Polyphenolic composition of Lantana camara and Lippia chevalieri, and their Antioxidant and Antimicrobial Activities

In the present study, the antioxidant and antibacterial activities of methanolic extracts of two Verbenaceae (Lantana camara L. and Lippia chevalieri Moldenke: aerial part) were investigated. Their polyphenolic composition in the ethyl acetate and aqueous fractions were characterized by HPLC-DAD. The antioxidant capability of the methanolic extracts was assessed by the Ferric Reducing Antioxidant Power (FRAP) and the scavenging activity of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The Minimum Inhibitory Concentrations (MIC) of the methanolic extracts (25 µg mL-1), and the minimum bactericidal concentrations (MBC) (12.5 µg mL-1) against 13 pathogenic bacteria and four serotyped bacteria from the American Type Culture Collection (ATCC) were also determined by the agar-well diffusion method. The results indicated that the L. chevalieri extracts are rich in phenolic compounds (among the 27 polyphenolic compounds detected, 20 belong to L. chevalieri) and showed the highest antioxidant activities, simultaneously on iron (III) to iron (II)-reducing activity and the radical scavenging activity. However, L. camara displayed the best and the broadest antimicrobial spectrum, especially on Shigella flexneri and Pantoea sp. (two Gram-negative strains of bacteria). The nature of polyphenolics compounds detected (phenol acid and flavone) in the L. camara can justify this activity.Key words: Verbenaceae, HPLC-DAD, antioxidant activity, antimicrobial activity, polyphenolic compound

α-Glucosidase and α- amylase inhibition potentials of ten wild Mexican species of Verbenaceae

Purpose: To evaluate the inhibitory activity of 10 wild Verbenaceae species from Mexico against α- glucosidase and α-amylase.Methods: Ethanol leaf extracts of 10 Verbenaceae species from Mexico were prepared. The inhibitory activity of the extracts against α-glucosidase and α-amylase was evaluated using enzymatic protocols. At least four serial diluted concentrations of each extract was used to calculate the half-maximal inhibitory concentration (IC50).Results: The 10 evaluated Verbenaceae species showed high α-glucosidase inhibition activity, but a low inhibitory effect on α-amylase. Aloysia gratissima (IC50 = 0.122 mg/mL), Verbena carolina (IC50 = 0.112 mg/mL), Bouchea prismatica (IC50 = 0.122 mg/mL), Verbena menthiflora (IC50 = 0.071mg/mL) and Priva mexicana (IC50 = 0.032 mg/mL) exhibited the strongest inhibitory activities against α- glucosidase.Conclusion: All the Verbenaceae species studied possess α-glucosidase inhibitory effect, with P. mexicana being the one with the strongest activity. These findings demonstrate the highs potential of these species as a source of natural antihyperglycemic agents for type 2 diabetes therapy.Keywords: Hyperglycemic, Diabetes, α-Glucosidase, α-Amylase Verbenaceae, Aloysia gratissima, Bouchea prismatica, Priva mexican

Possible international directive for quality control of bee pollen

Comunicação oral da qual só está disponível a apresentação.Possible international directive for quality control of bee pollen.Fundação Ciência e Tecnologia de Portugal POCTI (FEDER) & COMPETE, Ciência Viv

Chemical analysis of Greek pollen - Antioxidant, antimicrobial and proteasome activation properties

<p>Abstract</p> <p>Background</p> <p>Pollen is a bee-product known for its medical properties from ancient times. In our days is increasingly used as health food supplement and especially as a tonic primarily with appeal to the elderly to ameliorate the effects of ageing. In order to evaluate the chemical composition and the biological activity of Greek pollen which has never been studied before, one sample with identified botanical origin from sixteen different common plant taxa of Greece has been evaluated.</p> <p>Results</p> <p>Three different extracts of the studied sample of Greek pollen, have been tested, in whether could induce proteasome activities in human fibroblasts. The water extract was found to induce a highly proteasome activity, showing interesting antioxidant properties. Due to this activity the aqueous extract was further subjected to chemical analysis and seven flavonoids have been isolated and identified by modern spectral means. From the methanolic extract, sugars, lipid acids, phenolic acids and their esters have been also identified, which mainly participate to the biosynthetic pathway of pollen phenolics. The total phenolics were estimated with the Folin-Ciocalteau reagent and the total antioxidant activity was determined by the DPPH method while the extracts and the isolated compounds were also tested for their antimicrobial activity by the dilution technique.</p> <p>Conclusions</p> <p>The Greek pollen is rich in flavonoids and phenolic acids which indicate the observed free radical scavenging activity, the effects of pollen on human fibroblasts and the interesting antimicrobial profile.</p

Genetic variability in natural populations of agave durangensis (agavaceae) revealed by morphological and molecular traits

Agave durangensis is an endemic species that occurs in a reduced area in southern Durango and northern Zacatecas, Mexico. We analyzed the genetic variability of three populations of the species using two pairs of Inverse-Sequence-Tagged-Repeat primers and nine morphological characters to determine the species of the morphologically variable populations. The primers generated characteristic amplification profiles, which distinguished between populations of A. durangensis and revealed interspecific variability when compared with individuals of A. asperrima. Some incongruence between morphological and molecular variability was detected. High genetic variability was indicated by an elevated level of polymorphism (24.18-61.50%) among 91 genetic loci amplified and by the level of gene diversity (0.0807-0.2337) among populations. Genetic differentiation (0.0328-0.4857), gene flow (0.5294-14.7511), genetic distance (0.0200-0.3019), and genetic identity (0.7653-0.9802) among populations suggested that one of the three populations of A. durangensis is in a present advanced diversification process but may still maintain some level of gene flow with the other two populations. Urgent conservation efforts, including protection from harvest, should be addressed for maintaining the genetic variability of the natural populations of A. durangensis

Los fenoles del polen del género Zea

The variability of the pollen phenol composition of 32 populations of Zea mays subsp. mexicana, Zea mays subsp. parviglumis, Zea mays subsp. mays, Zea diploperennis, Zea perennis, and Zea luxurians from Mexico and Guatemala were analyzed. The phenol profiles were assessed by HPLC-DAD, and UPLC-TOF-MS. A total of 23 phenolics (four phenolic acids, 16 flavonols, and three dihydroflavonoids) were found. Quercetin glycosides (seven derivatives besides the quercetin aglycone itself) were the predominant compounds in the pollen of all analyzed species and subspecies. The major compound in all the samples, including the pollen of maize, was identified as quercetin-3,3'-O-diglucoside. The pollen of all the species and subspecies of Zea examined showed very similar patterns of accumulated phenols; however, variation in the minor compounds (phenolic acids and dihydroflavonoids) allowed to discern some inter- and intraspecific variations, although the split of Zea in the sections Luxuriantes and Zea was not clearly supported. The low level of variability of the pollen phenol profiles throughout the genus Zea supports the proposal that maize and some teosintes are conspecific groups, and indicates that the pollen phenol composition is highly conserved in the different taxa of Zea