Anti-Advanced glycation end-product and free radical scavenging activity of plants from the yucatecan flora

Background: Formation and accumulation of advanced glycation end-products (AGE) is recognized as a major pathogenic process in diabetic complications, atherosclerosis and cardiovascular diseases. In addition, reactive oxygen species and free radicals have also been reported to participate in AGE formation and in cell damage. Natural products with antioxidant and antiAGE activity have great therapeutic potential in the treatment of diabetes, hypertension and related complications. Objective: to test ethanolic extracts and aqueous-traditional preparations of plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine for their anti-AGE and free radical scavenging activities. Materials and Methods: ethanolic extracts of leaves, stems and roots of nine medicinal plants, together with their traditional preparations, were prepared and tested for their anti-AGE and antioxidant activities using the inhibition of advanced glycation end products and DPPH radical scavenging assays, respectively. Results: the root extract of C. fistula (IC50= 0.1 mg/mL) and the leaf extract of P. auritum (IC50= 0.35 mg/mL) presented significant activity against vesperlysine and pentosidine-like AGE. Although none of the aqueous traditional preparations showed significant activity in the anti-AGE assay, both the traditional preparations and the ethanolic extracts of E. tinifolia, M. zapota, O. campechianum and P. auritum showed significant activity in the DPPH reduction assay. <65Conclusions: the results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation; however, the extracts with antioxidant activity may contain other metabolites which are able to prevent AGE formation through a different mechanism

Unusual chemical composition of a Mexican propolis collected in Quitana Roo, Mexico

Propolis, or bee glue, is a natural resinous hive product collected by honeybees from buds and exudates of various trees and plants. Mixed with beewax and salivary enzymes, it is used to fill in cracks and holes in the hive as well as a chemical weapon against intruders. It is well known that the chemical composition of propolis depends on the flora at the site of collection. The aim of this study was to compare two different propolis batches. The first one collected in France (south-west) and the second one in Quintana Roo, Mexico. The ethanolic extract of the French propolis (EEP) contained mainly polyphenols such as phenolic acids and their esters and flavonoids (poplar type), while the same kind of extract from the Mexican propolis showed only triterpenoids such as α and β-amyrin derivatives. Although the latter composition is quite unusual for a Mexican propolis, α and β-amyrins -and their derivatives- have been reported to occur in the resin of Bursera simaruba,1 a tree that grows in Quintana Roo. Both propolis were evaluated in terms of their biological activity, including antioxidant (DPPH), anti-AGEs, antifungal (Candida albicans and Aspergillus fumigatus), and antibacterial (21 Gram-positive and Gram-negative strains including Staphyloccocus aureus). Whereas French EEP exhibited high antioxidant and anti-AGEs activities,2 as well as very good antifungal (towards C. albicans) and antibacterial (towards S. aureus) activities, Mexican EEP proved to be inactive. These results suggest that the chemical composition of the propolis collected in Quintana Roo is qualitatively and quantitatively of particular importance in the ecological interaction between the bees and the parasites and microorganisms that occur specifically in that region

Unusual chemical composition of a Mexican propolis collected in Quintana Roo, Mexico

Propolis is a resinous natural substance collected by honeybees from buds and exudates of various trees and plants; it is widely accepted that the composition of propolis depends on the phytogeographic characteristics of the site of collection. In this study we have analyzed the chemical composition of a propolis collected in Quintana Roo, Mexico, and evaluated its antioxidant, antifungal and antibacterial activities. Unexpectedly, the chemical analysis showed that the main components of the ethanolic extract of a Mexican propolis appeared to be pentacyclic triterpenoids, such as α and β-amyrin derivatives, and sterols. The crude extract did not show antioxidant activity when tested using the DPPH-reduction assay, and it also proved inactive when tested for antifungal and antibacterial activities using microdilution and agar diffusion assays, respectively. The fact that the presence of both α and β-amyrins and their derivatives have been reported from the resin of Bursera simaruba, one of the plants used by the bees for propolis production in Quintana Roo, Mexico, confirms the relationship that exists between the flora available to bees in a given region and the chemical composition of the propolis that they produce

Unusual chemical composition of a Mexican Propolis collected in Yucatan

Introduction: Propolis, or bee glue, is a natural resinous hive product collected by honeybees from buds and exudates of various trees and plants. Mixed with beewax and salivary enzymes, it is employed to fill cracks and embalm dead invaders in the hive. Several studies about mexican propolis have revealed chemical profiles where cinnamic and phenylpropanoic acid derivatives as well as flavonoids dominated, whereas these extracts exhibited cytotoxic and/or antifungal activities. Research methods: An ethanolic extract of a batch of mexican propolis, collected in the state of Quintana Roo, Mexico, was first analysed by High Performance Liquid Chromatography coupled with Diode Array Detector (HPLC/DAD) but no major components could be detected. Its antioxidant activity was evaluated by 1,1-diPhenyl-2-PicrylHydrazyl (DPPH) assay as well, and its antibacterial (against 21 Gram-positive and Gram-negative strains including Staphyloccocus aureus) and antifungal (against Candida albicans and Aspergillus fumigatus) properties were evaluated through microdilution assays. Then, this extract was fractionated by Flash chromatography. Three of the fractions, containing the major constituents, were analysed by Gas Chromatography coupled with Mass Spectrometry (GC/MS). Results and discussion: This Mexican propolis did not show any antioxidant neither antibacterial nor antifungal activity. The main constituents of this Mexican propolis were identified as triterpenes (amyrenone, amyrin and amyrin-3-acetate) and sterols (fucosterol and sistosterol). This unusual composition associated with a Mexican propolis would thus explain the lack of biological activities. Further investigations will be conducted in order to link this chemical composition with the propolis plant sources