Analysis of chemical composition of Cupressus torulosa (D.Don) essential oil and bioautography guided evaluation of its antimicrobial fraction

ABSTRACT

Cupressus torulosa D. Don, known as the Himalayan or Bhutan cypress, is one of the medicinal plants commonly used in the Indian System of Medicine for various ailments. The present study evaluates the chemical composition and inhibitory potential of the essential oil and three different extracts (chloroform, methanol and aqueous) of aerial parts of C. torulosa. Chemical composition of essential oil was determined by GC-MS that showed the presence of four major components viz., α-pinene (45.44%), 3-carene (38.34%), terpinolene (5.36%) and aromadendrene (6.32%). Essential oil showed significant inhibitory activity against Bacillus subtilis, Pseudomonas alcaligenes, Micrococcus luteus and Bacillus cereus in comparison to the different extracts. Essential oil also showed good antifungal activity against the three fungal pathogens viz., Alternaria alternata, Curvularia lunata and Bipolaris specifera. TLC-bioautography was used to screen the antibacterial components of the essential oil. Analysis showed the presence of four zones of inhibition on bioautography plate at Rf values 0.80, 0.70, 0.61 and 0.46. This study has demonstrated the presence of four potential antibacterial compounds in the essential oil of Cupressus torulosa.