This study was designed to assess the susceptibility of various microorganisms and inhibition on heat-induced protein denaturation against diosgenin and santonin, isolated from Polygonatum verticillatum rhizomes. Both diosgenin and santonin showed significant zone of inhibition when studied against various Gram-positive (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Escherichia coli and Salmonella typhi). In antifungal assay, only santonin exhibited profound sensitivity against various fungi (Aspergillus flavus, Aspergillus niger, Trichoderma harzianum and Fusarium oxysporum) used in the test. Both diosgenin and santonin also exhibited marked attenuation on heat-induced protein denaturation in a concentration-dependent manner with EC50 values of 375 and 310 μg/mL, respectively. In conclusion, both the isolated compounds have antimicrobial potential supported by strong inhibition on protein denaturation and thus support the antimicrobial uses of plant in traditional system of treatment.
Keywords: Polygonatum verticillatum; antimicrobial; diosgenin; protein denaturation activities; santonin.