The antioxidant properties of calafate (Berberis microphylla) fruits from four different locations in southern Chile
The antioxidant capacity (AC), total anthocyanins (TA) and total phenols (TP) of calafate fruit from four locations in southern Chile (El Blanco, Lonquimay, Mañihuales and Temuco) were determined using both the free radical 2.2-diphenyl-1-picrylhydrazyl (DPPH) method and the linoleic acid oxidation inhibition method as well as the pH-differential and Folin-Ciocalteu methods. Phenolic compounds were also identified using HPLC-DAD (High Performance Liquid Chromatography-Diode-Array Detection). The results showed that TP varied significantly according to the location. Mañihuales was noteworthy, with 34.9 mg of GAE g-1 dried fruit. The measured AC level depended on the methodology used, varying significantly between locations according to the DPPH results. Mañihuales was again noteworthy, with the highest AC values (9.4 mg of TE g-1 dried fruit). The results based on the inhibition of linoleic acid oxidation showed no significant differences between Temuco and El Blanco, and the highest value was found for Mañihuales (0.25 mg of TE g-1 dried fruit). The TA showed significant differences among locations and was highest for El Blanco (0.64 mg of cyanidin g-1 dried fruit). The phenolic acid compounds that were identified included gallic acid, chlorogenic acid, caffeic acid, coumaric acid, ferulic acid and flavonoids such as rutin, myricetin, quercetin and kaempferol. These compounds varied according to location. Temuco showed a higher content of coumaric acid; Lonquimay of chlorogenic acid, caffeic acid, coumaric acid and flavonoids such as rutin and quercetin; Mañihuales of gallic acid, chlorogenic acid, caffeic acid, ferulic acid and flavonoids such as rutin and quercetin; and El Blanco of caffeic acid and flavonoids such as myricetin, quercetin and kaempferol. The AC was positively correlated with TP (DPPH r=1, linoleic acid r=0.84). In contrast, a low correlation was obtained between AC and TA (DPPH r=0.31; linoleic acid r=-0.28) and between TP and AT (r=0.27). It is concluded that calafate fruits from different geographical areas of southern Chile show statistically significant differences in antioxidant capacity, total phenols, anthocyanins and phenolic compounds, with Mañihuales showing the highest values for these parameters. The chemical composition of the fruits also varies with the origin of the samples.