Protective effects of proanthocyanidins extracts from the bark of deciduous trees in lipid systems

Abstract

Abstract Oligomeric proanthocyanidins (OPC) rich extracts (OPCEs) were isolated by sequential extraction from the bark of the deciduous trees grey alder (Alnus incana), black alder (Alnus glutinosa) and goat willow (Salix caprea). The yields of OPCE from all barks under study were rather similar and varied between 12.3% and 15.4% based on the oven dry (o.d.) bark. Content of proanthocyanidins in OPCEs ranged from 16.6% to 25% based on o.d. extract. The OPCEs were characterised by means of antioxidant activity with ABTS˙+ and DPPH˙ radical scavenging tests. All extracts being introduced into lipid-based substrates, i.e. mayonnaise and a basic composition of a cosmetic cream, showed antioxidant activity comparable to the reference commercial antioxidant tert-butylhydroquinone (TBHQ). The results of in vitro tests have revealed that the OPCEs could be useful for the human organism as they activated malfunctions of amylase, inhibited pancreatic lipase activity (duodenal digestion model), decreased lipid absorption in blood and decreased pyruvate level in blood plasma essential for regulation of carbohydrate metabolism. The data obtained confirms the advantages of OPC and OPCEs applications as an antioxidant additive for food, cosmetic and health industries.