Inhibitory Effects of Extracts from Plant Materials on In Vitro Glycation and Oxidation

Abstract

Extracts from Aloe vera leaves, Aloe arborescens leaves, Aloe vera callus, Portulaca oleracea and cacao (Theobroma cacao L.) bean husk (CBH) were prepared using acetone, chloroform, ethanol, hexane, and water. Solvent extracts of Aloe vera leaf had very high antioxidant activities showing IC 50 values in the ranges of 0.02-0.17 mg/ mL, and had the highest total phenolic and flavonoid content among the tested samples. We hypothesized that Aloe vera leaf and CBH extracts might possess considerable in vitro anti-glycation activities. Indeed, these extracts strongly inhibited the formation of advanced glycation end-products from RNase in the presence of ribose. The chloroform extract of Aloe vera leaf showed the strongest inhibition of AGE formation (99.9%), followed by the 95% acetone extract (92.8%) at a concentration of 1 mg/mL, exhibiting higher anti-glycation activities than those of AG and rutin (73.4% and 96.1% at 1 mg/mL, respectively). The anti-glycation activity of all extracts was correlated positively with their total contents of phenolics and flavonoids. We conclude that Aloe vera leaf extracts and their constituents may be used as anti-glycation agents.