Antibacterial and antioxidant activities of hydroalcoholic stem bark extract of Schotia latifolia Jacq

Abstract

Objective: To investigate the antibacterial and antioxidant activities of hydroalcoholic extract of Schotia latifolia (S. latifolia) bark commonly used in South Africa traditional medicine for the treatment of various ailments.

Methods: The antibacterial test and MIC was determined by using agar well diffusion and dilution methods respectively against eight strains of bacteria. The total phenol, proanthocyanidin and flavonoid contents of S. latifolia were assessed using standard methods. The antioxidant activity of the extract was evaluated using ferric reducing power and the free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS), nitric oxide (NO), hydrogen peroxide (H(2)O(2)) and lipid oxidation (LO).

Results: The antibacterial activity demonstrated an appreciable effect against all the gram positive bacteria at MIC between 0.016 and 10 mg/mL while that of gram negative bacteria was above 10 mg/mL. The plant extract exhibited high concentration of proanthocyanidin [(300.00±0.10) mg CE/g], followed by flavonoid [(12.46±0.04 mg) TE/g] and phenol [(11.06±0.03) mg QE/g] contents. Similarly, the extract at 0.5 mg/mL scavenges DPPH, ABTS, H(2)O(2), LO and NO by 87.55%, 89.47%, 77.15%, 86.48% and 77.75% of the radicals respectively. The reducing power was also found to be concentration dependent.

Conclusions: Our data suggest that S. latifolia extract has antibacterial and antioxidants activity and thus could be used as alternative therapy against antibiotic resistance bacteria and to prevent many radical related diseases.