Evaluation of antioxidant activity and total phenol in different varieties of Lantana camara leaves

BACKGROUND: Phytochemicals like carotenoids, tocopherols, ascorbates and phenols present in the plants are strong antioxidants and have an important role in the health care system. There is growing interest in correlating the phytochemical constituents of a plant with its pharmacological activity. Therefore, the present study investigates the content of total phenolics, flavonoids and the antioxidant activity of four different varieties of Lantana camara L. (Verbenaceae) leaves by using in vitro antioxidant models. METHODS: The leaves of Chandigarh purple variety (CPV), Palampur red variety (PRV), Chandigarh yellow turning pink variety (YTPV) and Chandigarh yellow variety (CYV) Lantana camara were collected and the total phenolic, flavonoid content, antioxidant and free radical scavenging activities were determined in their methanolic extracts. RESULTS: The phenolic content was found to be highest in the CYV extract (232.99 ± 15.97 mg GAE/ g extract). The content of the flavonoids are in the order of YTPV, PRV, CPV and CYV. The IC(50) values for the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test were in the order of CYV (33.30 ± 2.39) < PRV (40.32 ± 2.94) < YTPV (475.33 ± 5.20) < CPV (927.16 ± 2.88 μg/mL). The highest total antioxidant capacity was observed in CYV (222.20 ± 5.05 mg AAE/ g). The Ferric ion reducing antioxidant potential (FRAP) value of the extracts were in the order of CYV > PRV > YTPV > CPV. The IC(50) values of 2, 2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) scavenging assay for CYV, PRV, YTPV, CPV were 18.25 ± 0.19, 18.24 ± 1.82, 50.43 ± 9.49, 52.84 ± 1.82 μg/mL respectively. PRV extract showed the maximum in vitro lipid peroxidation inhibition effect with an IC(50) value of 68.50 μg/mL which is even stronger as compared to the standard Rutin (79.69 μg/mL). The extracts showed a strong correlation between the phenolic content and their antioxidant activities. The highest correlation (r = 0.998, R(2) = 0.997) was found between total phenolic content and ABTS scavenging assay. CONCLUSION: Among the four varieties investigated, CYV and PRV extracts showed strong antioxidant activities and may be used as a potential source of natural antioxidant against free radical associated diseases.