title: Antioxidants and α-glucosidase inhibitors from Ipomoea batatas leaves identified by bioassay-guided approach and structure-activity relationships.
abstract: Sweet potato (Ipomoea batatas) leaf (SPL) is an underused commercial vegetable with considerable bio-activities. By means of DPPH scavenging ability and α-glucosidase inhibitory oriented isolation, 9 and 7 compounds were isolated and identified, respectively. Among them, trans-N-(p-coumaroyl)tyramine (1), trans-N-feruloyltyramine (2), cis-N-feruloyltyramine (3), 4,5-feruloylcourmaoylquinic acid (8), caffeic acid ethyl ester (10), 7-hydroxy-5-methoxycoumarin (11), 7,3'-dimethylquercetin (13) and indole-3-carboxaldehyde (15), were firstly identified from SPL, and four of them (1, 2, 3 and 10) were firstly identified from genus Ipomoea. Phenethyl cinnamides and 3,4,5-triCQA exhibited the strongest α-glucosidase inhibition, while 3,4,5-triCQA and diCQAs were the dominant antioxidants. Structure-activity relationship revealed that higher caffeoylation of quinic acid and lower methoxylation of flavonols resulted in stronger antioxidant activity, and methylation and cis-configuration structure of phenethyl cinnamides weaken the α-glucosidase inhibition. Aforementioned results could help to explain the antioxidant activity and anti-diabetic activity of SPL, and provide theoretical basis for its further application.
authors.affiliation: Key Laboratory of Functional Small Organic Molecule, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, Jiangxi 330022, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Functional Small Organic Molecule, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, Jiangxi 330022, China; State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China. Electronic address: tuzc_mail@aliyun.com.
authors.forename: Zong-Cai
authors.initials: ZC
authors.lastname: Tu
authors.affiliation: Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China.
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Fu
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001681:Biological Assay; D002109:Caffeic Acids / Q000032:analysis; D003373:Coumaric Acids / Q000032:analysis; D044948:Flavonols / Q000032:analysis; D065089:Glycoside Hydrolase Inhibitors / Q000032:analysis*; D007211:Indoles / Q000032:analysis; D027723:Ipomoea batatas / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D011801:Quinic Acid / Q000032:analysis; D013329:Structure-Activity Relationship; D014439:Tyramine / Q000031:analogs & derivatives / Q000032:analysis; D000520:alpha-Glucosidases / Q000032:analysis
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D003373:Coumaric Acids; D044948:Flavonols; D065089:Glycoside Hydrolase Inhibitors; D007211:Indoles; C001411:N-(4-hydroxy-beta-phenethyl)-4-hydroxycinnamide; D011801:Quinic Acid; C074004:feruloyltyramine; C032773:ethyl caffeate; C012381:indole-3-carbaldehyde; D000520:alpha-Glucosidases; D014439:Tyramine
keywords: Antioxidant activity; Identification; Ipomoea batatas leaves; α-Glucosidase