CORRELATION ANALYSIS OF PHYTOCHEMICALS AND ANTIOXIDANT ACTIVITIES OF HELIOTROPIUM INDICUM L. LEAVES EXTRACTS

The present study aimed to investigate the correlation between the total phenolic and flavonoid contents and in-vitro antioxidant activity of the Soxhlet-extracted leaves extracts (hexane, chloroform, ethyl acetate, methanol and aqueous) of Heliotropium indicum L, a medicinal weed. The preliminary phytochemical analysis was carried out in all five solvents using the standard methods of Harbonne. The phenols were quantified using a spectrophotometer by using Folin-Ciocalteau method by Singleton and Rossi and used catechol as standard. Flavonoids were quantified by using the aluminium chloride colorimetric method by Woisky and Salatino and used quercetin as standard. Soxhlet extracts of plant leave to scavenge DPPH radicals using Mensor et al., method and reducing power was studied using Gow-Chin et al. method. The qualitative phytochemical studies of the crude extracts showed the presence of alkaloids, flavonoids, phenols, saponins, terpenoids, glycosides, proteins, fats and oils, and carbohydrates. The aqueous extract had the highest total phenol contents (165.6 mgGAE/g), and the ethyl acetate extract had the highest flavonoid contents (28.01 mgQE/g) at a concentration of 500 μl. Aqueous extract exhibited higher radical scavenging activity, with an IC₅₀ value of 198.34μg/ml, and the reference standard, ascorbic acid with an IC₅₀ value of 12.51 μg/ml. High correlations were observed between antioxidant activity and total phenols, and total flavonoid contents. H. indicum L. aqueous leaves extract exhibited significant DPPH radical scavenging and reducing power abilities. The present study concluded that the H. indicum L. aqueous leaves extract contained high amounts of total phenolic contents and exhibited significant antioxidant activity.