Toxicological evaluation of polar and nonpolar components of Isodon coetsa (Lamiaceae)

Abstract

Isodon coetsa (Buch.-Ham. ex D.Don) Kudo, a perennial herb used in traditional Chinese folk medicines as an antibacterial, antiinflammatory, and antitumour agent, was subjected to toxicity analysis. Cytotoxic screening using the Allium L. assay was done with extracts containing polar and nonpolar compounds as well as with polar compounds alone. Root tips were treated with different concentrations of both the extracts, 0.005%, 0.01%, 0.05%, and 0.1%, for varying time durations (30 min, 1 h, 2 h, and 3 h). Extremely significant levels of chromosome abnormality (P < 0.001) were observed with the extracts when compared with the positive control (0.01% methyl parathion), but the extract with polar and nonpolar compounds showed higher abnormality percentage. Not much variation was observed in the mitotic index when compared to the negative control (distilled water). Studies revealed many clastogenic and nonclastogenic abnormalities. The major abnormalities included chromosome fragments, stickiness, ring chromosomes, chromosome bridges, pulverization, binucleate cell, micronucleus, ball metaphase, chromosome laggards, and shift in microtubule organizing center. The results showed that the nonpolar components possessed more clastogenic activity, which can be specifically targeted in order to destroy cancer cells. The toxic activity of extracts also suggests the need of judicious use of I. coetsa in folk medicines.