Correlation of TPC and TFC with Antioxidant Activity of Selected Indian Medicinal Plants

In recent times, interest has focused on phytochemicals as new sources of natural antioxidants. Therefore, the methanolic crude extracts of Acorus calamus, Lantana camara, Plumbago zeylanica and clitoria ternatea, were screened for total phenols, flavonoids, and free radical scavenging activity. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH). Significant differences in DPPH scavenging activity were found between the species investigated, ranging from 26.36 ± 1.00% to 91.14 ± 1.02%. The highest radical scavenging activity was observed in Acorus calamus (91.14 ±1.02% inhibition). The total phenol content of the investigated species ranged from 23.43±0.18 to 57.33± 2.21 mg GAE/g extract, while flavonoid content ranged from 5.76±2.12 to 20.17 ± 2.72 mg QE/g extract. A weak linear correlation between total phenolic or flavonoid content and antioxidant activity was found (correlation coefficient, R2 =0.2319 and R2 = 0.2605, respectively). Key Words: Acorus calamus, Lantana camara, Plumbago zeylanica and Clitoria ternatea, phenolic content, flavonoid content, antioxidant