Antiradical and Lipid Peroxidation Inhibitory Activity of Ripe and Unripe Fruit of Rubus steudneri Schweinf. (Rosaceae)

Objectives: A free radical is a molecular species characterized by the presence of an unpaired electron in its outer orbital. Free radicals are highly reactive and are known to damage biomolecules including lipids resulting in a myriad of pathophysiological conditions. The present investigation was carried out to screen antiradical and lipid peroxidation inhibitory activity of ripe and unripe fruit of R. steudneri. Methods: The powdered ripe and unripe fruit materials were extracted by maceration process using methanol. Antiradical activity of extracts was evaluated by DPPH and hydroxyl radical scavenging assays. Lipid peroxidation inhibition assay was carried out by estimating the thiobarbituric acid reactive substances. Both ripe and unripe fruit extracts were screened for the presence of phytochemicals viz. alkaloids, flavonoids, tannins, phenolic compounds, saponins, glycosides, sterols and triterpenoids by standard tests. Results: Preliminary phytochemical analysis indicated that both ripe and unripe fruit extracts contain saponins, alkaloids, phenolic compounds, flavonoids, tannins, sterols and triterpenoids. When compared to unripe fruit extract, ripe fruit extract displayed marked scavenging of DPPH and hydroxyl radicals and inhibition of lipid peroxidation as indicated by lower IC₅₀ values. Conclusion: Overall, ripe fruit extract displayed marked free radical scavenging and lipid peroxidation inhibitory activity. The presence of phenolic and flavonoid compounds in the extracts might be responsible for observed bioactivities of ripe and unripe fruit of R. steudneri.