BIOLOGICAL POTENTIALS OF EXTRACTS AND COMPOUNDS FROM MAMMEA USAMBARENSIS VERDC FRUIT

Abstract

In attempt to investigate some biological activities of Mammea usambarensis fruit, absolute ethanolic crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were subjected to toxicity test in brine shrimps and mice, antimicrobial activity by disc diffusion and broth dilution method and antioxidant activity by DPPH scavenging activity. In the brine shrimps toxicity test, the crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB were highly toxic with LC50 values of 1.58, 1.14, 3.89 and 5.21 μg/ml, respectively. The crude extract was non-toxic to mice even at a dose above 2000 mg/kg body weight. The crude extract, 80% DCM/PE 5% MeOH/DCM fractions and mammea B/AB exhibited low activity with zone of inhibition of 8.3-16 mm for Salmonella kisarawe, 8.7-14 mm for Staphylococcus aureus and 8.3-10 mm for Klebsiella oxytoca. The minimum inhibitory concentrations ranged from 3.75 μg/μl-25 μg/μl. All samples tested had no activity against Candida albicans and Cryptococcus neoformans. In DPPH assay crude extract, 80% DCM/PE fraction, 5% MeOH/DCM fraction and mammea B/AB had lower scavenging activity of 86, 69, 72 and 77 μg/ml: mM, respectively, compared to the standard compound, propagyl gallate, which had a value of 93 μg/mL: mM. To conclude, the antioxidant activity exhibited prompt further studies aimed at discovery of antioxidant agents.