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En la presente investigación se determinó la capacidad antioxidante de una crema cosmética facial, elaborada a partir del extracto aislado (isolado) de cannabidiol. Para establecer la capacidad antioxidante. Se utilizó la metodología por 2,2-difenil-1-picrilhidrazilo en un diseño experimental cuantitativo, empleando el ácido ascórbico como control positivo. Se determinó la capacidad antioxidante del extracto de cannabidiol y de la crema formulada con el extracto. Se varió las concentraciones de cannabidiol en la composición de la crema entre 0,5 y 10 %. El porcentaje de inhibición del radical 2,2-difenil-1-picrilhidrazilo por el extracto de cannabidiol fue 91,93 % y cuando formó parte de la crema de 83,0 %, con un contenido de cannabidiol de 333,33 µg/mL. Los valores de IC50 del extracto de cannabidiol y en la crema fueron 62,60 µg ± 6,27 µg/mL y 77,93 ± 1,12 µg/mL, respectivamente. El valor de IC50 del extracto es menor que el de la crema, lo que significa una mayor capacidad antioxidante del extracto isolado de cannabidiol en relación al formulado de la crema en base al extracto.

Zephyranthes carinata Herb., a specie of the Amaryllidoideae subfamily, has been reported to have inhibitory activity against acetylcholinesterase. However, scientific evidence related to their bioactive alkaloids has been lacking. Thus, this study describes the isolation of the alkaloids of this plant, and their inhibition of the enzymes acetylcholinesterase (eeAChE) and butyrylcholinesterase (eqBuChE), being galanthine the main component. Additionally, haemanthamine, hamayne, lycoramine, lycorine, tazettine, trisphaeridine and vittatine/crinine were also isolated. The results showed that galanthine has significant activity at low micromolar concentrations for eeAChE (IC50 = 1.96 μg/mL). The in-silico study allowed to establish at a molecular level the high affinity and the way galanthine interacts with the active site of the TcAChE enzyme, information that corroborates the result of the experimental IC50. However, according to molecular dynamics (MD) analysis, it is also suggested that galanthine presents a different inhibition mode that the one observed for galanthamine, by presenting interaction with peripheral anionic binding site of the enzyme, which prevents the entrance and exit of molecules from the active site. Thus, in vitro screening assays plus rapid computer development play an essential role in the search for new cholinesterase inhibitors by identifying unknown bio-interactions between bioactive compounds and biological targets.

Cancer is a major cause of death and an impediment to increasing life expectancy worldwide. With the aim of finding new molecules for chemotherapeutic treatment of epidemiological relevance, ten alkaloid fractions from Amaryllidaceae species were tested against six cancer cell lines (AGS, BT-549, HEC-1B, MCF-7, MDA-MB 231, and PC3) with HaCat as a control cell line. Some species determined as critically endangered with minimal availability were propagated using in vitro plant tissue culture techniques. Molecular docking studies were carried out to illustrate binding orientations of the 30 Amaryllidaceae alkaloids identified in the active site of some molecular targets involved with anti-cancer activity for potential anti-cancer drugs. In gastric cancer cell line AGS, the best results (lower cell viability percentages) were obtained for Crinum jagus (48.06 ± 3.35%) and Eucharis bonplandii (45.79 ± 3.05%) at 30 µg/mL. The research focused on evaluating the identified alkaloids on the Bcl-2 protein family (Mcl-1 and Bcl-xL) and HK2, where the in vitro, in silico and statistical results suggest that powelline and buphanidrine alkaloids could present cytotoxic activity. Finally, combining experimental and theoretical assays allowed us to identify and characterize potentially useful alkaloids for cancer treatment.

Cocoa beans contain antioxidant molecules with the potential to inhibit type 2 coronavirus (SARS-CoV-2), which causes a severe acute respiratory syndrome (COVID-19). In particular, protease. Therefore, using in silico tests, 30 molecules obtained from cocoa were evaluated. Using molecular docking and quantum mechanics calculations, the chemical properties and binding efficiency of each ligand was evaluated, which allowed the selection of 5 compounds of this series. The ability of amentoflavone, isorhoifolin, nicotiflorin, naringin and rutin to bind to the main viral protease was studied by means of free energy calculations and structural analysis performed from molecular dynamics simulations of the enzyme/inhibitor complex. Isorhoifolin and rutin stand out, presenting a more negative binding ΔG than the reference inhibitor N-[(5-methylisoxazol-3-yl)carbonyl]alanyl-l-valyl-N~1~-((1R,2Z)−4-(benzyloxy)−4-oxo-1-{[(3R)−2-oxopyrrolidin-3-yl]methyl}but-2-enyl)-L-leucinamide (N3). These results are consistent with high affinities of these molecules for the major SARS-CoV-2. The results presented in this paper are a solid starting point for future in vitro and in vivo experiments aiming to validate these molecules and /or test similar substances as inhibitors of SARS-CoV-2 protease.

In Alzheimer’s disease (AD), amyloid beta (Aβ) plaques initiates a cascade of pathological events where the overactivation of N-methyl-d-aspartate receptors (NMDA) by excess glutamate (Glu) triggers oxidative processes that lead to the activation of microglial cells, inflammation, and finally neuronal death. Amaryllidaceae alkaloids exert neuroprotective activities against different neurotoxin-induced injuries in vitro, and although their biological potential is well demonstrated, their neuroprotective activity has not been reported in an in vivo model of AD. The aim of our study was to determine the in vitro and in vivo neuroprotective potential of standardized alkaloidal fractions of Zephyranthes carinata. In this work, the neuroprotective effect of two alkaloidal fractions extracted from Z. carinata (bulbs and leaves) was analyzed in an in vitro excitotoxicity model in order to select the most promising one for subsequent evaluation in a triple transgenic mouse model of AD (3xTg-AD). We found that Z. carinata bulbs protect neurons against a Glu-mediated toxic stimulus in vitro, as evidenced by the decrease in apoptotic nuclei, the reduction in the lipid peroxidation product malondialdehyde and the conservation of dendritic structures. The effects of intraperitoneal administration of Z. carinata bulbs (10 mg/kg) every 12 h for 1 month on 3xTg-AD (18 months old) showed improved learning and spatial memory. Histopathologically, the alkaloidal fraction-treated 3xTg-AD mice exhibited a significant reduction in tauopathy and astrogliosis, as well as a significant decrease in the proinflammatory marker COX-2 and an increase in pAkt. The results suggest that Z. carinata bulbs provide neuroprotective effects both in vitro and in 3xTg-AD mice by intervening in the inflammatory processes, regulating the aggregation of pair helical filaments (PHFs) and activating survival pathways.

The family Amaryllidaceae has been postulated as a monophyletic group in different analyses, in which three big clades are recognized as subfamilies (Agapanthoideae, Allioideae and Amaryllidoideae). We examined specimens of the family and explored different areas of the country where there were previous records or potential occurrence of the group, in order to determine the diversity of this family in Colombia. The Amaryllidaceae are represented in Colombia by 18 genera and 48 species, of which 11 genera and 27 species are native, including 9 species endemic to the country. The areas with the largest species diversity are the Western and Eastern Cordillera, and the biogeographic Chocó, especially in the departments of Cauca, Cundinamarca and Valle del Cauca. We present an updated definition of the family, considering its current circumscription, and describe the genera occurring in Colombia, as well as the inventory of the species and their distribution.

This study aimed to assess the anti-aging potential of the ethanol extract of Passiflora edulis f. edulis Sims seeds, through in vitro determination of antioxidant activity and inhibition assays of some enzymes related to skin aging. Furthermore, using in silico methods (docking and molecular dynamics), were established the affinity of the majority compounds of the extract on the target enzymes, ending with the prediction of drug-likeness properties. The extract showed a high total phenolic content, represented mainly by flavonoids and phenolic acids, as well as a considerable antioxidant potential measured through the DPPH, FRAP and ORAC methods. In the inhibition assays of the enzymes collagenase, elastase and tyrosinase, IC50 values presented were optimal. Docking studies demonstrated marked binding ability of the extract constituients (specially, fisetin, galangin and S-eriodictyol) to the Collagenase and Tyrosinase. Molecular dynamics validated the stability and rationality of these molecular docking studies, MM/PBSA calculations provide strong evidence for both their specific heavy binding and how enzyme-ligand complex stabilized inside the catalytic domain, and drug-likeness studies showed suitable dermato-pharmacokinetics indices for most of components of extract. Findings from this study suggest that ethanol extract of P. edulis has a great potential as an anti-aging agent.

Spearmint (Mentha spicata L.) has been widely studied for its diversity of compounds for product generation. However, studies describing the chemical and biological characteristics of commercial spearmint materials from different origins are scarce. For this reason, this research aimed to bioprospecting spearmint from three origins: Colombia (Col), Mexico (Mex), and Egypt (Eg). We performed a biological activity analysis, such as FRAP, DPPH, and ABTS, inhibition potential of S. pyogenes, K. pneumoniae, E. coli, P. aeuroginosa, S. aureus, S aureus Methicillin-Resistant, and E. faecalis. Furthermore, we performed chemical assays, such as total polyphenol and rosmarinic acid, and untargeted metabolomics via HPLC-MS/MS. Finally, we developed a causality analysis to integrate biological activities with chemical analyses. We found significant differences between the samples for the total polyphenol and rosmarinic acid contents, FRAP, and inhibition analyses for Methicillin-Resistant S. aureus and E. faecalis. Also, clear metabolic differentiation was observed among the three commercial materials evaluated. These results allow us to propose data-driven uses for the three spearmint materials available in current markets.

In the present study, the effect of biotization of Mentha spicata microplants with Trichoderma asperellum and Bacillus subtilis on growth, Rhizoctonia sp., incidence, and specialized metabolites content was evaluated. Analyses of root tissues of the microplants showed 100% endophytism with both microorganisms. During the acclimatization phase, plants with the endophytes T. asperellum and B. subtilis had a survival rate of 95% and 93%, respectively, compared to 75% for control plants. Then, under greenhouse conditions, a trial was carried out with biotized plants with or without Rhizoctonia sp. inoculation, plants inoculated with Rhizoctonia sp., and endophyte- and pathogen-free control. Biotized plants with the endophytes showed higher dry biomass and the incidence of Rhizoctonia was lower (8% for T. asperellum and 10% for B. subtilis) compared to plants inoculated with the pathogen (82%). In addition, plants with T. asperellum had the highest contents of total polyphenols (280 GAE/100 mg sample) and rosmarinic acid (28 mg RA/100 g sample). Thus, this study shows the potential of the technique of using the endophytes T. asperellum and B. subtilis on M. spicata microplants to improve plant survival and growth, decrease the incidence of Rhizoctonia sp., and improve the contents of specialized metabolites, which can contribute to the sustainable management of this crop.

The aim of this study was to evaluate the levels of chemical markers in raw cacao beans in two clones (introduced and regional) in Colombia over several years. Multivariate statistical methods were used to analyze the flavanol monomers (epicatechin and catechin), flavanol oligomers (procyanidins) and methylxanthine alkaloids (caffeine and theobromine) of cocoa samples. The results identified genotype as the main factor contributing to cacao chemistry, although significant differences were not observed between universal and regional clones in PCA. The univariate analysis allowed us to establish that EET-96 had the highest contents of both flavanol monomers (13.12 ± 2.30 mg/g) and procyanidins (7.56 ± 4.59 mg/g). In addition, the geographic origin, the harvest conditions of each region and the year of harvest may contribute to major discrepancies between results. Turbo cocoa samples are notable for their higher flavanol monomer content, Chigorodó cocoa samples for the presence of both types of polyphenol (monomer and procyanidin contents) and the Northeast cocoa samples for the higher methylxanthine content. We hope that knowledge of the heterogeneity of the metabolites of interest in each clone will contribute to the generation of added value in the cocoa production chain and its sustainability.

The purpose of this study was to chemically compare samples of Mentha spicata (marketing byproducts, production byproducts, and export material), cultivated in the open field and under greenhouse, using an integrated approach by HPLC/DAD and GC/MS analysis. The presence of phenolic compounds was higher in the marketing byproducts cultivated in the open field. Marketing byproducts also had the highest amount of carvone. For this reason, this byproduct was selected as a candidate for the development of natural ingredients. With the best selected material, the optimization of simultaneous high-intensity ultrasound-assisted extraction processes was proposed for the recovery of the compounds of interest. This extraction was defined by Peleg’s equation and polynomial regression analysis. Modeling showed that the factors amplitude, time, and solvent were found to be significant in the recovery process (p < 0.005). The maximum amount of compounds was obtained using 90% amplitude for 5 min and ethanol/water mixture (80:20) for extraction to simultaneously obtain phenolic and terpenoid compounds. This system obtained the highest amount of monoterpenoid and sesquiterpenoid compounds from the essential oil of M. spicata (64.93% vs. 84.55%). Thus, with an efficient and eco-friendly method, it was possible to optimize the extraction of compounds in M. spicata as a starting point for the use of its byproducts.

Oxidized low-density lipoprotein (oxLDL) is a well-recognized proatherogenic particle that functions in atherosclerosis. In this study, we established conditions to generate human oxLDL, characterized according to the grade of lipid and protein oxidation, particle size and oxylipin content. The induction effect of the cellular proatherogenic response was assessed in foam cells by using an oxLDL-macrophage interaction model. Uptake of oxLDL, reactive oxygen species production and expression of oxLDL receptors (CD36, SR-A and LOX-1) were significantly increased in THP-1 macrophages. Analyses of 35 oxylipins revealed that isoprostanes (IsoP) and prostaglandins (PGs) derived from the oxidation of arachidonic, dihomo gamma-linolenic and eicosapentaenoic acids were strongly and significantly induced in macrophages stimulated with oxLDL. Importantly, the main metabolites responsible for the THP1-macrophage response to oxLDL exposure were the oxidative stress markers 5-epi-5-F2t-IsoP, 15-E1t-IsoP, 8-F3t-IsoP and 15-keto-15-F2t-IsoP as well as inflammatory markers PGDM, 17-trans-PGF3α, and 11β-PGF2α, all of which are reported here, for the first time, to function in the interaction of oxLDL with THP-1 macrophages. By contrast, a salvage pathway mediated by anti-inflammatory PGs (PGE1 and 17-trans-PGF3α) was also identified, suggesting a response to oxLDL-induced injury. In conclusion, when THP-1 macrophages were treated with oxLDL, a specific induction of biomarkers related to oxidative stress and inflammation was triggered. This work contributes to our understanding of initial atherogenic events mediated by oxLDL-macrophage interactions and helps to generate new approaches for their modulation.

Methylxanthines and polyphenols from cocoa byproducts should be considered for their application in the development of functional ingredients for food, cosmetic and pharmaceutical formulations. Different cocoa byproducts were analyzed for their chemical contents, and skincare properties were measured by antioxidant assays and anti-skin aging activity. Musty cocoa beans (MC) and second-quality cocoa beans (SQ) extracts showed the highest polyphenol contents and antioxidant capacities. In the collagenase and elastase inhibition study, the highest effect was observed for the SQ extract with 86 inhibition and 36% inhibition, respectively. Among cocoa byproducts, the contents of catechin and epicatechin were higher in the SQ extract, with 18.15 mg/100 g of sample and 229.8 mg/100 g of sample, respectively. Cocoa bean shells (BS) constitute the main byproduct due to their methylxanthine content (1085 mg of theobromine and 267 mg of caffeine/100 g of sample). Using BS, various influencing factors in the extraction process were investigated by response surface methodology (RSM), before scaling up separations. The extraction process developed under optimized conditions allows us to obtain almost 2 g/min and 0.2 g/min of total methylxanthines and epicatechin, respectively. In this way, this work contributes to the sustainability and valorization of the cocoa production chain.

Objective: This study was designed to investigate the wound healing activity of aqueous extracts of Ullucus tuberosus (U. tuberosus) using in vitro models. Methods: Lyophilized pulp and acetone extracts of U. tuberosus were produced using ultrasound extraction. The capacity for collagenase activation was evaluated using fluorescence detection of the enzymatic activity. Then, the influence of U. tuberosus extracts on cell proliferation, cell migration and synthesis of the extracellular matrix (ECM) proteins, metalloproteinase (MMP-1) and pro-collagen was analyzed using human dermal fibroblasts in culture. Results: An increase in collagenase activity of 12% supports the utility of U. tuberosus as an agent for scar treatment. In addition, the extracts showed an increase in the proliferation and migration of human dermal fibroblasts and the production of pro-collagen and MMP-1 after treatment with U. tuberosus extracts. The increase in proliferation, migration and pro-collagen levels positively influenced the regeneration of scarless tissue during the proliferation phase, whereas the increase in MMP-1 may have favored the wound healing process during the remodeling and cellular differentiation phases. Conclusion: The results of this study show for first time that U. tuberosus is a promising candidate to support scarless tissue regeneration.

The aim of the study was to determine the qualitative and quantitative plant secondary metabolite profile of Garcinia madruno by LC-MSn and to evaluate the structure–activity relationship (SAR) with its antioxidant properties. A total of 21 biflavonoids and 3 organic acids were identified. The leaves were the most promising source of biflavonoids, and the epicarp was the richest source of morelloflavone type biflavonoids (>10%). Morelloflavone and fukugiside were the major biflavonoids found in all samples as well as the compounds responsible for antioxidant activity. The inter-flavonoid bond did not increase the antioxidant activity by single electron transfer (SET) mechanism but increased the activity by single proton-loss electron transfer (SPLET) mechanism. The results suggest that G. madruno contains potentially useful amounts of bioactive biflavonoids; in particular, the leaves and epicarp may be a potential source of functional products.

It was recently shown that, when tested in cellular systems, quercetin oxidized products (Qox) have significantly better antioxidant activity than quercetin (Q) itself. The main Qox identified in the experiments are either 2,5,7,3′,4′-pentahydroxy-3,4-flavandione (Fl) or its tautomer, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Bf). We have now performed a theoretical evaluation of different physicochemical properties using density functional theory (DFT) calculations on Q and its main Qox species. The most stable structures (for Q and Qox) were identified after a structural search on their potential energy surface. Since proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs) of phenolic hydrogens, we consider that direct antioxidant activity in these species is mainly due to the sequential proton loss electron transfer (SPLET) mechanism. Moreover, our kinetic studies, according to transition state theory, show that Q is more favored by this mechanism. However, Qox have lower PAs than Q, suggesting that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivity to transfer protons (which favors Qox) and the reaction kinetics of the conjugated base in the sequential electron transfer mechanism (which favors Q). Therefore, our results support the idea that Q is a better direct antioxidant than its oxidized derivatives due to its kinetically favored SPLET reactions. Moreover, our molecular docking calculations indicate a stabilizing interaction between either Q or Qox and the kelch-like ECH-associated protein-1 (Keap1), in the nuclear factor erythroid 2-related factor 2 (Nrf2)-binding site. This should favor the release of the Nrf2 factor, the master regulator of anti-oxidative responses, promoting the expression of the antioxidant responsive element (ARE)-dependent genes. Interestingly, the computed Keap1-metabolite interaction energy is most favored for the Bf compound, which in turn is the most stable oxidized tautomer, according to their computed energies. These results provide further support for the hypothesis that Qox species may be better indirect antioxidants than Q, reducing reactive oxygen species in animal cells by activating endogenous antioxidants.

Oxidative stress diseases are usually treated or prevented by using antioxidants from natural or artificial sources. However, as a sustainable source of phytochemicals, plants got a renewed interest in obtaining their active agents using green extraction technologies, i.e., sustainable extraction techniques that reduce energy consumption, use renewable sources and result in less post-extraction wastes. The high-pressure homogenization (HPH) technique was introduced into the food industry since it was invented in 1900 to homogenize milk and later to produce fruit juices with a longer shelf-life without preservatives. Recently, HPH was introduced as an eco-friendly method to nanomill plants for improved extraction efficacy without using organic solvents. In this study, sumac was used as an antioxidants-rich spice model to investigate the effects of HPH on its antioxidant capacity (AOC). Sumac was rendered into PlantCrystals by using HPH. Particle size characterization proved the presence of submicron-sized particles (about 750 nm). Thus, HPH was able to produce sumac PlantCrystals and increased the AOC of bulk sumac by more than 650% according to the ORAC (oxygen radical absorbance capacity) assay. The polyphenol and flavonoid contents showed higher values after HPH. Interestingly, the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay also showed a well improved AOC (similar to ascorbic acid) after HPH. In fact, in this study, the PlantCrystal-technology was demonstrated to cause an efficient cell rupture of the sumac plant cells. This caused an efficient release of antioxidants and resulted in sumac PlantCrystals with a 6.5-fold higher antioxidant capacity when compared to non-processed sumac bulk material.

The mechanism for the walk rearrangement in Dewar thiophenes has been clarified theoretically by studying the evolution of chemical bonds along the intrinsic reaction coordinates. Substituent effects on the overall mechanism are assessed by using combinations of the ring (R = H, CF3) and traveling (X = S, S = O, and CH2) groups. The origins of fluxionality in the S−oxide of perfluorotetramethyl Dewar thiophene are uncovered in this work. Dewar rearrangements are chemical processes that occur with a high degree of synchronicity. These changes are directly related to the activation energy.

Botanical ingredients are widely used in food, dietary supplements, cosmetics, drugs, and other products. These ingredients may either be made as fresh material, dry and ground material, or as valorized sub-products obtained following more complex industrial process such as extraction, concentration, and purification. The plant sources of botanical ingredients are diverse. Roots, flowers, fruits, leaves, or seeds could be obtained from i) industrial crops (food and non-food); ii) wild plants (non-agroindustrial development); or iii) agroindustrial wastes (byproducts obtained during harvesting, post-harvesting, and industrial processing). Each of these sources is associated with specific challenges and advantages in the botanical ingredient industry. For example, industrial crops provide the most homogeneous raw material, but the degree of novelty and innovation in the development of these ingredients could be limited. Conversely, wild plants are the best source of novel ingredients; however, they require a lot of time and money to develop. These increased expenditures normally emerge from bioprospecting studies and legal procedures, given that the inclusion of a new ingredient is required. On the other hand, agroindustrial wastes are the most sustainable and environmentally friendly bioingredient sources; however their availability, homogeneity, and innocuousness are the most important challenges to solve.

Skin cancer has evolved as the most common malignant disease, accounting for 4.5% of all new cancer cases. [...]

The subfamily Amaryllidoideae within of the Amaryllidaceae family has an exclusive group of compounds called Amaryllidaceae alkaloids. Galanthamine, the most known Amaryllidaceae alkaloid, is approved by the FDA as an inhibitor of the enzyme acetylcholinesterase (AChE) for the palliative treatment of Alzheimer Disease (AD). However, butyrylcholinesterase (BChE) contributes critically to cholinergic dysfunction associated with AD. Thus, the development of novel therapeutics may involve the inhibition of both cholinesterase enzymes. Zephyranthes carinata, a species of the Amaryllidaceae family, has been reported to have inhibitory activity against cholinesterases. In order to determine the enzymatic inhibition potential, the major alkaloids of bulbs and leaves of Z. carinata were evaluated in both AChE and BChE. A purification and characterization process was made using different chromatographic and spectrometric techniques, and the inhibitory activity was evaluated with the Ellman method. Alkaloidal extracts of bulbs and leaves exhibited an inhibitory activity with IC50 values of 5.8 ± 0.2 and 8.7 ± 0.3 μg/mL, respectively, against AChE. Further, bulb extract showed IC50 values of 77.9 ± 3.4 μg/mL against BChE. Amaryllidaceae alkaloids hamayne, pseudolycorine, galanthine, criasbetaine, tazettine, lycoramine, hippeastidine, galanthamine, trisphaeridine, 3-epimacronine, haemanthamine, lycorine, and vittatine were purified and evaluated for their AChE and BChE inhibitory activities. Lycoramine (galanthamine type) presented the lowest IC50 value in AChE (17 ± 0.7 μg/mL), and trisphaeridine (narciclasine type) showed the lowest IC50 value in BChE (33.1 ± 3.6 μg/mL). Combined major alkaloids (>10%) were analyzed to observe synergistic behavior. The mixture alkaloids lycoramine and galanthine presented IC50 values of 14.55 ± 1.0 μg/mL against AChE, and the lycoramine, trisphaeridine, and vittatine mix presented IC50 values of 38.42 ± 3.4 μg/mL in BChE. These results showed prominent inhibitory activity against AChE and BChE enzymes, indicating their potential as agents for treating AD through a combined strategy.

Introducción. La dihidrofolato reductasa (DHFR) se ha utilizado como blanco molecular en tratamientos antibacterianos, anticancerígenos y antipalúdicos. También, actúa como blanco molecular en Leishmania; sin embargo, no existen reportes de la enzima bifuncional en especies de Leishmania (Viannia). Materiales y métodos. Se ha aislado y expresado en Escherichia coli el gen que codifica para la enzima bifuncional DHFR y la timidilato-sintasa (TS) de Leishmania braziliensis. La enzima recombinante se purificó y caracterizó, y se evaluó el efecto inhibitorio de algunos antifolatos, así como de cuatro alcaloides aporfínicos. Resultados. El gen se compone de aproximadamente 1.560 pb y codifica un péptido de 58 kDa que contiene los dominios DHFR y TS ligados en una sola cadena polipeptídica. La enzima recombinante DHFR-TS, utilizando el dihidrofolato (H2F) como sustrato, presentó valores de Km y Vmax de 55,35± 4,02 (media ± el error estándar de la media) y de 0,02 ± 5,34 x 10-4, respectivamente. La enzimar DHFR-TS de L. braziliensis presentó valores de Ki para los antifolatos en el rango de micras. El metotrexato fue el inhibidor más potente de la actividad enzimática (Ki=22,0 mM) en comparación del trimetoprim (Ki=33 mM) y la pirimetamina (Ki=68 mM). Estos valores de Ki son significativamente más bajos en comparación con los obtenidos para los alcaloides aporfínicos. Conclusión. Los resultados muestran el efecto inhibitorio de los antifolatos sobre la actividad enzimática, lo cual indica que la rDHFR-TS de L. braziliensis podría ser un modelo para estudiar moléculas antiprotozoarias potenciales. doi: http://dx.doi.org/10.7705/biomedica.v33i3.1434

Six biflavonoids were isolated from G. madruno, one of which, 7''-O-(6''''-acetyl)-glucoside of morelloflavone, is a new compound identified on the basis of 1D, 2D NMR (HMQC and HMBC) spectroscopic methods and chemical evidence. The antioxidant activity of the biflavonoids against low-density lipoprotein (LDL) peroxidation induced with Cu2+, was studied by means of a TBARS assay. The antioxidant potential of a biflavonoid fraction (BF) was also evaluated and correlated with its biflavonoid content. The flavanone-(3→8'')-flavone biflavonoids displayed antioxidant activity, particularly morelloflavone, which was significantly more potent than quercetin, with a CE50 of 12.36 μg/mL. Lipid peroxidation, was also significantly reduced in the presence of the BF (EC50 = 11.85 μg/mL). These results suggest that the BF is an excellent antioxidant.

A new procedure has been used to separate and quantify the free radical-scavenging activity of individual compounds 18 samples of Thymus vulgaris and 12 samples of Rosmarinus officinalis (both used as natural food preservatives), based on the combination of HPTLC (High Performance Thin Layer Chromatography) and postchromatographic DPPH● radical derivatization. The compounds thymol and rosmarinic acid in T. vulgaris and R. officinalis, respectively, were identified by comparisons of their Rf values and UV spectra to standards analyzed under identical analytical conditions, while the quantitative data were calculated from their calibration curves. We found that not only that the biomass yield but also the metabolite content in herbs, depend on the ecotype (genetics) and on the agro ecological conditions. The effect of the ambient on the metabolite content is extremely significant and also on their antioxidant activity (One-way ANOVA with Newman-Keuls Multiple Comparison post test was performed using GraphPad Prism version 4.00 for Windows, GraphPad Software). This work pretends to demonstrate the great importance of using new technologies for the selection of the best materials used as natural food preservatives.

Un nuevo procedimiento ha sido utilizado para la separación y cuantificación de la actividad captadora de radicales libres de cada uno de los compuestos de 18 muestras de Thymus Vulgaris y 12 muestras de Rosmarinus Officinalis (ambos usados en alimentos como conservantes naturales), basado en la combinación de HPTLC (cromatografía en capa fina de alto rendimiento) y derivatización postcromatografica con el radical DPPH●. Los compuestos timol y ácido rosmarinico en T. vulgaris y R. officinalis respectivamente, fueron identificados por comparación de sus valores Rf y espectro UV de estándares analizados bajo iguales condiciones analíticas, mientras que los datos cuantitativos fueron calculados a partir de sus curvas de calibración. Hemos encontrado que no solo la producción de biomasa, sino también el contenido de metabolitos en los plantas, dependen del ecotipo (génetica) y de las condiciones agroecológicas. El efecto del ambiente sobre el contenido de metabolitos y su actividad antioxidante es extremadamente significativo (ANOVA, Newman-Keuls Multiple Comparison post test was performed using GraphPad Prism version 4.00 for Windows, GraphPad Software).

A una fracción biflavonoide (FB) caracterizada fitoquímicamente de Garcinia madruno (Clusiaceae), se le evalúa su potencial inhibitorio de la oxidación de LDL y su capacidad estabilizadora de especies radicalarias, correlacionando dichas actividades con su contenido en biflavonoides. Los biflavonoides morelloflavona, volkensiflavona y amentoflavona se identifican a partir de la FB. El extracto que contiene la FB (extracto AcOEt) se determina como el principal factor involucrado en la actividad estabilizadora de radicales libres de esta especie vegetal, obteniendo la actividad estabilizadora del radical DPPH• a una concentración de 4,50 µg/mL. La peroxidación inducida con CuSO4 de las lipoproteínas de baja densidad, se reduce significativamente en presencia de FB (CE50 = 11,85 µg/mL). El biflavonoide morelloflavona se determina como el principal responsable de la protección ejercida por la FB frente a la actividad estabilizadora de radicales libres y la peroxidación lipídica, aunque posiblemente existan procesos de sinergismo. Estas propiedades sugieren que la FB de G. madruno es un excelente candidato para ser utilizado como antioxidante.The inhibitory LDL oxidation potential and free radical stabilization capacity of a characterized biflavonoid fraction (FB) was evaluated and correlated by its biflavonoid content. Morelloflavone, volkensiflavone and amentoflavone were identified in the FB. The extract containing the FB (AcOEt extract) was found to be the major contributor to the free radical-scavenging activity of G. madruno. The DPPH activity for the FB was 4.50 µg/mL. Lipid peroxidation, induced with CuSO4, was significantly reduced in the presence of the FB (CE50 = 11.85 µg/mL). Morelloflavone was found to be the main biflavonoid in the fraction responsible for its protection against lipid peroxidation and free radical-scavenging activity, although processes of synergy are possible. These properties suggest that the FB of G. madruno is an excellent candidate for use as an antioxidant.

The inhibitory LDL oxidation potential and free radical stabilization capacity of a characterized biflavonoid fraction (FB) was evaluated and correlated by its biflavonoid content. Morelloflavone, volkensiflavone and amentoflavone were identified in the FB. The extract containing the FB (AcOEt extract) was found to be the major contributor to the free radical-scavenging activity of G. madruno. The DPPH activity for the FB was 4.50 μg/mL. Lipid peroxidation, induced with CuSO4, was significantly reduced in the presence of the FB (CE50 = 11.85 μg/mL). Morelloflavone was found to be the main biflavonoid in the fraction responsible for its protection against lipid peroxidation and free radical-scavenging activity, although processes of synergy are possible. These properties suggest that the FB of G. madruno is an excellent candidate for use as an antioxidant.