS, 60TS and 80TS). Three fish each were fed with low levels (150 mg kg-1 diet) of saponins in the diet and a control diet without saponins. Growth, feed and nutrient utilization, proximate composition, oxygen consumption and metabolic performance were evaluated. The fish grew between 224% (40TS) and 266% (Control) over the eight week period. Feed conversion ratios were between 0.94 (80TS) and 1.15 (40TS) and protein efficiency ratios between 2.54 (80TS) and 2.16 (40TS). Due to low sample sizes, no statistical differences were found between control fish and saponin fed fish. However, numerically one of the tested saponin fractions (40TS) showed inferior performance (Table 1). It is concluded that the tested saponins in the tested concentrations are no potential growth promoter for Nile tilapia. On the contrary, one fraction appears to be a growth inhibitor.
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- 2013
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8. Potential Antimalarial Activity from Alcoholic Extracts of Wild Salvia palaestina Leaves
- Author
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Jaber, S., primary, Abu-Lafi, S., additional, Asharif, A., additional, Qutob, M., additional, Aburemeleh, Q., additional, and Akkawi, M., additional
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- 2013
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9. Effects of saponin fractions from fenugreek and the soap bark tree in the diet on performance of Nile tilapia, Oreochromis niloticus (L.)
- Author
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Stadtlander, T, primary, Khalil, WK, additional, Levavi-Sivan, B, additional, Kerem, Z, additional, Dweik, H, additional, Qutob, M, additional, Abu-Lafi, S, additional, Focken, U, additional, and Becker, K, additional
- Published
- 2013
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10. Effects of a saponin fraction extracted from Trigonella foenum-graecumL. and two commercially available saponins on sex ratio and gonad histology of Nile tilapa fry, Oreochromis niloticus (L.)
- Author
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Stadtlander, T., primary, Levavi-Sivan, B., additional, Kerem, Z., additional, Dweik, H., additional, Qutob, M., additional, Abu-Lafi, S., additional, Francis, G., additional, Focken, U., additional, and Becker, K., additional
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- 2012
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11. Saponin fractions from Trigonella foenum-graecum in the diet affect growth and expression of GH and IGF-1 encoding genes in tilapia (Oreochromis niloticus)
- Author
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Khalil, B., primary, Stadtlander, T., additional, Francis, G., additional, Focken, U., additional, Becker, K., additional, Levavi-Sivan, B., additional, Kerem, Z., additional, Dweik, H., additional, Qutob, M., additional, and Abu-Lafi, S., additional
- Published
- 2008
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12. Determination of potential volatiles markers from citrus, eucalyptus, cotton and wildflower Palestinian honeys using SPME followed by GCMS analysis.
- Author
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Odeh, I., Abu-Lafi, S., and Al-Najjar, I.
- Subjects
VOLATILE organic compounds ,HONEY ,CITRUS ,EUCALYPTUS ,COTTON - Abstract
The volatiles of Palestinian honeys from citrus of the orange blossom (citrus spp.), eucalyptus (eucalyptus camaldulensis), cotton (Gossypium hirsutum L.) and wildflower {poyfloral) were investigated. They were separated, identified and quantitatively analyzed by using Headspace Solid-Phase Microextraction and Gas Chromatography Mass Spectrometry (HS-SPME-GCMS) technology to estimate the amount of volatiles evolved. Although the investigated honeys have some volatiles in common but still each of them possess specific characteristic volatiles. For example, citrus honey was characterized by the presence of three volatile compounds namely, 2-methoxy-4 (1-propanol) phenol, 1-hydroxylinalool, and 2-amino benzoic acid methylester. These compounds are absent from all other honeys. Eucalyptus honey was found to have 2-propyl-1-pentanol and pentadecane as potential markers. Cotton honey was characterized by the presence of three markers, 2-furanomethanol, eicosane and 2-methyl decanol. The wildflower honey is distinguished from other floral honey by the presence of three volatile marker compounds the hexadecane, heptadecane and 3,4-dimethyl benzaldehyde. [ABSTRACT FROM AUTHOR]
- Published
- 2013
13. Comparison of the enantioseparation of racemic uridine analogs on Whelk-O 1 and ChiralPak-AD columns
- Author
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Magora, A., Abu-Lafi, S., and Levin, S.
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- 2000
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14. Reproducibility of the separation of astaxanthin stereoisomers on Pirkle covalent l-leucine and d-phenylglycine columns
- Author
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Abu-Lafi, S. and Turujman, S.A.
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- 1999
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15. Quillaja saponins inhibit tilapia aromatase activity in vitro
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Golan, M., Avitan, A., Qutob, M., Dweik, H., Abu-Lafi, S., Focken, U., Francis, G., Becker, K., Kerem, Z., and Berta Levavi-Sivan
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17-α-methyltestosterone, Aromatase, Quillaja saponins, Saponins, Sex inversion, Tilapia - Abstract
Growing monosex, all-male population of fish is highly desirable in some species in aquaculture, including tilapia, due to higher growth rates of males, better coloration and as a mean of controlling reproduction. The most widespread method for producing monosex populations in fish is administration of exogenous synthetic androgens in the feed during the critical period of sexual differentiation. The present study designed to investigate the possibility of natural saponins derived from Quillaja saponaria to inhibit aromatase activity, and isolate the most promising saponins for future in vivo sex inversion trials. The in vitro aromatase activity assay was based on the tritiated water assay using microsomes isolated from ovaries of previtellogenic females. Quillaja extract was separated on a column and fractions containing saponins were visualized and stained using TLC, collected, dried and redissolved in ethanol. In accordance with the staining of TLC plates with either sulphuric acid or anisealdehyde, that showed highest concentration of saponins in the 80% ethanol eluate, saponins proved to be the active chemical identities that are most potent in inhibiting aromatase activity and thus was assumed to be most promising for masculinization treatments.
16. Phytochemical analysis and comparison for differentiation of Boswellia carterii and B. serrata
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Harmš, L. O., Arieh Moussaieff, Řezanka, T., Abu-Lafi, S., and Dembitsky, V. M.
17. Role of hydroxyl groups in chiral recognition of cannabinoids by carbamated amylose
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Abu-Lafi, S., Sterin, M., and Levin, S.
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- 1994
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18. Use of system peaks for the determination of the distribution of resorcinol, catechol and phenol in liquid chromatography
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Levin, S., Abu-Lafi, S., Golshan-Shirazi, S., and Guiochon, G.
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- 1994
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19. Structural features affecting chiral discrimination of terpene derivatives on a carbamated amylose stationary phase
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Abu-Lafi, S., Sterin, M., Levin, S., and Mechoulam, R.
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- 1994
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20. Resolution of chiral cannabinoids on amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase: effects of structural features and mobile phase additives
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Levin, S., Abu-Lafi, S., Zahalka, J., and Mechoulam, R.
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- 1993
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21. From Sequence to Solution: Intelligent Learning Engine Optimization in Drug Discovery and Protein Analysis.
- Author
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Raiyn J, Rayan A, Abu-Lafi S, and Rayan A
- Abstract
This study introduces the intelligent learning engine (ILE) optimization technology, a novel approach designed to revolutionize screening processes in bioinformatics, cheminformatics, and a range of other scientific fields. By focusing on the efficient and precise identification of candidates with desirable characteristics, the ILE technology marks a significant leap forward in addressing the complexities of candidate selection in drug discovery, protein classification, and beyond. The study's primary objective is to address the challenges associated with optimizing screening processes to efficiently select candidates across various fields, including drug discovery and protein classification. The methodology employed involves a detailed algorithmic process that includes dataset preparation, encoding of protein sequences, sensor nucleation, and optimization, culminating in the empirical evaluation of molecular activity indexing, homology-based modeling, and classification of proteins such as G-protein-coupled receptors. This process showcases the method's success in multiple sequence alignment, protein identification, and classification. Key results demonstrate the ILE's superior accuracy in protein classification and virtual high-throughput screening, with a notable breakthrough in drug development for assessing drug-induced long QT syndrome risks through hERG potassium channel interaction analysis. The technology showcased exceptional results in the formulation and evaluation of novel cancer drug candidates, highlighting its potential for significant advancements in pharmaceutical innovations. The findings underline the ILE optimization technology as a transformative tool in screening processes due to its proven effectiveness and broad applicability across various domains. This breakthrough contributes substantially to the fields of systems optimization and holds promise for diverse applications, enhancing the process of selecting candidate molecules with target properties and advancing drug discovery, protein classification, and modeling.
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- 2024
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22. Alkyl Gallates as Potential Antibiofilm Agents: A Review.
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Rayan M, Abu Lafi S, Falah M, Kacergius T, Kirkliauskiene A, Gabe V, and Rayan A
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- Quorum Sensing, Biofilms, Gallic Acid pharmacology, Anti-Bacterial Agents pharmacology
- Abstract
Biofilms, which consist of microorganisms embedded in a polymer-rich matrix, contribute to a variety of infections and increase antimicrobial resistance. Thus, there is a constant need to develop new chemotherapeutic agents to combat biofilms. This review article focuses on the use of alkyl gallates, gallic acid and its esters (methyl, ethyl, propyl, butyl, hexyl, octyl, and dodecyl gallate), most of which are found in plants, to inhibit biofilm formation. The studies under review reveal that alkyl gallates have the capacity to prevent biofilm development and eradicate mature biofilms through mechanisms that suppress the synthesis of the extracellular polymeric matrix, inhibit quorum-sensing signaling, and alter the microbial cell membrane. The effects are stronger the greater the length of the alkyl chain. Moreover, the alkyl gallates' preventive activity against biofilm formation occurs at doses below the minimum inhibitory concentration. More importantly, combining alkyl gallates with antimicrobials or blue-light irradiation produces a synergistic effect on the inhibition of biofilm formation that can be used to treat infections and overcome microbial resistance.
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- 2023
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23. A Novel Docetaxel-Biotin Chemical Conjugate for Prostate Cancer Treatment.
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Rayan M, Shadafny S, Falah A, Falah M, Abu-Lafi S, Asli S, and Rayan A
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- Animals, Antineoplastic Agents chemistry, Apoptosis, Cell Proliferation, Docetaxel chemistry, Female, Humans, Male, Mice, Mice, Inbred BALB C, Mice, Nude, Prostatic Neoplasms metabolism, Prostatic Neoplasms pathology, Tumor Cells, Cultured, Xenograft Model Antitumor Assays, Antineoplastic Agents pharmacology, Biotin chemistry, Docetaxel pharmacology, Prostatic Neoplasms drug therapy
- Abstract
A novel conjugate of docetaxel and biotin (designated as IDD-1010) was designed and chemically synthesized via an ester linkage at position 2' carbon in docetaxel. The synthesized pure IDD-1010 exhibits a potent anti-cancer activity in in vitro and in vivo studies. At 10 nM, IDD-1010 has induced increased apoptosis and mitotic arrest of PC3-Luc prostate cancer cells, causing aneuploidy and cell death at higher concentrations. Toxicology studies indicate that the maximal tolerated dose (MTD) of IDD-1010 is 150 mg/kg in mice; equivalent to about 12.2 mg/kg of body weight, or to about an 850 mg dose for a patient weighing 70 kg. The MTD-treated mice exhibited weight gain similar to that of the control group, with no gross pathological signs at 14 days post-dosing. At a lower dose, IDD-1010 treatment did not lead to any significant weight loss in mice, although decreased the tumor volume stemming from injecting cancer cells into the dorsal loop of mouse prostate, and it was found to be more potent than Paclitaxel (reference drug). Similarly, IDD-1010 treatment significantly reduced tumor weight and thereby increased the percentage of mice survival as compared to reference drug-treated and control groups. To summarize, the described experiments using IDD-1010, as compared to the reference drug, strongly suggest a potential treatment utility with a wider therapeutic window for prostate cancer. Henceforth, clinical research on such a novel drug candidate would be greatly worthwhile.
- Published
- 2022
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24. The dual impact of Jordanian Ephedra alte for inhibiting pepsin and treating microbial infections.
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Salman HA, Yaakop AS, Al-Mustafa A, Tarawneh K, Aladaileh S, Al-Rimawi F, Alakhras F, Abu-Lafi S, Zarzour RA, and Wahab H
- Abstract
Screening of phytochemical Ephedra alte crude extract by GC-MS and HPLC analysis indicated the presence of alkaloids, tannins, flavonoids, terpenoids, and phenolic acid in the extract. The total phenolic content of E. alte methanol extract was 39.43 mg of Gallic acid eq/g, crude E. alte with 56.74, and 2.42 µg Trolox equivalent antioxidant capacity (TEAC)/g of plant extract according to DPPH and FRAP assay, respectively. The antimicrobial activity of E. alte against Staphylococcus aureus, staphylococcus epidermidis, Escherichia coli, and Klebsiellaoxytoca demonstrated a mean zone diameter of inhibition ranging from 0 to 17 mm. The MIC of the extracts ranged from 0.5 to 1.0 mg/mL. E. alte extract inhibits pepsin enzyme activity with IC50 values of 213.67 µg/ml. This study revealed that E. alte extract has pepsin enzyme inhibitory, antibacterial, antioxidant activities. The current outcomes indicate that E. alte might be employed as a natural agent for managing GERD and infectious diseases., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)
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- 2021
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25. Suppressive Effects of Octyl Gallate on Streptococcus mutans Biofilm Formation, Acidogenicity, and Gene Expression.
- Author
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Gabe V, Kacergius T, Abu-Lafi S, Zeidan M, Abu-Farich B, Austys D, Masalha M, and Rayan A
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- Anti-Bacterial Agents pharmacology, Biomass, Gallic Acid chemistry, Gallic Acid pharmacology, Genes, Bacterial, Glass chemistry, Polystyrenes chemistry, Streptococcus mutans drug effects, Surface Properties, Acids metabolism, Biofilms drug effects, Gallic Acid analogs & derivatives, Gene Expression Regulation, Bacterial drug effects, Streptococcus mutans genetics, Streptococcus mutans physiology
- Abstract
The accumulation of biofilm by Streptococcus mutans bacteria on hard tooth tissues leads to dental caries, which remains one of the most prevalent oral diseases. Hence, the development of new antibiofilm agents is of critical importance. The current study reports the results from testing the effectiveness of octyl gallate (C8-OG) against: (1) S. mutans biofilm formation on solid surfaces (polystyrene, glass), (2) acidogenicity, (3) and the expression of biofilm-related genes. The amount of biofilm formed by S. mutans bacteria was evaluated using the colorimetric method and optical profilometry. The pH of the biofilm growth medium was measured with microelectrode. A quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to assess the expression of genes encoding glucan binding protein B ( gbpB ), glucosyltransferases B, -C, -D ( gtfB, -C, -D ), and the F-ATPase β subunit of the F
1 protein ( atpD ). The results show that C8-OG significantly diminished biofilm formation by exposed S. mutans on solid surfaces and suppressed acidogenicity in a dose-dependent manner, compared to unexposed bacteria ( p < 0.05). The C8-OG concentration of 100.24 µM inhibited S. mutans biofilm development on solid surfaces by 100% and prevented a decrease in pH levels by 99%. In addition, the RT-qPCR data demonstrate that the biofilm-producing bacteria treated with C8-OG underwent a significant reduction in gene expression in the case of the four genes under study ( gbpB , gtfC , gtfD , and atpD ), and there was a slight decrease in expression of the gtfB gene. However, C8-OG treatments did not produce significant expression change compared to the control for the planktonic cells, although there was a significant increase for the atpD gene. Therefore, C8-OG might be a potent antibiofilm and/or anticaries agent for oral formulations that aim to reduce the prevalence of dental caries.- Published
- 2019
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26. Phytochemical Composition and Biological Activities of Wild Scolymus maculatus L.
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Abu-Lafi S, Rayan M, Masalha M, Abu-Farich B, Al-Jaas H, Abu-Lafi M, and Rayan A
- Abstract
Background: The wild population of spotted golden thistle, Scolymus maculatus , which belongs to the Compositae family, is believed to be one of the multi-curative wild plants mentioned in Flora Palaestina . This study aims to disclose the phytochemical composition, antioxidant potential, and antimicrobial activity of wild S. maculatus collected from the farms of Kabul, a village in northwest Galilee, for the first time. Methods: The phytochemical components of crude S. maculatus extracts from methanol, ethyl acetate, and n -hexane solvents were separated and identified using gas chromatography-mass spectrometry (GC-MS) in the electron impact (EI) mode. The free radical scavenging of the plant extracts was measured by DPPH assay. The microdilution test was used to determine the minimum inhibitory concentrations (MICs) of different S. maculatus extracts and to evaluate their antimicrobial activities. Results: Thirty-two phytochemicals were found in S. maculatus extracts including stigmasterol, γ-sitosterol, lupeol, lupeol acetate, and β-amyrin. Phytochemicals, such as 2-linoleoylglycerol, γ-sitosterol, β-amyrin, lupeol, (3α)-12-oleanen-3-yl acetate, and lupenyl acetate, were found to dominate the methanol extract. Most of these compounds were also observed in ethyl acetate and n -hexane extracts, but at different levels, in addition to some other minor compounds. The various extracts were investigated for their antioxidant and antimicrobial activity. The ethanolic and the methanolic extracts were shown to exhibit the highest free radical scavenging by DPPH assay with a half-maximally effective concentration (EC
50 ) of 0.37 and 0.65 mg/mL respectively, while the other three extracts (aqueous, ethyl acetate and n -hexane) were less active and their EC50 (effective concentration at which DPPH radical was scavenged by 50%) were above 1.0 mg/mL. Moreover, MICs were determined to be effective against Staphylococcus aureus , Salmonella typhimurium , and Candida albicans microorganisms. Ethyl acetate and the ethanolic extracts are active against the three types of microorganisms at a minimum inhibitory concentration (MIC) of 0.5 mg/mL, while aqueous and the n -hexane extracts are inactive against Salmonella typhimurium . Conclusions: The results show that S. maculatus extracts are a rich source of compounds that can play an important role in human health, and in a broader context, in the treatment of various diseases, such antimicrobial and antioxidant-related ailments.- Published
- 2019
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27. Inhibitory Effects of Ethyl Gallate on Streptococcus mutans Biofilm Formation by Optical Profilometry and Gene Expression Analysis.
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Gabe V, Kacergius T, Abu-Lafi S, Kalesinskas P, Masalha M, Falah M, Abu-Farich B, Melninkaitis A, Zeidan M, and Rayan A
- Subjects
- Bacterial Adhesion drug effects, Bacterial Proteins metabolism, Biofilms growth & development, Carrier Proteins genetics, Carrier Proteins metabolism, Culture Media chemistry, Dental Caries microbiology, Dental Caries prevention & control, Dose-Response Relationship, Drug, Gallic Acid pharmacology, Glass chemistry, Glucosyltransferases genetics, Glucosyltransferases metabolism, Humans, Hydrogen-Ion Concentration, Lectins genetics, Lectins metabolism, Microbial Sensitivity Tests, Polystyrenes chemistry, Proton-Translocating ATPases genetics, Proton-Translocating ATPases metabolism, Streptococcus mutans genetics, Streptococcus mutans growth & development, Streptococcus mutans metabolism, Anti-Bacterial Agents pharmacology, Bacterial Proteins genetics, Biofilms drug effects, Gallic Acid analogs & derivatives, Gene Expression Regulation, Bacterial drug effects, Streptococcus mutans drug effects
- Abstract
This study aimed to test the effectiveness of ethyl gallate (EG) against S. mutans biofilm formation on solid surfaces (polystyrene, glass) and acidogenicity, and to examine the effect on expression of related genes. The biofilm that is formed by S. mutans bacteria was evaluated using colorimetric assay and optical profilometry, while the pH of the biofilm growth medium was measured with microelectrode. The expression of genes encoding glucan binding protein B ( gbpB ), glucosyltranferases B, -C, -D ( gtfB, -C, -D ) and F-ATPase ( atpD , atpF ) was assessed using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). It was revealed that all of the EG concentrations significantly suppressed S. mutans biofilm build-up on polystyrene and glass surfaces, and inhibited acidogenicity, in a dose-dependent manner, compared to the activity of untreated bacteria ( p < 0.05). The highest concentration of EG (3.53 mM) reduced biofilm formation on polystyrene and glass surfaces by 68% and more than 91%, respectively, and prevented a decrease in pH levels by 95%. The RT-qPCR data demonstrate that the biofilm-producing bacteria treated with EG underwent significant gene expression changes involving the gtfC (a 98.6 increase in fold change), gtfB gene (a 47.5 increase in fold change) and the gbpB gene (a 13.8 increase in fold change). However, for the other genes tested ( gtfD , atpD and atpF ), the EG treatments did not produce significant expression change compared to the control. EG produced significant gene expression change in three genes- gtfC, gtfB , and gbpB ; it has the capacity to inhibit S. mutans biofilm formation on solid surfaces (polystyrene, glass), as well as acidogenicity. Therefore, EG might be used as an antibiofilm and/or anticaries agent for oral formulations in order to reduce the prevalence of dental caries.
- Published
- 2019
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28. Anticancer activity and phytochemical composition of wild Gundelia tournefortii .
- Author
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Abu-Lafi S, Rayan B, Kadan S, Abu-Lafi M, and Rayan A
- Abstract
Artichoke-like wild thistles are often used in Palestinian cuisine. One of the most commercially recognized species of these wild edible thistles is Gundelia tournefortii , a common plant in the Mediterranean region. G. tournefortii , or 'Akoob' in Arabic, remains uncultivated, harvested wild by local populations and considered highly valuable due to its reputed health benefits. The present study aimed to investigate the anticancer effects of G. tournefortii on the human colon carcinoma HCT-116 cell line. Methanol and hexane extracts were identified to exert considerable antitumor activity against the HCT-116 cancer cell line, while the aqueous extract was inactive. The phytochemical profiles of the methanol and hexane extracts were investigated using gas chromatography-mass spectrometry. A total of 6 of the 27 natural compounds identified, including sitosterol, stigmasterol, lupeol, gitoxigenin, α-amyrin and artemisinin, have been previously validated as being active against cancerous cells. Therefore, the presence of these phytochemicals in G. tournefortii is of importance in its role in preventing and treating cancer.
- Published
- 2019
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- View/download PDF
29. Indexing Natural Products for their Antifungal Activity by Filters-based Approach: Disclosure of Discriminative Properties.
- Author
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Rayan M, Abdallah Z, Abu-Lafi S, Masalha M, and Rayan A
- Subjects
- Algorithms, Antifungal Agents chemistry, Biological Products chemistry, Databases, Pharmaceutical, Antifungal Agents classification, Antifungal Agents pharmacology, Biological Products classification, Biological Products pharmacology
- Abstract
Background: A considerable worldwide increase in the rate of invasive fungal infections and resistance toward antifungal drugs was witnessed during the past few decades. Therefore, the need for newer antifungal candidates is paramount. Nature has been the core source of therapeutics for thousands of years, and an impressive number of modern drugs including antifungals were derived from natural sources. In order to facilitate the recognition of potential candidates that can be derived from natural sources, an iterative stochastic elimination optimization technique to index natural products for their antifungal activity was utilized., Methods: A set of 240 FDA-approved antifungal drugs, which represent the active domain, and a set of 2,892 natural products, which represent the inactive domain, were used to construct predictive models and to index natural products for their antifungal bioactivity. The area under the curve for the produced predictive model was 0.89. When applying it to a database that is composed of active/inactive chemicals, we succeeded to detect 42% of the actives (antifungal drugs) in the top one percent of the screened chemicals, compared with one-percent when using a random model., Results and Conclusion: Eight natural products, which were highly scored as likely antifungal drugs, are disclosed. Searching PubMed showed only one molecule (Flindersine) out of the eight that have been tested was reported as an antifungal. The other seven phytochemicals await evaluation for their antifungal bioactivity in a wet laboratory., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
- Published
- 2019
- Full Text
- View/download PDF
30. A New Approach for Indexing Honey for Its Heath/Medicinal Benefits: Visualization of the Concept by Indexing Based on Antioxidant and Antibacterial Activities.
- Author
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Masalha M, Abu-Lafi S, Abu-Farich B, Rayan M, Issa N, Zeidan M, and Rayan A
- Abstract
Background: The goals of the current study were to address a new concept termed a health benefits' index (HBI) and to verify the type of correlation between the pricing of honey and its HBI/medicinal properties. Diverse types of honey from different origins and places were investigated for their antioxidant and antimicrobial activity. Methods: We have utilized a modified protocol of the DPPH assay for measuring free radical scavenging and the microdilution test for the determination of antibacterial/antifungal minimum inhibitory concentrations (MICs). MICs were determined against Staphylococcus aureus , Escherichia coli , Salmonella typhimurium , and Candida albicans microorganisms. Employing a "combined benefits approach" enabled us to attach to each honey type a unique number of HBI that correlate with honey health and medicinal values. Results: The various types of honey demonstrated significant but variable antioxidant, antibacterial, and antifungal activities. Types of wildflower-labeled honey were found to have a wide range of HBI values and medicinal properties, probably due to their containing different nectar contents/phytochemicals. Moreover, an inconsiderable correlation was detected between the market prices of different types of honey and their HBIs. Conclusions: The proposed index of health benefits could be recalculated/updated following measurement of more and more medicinal properties, such as anti-inflammatory, antidiabetic, and anticancer activities. This index could be used as an effective tool for consumers of honey to evaluate the real value of the purchased product.
- Published
- 2018
- Full Text
- View/download PDF
31. Sesamin from Cuscuta palaestina natural plant extracts: Directions for new prospective applications.
- Author
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Abu-Lafi S, Makhamra S, Rayan I, Barriah W, Nasser A, Abu Farkh B, and Rayan A
- Subjects
- Calibration, Cuscuta metabolism, Gas Chromatography-Mass Spectrometry, Lignans biosynthesis, Cuscuta chemistry, Dioxoles chemistry, Dioxoles isolation & purification, Lignans chemistry, Lignans isolation & purification
- Abstract
The aim of this study is to disclose the potential bioactive components of Cuscuta palaestina, a native parasitic natural plant of flora palaestina and to open direction towards new prospective application. GC-MS analysis identified 18 components in the methanolic extract of C. palaestina for the first time. The most appealing among them are Sesamin and two other phytosterols (Campesterol and Stigmasterol), all of which are documented in the scientific literature for their anticancer activity. Quantitation of Sesamin extracted from C. palaestina by HPLC-PDA with the use of three organic solvents showed that the Sesamin content in the methanolic extract was the highest. Following the disclosure of Sesamin presence in C. palaestina, we raised the question of whether it is produced naturally in C. palaestina or acquired from the host plant. The quantitation of Sesamin in C. palaestina was performed while being with five different host plants, and was compared with the amount of Sesamin in C. palaestina grown alone. The findings reveal that Sesamin is an endogenous secondary metabolite in C. palaestina. Thus, further studies are required to prove if C. palaestina can be used as an alternative source of anticancer phytochemicals, mainly Sesamin, and if proteins in the Sesamin production pathway could be valid biological targets for the development of novel and selective pesticides for control/ eradication of C. palaestina and maybe some other Cuscuta species. As well, the findings from this study raise a big question of whether inferring Sesamin production in C. palaestina could reduce its attack ability to host plants.
- Published
- 2018
- Full Text
- View/download PDF
32. Nature is the best source of anti-inflammatory drugs: indexing natural products for their anti-inflammatory bioactivity.
- Author
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Aswad M, Rayan M, Abu-Lafi S, Falah M, Raiyn J, Abdallah Z, and Rayan A
- Subjects
- Anti-Inflammatory Agents chemistry, Biological Products chemistry, Phytochemicals chemistry, Anti-Inflammatory Agents classification, Biological Products classification, Models, Theoretical, Phytochemicals classification
- Abstract
Objectives: The aim was to index natural products for less expensive preventive or curative anti-inflammatory therapeutic drugs., Materials: A set of 441 anti-inflammatory drugs representing the active domain and 2892 natural products representing the inactive domain was used to construct a predictive model for bioactivity-indexing purposes., Method: The model for indexing the natural products for potential anti-inflammatory activity was constructed using the iterative stochastic elimination algorithm (ISE). ISE is capable of differentiating between active and inactive anti-inflammatory molecules., Results: By applying the prediction model to a mix set of (active/inactive) substances, we managed to capture 38% of the anti-inflammatory drugs in the top 1% of the screened set of chemicals, yielding enrichment factor of 38. Ten natural products that scored highly as potential anti-inflammatory drug candidates are disclosed. Searching the PubMed revealed that only three molecules (Moupinamide, Capsaicin, and Hypaphorine) out of the ten were tested and reported as anti-inflammatory. The other seven phytochemicals await evaluation for their anti-inflammatory activity in wet lab., Conclusion: The proposed anti-inflammatory model can be utilized for the virtual screening of large chemical databases and for indexing natural products for potential anti-inflammatory activity.
- Published
- 2018
- Full Text
- View/download PDF
33. From medicinal plant extracts to defined chemical compounds targeting the histamine H 4 receptor: Curcuma longa in the treatment of inflammation.
- Author
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Frank A, Abu-Lafi S, Adawi A, Schwed JS, Stark H, and Rayan A
- Subjects
- Binding, Competitive drug effects, Cell Line, Cell Membrane drug effects, Curcumin analogs & derivatives, Curcumin chemistry, Curcumin pharmacology, Diarylheptanoids, Dose-Response Relationship, Drug, Humans, Plant Extracts chemistry, Plants, Medicinal, Radioligand Assay, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Curcuma chemistry, Plant Extracts pharmacology, Receptors, Histamine H4 drug effects
- Abstract
Objectives: The aim was to evaluate the activity of seven medicinal, anti-inflammatory plants at the hH
4 R with focus on defined chemical compounds from Curcuma longa., Materials: Activities were analyzed with membrane preparations from Sf9 cells, transiently expressing the hH4 R, Gαi2 and Gβ1γ2 subunits., Methods: From the methanolic extract of C. longa curcumin (1), demethoxycurcumin (2) and bis(4-hydroxy-cinnamoyl)methane (3) were isolated, purified with HPLC (elution-time 10.20, 9.66, 9.20 min, respectively) and together with six additional extracts, were characterized via radioligand binding studies at the hH4 R., Results: Compounds from C. longa were the most potent ligands at the hH4 R. They exhibited estimated Ki values of 4.26-6.26 µM (1.57-2.31 µg/mL) (1); 6.66--8.97 µM (2.26-3.04 µg/mL) (2) and 10.24-14.57 µM (3.16-4.49 µg/mL) (3) (95% CI). The estimated Ki value of the crude extract of curcuma was 0.50-0.81 µg/mL. Fractionated curcumin and the crude extract surpassed the effect of pure curcumin with a Ki value of 5.54 µM or 2.04 µg/mL [95% CI (4.47-6.86 µM), (1.65-2.53 µg/mL)]., Conclusion: Within this study, defined compounds of C. longa were recognized as potential ligands and reasonable lead structures at the hH4 R. The mode of anti-inflammatory action of curcumin was further elucidated and the role of extracts in traditional phytomedicine was strengthened.- Published
- 2017
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- View/download PDF
34. Homology-based Modeling of Rhodopsin-like Family Members in the Inactive State: Structural Analysis and Deduction of Tips for Modeling and Optimization.
- Author
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Pappalardo M, Rayan M, Abu-Lafi S, Leonardi ME, Milardi D, Guccione S, and Rayan A
- Subjects
- Amino Acid Sequence, Humans, Molecular Dynamics Simulation, Protein Binding, Protein Interaction Domains and Motifs, Receptors, G-Protein-Coupled chemistry, Structure-Activity Relationship, Models, Molecular, Protein Conformation, Rhodopsin chemistry
- Abstract
Modeling G-Protein Coupled Receptors (GPCRs) is an emergent field of research, since utility of high-quality models in receptor structure-based strategies might facilitate the discovery of interesting drug candidates. The findings from a quantitative analysis of eighteen resolved structures of rhodopsin family "A" receptors crystallized with antagonists and 153 pairs of structures are described. A strategy termed endeca-amino acids fragmentation was used to analyze the structures models aiming to detect the relationship between sequence identity and Root Mean Square Deviation (RMSD) at each trans-membrane-domain. Moreover, we have applied the leave-one-out strategy to study the shiftiness likelihood of the helices. The type of correlation between sequence identity and RMSD was studied using the aforementioned set receptors as representatives of membrane proteins and 98 serine proteases with 4753 pairs of structures as representatives of globular proteins. Data analysis using fragmentation strategy revealed that there is some extent of correlation between sequence identity and global RMSD of 11AA width windows. However, spatial conservation is not always close to the endoplasmic side as was reported before. A comparative study with globular proteins shows that GPCRs have higher standard deviation and higher slope in the graph with correlation between sequence identity and RMSD. The extracted information disclosed in this paper could be incorporated in the modeling protocols while using technique for model optimization and refinement., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2017
- Full Text
- View/download PDF
35. Inhibitory capacity of Rhus coriaria L. extract and its major component methyl gallate on Streptococcus mutans biofilm formation by optical profilometry: Potential applications for oral health.
- Author
-
Kacergius T, Abu-Lafi S, Kirkliauskiene A, Gabe V, Adawi A, Rayan M, Qutob M, Stukas R, Utkus A, Zeidan M, and Rayan A
- Subjects
- Anti-Bacterial Agents chemistry, Anti-Bacterial Agents isolation & purification, Gallic Acid analogs & derivatives, Gallic Acid chemistry, Gallic Acid pharmacology, Humans, Hydrogen-Ion Concentration, Molecular Structure, Oral Health, Phytochemicals chemistry, Phytochemicals pharmacology, Plant Extracts chemistry, Plant Extracts isolation & purification, Spectrum Analysis, Anti-Bacterial Agents pharmacology, Biofilms drug effects, Plant Extracts pharmacology, Rhus chemistry, Streptococcus mutans drug effects, Streptococcus mutans growth & development
- Abstract
Streptococcus mutans (S. mutans) bacterium is the most well recognized pathogen involved in pathogenesis of dental caries. Its virulence arises from its ability to produce a biofilm and acidogenicity, causing tooth decay. Discovery of natural products capable to inhibit biofilm formation is of high importance for developing health care products. To the best of our knowledge, in all previous scientific reports, a colorimetric assay was applied to test the effect of sumac and methyl gallate (MG) on S. mutans adherence. Quantitative assessment of the developed biofilm should be further performed by applying an optical profilometry assay, and by testing the effect on both surface roughness and thickness parameters of the biofilm. To the best of our knowledge, this is the first study to report the effect of sumac extract and its constituent MG on biofilm formation using an optical profilometry assay. Testing antibacterial activity of the sumac extract and its fractions revealed that MG is the most bioactive component against S. mutans bacteria. It reduced S. mutans biofilm biomass on the polystyrene surface by 68‑93%, whereas 1 mg/ml MG was able to decrease the biofilm roughness and thickness on the glass surface by 99%. MG also prevented a decrease in pH level by 97%. These bioactivities of MG occurred in a dose‑dependent manner and were significant vs. untreated bacteria. The findings are important for the development of novel pharmaceuticals and formulations of natural products and extracts that possess anti‑biofilm activities with primary applications for oral health, and in a broader context, for the treatment of various bacterial infections.
- Published
- 2017
- Full Text
- View/download PDF
36. ANALYSIS OF PHENOLIC AND FLAVONOIDS OF WILD EPHEDRA ALATA PLANT EXTRACTS BY LC/PDA AND LC/MS AND THEIR ANTIOXIDANT ACTIVITY.
- Author
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Al-Rimawi F, Abu-Lafi S, Abbadi J, Alamarneh AAA, Sawahreh RA, and Odeh I
- Subjects
- Antioxidants analysis, Chromatography, High Pressure Liquid, Flavones analysis, Flavones pharmacology, Flavonoids analysis, Glycosides analysis, Glycosides pharmacology, Luteolin analysis, Luteolin pharmacology, Mass Spectrometry methods, Oxidation-Reduction, Phenols analysis, Plant Extracts chemistry, Polyphenols analysis, Polyphenols pharmacology, Solvents, Antioxidants pharmacology, Ephedra chemistry, Flavonoids pharmacology, Phenols pharmacology, Plant Extracts pharmacology
- Abstract
Background: Ephedra is among Palestinian medicinal plants that are traditionally used in folkloric medicine for treating many diseases. Ephedra is known to have antibacterial and antioxidant effects. The goal of this study is to evaluate the antioxidant activity of different extracts from the Ephedra alata plant growing wild in Palestine, and to analyze their phenolic and flavonoid constituents by HPLC/PDA and HPLC/MS., Materials and Methods: Samples of the Ephedra alata plant grown wild in Palestine were extracted with three different solvents namely, 100% water, 80% ethanol, and 100% ethanol. The extracts were analyzed for their total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (AA), as well as phenolic and flavonoids content by HPLC/PDA/MS., Results: The results revealed that the polarity of the extraction solvent affects the TPC, TFC, and AA of extracts. It was found that both TPC and AA are highest for plant extracted with 80% ethanol, followed by 100% ethanol, and finally with 100% water. TFC however was highest in the following order: 100% ethanol > 80% ethanol > water. Pearson correlation indicated that there is a significant correlation between AA and TPC, but there is no correlation between AA and TFC. Simultaneous HPLC-PDA and UHPLC-MS analysis of the ethanolic plant extracts revealed the presence of Luteolin-7-O-glucuronide flavone, Myricetin 3-rhamnoside and some other major polyphenolic compounds that share myricetin skeleton., Conclusion: Ephedra alata extract is rich in potent falvonoid glycosidic compounds as revealed by their similar overlaid UV-Vis spectra and UHPLC-MS results. On the basis of these findings, it is concluded that Ephedra alata constitutes a natural source of potent antioxidants that may prevent many diseases and could be potentially used in food, cosmetics, and pharmaceutical products.
- Published
- 2017
- Full Text
- View/download PDF
37. Enrichment of Phenolic Compounds from Olive Mill Wastewater and In Vitro Evaluation of Their Antimicrobial Activities.
- Author
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Abu-Lafi S, Al-Natsheh MS, Yaghmoor R, and Al-Rimawi F
- Abstract
The production of olive oil generates massive quantities of by-product called olive mill wastewater (OMWW). The uncontrolled disposal of OMWW poses serious environmental problems. The OMWW effluent is rich in several polyphenolic compounds. Liquid-liquid extraction of OMWW using ethyl acetate solvent was used to enrich phenolic compounds under investigation. Total phenolic and flavonoid content and antioxidant activity of the extract were determined. HPLC coupled to photodiode array (PDA) detector was used to analyze the main three phenolic compounds of OMWW, namely, hydroxytyrosol, tyrosol, and oleuropein. The antimicrobial activity of the extract was also investigated. Additionally, the OMWW extract was used as natural preservative and antioxidants for olive oil. Results showed that OMWW is very rich in phenolic compounds and has strong antioxidant activity. HPLC analysis showed that the extract contains mainly hydroxytyrosol and tyrosol but no oleuropein. The OMWW extract showed also positive activities as antibacterial (gram positive and gram negative) and antifungal as well as activities against yeast. The addition of OMWW extract to olive oil samples has an effect on the stability of olive oil as reflected by its acid value, peroxide value, K
232 and K270 , and total phenolic content.- Published
- 2017
- Full Text
- View/download PDF
38. HPLC separation and in vitro antimalarial studies of Artemisia annua plants from two different origins: Cameroon versus Luxembourg.
- Author
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Akkawi M, Jaber S, Abu-Lafi S, Qutob M, Abu-Rmeleh Q, and Lutgen P
- Abstract
Background: Malaria is a devastating disease, particularly in Africa, due to development of resistance by Plasmodium falciparum against all known antimalarial drugs, including artemisinin. Therefore, the search for new antimalarial drugs is urgently needed, especially drugs that can impede the heme detoxification pathway in the malaria parasite, a crucial requirement for parasite survival in host erythrocytes., Materials and Methods: Water infusions of Artemisia annua plants from two different origins, Cameroon and Luxembourg, were used in this study. A semi-quantitative in vitro method, based on the inhibition of ferriprotoporphyrin IX (FP) biomineralisation developed by Deharo et al. [16], was used to reveal the differences in antimalarial activity of both plants. Reversed phase preparative liquid chromatography coupled to a photo diode array (PDA) detector was also used to test for differences in antimalarial activity., Results: Water extracts from the leaves of the Cameroon plant showed a higher potential antimalarial activity, represented by a higher ability to inhibit β -haematin formation in vitro than A. annua extracts from Luxembourg. Although extracts of the plants of both origins showed comparable efficiencies at high concentrations, the absorbance value at 405 nm of a 10% dilution of the Cameroon plant extract was 0.075, whereas it was 1.515 for the Luxembourg plant extract. The absorbance is inversely proportional to the antimalarial activity. According to the Prep-HPLC chromatogram of the Cameroon crude sample, seven major compounds at 325 nm were found. However, only four much less pronounced compounds appeared in the Luxembourg crude sample under the same chromatographic conditions and concentration. These were preliminarily identified as polyphenolic compounds., Conclusion: A. annua infusions are widely used by people who cannot afford other treatments. Depending on the cultivation locality different chemical profiles exist. This results in differences in hemozoin formation and will therefore also lead to alterations in antimalarial activity., Competing Interests: Competing Interests: No competing interests declared., (Copyright © 2014: Akkawi et al.)
- Published
- 2014
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39. Design, synthesis, and in vitro kinetics study of atenolol prodrugs for the use in aqueous formulations.
- Author
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Karaman R, Qtait A, Dajani KK, and Abu Lafi S
- Subjects
- Atenolol chemical synthesis, Chemistry, Pharmaceutical, Drug Design, Hydrolysis, Kinetics, Molecular Structure, Prodrugs chemical synthesis, Atenolol chemistry, Prodrugs chemistry
- Abstract
Based on DFT, MP2, and the density functional from Truhlar group (hybrid GGA: MPW1k) calculations for an acid-catalyzed hydrolysis of nine Kirby's N-alkylmaleamic acids and two atenolol prodrugs were designed. The calculations demonstrated that the amide bond cleavage is due to intramolecular nucleophilic catalysis by the adjacent carboxylic acid group and the rate-limiting step is determined based on the nature of the amine leaving group. In addition, a linear correlation of the calculated and experimental rate values has drawn credible basis for designing atenolol prodrugs that are bitterless, are stable in neutral aqueous solutions, and have the potential to release the parent drug in a sustained release manner. For example, based on the calculated B3LYP/6-31 G (d,p) rates, the predicted t1/2 (a time needed for 50% of the prodrug to be converted into drug) values for atenolol prodrugs ProD 1-ProD 2 at pH 2 were 65.3 hours (6.3 hours as calculated by GGA: MPW1K) and 11.8 minutes, respectively. In vitro kinetic study of atenolol prodrug ProD 1 demonstrated that the t1/2 was largely affected by the pH of the medium. The determined t1/2 values in 1N HCl, buffer pH2, and buffer pH 5 were 2.53, 3.82, and 133 hours, respectively.
- Published
- 2014
- Full Text
- View/download PDF
40. Design, synthesis and in vitro kinetic study of tranexamic acid prodrugs for the treatment of bleeding conditions.
- Author
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Karaman R, Ghareeb H, Dajani KK, Scrano L, Hallak H, Abu-Lafi S, Mecca G, and Bufo SA
- Subjects
- Drug Design, Hemorrhage pathology, Humans, Hydrogen-Ion Concentration, Hydrolysis, Kinetics, Prodrugs pharmacokinetics, Tranexamic Acid pharmacokinetics, Hemorrhage drug therapy, Prodrugs chemical synthesis, Tranexamic Acid chemical synthesis
- Abstract
Based on density functional theory (DFT) calculations for the acid-catalyzed hydrolysis of several maleamic acid amide derivatives four tranexamic acid prodrugs were designed. The DFT results on the acid catalyzed hydrolysis revealed that the reaction rate-limiting step is determined on the nature of the amine leaving group. When the amine leaving group was a primary amine or tranexamic acid moiety, the tetrahedral intermediate collapse was the rate-limiting step, whereas in the cases by which the amine leaving group was aciclovir or cefuroxime the rate-limiting step was the tetrahedral intermediate formation. The linear correlation between the calculated DFT and experimental rates for N-methylmaleamic acids 1-7 provided a credible basis for designing tranexamic acid prodrugs that have the potential to release the parent drug in a sustained release fashion. For example, based on the calculated B3LYP/6-31G(d,p) rates the predicted t1/2 (a time needed for 50 % of the prodrug to be converted into drug) values for tranexamic acid prodrugs ProD 1-ProD 4 at pH 2 were 556 h [50.5 h as calculated by B3LYP/311+G(d,p)] and 6.2 h as calculated by GGA: MPW1K), 253 h, 70 s and 1.7 h, respectively. Kinetic study on the interconversion of the newly synthesized tranexamic acid prodrug ProD 1 revealed that the t1/2 for its conversion to the parent drug was largely affected by the pH of the medium. The experimental t1/2 values in 1 N HCl, buffer pH 2 and buffer pH 5 were 54 min, 23.9 and 270 h, respectively.
- Published
- 2013
- Full Text
- View/download PDF
41. Thymol and carvacrol production from leaves of wild Palestinian Majorana syriaca.
- Author
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Abu-Lafi S, Odeh I, Dewik H, Qabajah M, Hanus LO, and Dembitsky VM
- Subjects
- Cymenes, Gas Chromatography-Mass Spectrometry, Middle East, Oils, Volatile analysis, Monoterpenes metabolism, Plant Leaves chemistry, Thymol metabolism, Thymus Plant chemistry
- Abstract
Majorana syriaca (Zaatar in Arabic), belonging to the mint family, Labiates, is cultivated widely and grows wild in the mountains of Palestine between the months April to August. In order to determine the secondary metabolites from wild leaves of Palestinian M. syriaca, comparative analysis by static headspace (HS) and steam distillation (SD) GC-MS was used. Among the samples examined, the major constituents identified varied greatly throughout the different harvesting periods. Headspace revealed major volatiles and semi-volatiles of alpha-pinene, beta-myrecene, o-cymene, p-cymene, gamma-terpinene, thymol, and carvacrol. We found that the most abundant monoterpenes, i.e. gamma-terpinene and p-cymene were decreased in the month of May since they are the biogenetic precursors (via enzymic hydroxylation) of the phenolic terpenes, thymol and carvacrol. The harvesting time, location and the thyme type (i.e., wild) affects the yield of essential oils as reflected by normal steam distillation.
- Published
- 2008
- Full Text
- View/download PDF
42. Natural compounds of Palestine flora. Comparison analysis by static headspace and steam distillation GC-MS of semivolatile secondary metabolites from leaves of cultivated Palestinian Majorana syriaca.
- Author
-
Abu-Lafi S, Odeh I, Dewik H, Qabajah M, Imam A, Dembitsky VM, and Hanus LO
- Subjects
- Cymenes, Gas Chromatography-Mass Spectrometry, Middle East, Plant Leaves chemistry, Monoterpenes analysis, Origanum chemistry, Thymol analysis, Thymus Plant chemistry
- Abstract
Background: A comparative analysis by using static headspace (HS) and steam distillation (SD) GC-MS of the volatile and the semi-volatile secondary metabolites from leaves of cultivated Majorana syriaca., Methods: The essential oils endogenous to cultivated thyme were isolated and identified by HS-GC-MS technology and compared to those from SD-GC-MS., Results: The HS-GC-MS results showed that the Palestinian cultivated thyme is rich in monoterpene hydrocarbons and phenolic monoterpenes such as alpha-phellandrene, alpha-pinene, beta-myrcene, m-cymene, p-cymene, gamma-terpinene, thymol and carvacrol. In all the samples gamma-terpinene, p-cymene, thymol and carvacrol were the most abundant compounds., Conclusions: HS and SD-GC-MS have proved that most of the cultivated thyme samples examined has thymol isomer as the major phenolic constituent.
- Published
- 2007
- Full Text
- View/download PDF
43. N-arachidonoyl L-serine, an endocannabinoid-like brain constituent with vasodilatory properties.
- Author
-
Milman G, Maor Y, Abu-Lafi S, Horowitz M, Gallily R, Batkai S, Mo FM, Offertaler L, Pacher P, Kunos G, and Mechoulam R
- Subjects
- Animals, Aorta cytology, Aorta drug effects, Arachidonic Acids isolation & purification, Cattle, Cells, Cultured, Endothelium, Vascular drug effects, Endothelium, Vascular enzymology, Mesenteric Arteries cytology, Mesenteric Arteries drug effects, Mice, Mitogen-Activated Protein Kinase 1 drug effects, Mitogen-Activated Protein Kinase 3 drug effects, Phosphorylation, Proto-Oncogene Proteins c-akt drug effects, Rats, Receptor, Cannabinoid, CB1 metabolism, Receptor, Cannabinoid, CB2 metabolism, Serine chemistry, Serine isolation & purification, Serine pharmacology, TRPV Cation Channels metabolism, Vasodilator Agents isolation & purification, Arachidonic Acids chemistry, Arachidonic Acids pharmacology, Cannabinoid Receptor Agonists, Serine analogs & derivatives, Vasodilator Agents chemistry, Vasodilator Agents pharmacology
- Abstract
The endocannabinoid N-arachidonoyl ethanolamine (anandamide), found both in the CNS and in the periphery, plays a role in numerous physiological systems. One might expect that the chemically related N-arachidonoyl-L-serine (ARA-S) could also be formed alongside anandamide. We have now isolated ARA-S from bovine brain and elucidated its structure by comparison with synthetic ARA-S. Contrary to anandamide, ARA-S binds very weakly to cannabinoid CB1 and CB2 or vanilloid TRPV1 (transient receptor potential vanilloid 1) receptors. However, it produces endothelium-dependent vasodilation of rat isolated mesenteric arteries and abdominal aorta and stimulates phosphorylation of p44/42 mitogen-activated protein (MAP) kinase and protein kinase B/Akt in cultured endothelial cells. ARA-S also suppresses LPS-induced formation of TNF-alpha in a murine macrophage cell line and in wild-type mice, as well as in mice deficient in CB1 or CB2 receptors. Many of these effects parallel those reported for abnormal cannabidiol (Abn-CBD), a synthetic agonist of a putative novel cannabinoid-type receptor. Hence, ARA-S may represent an endogenous agonist for this receptor.
- Published
- 2006
- Full Text
- View/download PDF
44. 2-arachidonyl glyceryl ether, an endogenous agonist of the cannabinoid CB1 receptor.
- Author
-
Hanus L, Abu-Lafi S, Fride E, Breuer A, Vogel Z, Shalev DE, Kustanovich I, and Mechoulam R
- Subjects
- Animals, Cannabinoid Receptor Modulators, Cannabinoids isolation & purification, Cannabinoids pharmacology, Female, Gastrointestinal Motility drug effects, Glycerides pharmacology, Hypothermia chemically induced, Mice, Models, Animal, Receptors, Cannabinoid, Receptors, Drug metabolism, Swine, Brain Chemistry, Glycerides isolation & purification, Receptors, Drug agonists
- Abstract
Two types of endogenous cannabinoid-receptor agonists have been identified thus far. They are the ethanolamides of polyunsaturated fatty acids--arachidonoyl ethanolamide (anandamide) is the best known compound in the amide series--and 2-arachidonoyl glycerol, the only known endocannabinoid in the ester series. We report now an example of a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), isolated from porcine brain. The structure of noladin ether was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by comparison with a synthetic sample. It binds to the CB(1) cannabinoid receptor (K(i) = 21.2 +/- 0.5 nM) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds weakly to the CB(2) receptor (K(i) > 3 microM).
- Published
- 2001
- Full Text
- View/download PDF
45. A chiral HPLC method for the simultaneous separation of configurational isomers of the predominant cis/trans forms of astaxanthin.
- Author
-
Abu-Lafi S and Turujman SA
- Subjects
- Animals, Chromatography, High Pressure Liquid methods, Glycine analogs & derivatives, Reproducibility of Results, Solvents, Stereoisomerism, Xanthophylls, beta Carotene isolation & purification, Adjuvants, Immunologic isolation & purification, Salmon metabolism, beta Carotene analogs & derivatives
- Abstract
We report an HPLC method that allows the simultaneous separation of configurational isomers of the predominant cis/trans forms of astaxanthin. The configurational isomers of the all-trans-, and most of the configurational isomers of the 9-cis-, 13-cis- and 15-cis-astaxanthin were separated on a Sumichiral OA-2000 column, which is manufactured and packed in Japan with a Pirkle covalent D-phenylglycine chiral stationary phase (CSP). The large separation of the cis isomers from the all-trans isomers that we report here ensure the suitability of this method for the routine determination of the ratio of the configurational isomers of all-trans-astaxanthin.
- Published
- 1997
46. The role of enantioselective liquid chromatographic separations using chiral stationary phases in pharmaceutical analysis.
- Author
-
Levin S and Abu-Lafi S
- Subjects
- Animals, Carbohydrate Sequence, Chromatography, Liquid instrumentation, Humans, Molecular Sequence Data, Pharmaceutical Preparations chemistry, Stereoisomerism, Chromatography, Liquid methods, Pharmaceutical Preparations isolation & purification
- Published
- 1993
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