New acylated anthocyanins from purple yam and their antioxidant activity

Abstract

Purple yam (Dioscorea alata L.), which is widely distributed in tropical and subtropical regions, is characterized by its color and viscosity. Previous studies have shown that purple yams contain a variety of acylated anthocyanins that exhibit higher levels of antioxidant activity than the corresponding nonacylated compounds. In this study, the pigments found in purple yams from the Philippines (D. alata) were isolated and evaluated in terms of antioxidant activity. Four new acylated anthocyanins, alanins (1–4) were isolated from the MeOH extracts of purple yam, which were subsequently determined to be cyanidin (1, 2, and 4) and peonidin (3) type compounds, along with four known anthocyanins (5–8). The structures of 1–4 were determined by spectroscopic methods, including NMR and MS analyses. The antioxidant activities of anthocyanins 1–8 were investigated using oxygen radical absorbing capacity and ferric reducing antioxidant power assays.

Profiling Anthocyanins in Thai Purple Yams (Dioscorea alata L.)

“…Mass spectral characteristics of the extract indicated that peaks 1, 4, and 7 had the same precursor [M] + at 611 but different retention times. From their fragmentation patterns, they were most likely cyanidin glycoside isomers, which are commonly found in Dioscorea species [ 2 , 12 , 15 ].…”

“…Some yam species have attractive purplish colours, i.e., D. alata or ube yam from the Philippines, raja-ala from Sri Lanka [ 11 ], and D. trifida L. from South America [ 12 ]. Anthocyanins in D. alata are cyanidin–based such as cyanidin 3- O -gentiobioside; alatanin 1 [ 13 ]; alatanin 2 [ 13 ]; alatanins A, B, and C [ 14 ]; and alatanins D, E, F, and G [ 15 ]. The purple pigment in D. trifida L., however, was mainly peonidin glycoside [ 12 ].…”

Grown to be Blue—Antioxidant Properties and Health Effects of Colored Vegetables. Part I: Root Vegetables

“…The root color of purple yam (D. alata) is attributed to the high content of anthocyanins which exhibit significant antibacterial activities [212], anti-inflammatory effects on trinitrobenzenesulfonic acid (TNBS)-induced colitis in mice [213], antiglycative properties [214], and antidiabetic properties [215,216]. The main detected anthocyanins in this species were identified as cyanidin, pelargonidin, and peonidin-type compounds and alatanins A-C [43]; however, the individual compound profile and the overall anthocyanin content are affected by maturity stage and the expression of the concomitant genes [44]. Apart from D. alata, which is considered the main purple yam, there are also cultivars of D. trifida or cush-cush yam which contain peonidin, cyanidin, and pelargonidin aglycones [45].…”

“…Cyanidin, pelargonidin, and peonidin-type compounds; alatanins A-C Cyanidin 3-hexoside acylated with two hydroxycinnamic acids, cyanidin 3-glycoside acylated with one hydroxycinnamic acid, cyanidin 3-glycoside acylated with one hydroxycinnamic acid, peonidin 3-glycoside acylated with one hydroxycinnamic acid, alatanin-C [43][44][45][46] Yellow Carotenoids β-Carotene [47] Onion (Allium cepa L.) Bulb (swollen basis of leaves) Purple Flavonols and acylated and non-acylated cyanidin glucosides Dihydroflavonol taxifolin and its 3-, 7-, and 4 -glucosides [48,49] Radish (Raphanus sativus L.) Taproot (swollen root and hypocotyl)…”

ANTIOXIDANT, ANTIBACTERIAL POTENTIAL AND HPLC ANALYSIS OF Dioscorea alata BULB

“…cyanidin-3-rhamnoglucoside; (Lula et al, 2015) hydro-Q chromene; gamma-tocopherol-9; RRR-alpha-tocopherol; coenzyme Q; 1-feruloylglycerol; (Cheng et al, 2007) 4-Phenylbutan-2-one; (Gramshaw and Osinowo, 1982) alanins, cyaniding, peonidin (Moriya et al, 2015) in D alata. In Bangladesh traditionally it is used against leprosy and tumor.…”