New acylated anthocyanins from purple yam and their antioxidant activity

• Published in: Bioscience, biotechnology, and biochemistry Vol. 79; no. 9; pp. 1484 - 1492
• Main Authors: Moriya, Chiemi, Hosoya, Takahiro, Agawa, Sayuri, Sugiyama, Yasumasa, Kozone, Ikuko, Shin-ya, Kazuo, Terahara, Norihiko, Kumazawa, Shigenori
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 02.09.2015; Oxford University Press
• Subjects: Acylation; anthocyanin; Anthocyanins - chemistry; Anthocyanins - isolation & purification; Anthocyanins - pharmacology; antioxidant activity; Antioxidants - chemistry; Antioxidants - isolation & purification; Antioxidants - pharmacology; Dioscorea - chemistry; Dioscorea alata; Magnetic Resonance Spectroscopy; Plant Roots - chemistry; purple yam; the Philippines; the Philippines; purple yam; anthocyanin; antioxidant activity; Dioscorea alata
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1080/09168451.2015.1027652

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. alatanins D-G, acylated anthocyanins, were newly isolated from purple yam from the Philippines. These structures were determined and the antioxidant activities were evaluated.