Antimicrobial and cytotoxic activities of extracts from Sterculia quinqueloba (Garcke) K. Schum and Canthium crassum Hiern

Sterculia quinqueloba (Garcke) K. Schum and Canthium crassum Hiern extracts were evaluated for antimicrobial activity using 96-well-microtitre serial micro-dilution method against Vibrio cholera, Klebsiella oxytoca, Klebsiella pneumonia, Streptococcus pyogenes, Staphylococcus aureus and Candida albicans. All extracts exhibited antimicrobial activity with minimum inhibition concentration range of 0.39 – 12.5 mg/mL. The S. quinqueloba leaf methanolic extract had the highest activity with minimum inhibitory concentration range of 0.78 – 1.56 mg/mL and 0.78 – 1.50 mg/mL against bacterial and fungal species respectively. The lethality test against brine shrimp larvae revealed that S. quinqueloba and C. crassum leaf extracts with LC50 value range of 113.439 – 840.537 µg/mL is non-cytotoxic. The antimicrobial activity and lethality results indicate therapeutic potency of Sterculia quinqueloba and Canthium crassum.