Lycium barbarum L. JUICE - NATURAL SOURCE OF BIOLOGICALLY ACTIVE COMPOUNDS

Abstract

The objective of this study was to evaluate the quantity of some phenolic compounds, free radical scavenging activity and antibacterial activity of goji berry fruits (Lycium barbarum L.) in order to highlight which of these biotypes fulfills the best nutraceutical qualities. Freshly harvested fruits of three goji berry biotypes ('Biotype 1(B1)’, Biotype 2’ (B2), and 'Biotype Ua’ (BUa) were smashed and the juice was subjected to analysis. The phenolic compouns were analyzed as follows: total phenolic content (TPC) expressed as g gallic acid equivalents (GAE), total flavonoid content (TFC) expressed as g of rutin equivalents (RE), and free radical scavenging activity expressed as inhibition % (I %). The evaluation of antibacterial activity consisted of using Gram positive and negative bacteria based on the standard agar disk diffusion method. With regard to the TPC, all analysed juices have revealed 'Biotype BUa’ with a maximum content of 8.95 mM ± 0.48 GAE / ml juice. Also, the same biotype recorded high levels of free radical inhibition rate of 40%. In terms of flavonoid content, 'Biotype 1’ highlighted the best results. With regard to the evaluation of antibacterial activity, all juices showed good results. The most susceptible to all three juices was S. aureus and the least, P. aeruginosa. The highest inhibitory activity was registered in the case of 'Biotype 1’ juice against E. coli, showing an average inhibition diameter of 1.84 ± 0.13 and 1.81 ± 0.20 cm.