Antioxidant Activities and Major Bioactive Components of Consecutive Extracts from Blue Honeysuckle (Lonicera Caerulea L.) Cultivated in China

Abstract

Blue honeysuckle (Lonicera caerulea L.) fruits were extracted consecutively by five solvents of different polarity, and the antioxidant activities of the extracts were evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (ferric reducing antioxidant power), ABTS [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)] and CV (cyclic voltammetry) assays. The antioxidant activities were well correlated with the total phenolic and total anthocyanin contents. Among the five extracts, the methanol extract with the strongest antioxidant activity was selected for further study. It showed protective effects on 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced DNA and erythrocyte oxidative damage. Moreover, bioactive components of the methanol extract were identified by liquid chromatography–mass spectrometry analysis. Six polyphenols were characterized, including chlorogenic acid, cyanidin-3-glucoside, peonidin-3-glucoside, quercetin-3-rutinoside, quercetin-3-glucoside and apigenin-(malonyl)-hexoside. Among these, cyanidin-3-glucoside was the predominant antioxidant component. These results suggested that the methanol extract of blue honeysuckle fruits could be used as a promising ingredient for functional foods or nutraceuticals to prevent diseases arising from oxidative processes. Practical Applications Berries are important sources of natural antioxidants, which can protect the body from oxidative damage. Blue honeysuckle (Lonicera caerulea L.) has been harvested from the wild in regions of China, Russia and Japan for hundreds of years. It is more winter-hardy than blueberry. The berries are similar in appearance and taste to blueberries. For the above reasons, blue honeysuckle has a certain market at early season. The results of the present study indicate that the methanol extract of blue honeysuckle showed notable antioxidant activity in different assays in vitro. The methanol extract is rich in polyphenolics, particularly in anthocyanins. Therefore, the methanol extract of blue honeysuckle could be explored as a natural antioxidant for application in functional foods or nutraceuticals.