Antioxidant activity of Gardenia jasminoides Ellis fruit extracts

The objective of this study was to characterise the antioxidant properties of both water and ethanol extracts from the fruit of Gardenia jasminoides Ellis (GJE). The IC₅₀ values for DPPH (1,1-diphenyl-2-picryl-hydrazyl), ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)diammonium salt], hydroxyl and superoxide radical-scavenging activities were 0.14, 0.21, 1.08 and 1.43 mg/ml for the water-based extract, and 0.36, 0.39, 1.56 and 1.99 mg/ml for the ethanol-based extract, respectively. The extracts also showed strong reducing power, nitrite-scavenging activity, inhibition of linoleic acid oxidation, superoxide dismutase-like (SOD-like) activity and catalase activity. However, the water extract had a higher antioxidant activity than the ethanol extract. In addition, the antioxidant activities were highly correlated with the observed phenolic and flavonoid contents. Therefore, our study strongly suggests that extracts derived from the fruit of Gardenia jasminoides could be an excellent source of antioxidants as dietary supplements.