Antibacterial, antifungal and cytotoxic activities of amblyone isolated from Amorphophallus campanulatus

OBJECTIVE: To assess the in vitro antibacterial, antifungal and cytotoxic activities of amblyone, a triterpenoid isolated from Amorphophallus campanulatus (Roxb). METHODS: Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimum inhibitory concentration (MIC) was determined using serial dilution technique to determine the antibacterial potency. RESULTS: Large zones of inhibition were observed in disc diffusion antibacterial screening against four Gram-positive bacteria (Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus and Streptococcus pyogenes) and six Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Pseudomonas aeruginosa and Salmonella typhi). The MIC values against these bacteria ranged from 8 to 64 μg/ml. In antifungal screening, the compound showed small zones of inhibition against Aspergillus flavus, Aspergillus niger and Rhizopus aryzae. Candida albicans was resistant against the compound. In the cytotoxicity determination, LC(50) of the compound against brine shrimp nauplii was 13.25 μg/ml. CONCLUSIONS: These results suggest that the compound has good antibacterial activity against the tested bacteria, moderate cytotoxicity against brine shrimp nauplii and insignificant antifungal activity against the tested fungi.