Chemical Composition and Biological Activities of Natural Essential Oil Extracted from Flowers of <i>Cassia sophera</i> Linn.

Background: Natural essential oil comprises a galaxy of low-molecular-weight (usually less than 500 daltons) and volatile phytoconstituents that exhibit a handful of biological and pharmaceutical properties; they exhibit several applications chiefly in agriculture, cosmetic, perfumeries, and food industries. Methods: The extraction of essential oil from fresh flowers of C. sophera was performed by hydrodistillation, and the determination of its chemical composition was carried out by Gas Chromatography/Mass Spectrometry (GC-MS). The antibacterial activity of the essential oil was executed by the disc diffusion method against the four pathogenic bacteria. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) was also performed for free radical scavenging assay, and a scanning electron microscopic study was also executed to get an idea of the effect of C. sophera essential oil on bacterial morphology. Results: The GC/MS analysis indicated that the essential oil is constituted primarily of aromatic compounds (68.75%), and the principal compounds are the dialkyl phthalates esters (58.32%). The zones of inhibition range from 8-16 mm in the case of Gram-negative E. coli, whereas, in Gram-positive S. aureus, these range from 7-13.5 mm. The minimum inhibition concentration (MIC) was found to be 0.3 mg/mL against all the Gram-negative bacteria tested and 0.4 mg/mL against the Gram-positive bacteria S. aureus. The oil also showed moderate antioxidant properties by scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical with an IC50 value of 126 μg/mL. Conclusion: As per the present study, the essential oil of C. sophera flowers may be suggested as a new potential source of natural antimicrobial and antioxidant agents.