Secondary volatiles and metabolites from Nigella sativa L. seed

Abstract

Despite Indian nigella being widely used in various herbal preparation across the world, the composition of volatile fraction and seed metabolite content has been poorly investigated. The nigella crop was raised in Coastal Humid Tropics of Andhra Pradesh and the seed collected was used for chemoprofiling. The extraction was done with MTBE solvent for 2 h to extract volatile fraction and 24 h for extracting entire seed metabolite content. The volatile fraction contained 28 different compounds where as the entire seed metabolite content composed of as many as 150 compounds. The thymoquinone content, which is the most important bioactive compound, was 28.70 %, followed by p-cymene which contained 27.8 % in the volatile fraction. The seed metabolites of nigella seed contained fatty acids, volatiles, and other metabolites. The GC-MS profile of fatty acids and related compounds in the seed metabolites contained five fatty acids (Linoleic acid, palmitic acid, cis-13,16-docosadienoic acid, stearic acid, and myristic acid) and one methyl ester of oleic acid (Methyl oleate). A total of 91.39 % in the total seed metabolite content were fatty acid and related compounds. The volatile fraction was only 5.94 %, remaining were other metabolites (2.67 %). Among these, thymoquinone and p-cymene were the most important compounds (≥ 1 %). The seed of nigella is a storehouse of diverse compounds. Research on chemical nature and bio-potent action of seed metabolites other than secondary volatile metabolites is vastly unexplored and needs immense attention.