Vanessa de Andrade Royo

Antibacterial activity tannin-rich fraction from leaves of Anacardium humile

In vitro tests conducted with extracts rich in tannins have identified several biological activities of this class of substance. Thus, this paper intends to evaluate the antibacterial activity of tannin-rich fraction obtained from leaf extracts of Anacardium humile A.St.-Hil. Extracts of A. humile leaves in 70% acetone were semi-purified with ethyl acetate and butanol. We quantified the total tannins of the semi-purified fractions, of the crude extract and of aqueous residues and then performed tests of the antibacterial activity of the tannins against Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212. All positive extracts underwent tannin isolation using a Sephadex LH-20 column. The tannins isolated from the samples were quantified and tested for the minimal inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). The tannins from crude extracts, semi-purifications and residues showed inhibition of S. aureus growth with MIC=500 g mL-1. All tannin fractions showed MIC against all strains and MBC, except against E. faecalis. The tannin fractions from Anacardium humile have antibacterial activity against Staphylococcus aureus, Pseudomononas aeruginosa and Enterococcus faecalis and, therefore, may be promising for future synthesis of new antibacterial agents.

Antioxidant activity, total flavonoids and volatile constituents of Magonia pubescens A.St.-Hil.

Magonia pubescens A.St.-Hil (Sapindaceae) (‘tingui’) is a typical medicinal plant of the Cerrado biome. This plant is used as a larvicide and employed in poison fishing. However, little is known of its secondary metabolites. In this study, it is described for the first time as the volatile constituents of M. pubescens, collected via headspace. Qualitative phytochemical analyses were performed. In addition, the antioxidant activity of the ethanol extracts of flowers and leaves were evaluated, and the total flavonoids were quantified. The ethanol extracts of flowers (12.67 ± 0.05 rutin equivalent (EQ) g -1 ) and leaves (11.81 ± 0.05 rutin EQ g -1 ). The leaf extracts exhibited higher IC50 values (18.14 ± 0.02 rutin EQ g -1 ) than did the flower extracts (31.19 ± 0.05 rutin EQ g -1 ). Twenty volatile compounds were identified in M. pubescens flowers through gas chromatography coupled with mass spectrometry (GC-MS), being identified as benzilic acid (17.9%) and styrene (13.9%) as the major compounds. The antioxidant activity of M. pubescens could be related to the presence of flavonoids and tannins, but further studies need to be conducted to fully understand that correlation. The identified volatiles have the potential to be used in the cosmetics industry due to their socio-economic relevance, and the may also contribute to the understanding of the reproductive success of this species.

Structure and genetic diversity of Anacardium humile (Anacardiaceae): a tropical shrub

Anacardium humile Saint Hilaire is a tropical shrub native to the Cerrado biome. It is a fruiting species with biological, medicinal, and socioeconomic significance. Thus, knowing how the genetic variability of natural populations is organized allows for the establishment of strategies for conservation and the sustainable use of the species and its biome. Six microsatellite loci previously developed from Anacardium occidentale were used to investigate the spatial genetic structure and genetic diversity of eight natural A. humile populations based on analyses of 242 adult plants. The results obtained indicate that these populations show a high level of genetic diversity (expected heterozygosity = 0.710). The endogamy coefficient was positive and significant for most populations, with a mean of 0.142 (P = 0.001). The genetic differentiation between populations was low (θ = 0.075 and GST = 0.066) but significant (P = 0.0001). The genotypes of five of the eight populations were non-randomly distributed with clusters of related plants for which the coancestry values were positive and significant. These populations exhibited high and significant endogamy indices. The results obtained for A. humile populations show that genetic conservation programs should be implemented to maintain this species.