title: Phenolic composition and antioxidant activities of two Phlomis species: A correlation study.
abstract: Two traditional Chinese medicines (Phlomis umbrosa Turcz. and Phlomis megalantha Diels), as well as five pure phenolic compounds (protocatechic, chlorogenic, benzoic, rosmarinic acid, and rutin) have been studied for antioxidant activities in acetone and methanol extracts from leaves. An HPLC method was developed to quantify the amounts of 14 phenolic compounds in the leaf extracts. The antioxidant capacities of the studied species are high. Almost all samples were capable of directly scavenging DPPH and superoxide free radicals, inhibiting linoleic acid oxidation, acting as reducing agents, and reducing plasmid DNA damage induced by hydroxyl radicals. Among different extracts, the acetone extract of P. megalantha exhibited the highest antioxidant activity. The major phenolic compounds identified were protocatechic, chlorogenic, caffeic, rosmarinic acid, and (-)-epicatechin. Antioxidant activities of pure compounds and correlation analysis indicated that protocatechic and rosmarinic acids were the major contributors to the observed antioxidant activities of the investigated Phlomis extracts.
authors.affiliation: Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710062, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhe-zhi
authors.initials: ZZ
authors.lastname: Wang
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004249:DNA Damage; D005290:Ferric Compounds / Q000737:chemistry; D005419:Flavonoids / Q000032:analysis; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D019787:Linoleic Acid; D016877:Oxidants / Q000737:chemistry / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D031345:Phlomis / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D019163:Reducing Agents / Q000737:chemistry / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet; D013481:Superoxides / Q000378:metabolism; D019207:beta Carotene
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D005290:Ferric Compounds; D005419:Flavonoids; D016166:Free Radical Scavengers; D016877:Oxidants; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D019163:Reducing Agents; D019207:beta Carotene; D013481:Superoxides; D019787:Linoleic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl