title: Protein glycation inhibitory activity and antioxidant capacity of clove extract.
abstract: Syzygium aromaticum (L.) (clove) is one of the most widely cultivated spices in many tropical countries. The aim of this study was to determine the phytochemical content, the antioxidant properties and the antiglycation properties of aqueous extract of clove against fructose-mediated protein glycation and oxidation. The result showed that the content of total phenolics and flavonoids in clove extract was 239.58 ± 0.70 mg gallic acid equivalents/g dried extract and 65.67 ± 0.01 mg catechin equivalents/g dried extract, respectively. In addition, clove exhibited antioxidant properties including DPPH radical scavenging activity (IC50 = 0.29 ± 0.01 mg/ml), Trolox equivalent antioxidant capacity (4.69 ± 0.03 μmol Trolox equivalents/mg dried extract), ferric reducing antioxidant power (20.55 ± 0.11 μmol ascorbic acid equivalents/mg dried extract), Oxygen radical absorbance capacity (31.12 ± 0.21 μmol Trolox equivalents/mg dried extract), hydroxyl radical scavenging activity (0.15 ± 0.04 mg Trolox equivalents/mg dried extract), and superoxide radical scavenging activity (18.82 ± 0.50 mg Trolox equivalents/mg dried extract). The aqueous extract of clove (0.25-1.00 mg/ml) significantly inhibited the formation of fluorescent advanced glycation end products (AGEs) and non-fluorescent AGEs (N(ɛ)-(carboxymethyl) lysine (CML)) in glycated BSA during 4 weeks of incubation. The extract also markedly prevented oxidation-induced protein damage by decreasing protein carbonyl formation and protecting against the loss of protein thiol group. These results clearly demonstrated that a polyphenol enriched clove extract, owing to its antioxidant, was capable to inhibit the formation of AGEs and protein glycation. The findings might lead to the possibility of using the clove extract for targeting diabetic complications.
authors.affiliation: Program in Biomedical Sciences, Graduate School, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Tanyawan
authors.initials: T
authors.lastname: Suantawee
authors.affiliation: Program in Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Krittaporn
authors.initials: K
authors.lastname: Wesarachanon
authors.affiliation: Program in Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Kanokphat
authors.initials: K
authors.lastname: Anantsuphasak
authors.affiliation: Program in Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Tanuch
authors.initials: T
authors.lastname: Daenphetploy
authors.affiliation: Program in Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Sroshin
authors.initials: S
authors.lastname: Thien-Ngern
authors.affiliation: Program in Biomedical Sciences, Graduate School, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Thavaree
authors.initials: T
authors.lastname: Thilavech
authors.affiliation: Food and Nutrition Program, Department of Home Economics, Faculty of Agriculture, Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Porntip
authors.initials: P
authors.lastname: Pasukamonset
authors.affiliation: Research Group of Herbal Medicine for Prevention and Therapeutic of Metabolic diseases, Department of Nutrition and Dietetics, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Sathaporn
authors.initials: S
authors.lastname: Ngamukote
authors.affiliation: Research Group of Herbal Medicine for Prevention and Therapeutic of Metabolic diseases, Department of Nutrition and Dietetics, Chulalongkorn University, Bangkok, 10330 Thailand.
authors.forename: Sirichai
authors.initials: S
authors.lastname: Adisakwattana
keywords: Advanced glycation end-products; Antiglycation; Antioxidant; Clove; Syzygium aromaticum (L.)