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Bioassay-guided fractionation of the CH2Cl2-MeOH (1:1) leaves extract of Trichilia gilgiana, yielded two new vilasinin-type limonoids named gilgianin A (1) and gilgianin B (2), one new phenyl alken...

The present work concerns the anti-inflammatory activity of chemical constituents isolated from the roots of Echinops gracilis. The anti-inflammatory activity of the ethyl acetate extract as well as compounds 1, 2, and 3 were evaluated using inhibition of protein denaturation and antiproteinase methods. Structural elucidation was achieved through analysis of NMR spectra (1H and 13C, 1H1H COSY, HSQC, HMBC) and literature survey. Seven compounds were identified as erythrinasinate (1), vogelate (2), ferulic acid (3), p-coumaric acid (4), ursolic acid (5), oleanolic acid (6), and quercetin (7). All the isolated compounds were reported for the first time from this plant. Ethyl acetate extract showed potent inhibitory activity against protein denaturation (IC50 = 125.54 µg/mL). Erythrinasinate (1) and vogelate (2) showed a significant anti-inflammatory activity with an IC50 value of 469.43 and 413.71 µg/mL, respectively. The results obtained from the ethyl acetate extract can justify the use of E. gracilis roots in traditional medicine for the treatment of rheumatism.

Bioassay-guided fractionation of the CH

Introduction The genus Quassia is a promising source of secondary metabolites with biological potential including antimalarial and cytotoxic activities. Limited data are available on the phytochemistry and pharmacology of Quassia silvestris Cheek & Jongkind, a Cameroonian medicinal plant used to treat various ailments. Objectives To carry out the bioassay-guided fractionation and LC-HR-ESI-MS analyses of the leaves extract from Q. silvestris; to purify the active fractions and isolate the major compounds using different chromatographic and spectroscopic methods. The obtained compounds will be evaluated for their biological activity. Material and methods Following the cytotoxic screening and LC-HR-ESI-MS profiling of fractions obtained from partition of the methanolic extract of Q. silvestris leaves, the CH2Cl2-soluble fraction which exhibited the highest cytotoxicity was retained for further investigations. Results Sixteen squalene-derived metabolites were identified with oxasqualenoid derivatives being the most predominant. Among the isolates, structure elucidation of two new oxasqualenoids quassiols E (1) and F (2), were achieved by NMR (one-dimensional (1D) and two-dimensional (2D)) and MS methods. The newly characterised compounds 1 and 2, together with the known tetraol (3) and 3-oxo-oleanoic acid (16) displayed moderate cytotoxicity. Conclusion The identification and structural characterisation of highly oxidised squalene derived metabolites from this plant may provide important insight data for further pharmacological investigations. The LC-HR-ESI-MSn method reported here could be developed as a rapid and efficient tool for the analyses of structurally related compounds in the genera Quassia, Simarouba, and Eurycoma of the subfamily Simarouboideae. Copyright © 2016 John Wiley & Sons, Ltd.

Resume L'etude phytochimique de l'extrait au dichloromethane des ecorces du tronc Vitex thyrsiflora Baker (Verbenaceae) a permis d'isoler six composes identifies a l'acide 20(R),24(E)-3-oxo-9β-lanosta-7,24-dien-26-oique (1), α-amyrine (2), β-amyrine (3), friedeline (4), au palmitate de β-sitosterol (5) et au glucoside de β'-sitosterol (6). Tous ces composes ont ete isoles pour la premiere fois de cette plante. Leurs structures ont ete elucidees sur la base de leurs donnees spectroscopiques et par comparaison avec celles de la litterature. Le compose 5 a presente une activite antiplasmodiale significative avec des CI50 de 3,09 et 8,98 μg/mL, contre les souches multi-resistantes Dd2 et K1 de P. falciparum, tandis que celle des composes 1 et 4 etait moderee. Toutes les molecules testees ont ete non cytotoxiques sur la souche de cellule epitheliale de singe (LLC-MK2). Les resultats obtenus peuvent justifier l'utilisation traditionnelle des ecorces du tronc de Vitex thyrsiflora dans le traitement du paludisme.

One new cerebroside derivative, namely liebrechtsianoside A (1), along with five known compounds: tetracosanoic acid (2), swertiaperennin (3), decussatin (4), swertianin (5) and β-sitosterol glucoside (6) were isolated from the the stem bark of Anthocleista liebrechtsiana . Their structures were elucidated by interpretation of NMR and MS data, and by comparison of these data with those reported in literature. Compound 1 showed the highest antiplasmodial activity against Dd2 chloroquine-resistant strain of Plasmodium falciparum.

One new limonoid, trigilgianin (

One new limonoid, trigilgianin (1), one new phenyl alkene, epoxy gilgialkene (2), together with five known compounds: scopoletin (3), sitosteryl-6’-O-undecanoate-β-D-glucoside (4), sitosteryl-O-β-D-glucopyranoside (5), cinchonain A (6) and cinchonain B (7) were isolated from the stem bark of Trichilia gilgiana Harms. (Meliaceae). All compounds were isolated for the first time from this species. The structures were elucidated on the basis of spectral studies and by comparison of these data with those from the literature. Compounds 1, 2, 3, 6 and 7 were tested for in vitro antileishmanial activity against visceral leishmaniasis parasite Leishmania donovani and cytotoxicity against macrophage RAW 264.7 cell line. Compounds 1 and 3 showed the highest antileishmanial activity (IC50 values of 6.044 and 6.804 µg/mL, respectively) with low cytotoxicity (CC50 values of >200 and 47.47 µg/mL, respectively), while compound 2 was moderately active on L. donovani promastigotes (IC50 56.81 µg/mL).

Bioassay guided fractionation of Hypericum riparium leaves extract has resulted in the isolation and characterization of three new compounds namely chipericumin E (1), hyperenone C (3), and hyperixanthone (5), together with twenty known compounds. Their structures were elucidated based on comprehensive interpretation of spectroscopic and spectrometric data. Compounds 1-4, and 6-8 displayed moderate antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and cytotoxic effects on the human gastric cell line BGC-823 with IC50 values ranging from 6.54 to 18.50μM.

For thousands of years, traditional medicinal plants have been used to control several diseases, based on traditional knowledge and experience. Nevertheless, many potential medicinal plants have not attracted attention to their useful pharmacological properties and remain to be discovered. In recent years, a number of plants from various genera, species and families have been scientifically studied for their pharmacological potential. Among them, the genus Polygonum contains 300 species worldwide. Many document reported various studies of phytochemical and pharmacological potential of crude extracts and compounds isolated from several Polygonum species. Aims: The present review describes some traditional uses from the Polygonum genus, the phytochemistry, the pharmacological effects, the pharmacokinetics, the toxicology and the known potential phytoconstituents of therapeutic importance that have been isolated. Place and Duration of Study: Department of Chemistry, Faculty of Science, University of Review Article Nkuete et al.; EJMP, 6(1): 1-16, 2015; Article no.EJMP.2015.037 2 Dschang, Dschang, Cameroon and Centro de Analises Proteomicas e Bioquimicas, PosGraduacao em Ciencias Genomicas e Biotecnologia, Universidade Catolica de Brasilia, Brasilia, DF, Brazil, between September 2012 and September 2013. Methodology: A review of literature was carried out using several resources such as scientific papers, classical books, pubmed, Scifinder, Sirus, the web of Science and ethnobotanical information. Results: Plants from Polygonum are widely distributed in the world and used as traditional medicine. Several compounds including phenolic compounds (flavonoids, chalcones, stibenes, coumarins and others) have been isolated and characterized from these plants and some of them are used as the effective pre-clinical to control various diseases in the world. Conclusion: The present review covers many medicinal properties of some species from the Polygonum genus, setting out further mechanism of actions and toxicity yet to be established. Studies on Polygonum plant extracts could be targeted to develop novel anticancer, anti allergic agents, potential antiplasmodial and anti-inflammatory drugs, from the active compounds. Apart from this, a new approach could be developed for preparing this herbal product, as well as in combination with other plants. Other pharmacological properties for use in artherosclerosis, neurological disorders, diabetes, hypertension and immunomodulatory effects should be evaluated.

Hypericum riparium A. Chev. is a Cameroonian medicinal plant belonging to the family Guttiferae. Chemical investigation of the methanol extract of the stem bark of H. riparium led to the isolation of four natural products, 7,7'-dihydroxy-6,6'-biscoumarin (1), 7,7'-dihydroxy-8,8'-biscoumarin (2), 7-methoxy-6,7'-dicoumarinyl ether (3), 2'-hydroxy-5'-(7″-methoxycoumarin-6″-yl)-4'-methoxyphenylpropanoic acid (4), together with one known 7,7'-dimethoxy-6,6'-biscoumarin (5), two flavones, 2'-methoxyflavone (6) and 3'-methoxy flavone (7), and two steroids, stigmast-4-en-3-one (8) and ergosta-4,6,8,22-tetraen-3-one (9). In addition, tetradecanoic acid (10), n-pentadecanoic acid (11), hexadecanoic acid (12), cis-10-heptadecenoic acid (13), octadecanoic acid (14) campesterol (15), stigmasterol (16), β-sitosterol (17), stigmastanol (18), β-eudesmol (19), 1-hexadecanol (20), and 1-octadecanol (21) were identified by GC-MS analysis. Compound 4 consists of a phenylpropanoic acid derivative fused with a coumarin unit, while compounds 2 and 3 are rare members of C8-C8' and C7-O-C6 linked biscoumarins. Their structures were elucidated by UV, IR, extensive 1D- and 2D-NMR experiments and electrospray (ESI) high resolution mass spectrometry (MS) including detailed MS/MS studies. This is the first report on the isolation of biscoumarins from the genus Hypericum, although simple coumarin derivatives have been reported from this genus in the literature. The cytotoxic activities of compounds 2-5 were evaluated against the human prostate cancer cell line PC-3 and the colon cancer cell line HT-29. They do not exhibit any significant cytotoxic activity.

Two new anthraquinone dimers, schimperiquinones A (1) and B (2), together with the known 2-hydroxymethylanthraquinone (3), cleomiscosin A (4), oleanolic acid (5) and sitosterol 3-O-beta-D-glucoside (6) were isolated from the stem bark of Pentas schimperi. Their structures were elucidated on the basis of spectroscopic analysis and comparison with published data or by comparison with authentic samples. To the best of our knowledge, it is the first report of cleomiscosin A, a coumarinolignan from the genus Pentas. Compound 2 exhibited in vitro cytotoxicity (IC50 = 33.05 mu M) against the human cancer cell the BGC-823. (c) 2014 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.

Chemical investigation of the methanol extract of the leaves of Tectona grandis led to the isolation of one new anthraquinone derivative, grandiquinone A (3-acetoxy-8-hydroxy-2-methylanthraquinone) (1), along with nine known compounds: 5,8-dihydroxy-2-methylanthraquinone (2), hydroxysesamone (3), 3-hydroxy-2-methylanthraquinone (4), quinizarine (5), betulinic acid (6), ursolic acid (7), tectograndone (8), corosolic acid (9) and sitosterol 3-O-b-D-glucopyranoside (10). Compounds 2 and 3 were isolated for the first time from the leaves of this plant, while 5 has never been reported from the genus Tectona. Hydroxysesamone (3) and tectograndone (8) were subjected to cyclisation and acetylation reactions to afford two hemisynthetic derivatives, 6,9-dihydroxy-2,2-(dimethyldihydropyrano)-3,4-dihydro-2Hbenzo[g] chromene-5,10-dione (11) and acetyltectograndone (12) respectively, which are reported here for the first time. The ethyl acetate-soluble portion, some of the isolated compounds and hemisynthetic derivatives were evaluated for their antiplasmodial activity against the multidrug-resistant Dd2 strain of Plasmodium falciparum. Compound 3 showed a prominent activity, while 2, 8, 9, 11 and 12 showed significant in vitro anti-malarial activity. Compound 1 was weakly active in this test. The structures of the compounds were elucidated by spectroscopic methods and comparison of the data with the literature. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.

An investigation of MeOH extract of Embelia schimperi stem led to the isolation of a new resorcinol derivative, 5-(7’Z-pentadecenyl)resorcinol (1), along with the known compounds lupeol (2) and β-sitosterol glucoside (3). The structures of isolated compounds were elucidated using spectroscopic methods. Compound 1 exhibited moderate in vitro cytotoxic activity against human Hela cell line.

A new prenylated xanthone, butyraxanthone F (1) together with 20 known compounds were isolated from the leaves of Pentadesma butyracea. Their identification was achieved by spectroscopic means and comparison of the data with literature or by direct comparison on TLC with authentic samples. To the best of our knowledge, this is the first report of 2-hydroxy-2,3-dihydrosqualene (17) from a natural source. Compounds 2-6 and 11-16 were found for the first time in this genus. The antiproliferative activity of the crude extract, fractions and some isolated compounds was evaluated against three human cancer cell lines, BGC-823, Hela and A549. The crude extract, fractions B and C showed weak activities. Globuxanthone (2) and 30-epi-cambogin (7) were found to be the most active compounds on the three cancer cells. The effect of 2 on Hela cells and that of 7 on BGC-823 cells were noteworthy. The antiproliferative potential of allanxanthone A (3), ergosta-4,6,8(14),22-tetraen-3-one (14) and 2-hydroxy-2,3-dihydrosqualene (17) against BGC-823 and Hela cells could be classified as moderate-to-weak. (C) 2013 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.

A new lanostane triterpenoid, 2-hydroxy-24-methylenelanostan-1,8-dien-3-one named klainedoxalanostenone (1) with one new steroid, 6-O-acyl-β-d-glucosyl-β-sitosterol named klainedoxasterol (2) together with ten known compounds including six triterpenoids (3-8), two steroids (9, 10) and two tanins (11, 12) were isolated from the stem bark of Klainedoxa gabonensis. To the best of our knowledge, this is the first report of lanostane-type triterpenoids from this genus. Their structures were determined by extensive analysis of spectroscopic data (1D and 2D NMR, MS) and by comparison with literature data. The xanthine oxidase inhibitory activity of nine compounds (1-6, 8, 10 and 11) were evaluated. Compound 5 showed a good xanthine oxidase inhibitory activity; the other tested compounds were moderately active.

Introduction The emergence of drug-resistant cancer cells drastically reduces the efficacy of many antineoplasic agents and, consequently, increases the frequency of therapeutic failure. Benzophenones are known to display many pharmacological properties including cytotoxic activities. The present study was aimed at investigating the cytotoxicity and the modes of action of four naturally occurring benzophenones 2,2′,5,6′-tetrahydroxybenzophenone ( 1 ), isogarcinol ( 2 ), isoxanthochymol ( 3 ) and guttiferone E ( 4 ) on a panel of eleven cancer cell lines including various sensitive and drug-resistant phenotypes. Methods The cytotoxicity of the compounds was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect the activation of caspases 3/7, caspase 8 and caspase 9 in cells treated with compounds 2 – 4 . Flow cytometry was used for cell cycle analysis and detection of apoptotic cells, analysis of mitochondrial membrane potential (MMP) as well as measurement of reactive oxygen species (ROS). Results The four tested benzophenones inhibited the proliferation of all tested cancer cell lines including sensitive and drug-resistant phenotypes. Collateral sensitivity of cancer cells to compounds 1 – 4 was generally better than to doxorubicin. Compound 2 showed the best activity with IC 50 values below or around 1 μM against HCT116 colon carcinoma cells ( p53 +/+) (0.86 μM) and leukemia CCRF–CEM (1.38 μM) cell lines. Compounds 2 – 4 strongly induced apoptosis in CCRF–CEM cells via caspases 3/7, caspase 8 and caspase 9 activation and disruption of MMP. Conclusions The studied benzophenones are cytotoxic compounds that deserve more detailed exploration in the future, to develop novel anticancer drugs against sensitive and otherwise drug-resistant phenotypes.

Betulinic acid (1), 5-hydroxy-3-methoxyxanthone (2), 1,6-dihydroxy-7-methoxyxanthone (3), daucosterol (4), bijaponicaxanthone C (5), hypercalin C (6), 1-hydroxy-6,7-dimethoxyxanthone (7), cadensin D (8) and 5-hydroxy-1,3-dimethoxyxanthone (9) were isolated from the roots of Hypericum riparium. These compounds are reported for the first time from this plant. The extracts and two of the isolated compounds (2 and 8) exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 0.97-250 µg/mL). In addition, the brine-shrimp (Artemia salina) lethality bioassay of compound 6 showed potent cytotoxicity with LD 50 of 3.23 µg/mL.

Five new alkylbenzoquinone derivatives, ardisiaquinones L–P ( 1–5 ) along with the known ardisiaquinone K were isolated from the MeOH extracts of leaves and stems of Ardisia kivuensis Taton (Myrsinaceae). Ardisiaquinones L, M and N were isolated from the leaves while ardisiaquinones K, O and P were obtained from the stem. Ardisiaquinone O was obtained in mixture with ardisiaquinone N, and P together with K, respectively. Their structures were elucidated on the basis of spectroscopic data. All the compounds showed cytotoxicity against Artemia salina and moderate antimicrobial activity.

Chemical investigation of the roots of Vernonia guineensis (Asteraceae) afforded a new stigmastane derivative, vernoguinoside A ( 1 ) and the known vernoguinoside ( 2 ), stigmasterol 3- O -β- d -glucoside ( 3 ) and sitosterol 3- O -β- d -glucoside ( 4 ). Their structures were elucidated by spectroscopic analysis. Antimicrobial activities of 1 – 3 and CH 2 Cl 2 –MeOH (1:1) extract were evaluated against three bacteria species ( Salmonella typhi , Staphylococcus aureus and Shigella flexneri ) and three yeasts species ( Candida albicans , Candida parapsilosis and Cryptococcus neoformans ). Compounds 1 and 2 exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 7.81–125 μg/mL) while S. flexneri and C. albicans were sensitive to all the tested compounds.

Two new cycloartane-type triterpenoids, glaucartanoic acids A (1) and B (2), together with five known compounds were isolated from the fruits of Caloncoba glauca. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques, by chemical evidence and by comparison with literature data. The new compounds were evaluated for their in vitro cytotoxicity against five human cancer cell lines. (C) 2011 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.

A benzophenone, 2,2’,5,6’-tetrahydroxybenzophenone (1), and one xanthone, 5-hydroxy-3-methoxyxanthone (2), were newly described as natural products from the leaves and the stem barks of Hypericumlanceolatum, along with the known compounds friedelin (3), betulinic acid (4), allanxanthone A (5), 1,3,6-trihydroxyxanthone (6), isogarcinol (7), sitosterol 3-O- β -D-glucopyranoside (8), 1-hydroxy-6-methoxyxanthone (9), 6,7-dihydroxy-1,3-dimethoxyxanthone (10), 3-hydroxy-5-methoxyxanthone (11), 1,7-dihydroxy-3,6-dimethoxyxanthone (12) and calophyllumin A (13). Their structures were elucidated by spectroscopic means and comparison with published data.

Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki,Aoba-ku, Sendai 980-8578, Japan*E-mail: sopbue@yahoo.frReceived June 7, 2010 Revised 21 October 2010; accepted 24 October 2010DOI 10.1002/jhet.757Published online 2 August 2011 in Wiley Online Library (wileyonlinelibrary.com).Dedicated to the memory of Professor Zacharias TANEE FOMUM.

A new xanthone, 1,8-dihydroxy-3-methoxy-6-methylxantone and a new polyketide derivative, (4R∗,5S∗,6E,8Z)-ethyl-4-((E)-but-1-enyl)-5-hydroxypentdeca-6,8-dienoate, together with 20 known secondary metabolites, including 2 steroids, 4 xanthones, 10 anthraquinones, 2 triterpenoids, 1 fatty ester, and (E)-eicos-14-enoic acid, were isolated from the leaves of Cassia obtusifolia. To the best of our knowledge, the last compound was isolated from a natural source for the first time. The structures of all the compounds were elucidated on the basis of 1D and 2D NMR experiments. Some of the compounds were tested against Salmonella typhi, Staphylococcus aureus, Candida albicans ATCC 9002, and Candida tropicalis, they did not show any activity.

The aqueous, hexane, acetone, and methanol extracts of the stem bark of Anthocleista vogelii. Planch. (Loganiaceae) were screened for antiulcerogenic activity using HCl/ethanol gastric necrotizing solution. The methanol extract showed 100% inhibition at a dose of 500 mg/kg compared with the aqueous, hexane, and acetone extracts, which produced 87.91%, 61.39%, and 76.89%, respectively. The methanol and aqueous extracts were further tested against ulceration induced by indomethacin (30 mg/kg) and pylorus ligation at doses of 125, 250, and 500 mg/kg. The aqueous extract at a dose of 500 mg/kg significantly (p ≤ 0.01) reduced indomethacin-induced gastric lesions by 78.62% while the methanol extract at the same dose completely inhibited the action of indomethacin. The aqueous extract of A. vogelii. at doses of 250 and 500 mg/kg induced a decrease of about 15% and 40%, respectively, of the surface area in the pylorus-ligated rats. Similarly, the methanol extract at doses 250 and 500 mg/kg produced a dec...

A novel pyranoquinoline alkaloid 3,4-dihydro-3-hydroxy-5-methoxy-2,2,10-trimethylpyrano [2,3-b]quinoline named tabouensinium chloride (1), was isolated from the stem bark of Araliopsis tabouensis along with twelve known quinoline alkaloids. In addition, the known flindisol, lupeol and beta-sitosterol glucoside were also identified. Their structures were deduced from spectral data.

Background In our previous studies, it was evident that the dichloromethane-methanol (1:1 v/v) stem barks extract of Polyscias fulva and fractions (ethyl acetate, n-butanol and residue) demonstrated interesting antidermatophytic activities. So, as a continuity of that, this work aimed at identifying active principles with antifungal properties from P. fulva that could be used as markers for possible standardization of this plant as phytomedicine. Methods The ethyl acetate, n-butanol and residual fractions of the dichloromethane-methanol (1:1 v/v) stem bark extract of Polyscias fulva were further fractionated by column chromatography and the structures of isolated compounds elucidated based on their spectroscopic data in comparison with existing literature information. Antifungal activity was assayed by broth microdilution techniques on yeasts and dermatophytes spores. Results The fractionation of the crude dichloromethane-methanol (1:1 v/v) stem bark extract of Polyscias fulva led to the isolation of 10 known compounds (1 to 10) and one new saponin (11: 3-O-[α-L-rhamnopyranosyl (1–2)-α-L-arabinopyranosyl]-28-O-[α-L-4-O-acetyl-rhamnopyranosyl (1–4)-β-D-glucopyranosyl-(1–6)-β-D-glucopyranosyl]-hederagenin). Among these compounds, 3-O-α-L- arabinopyranosyl-hederagenin and 3-O-[α-L-rhamnopyranosyl (1–2)-α-L-arabinopyranosyl]-hederagenin were the most active on the tested fungi with MIC values ranging from 0.78 to 100 μg/ml against both yeasts and dermatophytes. Conclusion The results of this work constitute a step forward in the possible development of an antidermatophytic phytomedicine from Polyscias fulva stem bark, the isolated compounds being possible markers for the standardisation. Electronic supplementary material The online version of this article (doi:10.1186/s12906-015-0541-7) contains supplementary material, which is available to authorized users.

Background Well known as teak, Tectona grandis is widely used in African folk medicine for its pharmacological relevance. In Cameroon, this species is a reputed laxative in the Northern Region while in the Western Region, it is used in the treatment of skin diseases and diarrhoea. Materials and methods Separation and isolation of compounds were performed using different chromatographic methods while their structures were elucidated by spectroscopic techniques including MS and NMR, and by comparison of data with those reported in the literature. Isolated compounds as well as crude ethanol extract were tested for their antibacterial activities using broth micro-dilution method against four Gram negative bacteria strains Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (PA 01), Klebsiella pneumonia (ATCC 11296) and Escherichia aerogenes (ATCC 13048). Results Three known compounds were isolated, including two quinones and one triterpene. They were identified as tectograndone (1), 6-methyl-1,4-dihydroxyanthraquinone (2), and 2β-hydroxyursolic acid (3) respectively. Crude ethanol extract showed good activity against the bacteria strains tested with MIC of 64–256 μg/mL. Among the isolated metabolites, 6-methyl-1,4-dihydroxyanthraquinone exhibited a strong activity against Escherichia aerogenes with MIC of 16 μg/mL, while tectograndone showed a moderate activity against Escherichia coli with MIC of 32 μg/mL. The antibacterial screening of the fruits of this plant as well as that of compounds 1 and 2 is reported herein for the first time. Conclusion The research work presented here shows that Tectona grandis fruits possess compounds which could be developed in the treatment of bacterial diseases.

Introduction Resistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4′-hydroxy-2′,6′-dimethoxychalcone ( 1 ), cardamomin ( 2 ), 2′,4′-dihydroxy-3′,6′-dimethoxychalcone ( 3 )], and four flavanones [( S )-(–)-pinostrobin ( 4 ), ( S )-(–)-onysilin ( 5 ) and alpinetin ( 6 )] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types. Methods The resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometry for the mechanistic studies of the most active molecule ( 1 ). Results IC 50 values in a range of 2.54 μM against CEM/ADR5000 leukemia cells to 58.63 μM toward hepatocarcinoma HepG2 cells were obtained with 1 . The lowest IC 50 values of 8.59 μM for 2 and 10.67 μM for 3 were found against CCRF-CEM cells leukemia cells, whilst the corresponding values were above 80 μM for 4 and 6 . P-glycoprotein-expressing and multidrug-resistant CEM/ADR5000 cells were much more sensitive toward compound 1 than toward doxorubicin and low cross-resistance or even collateral sensitivity was observed in other drug-resistent cell lines to this compound. Normal liver AML12 cells were more resistant to the studied compounds than HepG2 liver cancer cells, indicating tumor specificity at least to some extent. Compound 1 arrested the cell cycle between Go/G1 phase, strongly induced apoptosis via disrupted mitochondrial membrane potential (MMP) and increased production of reactive oxygen species (ROS) in the studied leukemia cell line. Conclusions Chalcone 1 was the best tested cytotoxic molecule and further studies will be performed in order to envisage its possible use in the fight against multifactorial resistant cancer cells.

A new compound containing a unique terpenoid-quinone skeleton, pycnanthuquinone C (1) along with the known sargachromenol (2), prunetin (3), biochanin A (4), calopiptin (5), (12 S,13 S)-12,13-dihydroxylabda-8(17),14-dien-18-oic acid (6), (12 R,13 S)-12,13-dihydroxylabda-8(17),14-dien-18-oic acid (7), and sitosterol 3- O-beta- D-glucopyranoside (8), were isolated from the stem bark of Pycnanthus angolensis. Their structures were elucidated by spectroscopic means and comparison with published data. The antifungal activity of compounds 1, 2 and 3 was evaluated. Compound 1 was active against Trichophyton soudanense. Compound 2 was active against Trichophyton mentagrophytes while compound 3 was active against Microsporum audouinii and Trichophyton mentagrophytes.

Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin-Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC(50) values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin.

The present study was designed to investigate the antimicrobial activity and the cytotoxicity of the methanol extract (PLA) as well as fractions (PLA1-4) and compounds [cardamomin (1), (+/-)-polygohomoisoflavanone (2), (S)-(-)-pinostrobin (3), 2',4'-dihydroxy-3',6'-dimethoxychalcone (4), (2S)-(-)-5-hydroxy-6,7-dimethoxyflavanone (5), and (2S)-(-)-5,7-dimethoxyflavanone (6)] obtained from leaves of Polygonum limbatum. The microbroth dilution was used to determine the minimal inhibitory concentration (MIC) of the samples against 11 microbial strains including Candida albicans, C. krusei, C. tropicalis, Aspergillus fumigatus, Pseudomonas aeruginosa, Escherichia coli, vancomycin-resistant Enterococcus faecalis (VRE), Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), S. epidermidis, and Mycobacterium tuberculosis H37Rv. The sulphorhodamine B cell growth inhibition assay was used to assess the cytotoxicity of the above samples on lung A549 adenocarcinoma, breast carcinoma MCF-7, prostate carcinoma PC-3, cervical carcinoma HeLa, and the acute monocytic leukemia cell line THP-1. The results of the MIC determination indicated that, apart from fraction PLA3, all other fractions as well as PLA and compound 3 were selectively active. MIC values were noted on 100% of the 11 tested microorganisms for fraction PLA3, 72.7% for PLA, fraction PLA2, and compound 4, 63.6% for PLA1, and 54.5% for fraction PLA4. The results of the cytotoxicity assay revealed that, except for A459 cells, more than 50% inhibition of the proliferation was obtained with each of the tested samples on at least one of the four other cell lines. IC50 values below 4 mu g/mL were obtained with 1 and 4 on THP-1 cells. The overall results of the present study provided baseline information for the possible use of Polygonum limbatum as well as some of the isolated compounds for the control of cancer diseases and mostly leukemia.

Five new triterpenoids, caloncobic acids A and B (1 and 2), caloncobalactones A and B (3 and 4), and glaucalactone (5), along with the known compounds 3 beta,21 beta-dihydroxy-30-nor-(D:A)-friedo-olean-20(29)-en-27-oic acid (6) and acetyltrichadenic acid B (7), were isolated from the leaves of Caloncoba glauca. The structures of 1-5 were elucidated using spectroscopic methods. Compounds 1-7 were evaluated for their inhibitory activities against two isozymes of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD1 and 11 beta-HSD2). Compounds 1 and 2 exhibited strong inhibitory activities against mouse (EC50 132 and 13 nM) and human (EC50 105 and 72 nM) 11 beta-HSD1.

A new ester, 2-(4'-hydroxyphenyl)ethyl dotriacontanoate (1), and a new inseparable mixture of octacosan-1,28-dioldiferulate and triacontan-1,30-dioldiferulate (2) were isolated from the stem barks of Stereospermum acuminatissimum, along with 24 known compounds including 4 triterpenoids, 11 anthraquinones, 2 lignans, 3 phenylpropanoids, 2 4-hydroxyphenethyl esters, 1 methoxyphenol, and 1 iridoid. The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. The compounds were tested against Candida albicans ATCC 24433, C. albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, and Candida parapsilosis ATCC 22019. Some of them were moderately active.

Background The aim of this study was to evaluate the antimicrobial and antioxidant activities of the methanol extract, fractions and isolated compounds from Entada abyssinica stem bark, plant used traditionally against gastrointestinal infections. Methods The methanol extract of E. abyssinica stem bark was pre-dissolved in a mixture of methanol and water, and then partitioned between n-hexane, ethyl acetate and n-butanol. The ethyl acetate portion was fractionated by column chromatography and the structures of isolated compounds elucidated by analysis of spectroscopic data and comparison with literature data. Antimicrobial activity was assayed by broth microdilution techniques on bacteria and yeasts. The antioxidant activity was determined by DPPH radical scavenging method. Results Four known compounds [(5S,6R,8aR)-5-(carboxymethyl)-3,4,4a,5,6,7,8,8a-octahydro-5,6,8a-trimethylnaphthalenecarboxylic acid (1), methyl 3,4,5-trihydroxybenzoate (2), benzene-1,2,3-triol (3) and 2,3-dihydroxypropyltriacontanoate (4)] were isolated. Compared to the methanol extract, fractionation increased the antibacterial activities of the n-hexane and ethyl acetate fractions, while the antifungal activities increased in ethyl acetate, n-butanol and aqueous residue fractions. The isolated compounds were generally more active on bacteria (9.7 to 156.2 μg/ml) than yeasts (78.1 to 312.5 μg/ml). Apart from compound 1, the three others displayed DPPH· scavenging activity (RSa), with RSa50 values of 1.45 and 1.60 μg/ml. Conclusion The results obtained from this study support the ethnomedicinal use of E. abyssinica in the treatment of gastrointestinal infections and the isolated compounds could be useful in the standardisation of antimicrobial phytomedicine from this plant.

BACKGROUND: Natural products are well recognized as sources of drugs in several human ailments. In the present work, we carried out a preliminary screening of six natural compounds, xanthone V(1) (1); 2-acetylfuro-1,4-naphthoquinone (2); physcion (3); bisvismiaquinone (4); vismiaquinone (5); 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone (6) against MiaPaCa-2 pancreatic and CCRF-CEM leukemia cells and their multidrug-resistant subline, CEM/ADR5000. Compounds 1 and 2 were then tested in several other cancer cells and their possible mode of action were investigated. METHODOLOGY/FINDINGS: The tested compounds were previously isolated from the Cameroonian medicinal plants Vismia laurentii (1, 3, 4, 5 and 6) and Newbouldia laevis (2). The preliminary cytotoxicity results allowed the selection of xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone, which were then tested on a panel of cancer cell lines. The study was also extended to the analysis of cell cycle distribution, apoptosis induction, caspase 3/7 activation and the anti-angiogenic properties of xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone. IC(50) values around or below 4 µg/ml were obtained on 64.29% and 78.57% of the tested cancer cell lines for xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone, respectively. The most sensitive cell lines (IC(50)

Ethnopharmacological relevance The plant, Vismia rubescens (Guttiferae) is popularly used in Cameroon and in several parts of Africa as febrifugal and for the treatment of various microbial infections (skin diseases, diarrhoea and venereal diseases). Aim of the study This study was mapped out to evaluate the antimicrobial activities of the methanol extract and compounds from the stem bark of Vismia rubescens . Materials and methods Structures of the compounds obtained after column chromatography of the methanol-soluble fraction were determined by spectroscopy and in comparison with published data. The broth micro-dilution method was used to evaluate the antimicrobial activities against three bacteria species ( Salmonella typhi , Stahylococcus aureus and Pseudomonas aeruginosa ) and four yeast species ( Candida albicans , Candida tropicalis , Candida parapsilosis and Cryptococcus neoformans ). Results Chemical analysis of the methanol extract from the stem bark of Vismia rubescens yielded five known compounds 1,4,8-trihydroxyxanthone ( 1 ), 1,7-dihydroxyxanthone ( 2 ), physcion ( 3 ), friedelin ( 4 ) and friedelanol ( 5 ). The crude extract and compounds 1 , 2 and 3 exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 3.12–1000 μg/ml). Compounds 2 and 3 were the most active (MIC = 3.12–100 μg/ml) while Stahylococcus aureus and Pseudomonas aeruginosa were sensitive to all the tested compounds. The antimicrobial activity of this plant as well as that of compounds 1 and 2 is being reported here for the first time. Conclusion These results provide promising baseline information for the potential use of this plant as well as some of the isolated compounds in the treatment of skin diseases and diarrhoea.

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V 1 (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V 1 (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.

Stem Bark of Vismia laurentii Michel F. Talaa, Karsten Krohnb, Hidayat Hussainb, Simeon F. Kouamc, Hippolyte K. Waboa, Pierre Tanea, Barbara Schulzd, and Qunxiu Hud a Department of Chemistry, University of Dschang, P.O. Box 67, Dschang, Cameroon b Department of Chemistry, University of Paderborn, Warburger Strase 100, 33098 Paderborn, Germany c Department of Chemistry, Higher Teachers’ Training College, University of Yaounde 1, BP47, Yaounde, Cameroon d Institute of Microbiology, Technical University of Braunschweig, D-38106 Braunschweig, Germany

A new benzophenanthridine alkaloid, 6-[2′-ethoxy-2′-(2″,4″,5″-trimethoxyphenyl)] ethyl-7,8-dimethoxy-5-methyl-2,3-methylenedioxy-5,6-dihydrobenzo[c]phenanthridine named buesgeniine (1), as well as the known decarine, were isolated from the extract of the stem bark of Zanthoxylum buesgenii. In addition, three known lignans, sesamine, matairesinol dimethylether, and methylpluviatilol, were also identified. The structure of 1 was elucidated using spectroscopic methods.

Chemical investigation of the stem bark of Turraeanthus africanus (Meliaceae) afforded a new pregnane derivative, 17α,20S-dihydroxypregn-4-ene-3,16-dione, named turraeasterodione, together with three known diterpenoids, methyl 14,15-epoxylabda-8(17),12E-dien-16-oate, 16-oxolabda-8(17),12E-dien-15-oic acid, and 16-acetoxy-12R,15-epoxylabda-8(17),13(16)-dien-15β-ol. Their structures were elucidated by spectroscopic and spectrometric methods. Methyl 14,15-epoxylabda-8(17),12E-dien-16-oate was found to exhibit anti-plasmodial activity against a chloroquine-resistant strain of Plasmodium falciparum.

Background The present report describes the semi-synthesis of a few O-prenylated phenolic derivatives and their in vitro antitumor activities. These compounds were prepared by modifying two naturally occurring antitumor phenols, 5,7-dihydroxy-3-(1′-hydroxy-1′-phenyl-methyl)-6-methoxy-chroman-4-one (A) and 2′,4′-dihydroxy-3′,6′-dimethoxychalcone (B), previously isolated from Polygonum limbatum Meisn. (Polygonaceae). The structures were elucidated by spectroscopic means and comparison with published data. The cytotoxicity of compounds was determined by using the resazurin assay in the parental drug-sensitive CCRF-CEM cell line and its multidrug-resistant P-glycoprotein-over-expressing subline, CEM/ADR5000. Results We describe in the present paper four new semi-synthetic derivatives of A and B: 5-hydroxy-6-methoxy-7-O-(3′-methylbut-2′-enyl)chroman-4-one (1), trivially named metapchromone, 5-acetoxy-6-methoxy-7-O-[3′-methylbut-2′enyl]chroman-4-one (2), trivially named sargisin, 2′-hydroxy-3′,6′-dimethoxy-4′-O-(3″-methylbut-2″-enyl)chalcone (3) trivially named limbachalcone A, and 2′-acetoxy-3′,6′-dimethoxy-4′-O-(3″-methylbut-2″-enyl)chalcone (4) trivially named tsedengchalcone. Their preliminary cytotoxic activities have been determined. We also report herein the isolation of 1-methylhydantoin (C) and betulinic acid (D) from Polygonum limbatum for the first time. Conclusions The study clearly suggests that semi-synthesis involving O-prenylation and acetylation of chalcones or other chromanones should be avoided in a search for anticancer drugs. This conclusion should be helpful when selecting substituents for the synthesis of potential anticancer drugs.

Background Psorospermun aurantiacum and Hypericum lanceolatum are plants locally used in Cameroon and other parts of Africa for the treatment of gastrointestinal and urinary tract infections, skin infections, venereal diseases, gastrointestinal disorder, infertility, epilepsy as well as microbial infections. The present study was designed in order to investigate the in vitro antimicrobial and radical scavenging activities of the extracts and isolated compounds from the leaves of these plants. Methods The plant extract was prepared by maceration in ethyl acetate and methanol and fractionated by column chromatography. The structures of isolated compounds were elucidated by spectroscopic analyses in conjunction with literature data. The broth microdilution method was used to evaluate the in vitro antimicrobial activity against bacteria, yeasts and dermatophytes. The antioxidant potentials of the extracts and their isolated compounds were evaluated using the DPPH radical scavenging method. Results Five known compounds: physcion (1), 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone (2), kenganthranol B (3), vismiaquinone (4), and octacosanol (5) were isolated from the leaves of P. aurantiacum while six compounds including friedelin (6), betulinic acid (7), 2,2’,5,6’-tetrahydroxybenzophenone (8), allanxanthone A (9), 1,3,6- trihydroxyxanthone (10) and isogarcinol (11) were isolated from H. lanceolatum. Compound 8 and 4 exhibited the highest antibacterial and antifungal activities with MIC ranges of 2–8 μg/ml and 4–32 μg/ml respectively. P. aurantiacum crude extract (Rsa50 = 6.359 ± 0.101) showed greater radical scavenging activity compared with H. lanceolatum extract (Rsa50 = 30.996 ± 0.879). Compound 11 showed the highest radical scavenging activity (RSa50 = 1.012 ± 0.247) among the isolated compounds, comparable to that of L-arscobic acid (RSa50 = 0.0809 ± 0.045). Conclusions The experimental findings show that the ethyl acetate and methanol extracts and isolated compounds from P. aurantiacum and H. lanceolatum stem bark possess significant antimicrobial and antioxidant activities justifying the use of these plants in traditional medicine, which may be developed as phytomedicines.