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  3. Antioxidant activity of different species and varieties of turmeric (Curcuma spp): Isolation of active compounds

Antioxidant activity of different species and varieties of turmeric (Curcuma spp): Isolation of active compounds

  • Comp Biochem Physiol C Toxicol Pharmacol. 2019 Jan;215:9-17. doi: 10.1016/j.cbpc.2018.09.002.
Jesmin Akter 1,  Md Amzad Hossain 2,  Kensaku Takara 3,  Md Zahorul Islam 4,  De-Xing Hou 5
Affiliations

Affiliations

  • 1 The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Faculty of Agriculture, University of the Ryukyus, Okinawa 903-0213, Japan.
  • 2 The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Faculty of Agriculture, University of the Ryukyus, Okinawa 903-0213, Japan. Electronic address: [email protected].
  • 3 The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Faculty of Agriculture, University of the Ryukyus, Okinawa 903-0213, Japan. Electronic address: [email protected].
  • 4 Faculty of Agriculture, University of the Ryukyus, Okinawa 903-0213, Japan; Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
  • 5 The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
PMID: 30266519 DOI: 10.1016/j.cbpc.2018.09.002
Abstract

There are >80 species of turmeric (Curcuma spp.) and some species have multiple varieties, for example, Curcuma longa (C. longa) has 70 varieties. They could be different in their chemical properties and biological activities. Therefore, we compared antioxidant activity, total phenolic and flavonoid content of different species and varieties of turmeric namely C. longa [variety: Ryudai gold (RD) and Okinawa ukon], C. xanthorrhiza, C. aromatica, C. amada, and C. zedoaria. The antioxidant activity was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, oxygen radical absorbance capacity (ORAC), reducing power and 2-deoxyribose (2-DR) oxidation assay. Our results suggested that RD contained significantly higher concentrations of total phenolic (157.4 mg gallic acid equivalent/g extract) and Flavonoids (1089.5 mg rutin equivalent/g extract). RD also showed significantly higher DPPH radical-scavenging activity (IC50: 26.4 μg/mL), ORAC (14,090 μmol Trolox equivalent/g extract), reducing power absorbance (0.33) and hydroxyl radical scavenging activity (IC50: 7.4 μg/mL). Therefore, RD was chosen for the isolation of antioxidant compounds using silica gel column, Toyopearl HW-40F column, and high-performance liquid chromatography. Structural identification of the compounds was conducted using 1H NMR, 13C NMR, and liquid chromatography-tandem mass spectrometry. The purified antioxidant compounds were bisabolone-9-one (1), 4-methyllene-5-hydroxybisabola-2,10-diene-9-one (2), turmeronol B (3), 5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-1-hepten-3-one (4), 3-hydroxy-1,7-bis(4-hydroxyphenyl)-6-hepten-1,5-dione (5), cyclobisdemethoxycurcumin (6), bisdemethoxycurcumin (7), demethoxycurcumin (8) and curcumin (9). The IC50 for DPPH radical-scavenging activity were 474, 621, 234, 29, 39, 257, 198, 47 and 18 μM and hydroxyl radical-scavenging activity were 25.1, 24.4, 20.2, 2.1, 5.1, 17.2, 7.2, 3.3 and 1.5 μM for compound 1, 2, 3, 4, 5, 6, 7, 8 and 9, respectively. Our findings suggested that the RD variety of C. longa, developed by the University of the Ryukyus, Okinawa, Japan, is a promising source of natural antioxidants.

Keywords

Active compound; Antioxidant; Flavonoid; Phenolic; Ryudai gold; Turmeric.

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