RESUMO
The biological activity and composition of the essential oil of Sclerorhachis leptoclada Rech. an endemic species from northeast of Iran was studied. The essential oil was isolated from the aerial flowering parts of the plant and analyzed by GC and GC-MS. Fifty-four compounds accounting for 95.9% of the total oil were characterized. The main constituents were [E]-nerolidol [14.5%], terpinen-4-ol [13.3%], camphor [6.1%], 1,8-cineole [4.8%] and p-cymene [4.5%]. The antimicrobial activity of the essential oil of S. leptoclada was tested against eight microbial strains and a fungi. The results of the bioassays showed that the Gram-positive bacteria, Bacillus subtilis and Staphylococcus epidermidis, were the most sensitive to the oil than others with the MIC value of 1.8 mg/mL. The tested fungi, Saccharomyces cerevisiae was highly inhibited by the oil of S. leptoclada with MIC value of 10 mg/mL. In the case of cytotoxicity, IC50 values estimated to be 312, 1250, 625 and 1250 microg oil/ml respectively, for the Vero, SW480, MCF7, and JET 3 cancer cell lines