Phytochemical profiling of Costus (Saussurea lappa Clarke) root essential oil, and its antimicrobial and toxicological effects

Purpose: To carry out gas chromatography-mass spectrometry (GC-MS) analysis of the phytochemical content of the root essential oil of Saussurea lappa Clarke Asteraceae (Costus, SLEO), and to evaluate its physicochemical, antimicrobial and cytoxic properties. Methods: The oil was extracted from the plant's roots by steam distillation using a Clevenger system. Various physicochemical parameters for the oil including refractive index, color, acid value, saponification number, ester and peroxide values were measured. Flavonoid content was assessed using thin layer chromatography (TLC). Thermoscientific trace ultra gas chromatograph equipped with a Thermoscientific capillary TR-5MS column was utilized to determine the volatile components of SLEO. Antimicrobial activity of SLEO was performed against various Gram (+ve) and Gram (-ve) microorganisms, viz, Bacillus subtilis, Staphylococcus aureus, Escherichia coil, Pseudomonas aeruginosa and Candida albicans, while cytotoxic effect was monitored using Artemia salina (brine shrimp) lethality assay. Results: Essential oil yield was good (3 %). Concentration-dependent antimicrobial effects were observed on all test microorganisms and no marked difference in lethality levels was observed among the tested SLEO concentrations on brine shrimp (p < 0.05). The main component of SLEO was costunolide or eudesma-5,11(13)-dien-8,12-olide (52.01 %). Conclusion: The results indicate the promising therapeutic properties of S. lappa. However, further phytochemical and biological investigations are required to establish the mechanism of action and toxicological the extract.