title: Flavonoids from Agrimonia pilosa Ledeb: Free Radical Scavenging and DNA Oxidative Damage Protection Activities and Analysis of Bioactivity-Structure Relationship Based on Molecular and Electronic Structures.
abstract: To clarify the substantial basis of the excellent antioxidant capacity ofAgrimonia pilosaLedeb. Fourteen flavonoids were isolated and identified fromAgrimonia pilosaLedeb, seven of which have notable DPPH radical scavenging activities, i.e., catechin, luteolin, quercetin, quercitrin, hyperoside, rutin, luteolin-7-O-β-glucoside with IC50values of 5.06, 7.29, 4.36, 7.12, 6.34, 6.36 and 8.12 µM, respectively. The DNA nicking assay showed that five flavonoids fromAgrimonia pilosaLedeb-taxifolin, catechin, hyperoside, quercitrin and rutin-have good protective activity against DNA oxidative damage. Further, we analyzed the bioactivity-structure relationship of these 14 flavonoids by applying quantum theory. According to their O-H bond dissociation enthalpy (BDE), C ring's spin density and stable molecular structure, the relationship between their structures and radical scavenging capacities was evaluated and clarified. We found that among flavonoid aglycones fromAgrimonia pilosaLedeb, the O-H BDE of quercetin is lowest with the values of 69.02 and the O-H BDE of apigenin is highest with the values of 79.77. It is interesting that the O-H BDE value of isovitexin (78.55) with glycoside at C-6 position is lower than that of its aglycone (79.77) and vitexin (99.20) with glycoside at C-8 position. Further analysis indicated that the glycosidation of flavonoids at C-6 in the A-ring makes a more uniform distribution of spin density and improves the stability of free radicals leading to the increase in antioxidant capacity. Flavonoids with good antioxidant capacity might contribute to the pharmacological effects ofAgrimonia pilosaLedeb.
authors.affiliation: Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China. zhuliancai75@126.com.
authors.forename: Liancai
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China. JinqiuChen@126.com.
authors.forename: Jinqiu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological & Chemical engineering, Chongqing University of Education, Chongqing 400067, China. tanjunmail@126.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Tan
authors.affiliation: Chongqing Key Laboratory of Medicinal Resources in the Three Gorges Reservoir Region, School of Biological & Chemical engineering, Chongqing University of Education, Chongqing 400067, China. liuxi900626@126.com.
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China. wangbc2000@126.com.
authors.forename: Bochu
authors.initials: B
authors.lastname: Wang
mesh_terms: D031981:Agrimonia / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects*; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D011794:Quercetin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D012431:Rutin / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; C012526:quercitrin; D012431:Rutin; C021304:hyperoside; D002392:Catechin; D011794:Quercetin; C003377:taxifolin
keywords: Agrimonia pilosa Ledeb; DNA oxidative damage; bioactivity-structure relationship; flavonoids; free radical scavenging activity