Gamma irradiation improves the extractability of phenolic compounds in Ginkgo biloba L

Eliana Pereira, Lillian Barros, Montserrat Dueñas, Amilcar L. Antonio, Celestino Santos-Buelga, Isabel C.F.R. Ferreira

Centro de Investigação de Montanha (CIMO), ESA, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 1172, 5301-855 Bragança, Portugal.

Abstract

Irradiation has been increasingly recognized as an effective decontamination technique that ensures the chemical and organoleptic quality of medicinal and aromatic plants. The aim of the present study was to evaluate the effects of gamma irradiation in the phenolic compounds of Ginkgo biloba L. (infusion and methanol/water extract), widely used in traditional medicine and in dietary supplements. Twenty-five compounds were detected, eighteen of which were flavonoids, one phenolic acid, five terpene lactones and one unknown compound. Among the quantified phenolic compounds, flavonoids were the main group present, being two kaempferol derivatives the major compounds found: kaempferol-3-O-dirhamnosylglucoside and kaempferol-3-O-rutinoside. The irradiation with the highest dose (10 kGy) is sufficient to guarantee the product disinfestation and microbial decontamination, also contributing to an increase in the extractability of phenolic compounds, both in methanol/water and infusion preparations.

Keywords: Ginkgo biloba; Phenolic compounds; Gamma irradiation.