摘要：Fruits of the plant Lycium barbarum L. (Goji berry) fruit have been widely used
around the world for their medicinal purposes and as a functional food for more than
4500 years. Studies indicate the effects of the fruits of Goji berry on aging,
neuroprotection, fatigue, energy expenditure, glucose control in diabetics, antioxidant
properties, immunomodulation, anti-tumor activity, and cytoprotection. Some authors
report that antioxidant molecules found in goji fruit might offer many health protective
benefits by alleviating oxidative stress when used as an additive or in a mixture with
other phytochemicals in fruit or herbal products. It was found that Goji berry fruit
growing in Bulgaria has a total polysaccharide content of about 4%. The content of
total polyphenol compounds in the different extracts was found to be between 5.5mg
and 8mg GAE/g of dry product. Polyphenols from dry Goji berry fruit were extracted
and studied by HPLC analysis for the type of polyphenols present. Antioxidant activity
of extracts rich in polyphenols was determined by DPPH, FRAP and CUPRAC
methods. The data was compared with a medicinal product containing an extract of
Goji berry, where synergistic effects were also established. Inhibitory effects of the
Goji berry extracts and their corresponding polyphenols were investigated in the
presence of α-glucosidase for antidiabetic activity. The 50% inhibitory concentration
found for organic extract was IC50=91.7 μg GAE/g of fruits. The study demonstrated
that some of the polyphenols in the investigated extracts exhibit competitive properties
towards the enzyme.
