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.
The authors are grateful to project Proder nº 53514 AROMAP for financial support and for E. Pereira grant, also to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for CIMO strategic project (PEst-OE/AGR/UI0690/2014). L. Barros thanks “Compromisso para a Ciência 2008” for her contract. The authors are also grateful to Mrs. Clarinda Paixão, from “Américo Duarte Paixão Lda”, for samples providing.
