Identification of anthocyanins in Chinese purple yam (Dioscorea alata L.) by high performance liquid chromatography - ion trap time of flight tandem mass spectrometry (LCMS-IT-TOF)

Chinese purple yam (Dioscorea alata) is a kind of yam which is cultivated in different regions of China. It contains high amount of vitamins, minerals, amino acids, and functional components such as mucin, anthocyanins and catechins. Traditionally, yams have been used as Chinese herbal medicines to prevent the diseases of diarrhoea, diabetes and also possess antioxidant and antimutagenic activities. The aim of this study was to identify the major phenolic compounds in Chinese purple yam. From fresh yam, 25 g of sample was blended and extracted with 250 mL 0.01% HCl in methanol (v/v) and stored at 5°C. The analyses were performed on a Shimadzu LCMS-IT-TOF instrument. Six kinds of anthocyanins were tentatively identified, namely cyanidin3-gentiobio-side, alatanin C, cyanidin 3-ferulyl gentiobioside, cyanidin3-sinapylgentianoside, peonidin 3-gentiobioside and alatanin 2. The dominant anthocyanin in Chinese purple yam is alatanin C which accounts for about 46.3% of the total anthocyanins.