Anticaries Activity of <i>Usnea pictoides</i> G. Awasthi -A macrolichen from Western Ghats of Karnataka, India
The present study was conducted to determine anticaries activity of solvent extracts of a macrolichen Usnea pictoides G. Awasthi (Parmeliaceae)  collected at Mullayanagiri, Western Ghats of Chikmagalur district,  Karnataka, India. The lichen material was sequentially extracted using solvents viz., petroleum ether, ethyl acetate, chloroform and methanol in a soxhlet assembly. Anticaries activity of solvent extracts was determined against four clinical isolates of Streptococcus mutans (recovered from dental caries subjects) by Agar well diffusion assay. All solvent extracts were effective against the clinical isolates. High inhibitory potential was observed in case of chloroform extract. Thin layer chromatogram showed the presence of Usnic acid. Inhibitory effect could be ascribed to the bioactive secondary   metabolites, mainly Usnic acid present in the lichen. Purification of bioactive principles and determination of their anticaries activity are to be conducted.