Antioxidant and antigenotoxic activities of post-digestion Ginkgo biloba extract

Abstract

Ginkgo biloba has been used in Chinese traditional medicine for many years and its beneficial effects have been widely spread, making it one of the most sold medicinal plants. Accordingly, many studies have been devoted to this plant, showing its strong antioxidant activity, which is the basis for many of the claimed beneficial effects. In some western countries, G. biloba is prescribed by doctors for memory improvement and against dementia in elderly people.

Due to the strong antioxidant activity, it is likely that G. biloba extract is able to protect cells from oxidative damage, including DNA damage, and therefore can act as a tumor preventive agent. By contributing to genomic stability of cells when taken orally, G. biloba extract might help to prevent one of the most prevalent cancers in western countries: colorectal cancer. Hence, G. biloba extract is a good candidate as functional ingredient of foods as it has the potential to increase shelf life and also contribute to a healthy colon.

In this work, an ethanolic leaf extract of G. biloba (GBE) was prepared and subjected to in vitro simulated digestion to obtain a post-digestion sample (DGBE) to study. Chemical analysis of both samples showed that the digestion process affects the chemical composition, mainly by hydrolysis of flavonoid glycosides. In vitro analysis of antioxidant activity revealed that the in vitro digestion decreased the DPPH scavenging activity and increased the NO scavenging activity and iron chelating activity of the extract, and also its total phenolic content estimated by Folin-Ciocalteu method. With human colorectal adenocarcinoma cell line (HT-29), GBE and DGBE were not cytotoxic and displayed antigenotoxicity upon oxidative stress. All these results indicate that although chemical modification occur during the digestive process, the beneficial properties are retained. Therefore, G. biloba extract has potential for application as functional food ingredient.