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
Introducción: las especies agroforestales son fuente importante de metabolitos secundarios de utilidad en la industria farmacéutica, cosmética y veterinaria. En los países con alta diversidad biológica como Colombia se busca ampliar el conocimiento biológico, químico y económico de especies vegetales con uso potencial. Objetivo: establecer la actividad antimicrobiana y antioxidante de los extractos de hojas de Jatropha curcas L. y de 3 variedades de Hibiscus cannabinus L. (Tainung, Everglades y Whitten). Métodos: las hojas se recolectaron en Restrepo (Meta) y se sometieron a extracción por soxhlet, y microondas con solventes de diferente polaridad como éter de petróleo, diclorometano y etanol (EP, CH2Cl2 y EtOH). La actividad antibacteriana se estableció por difusión en agar frente a cepas de Escherichia coli y Staphylococcus aureus, y la actividad antioxidante por el método autobiográfico utilizando como agentes reveladores 2,2-difenil-1-picrilhidrazilo y ß-caroteno. Resultados: de acuerdo con los porcentajes de extracción hallados, se determinó que la mayoría de los compuestos presentes en estas especies tienen alta polaridad. Los extractos que presentaron la mayor actividad antioxidante fueron los correspondientes a las variedades de Hibiscus cannabinus y, en especial, los extractos de baja y alta polaridad obtenidos por el método de soxhlet. El 20 % del total de los extractos presentaron una respuesta favorable frente a las 2 cepas; los extractos obtenidos por el método de microondas resultaron más selectivos para Escherichia coli. Conclusión: este trabajo se presenta como una contribución al avance de investigaciones biodirigidas, que identifiquen principios activos para el desarrollo de antibióticos y antioxidantes naturales a partir de residuos agroforestales.
Introduction: the agroforestry species are important sources of useful secondary metabolites for pharmaceutical, cosmetic and veterinary medicine. Those countries with high biodiversity like Colombia are looking to expand the biological, chemical and economic knowledge about plant species with potential uses. Objective: to determine the antimicrobial and antioxidant activity of leaf extracts of Jatropha curcas L. and three varieties of Hibiscus cannabinus L. (Tainung, Everglades and Whitten). Methods: the leaves were collected in Restrepo (Meta) and subjected to Soxhlet and microwave extraction processes with different polarity solvents such as petroleum ether, dichloromethane and ethanol (EP, CH2Cl2 and EtOH). The antibacterial activity was established by agar diffusion method against Escherichia coli and Staphylococcus aureus strains, whereas antioxidant activity was determined by the autobiographical method using developing agents 2,2-diphenyl-1-picrylhydrazyl and ß-carotene. Results: in accordance with the extraction percentages found, most of the compounds present in these species had high polarity. The extracts with the highest antioxidant activity were those of Hibiscus cannabinus varieties, particularly low and high polarity extracts obtained by the Soxhlet method. The 20 % of total extracts showed a positive response against the two strains, being the extracts obtained by the microwave method more selective for Escherichia coli strains. Conclusion: this paper is a contribution to the development of bio-directed research to identify the active principles for the development of antibiotics and natural antioxidants from agroforestry wastes.