Abstract

This study examined the phytochemicals and medicinal properties of the floral essential oil of O. basilicum var. purpureum from Nigeria. The GC and GC-MS analyses revealed the presence of twenty-five organic compounds making up 99.7% of the total percentage composition of the essential oil. The most abundant components was phenolic compound called methyleugenol (15.5%), followed by 2- phenyl-1-hexanol (14.0%), 1-(4,5-dimethyl-2-nitrophenyl)-1Htetraazole (14.0%), 2-methyl-3,5-dodecadiyne (14.0%), onitrocumene (14.0%) and patchoulane (6.7%). The total phenolic content was quantitatively determined as 459 μgmg-1 gallic acid equivalent (GAE) confirming the presence of high amount of phenolic compounds in the floral essential oil. The DPPH IC50 value was 1.0 μgml-1, the essential oil was capable of scavenging free radicals in a range of 73-86% and the antioxidant power of the essential oil increased with concentration. The essential oil was found to be 90% more active than the synthetic antioxidant (ascorbic acid). The essential oil was also found to exert excellent antibacterial properties compared to standard antibiotics. The floral essential oil was significantly active against all tested species of Gram-positive and Gram-negative bacteria with high zones of inhibition between 15-30mm. The bacteria inhibition of the essential oil was found to be positively correlated with their terpenoid and phenolic contents. The results from this study indicated that the floral essential oil showed potential as a good source of natural antioxidant and antimicrobial drugs and may impart health benefits by its pharmacological properties.