Isolation of bioactive fractions from Ocimum sanctum essential oil

Essential oil of O. sanctum L. (Tulsi) has been used in cure of many diseases in traditional system of medicine, but application of its bioactive fractions as antioxidant, antimicrobial and antitermitic ingredient is still unexplored. Yield (%) of Ocimum sanctum essential oil extracted by hydrodistillation was 0.197. Ocimum sanctum essential oil was distilled under vacuum to yield fractions with varied bioactive properties. The major components detected in Ocimum sanctum essential oil using Gas Chromatographic-Mass Spectroscopy (GC-MS) analyses were linalool (54.82%), eugenol (12.97%), estragole (5.35%) and α-bergamatene (3.59%). Ocimum sanctum essential oil and fractions showed varied total phenolic contents, total flavonoid contents, flavonol contents, DPPH scavenging activity, reducing power ability and hydroxyl scavenging activity. In many cases antioxidant activities of fractions were much higher than pure essential oil. Fractions isolated at 185 ± 2°C, 239 ± 2°C, 200 ± 2°C and 215 ± 2°C showed much higher antifungal activity against Aspergilus Niger, Penicillium fellutanum, Pleurotus sajor-caju and Ganoderma lucidum, respectively than Ociumum sanctum essential oil. It is previously known that Ocimum sanctum has great ability to inhibit the fungal growth, but isolation of fractions with superior antifungal activities is the new finding of this study.