Screening of the phenolic composition and in vitro biological activities of the fruit of Lycium ruthenicum Murray

Abstract

Lycium ruthenicum Murray (Solanaceae), also known as black goji or black wolfberry, has been used for centuries in traditional medicine and nutrition in Asian countries [1]. In recent years, black goji berries have been gaining attention as one of the most valuable sources of anthocyanins with many health-promoting effects [2]. Therefore, this study aimed to investigate the phytochemical composition and in vitro biological properties of black goji berry cultivated in southeastern Serbia. The total phenolics, flavonoids, anthocyanins, and tannins content were determined spectrophotometrically. HPLC-DAD-ESI-MS analysis was used to identify the phenolic compounds. Methanol extract from black goji berry was screened for in vitro antioxidant (DPPH∙, ABTS∙+, FRAP, CUPRAC, and β-carotene bleaching methods), antimicrobial, and hypoglycemic (α-amylase, α-glucosidase) potential. Phytochemical screening of the extract confirmed the dominant presence of anthocyanins and hydroxycinnamic acid derivatives, with petunidin 3-p-cumaroylrutinoside-5 glucoside as the main phenolic compound [3]. The total phenolic content was 18.13 ± 0.15 mg gallic acid equivalents/g freeze-dried sample. A high correlation is found between the total phenolic content and the antioxidant activities using different in vitro antioxidant assays. The antimicrobial activity of the black goji berry extract against eight laboratory control strains was not pronounced (MIC > 2 mg/ml). The IC50 values were 6.55 ± 0.38 mg/mL and 7.37 ± 0.02 mg/ml for α-amylase, and α-glucosidase inhibition activity, respectively. Overall, obtained results suggest that the black goji berry cultivated in Serbia should be considered a valuable source of bioactive compounds for further use in the food, nutraceutical, and cosmetic industries.