Phytochemical analysis and antioxidant activity of Lycium barbarum (Goji) cultivated in Greece

The fruit of Lycium barbarum L. (Solanaceae), known as goji berry, has been exploited for a long time in traditional Chinese medicine. In recent decades, it has received much attention as one of the trendiest functional foods with a wide array of pharmacological activities in Western diets.

In this study the phenolic profile and potential antioxidant capacity of Lycium barbarum cultivated in Crete (Greece) were investigated.

The berries were defatted with hexane and then extracted with dichloromethane and methanol using a Soxhlet apparatus. Furthermore, the methanol extract was fractionated with ethyl acetate and butanol. All fractions/extracts were tested for their antioxidant activity (DPPH, FRAP, chemiluminescence). Folin-Ciocalteu and LC-DAD-MS analyses were utilized for the identification of the phenolic compounds.

The total phenolic content ranged from 14.13 ± 0.40 (water fraction) to 109.72 ± 4.09 (ethyl acetate fraction) mg gallic acid equivalent/g dry extract. Ethyl acetate extract exhibited the highest scavenging activities determined as EC₅₀ (4.73 ± 0.20 mg/mL) and IC₅₀ (0.47 ± 0.001 mg/mL) using DPPH and chemiluminescence assays. Seventeen phenolic compounds, including cinnamoylquinic acids and derivatives, hydrocinnamic acids and flavonoid derivatives, were tentatively identified. To the best of our knowledge, quercetin 3-O-hexose coumaric ester and quercetin 3-O-hexose-O-hexose-O-rhamnose are reported for the first time in goji berry fruits.

The results of this study suggest that consumption of goji berry fruits could serve as a potential source of natural antioxidant compounds and that goji berry phenolic extracts could be exploited for nutritional pharmaceutical purposes.