Abstract

Dental caries is the most common infectious diseases of the oral cavity. Among the oral microbiota, Streptococcus mutans, plays a major role in causing dental caries. The present study was carried out to determine inhibitory activity of ethanol extract of ten macrolichens viz., Everniastrum cirrhatum, Ramalina conduplicans, R.hossei, R. pacifica, Heterodermia leucomela, Parmotrema tinctorum, P.pseudotinctorum, Usnea sinensis, Dirinaria consimilis and Roccella montagnei against 13 clinical isolates of Streptococcus mutans by Agar well diffusion method. All lichens were effective in inhibiting the caries isolates as evidenced by the formation of zone of inhibition around the wells. Extracts from lichens showed more or less similar inhibitory activity against bacterial isolates except extract of R.montagnei and H.leucomela which displayed lesser activity when compared to other lichens. The lichens of this study appear to be promising resources of bioactive agents with activity against cariogenic microflora. Further studies on isolation of bioactive principles from lichen extracts and their inhibitory activity against cariogenic flora are to be carried out.

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