Identification and quantification of anthocyanins in seeds of Kersting’s groundnut [Macrotyloma geocarpum (Harms) Marechal & Baudet] landraces of varying seed coat pigmentation

Abstract

The present study identified and quantified the anthocyanin pigments in seed of eight Kersting’s groundnut [Macrotyloma geocarpum (Harms) Marechal & Baudet] landraces of variable seed coat pigmentation. The analysis was carried out using ultra-performance liquid chromatography coupled with a photodiode array detector and mass spectrometry. Although the findings revealed similar anthocyanin profiles in seeds of the eight landraces tested, the relative concentrations of the individual anthocyanin compounds showed marked variations. Delphinidin-3-O-glucoside, cyanidin-3-O-glucoside and peonidin-3-O-glucoside were the most abundant anthocyanins, with concentrations ranging between 21.4–239.0, 23.6–130.6 and 21.4–135.4 µg/g of dry seed, respectively in seeds of the test landraces, while total anthocyanins ranged between 95 and 505 µg/g of dry seed. The preponderance of delphinidin 3-O-glucoside was observed in the black and brown mottled seeds. This study is the first report regarding the profile and concentrations of anthocyanins in Kersting’s groundnut and suggests that the seeds of this underutilized grain legume can potentially be exploited as a natural source of anthocyanins for the development of cosmetic, food and pharmaceutical products.