ABSTRACT
Phytochemical analysis, antimicrobial and antioxidant properties of the leaf extract and fractions of Sabicea brevipes were studied. Theleaveswere defatted and the marc extracted with methanol. The extractwas further purified by solvent-solvent partitioning using n-hexane, ethyl acetate and n-butanol to obtain the three solvent fractions. They were screened for phenolics, flavonoids, tannins, saponins, terpenoids, glycosides, and steroids. Total phenolics, flavonoids and tannins were determined quantitatively. The antimicrobial test was screened in vitroby agar diffusion method. Analysis of variance (ANOVA) was used to test for significant difference at p ≤ 0.05 in all study groups. The methanol extract exhibited the most significant amount of phenolics (110.78 ± 1.06 mg GAE/g) while ethyl acetate fraction had the least total phenolics content (50.55 ± 2.91 mg GAE/g). The same trend was observed for the total flavonoids content whereas the methanol extractmeasured (418.40 ± 14.03 mg QE/g) while ethyl acetate fraction had 192.40 ± 3.06 mg QE/g. Total tannins contents were: methanol extract (102.22 ± 7.58 mg GAE/g) and ethyl acetate (27.33 ± 0.77 mg GAE/g). The antioxidant results showed that the methanol extract had the highest DPPH free radical scavenging ability (93.69%) with half maximal inhibitory concentration (IC50) of 0.601± 0.02 and also highest ferric ion reducing power (50.381 ± 1.56 μmol Fe2+/g). Also, the methanol extract showed high total antioxidant capacity (96.79 ± 0.31 mg AAE) and IC50of 0.798± 0.01. The antimicrobial results revealed that the methanol extract showed better activity against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, andCandida albicans than the solvent fractions at concentrations of 200, 100, 50, 25, 12.5, mg/mL having various inhibition zone diameters (IZDs). The methanol extract and fractions of S. brevipescompared favourably in terms of zone of inhibition and minimum inhibition concentration (MIC) with the standard drug disc (Gentamycin and Ketoconazole) against the tested microorganisms. The MIC of the extract and solvent fractions ranged from 6.31 mg/mL to 50.12 mg/mL. The continual use of the extract of Sabicea brevipesin preventing oxidative stress and in the treatment of common infection is justified by these results.
ABSTRACT
A metodologia para doseamento de taninos através de difusão radial desenvolvido por Hagerman (1987) vem sendo utilizada em laboratórios de fitoterápicos devido, principalmente, à sua simplicidade de execução, rapidez e baixo custo; contudo, não há relato na literatura sobre a submissão desta metodologia a um estudo de validação. Baseando-se neste fato, o presente estudo visou validar a metodologia de Difusão Radial para o doseamento de taninos. Todos os parâmetros obrigatórios exigidos pela ANVISA foram avaliados. O método foi considerado linear e com alta sensibilidade de quantificação (27,72 µg/poço). Mostrou-se também robusto e com recuperação aceitável (85,96%). Os resultados obtidos para repetibilidade (intra-corrida) e precisão intermediária (inter-corridas), certificaram a precisão do método, obtendo-se valores entre 1,89 e 7,03%. Para a exatidão, valores entre 100,47 e 105,26% foram obtidos, os quais se encontram dentro dos limites preconizados pela ANVISA. O método foi considerado preciso, exato e reprodutível, além de ser de fácil execução e de baixo custo.
The method to determine tannins by radial diffusion developed by Hagerman (1987) has been explicitly used in herbal laboratories mainly because of its simplicity to implement, speed and low cost; yet, there are no reports in the literature on the submission of this method to a validation study. Based on this fact, this study sought to validate the method of Radial Diffusion in the tannin determination. All mandatory parameters required by ANVISA were evaluated. The method was considered linear and with high sensitivity quantitation (27.72 µg / well). It also showed robust and acceptable recovery (85.96%). The results obtained for repeatability (within-run) and intermediate precision (inter-run) certified the accuracy of the method, obtaining values between 1.89 and 7.03%. For accuracy, values between 100.47 and 105.26% were obtained, which is within the limits recommended by ANVISA. Thus, the method was considered as precise, accurate and reproducible, and is easy to perform and inexpensive.