Evaluation of cytotoxic effects and antimicrobial activities of Lecaniodiscus cupanioides (Planch.) leaf extract

Abstract

The present study assessed the cytotoxic and antimicrobial activities of Lecaniodicus cupanioides leaf extract, evaluated its killing rate and also determined the presence of certain phytochemicals. The antimicrobial activities were assessed via a susceptibility test and by determination of minimum bacteriotastic and bactericidal concentrations. The killing rate was evaluated at regular intervals over a 2h-period under different concentrations and the cytotoxicity was measured through a brine shrimp lethality test. Zones of inhibition exhibited by the extract at 20 mg/ml ranged between 20±0.00 and 23±0.58 mm against both bacteria and yeast isolates. The minimum inhibitory concentrations (MICs) were between 1.25 and 2.50 mg/ml against bacteria and 0.63 and 1.25 mg/ml against yeasts. The minimum bactericidal concentrations (MBCs) ranged from 2.50 to 5.00 mg/ml (bacteria) and 1.25 to 2.5 mg/ml (yeasts). At a concentration of 1×MIC after 15 min of contact time, the mortality against Shigella sonnei (ATCC 29930), Staphylococcus aureus (ATCC 6538) and Candida albicans as representative isolates were 52.3, 60.0 and 40.0%, respectively. Total mortality was achieved against S. sonnei (ATCC 29930) at a concentration of 2×MIC after 120 min of contact time while that of S. aureus (ATCC 6538) was achieved after 90 min of contact time at 3×MIC. Percentage mortality against the C. albicans after 120 min under a concentration of 3×MIC was 94.4%. The lethality concentrations at LC₅₀ and LC₉₀ of the leaf extract were 4.255 and 36.766 µg/ml, respectively. The results obtained support the therapeutic significance of L. cupanioides leaf extract and could be a veritable source of affordable broad spectrum antimicrobial and anti-tumour agent.

Keywords:

• inhibition zones
• killing rate
• lethal concentration
• minimum inhibitory concentrations (MICs)
• minimum bacterial concentrations (MBCs)

ACKNOWLEDGMENT

The authors express profound gratitude to the research committee of the University of the Free State for supporting the research.

DISCLOSURE STATEMENT

Authors declare no conflict of interest.