Anthocyanin contents in the seed coat of black soya bean and their anti-human tyrosinase activity and antioxidative activity

Objective The seed coat of black soya bean (SCBS) contains high amount of anthocyanins and shows antioxidant and anti‐mushroom tyrosinase activities. The objectives of this study were to analyse the anthocyanins in SCBS with different solvents and to find the relationship between anthocyanin profile with anti‐human and anti‐mushroom tyrosinase activities. Methods SCBS was extracted with hot water, 50 and 80% ethanol, 50 and 80% acetone and 50 and 80% acidified acetone. Total phenol and total flavonoid contents in the extracts were determined. Anthocyanins in the extracts were analysed using HPLC and LC/MS/MS. A genetically engineered human tyrosinase was used to evaluate the anti‐tyrosinase potential of the extracts from SCBS. Results 80% acetone extract from SCBS obtained the highest total phenol, total flavonoid and cyanidin‐3‐O‐glucoside (C3G) contents among all the extracts, whereas the hot water extract showed the lowest antioxidant contents. Three anthocyanin compounds were found in all the extracts from SCBS, and the analysis of HPLC and LC/MS/MS indicated that they were C3G, delphinidin‐3‐O‐glucoside (D3G) and peonidin‐3‐O‐glucoside (P3G). The ratios of C3G (2.84 mg g−1), D3G (0.34 mg g−1) and P3G (0.35 mg g−1) in 80% acidified acetone extract were 76.6, 9.1 and 9.3%, respectively. All the extracts from SCBS possessed anti‐human tyrosinase activity. Moreover, a good correlation was found between the anti‐human tyrosinase activities and C3G contents in the extracts. Conclusion Antioxidants in SCBS also possess anti‐human and anti‐mushroom tyrosinase activities. Résumé Objectif L'enveloppe de la graine du soja noir (SCBS) contient une quantité élevée des anthocyanes et possèdent des activités antioxydantes et anti‐tyrosinase de champignon. Les objectifs de cette étude étaient d'analyser les anthocyanes dans SCBS avec différents solvants et de trouver la relation entre le profil des anthocyanes avec les activités anti‐tyrosinase humaine et champignon. Méthodes SCBS a été extrait à l'eau chaude, à l'éthanol à 50 et 80%, à l'acétone 50 et 80% et à l' d'acétone acidifiée à 50 and 80%. Les phénols et le total des flavonoïdes contenus dans les extraits ont été déterminés. Les Anthocyanins dans les extraits ont été analysées par HPLC et LC / MS / MS. La tyrosinase humaine obtenue par génie génétique a été utilisée pour évaluer le potentiel anti‐tyrosinase des extraits de SCBS. Resultats L'extrait à l'acétone 80% à partir du SCBS a montré la plus haute teneu