title: Structure and antioxidant activity relationships of isoflavonoids from Dalbergia parviflora.
abstract: The antioxidant activities of 24 isoflavonoids that were previously isolated as pure compounds from Dalbergia parviflora were evaluated using three different in vitro antioxidant-based assay systems: xanthine/xanthine oxidase (X/XO), ORAC, and DPPH. The isolates consisted of three subgroups, namely isoflavones, isoflavanones, and isoflavans, each of which appeared to have diversified substituents, and were thus ideal for the study of their structure-activity relationships (SARs). The SAR analysis was performed using the results obtained from both the inter-subgroup isoflavonoids with the same substitution pattern and the intra-subgroup compounds with different substitution patterns. The inter-subgroup comparison showed that the isoflavones exhibited the highest antioxidant activities based on all three assays. The intra-subgroup analysis showed that the additional presence of an OH group in Ring B at either R3' or R5' from the basic common structure of the R7-OH of Ring A and the R4'-OH (or -OMe) of Ring B greatly increased the antioxidant activities of all of the isoflavonoid subgroups and that other positions of OH and OMe substitutions exerted different effects on the activities depending on the subgroup and assay type. Therefore, based on the structural diversity of the isoflavonoids in D. parviflora, the present study provides the first clarification of the detailed antioxidant SARs of isoflavonoids.
authors.affiliation: Division of General Science, Faculty of Education, Buriram Rajabhat University, Buriram 31000, Thailand. p_worrawat@yahoo.com.
authors.forename: Worrawat
authors.initials: W
authors.lastname: Promden
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. oramon_o@yahoo.com.
authors.forename: Orawan
authors.initials: O
authors.lastname: Monthakantirat
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan. umehara@mail.u-shizuoka-ken.ac.jp.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Umehara
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan. noguchi@u-shizuoka-ken.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Noguchi
authors.affiliation: Department of Pharmacognosy and Botany, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand. wanchai.d@chula.ac.th.
authors.forename: Wanchai
authors.initials: W
authors.lastname: De-Eknamkul
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D035782:Dalbergia / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry; D007529:Isoflavones / Q000737:chemistry* / Q000302:isolation & purification; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry; D013329:Structure-Activity Relationship; D014969:Xanthine Oxidase / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D007529:Isoflavones; D010936:Plant Extracts; D014969:Xanthine Oxidase