Oligomeric procyanidins of lotus seedpod inhibits the formation of advanced glycation end-products by scavenging reactive carbonyls.

It has been reported that oligomeric procyanidins of lotus seedpod (LSOPC) is effective in the alleviation of Alzheimer's disease and diabetes through its antioxidant and insulin-potentiating activities. This study investigated the anti-glycative activity of LSOPC in a bovine serum albumin (BSA)-glucose model. The level of glycation and conformational alterations were assessed by specific fluorescence, Congo red binding assay and circular dichroism. The results show that LSOPC has a significant anti-glycative activity in vitro and it can also effectively protect the secondary structure of BSA during glycation. LSOPC or catechin (a major constituent unit of LSOPC), were used to react with methylglyoxal. The structures of their carbonyl adducts were tentatively identified using HPLC-MS(2). Their capacity to scavenge methylglyoxal suggested carbonyl scavenging as a major mechanism of antiglycation. Therefore, LSOPC could be helpful to prevent AGEs-associated diseases, and with the potential to be used as functional food ingredients.

Increasing antioxidant activity of procyanidin extracts from the pericarp of Litchi chinensis processing waste by two probiotic bacteria bioconversions.

Litchi chinensis pericarp from litchi processing waste is an important plant source of A-type procyanidins, which were considered a natural dietary supplement because of their high biological activity in vivo. Litchi pericarp oligomeric procyanidins (LPOPCs) did not selectively modify the growth of Streptococcus thermophilus and Lactobacillus casei -01 at concentrations of 0.25 and 0.5 mg/mL, and it was demonstrated that the two strains could transform procyanidins during their log period of growth by two different pathways. S. thermophilus was able to metabolize procyanidin A2 to its isomer, and L. casei could decompose flavan-3-ols into 3,4-hydroxyphenylacetic acid, 4-hydroxyphenylpropionic acid, m-coumaric acid, and p-coumaric acid. The total antioxidant capability (T-AOC) of LPOPCs before and after microbial incubation was estimated, and the results suggested that probiotic bacteria bioconversion is a feasible and efficient method to convert litchi pericarp procyanidins to a more effective antioxidant agent.