Antimicrobial activities of Nitellopsis obtusa (Desvaux) Groves and Chara vulgaris L.

Abstract

The extracts of Nitellopsis obtusa (Desvaux) Groves and Chara vulgaris L. were investigated for antimicrobial activities against the following common microorganisms using an agar diffusion method: Staphylococcus aureus , Bacillus subtilis , Escherichia coli , Proteus vulgaris , Saccharomyces cerevisiae , and Candida albicans . The extracts strongly inhibited the growth of Gram-positive bacteria, but did not show inhibitory activity against Gram-negative bacteria and yeast. In this study, novel methods for extraction of antimicrobial substances from N . obtusa and C . vulgaris were reported. The optimum extraction conditions were investigated using single factor experimental design and L 27 3 (13) orthogonal experimental design. Results showed that the optimum extraction conditions for N . obtusa are: solid to liquid ratio 1:15, temperature 85°C, ethanol concentration 50%, extraction time 6h; and the optimum extraction conditions for C . vulgaris are: solid to liquid ratio 1:15, temperature 85°C, ethanol concentration 70%, extraction time 10h. Stability study demonstrated neuter and alkaline conditions enhanced the antimicrobial activities from N . obtusa and C . vulgaris , and both extracts were stable under ultraviolet (UV). These data suggest that extracts from both N . obtusa and C . vulgaris might be of potential use as bactericidal agents.