Chemical composition, antioxidant, anti-inflammatory, anti-microbial and in-vitro cytotoxic efficacy of essential oil of Curcuma caesia Roxb. leaves: An endangered medicinal plant of North East India

The present study was designed to study the chemical constituents of the leaf essential oil of Curcuma caesia and its anti-oxidant, anti-inflammatory, antimicrobial and genotoxic efficacies. Chemical constituents of the oil were determined using Gas Chromatography/Mass Spectroscopy, showed 32 components; the major components were eucalyptol (16.43%) and camphor (11.56%). The DPPH assay of the leaf oil confirmed significant amount of antioxidant activity (IC50 value = 1.487 mu g/mL), which is even more than the control, ascorbic acid. The maximum reducing power was observed at 48 mu g/mL. The total phenolic (TPC) and flavonoid content (TFC) of the leaf oil was 2.13 +/- 0.027 mg/mL and 11.36 +/- 0.096 mg/mL respectively, which provides the oil its strong antioxidant property. Moreover, the leaf essential oil showed in-vitro ant-inflammatory activity with IC50 value of 182.5 mu g/mL C. caesia leaf essential oil was also found to have antimicrobial potential against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Salmonella typhimurium; and antifungal effect against Aspergillus fumigatus, Aspergillus niger, Saccharomyces cerevisiae and Candida albicans. It has been observed that the leaf essential oil showed negligible amount of genotoxic effect in comparison to the standard, sodium diclofenac. Therefore, it can be stated that the C. caesia leaf essential oil has potential and biologically important activity. To the best of our knowledge, this is first scientific report on the chemical constituents of the leaf essential oil of Curcuma caesia and its biological activities, and it could be a scope for further research to be used in pharmaceutical and natural products industries.