In-vitro phytochemical analysis of essential oil and methanolic and hydromethanolic extracts of Ocimum gratissimum

The GC and GC/MS analysis of aerial parts of Ocimum gratissimum grown in Fars Province, southwestern Iran showed 51 constituents in volatile oil. Total percentage of identified constituents in the essential oil was equal to 99.05. The main components were linalool (32.2%), 1,8-cineole (15.57%), geraniol (14.7%) and epi-α-cadinol (5.5%). The essential oil yield was equal to 2.1%. The experiment continued using methanolic and hydromethanolic extracts of O. gratissimum to determine phenolic acid profiles as well as, antioxidant activity, total phenolic, and total flavonoid contents. Results showed total flavonoid contents of 151.90 and 15.77 μg QE mg −1 and phenolic contents of 63.05 and 74.59 μg GAE mg −1 for methanolic and hydromethanolic extracts, respectively. The IC50 values of the extracts were also reported as 714.49 for methanolic and 8724.39 μg mL −1 for hydromethanolic extracts, respectively. HPLC chromatograms showed the presence of 4.45 μg mg −1 DW of rosmarinic acid, 5.00 μg mg −1 DW of catechin, 3.30 μg mg −1 DW of gallic acid, and 2.47 μg mg −1 DW of sinapic acid for hydromethanolic extracts. The main phenolic acids were catechin (0.27 μg mg −1 DW), rosmarinic acid (0.1 μg mg −1 DW), sinapic acid (0.37 μg mg −1 DW), and eugenol (0.26 μg mg −1 DW) for methanolic extracts. All parameters showed significant differences in these extracts, while TPC presented a remarkable significant inverse relationship with TFC, FC, and anthocyanin at a significance level of 0.01, and a significant positive relationship was also reported between TFC and FC at a significance level of 0.01. Graphical Abstract