Studies On Perilla Seed Oil Fatty Acids, Ethanol Extract Components And Antioxidant Activities

The monotypic genus Perilla is an annual herbaceous plant belonging to the family Labiatae. It is also a traditional food and medicinal plant distributed widely in China. Perilla seeds, as the ripe fruits of the plant, were systematically investigated in this article with24Perilla seed samples in13provenances of five Perilla varieties. The research were included Perilla seed oil composition and content, the ethanol extract of composition and total polyphenols and flavonoids content, purification of cold-pressed Perilla seed flour and contents of compound in seed, the antioxidant activity of ethanlol extract and monomer compounds. Main results are as follows:(1)Fourteen fatty acids were found and divided into two groups of high (≥0.8%, six kinds) and eight low (≤0.3%, eight kinds) contents of fatty acids, with14-methyl-hexadecanoic acid (C17:0),18carbon diene acid (C18:2, n3) and23carbon acid (C23:0) being reported for the first time in Perilla oil. The relative content of a-linolenic acid was the highest. Certain metabolic conversion relationship was speculated between a-linolenic acid, linoleic acid and oleic acid. The results of fatty acid content in Perilla seeds by external standard method showed that the P. var. frutescens and P. var. auriculato-dentata were screened as high-quality breeding materials of higher oil and a-linolenic acid contents.(2) A significant difference was checked in ethanol extract of Perilla seed in different provenances and variants. And a high similarity was analysised among P. var. arguta, P. var. crispa, and P. var. acuta in intraspecific and interspecific. The most quantity of similar germplasm was found in P. var. arguta and P. var. crispa. The content of total polyphenols and flavonoid was highest in P. var. crispa and second highest in P. var. arguta.(3) A total of13monomer compounds were isolated from cold-pressed Perilla seed flour using column chromatography, and the chemical structures were identified as apigenin, luteolin. vanillic acid, rosmarinic acid, rosmarinic acid methyl ester, caffeic acid, cimidahurinine, caffeic acid-3-O-glucoside, luteolin-5-O-glucoside, sucrose, tryptophan, rosmarinic acid-3-O-glucoside, and3’-dehydroxyl-rosmarinic acid-3-O-glucoside using NMR and time-of-flight mass spectrometry. Among these components,3’-dehydroxyl-rosmarinic acid-3-O-glucoside is novel, and this is the first report of vanillic acid and cimidahurinine. And HPLC quantification revealed that apigenin, luteolin and rosmarinic acid were the main ingredient in Perilla seed.(4) The content of rosmarinic acid-3-O-glucoside, caffeic acid were the highest in P. var. frutescens. Rosmarinic acid methyl ester was the highest in P. var. arguta.3’-dehydroxyl-rosmarinic acid-3-O-glucoside and caffeic acid-3-O-glucoside were the highest in P. var. auriculato-dentata. Apigenin, luteolin, and luteolin-5-O-glucoside were the highest in P. var. crispa. Cimidahurinine, vanillic acid, and tryptophan were the highest in P. var. acuta. The average content of compounds from high to low was P. var. crispa, P. var.arguta, P. var.frutescens, P. var.acuta, and P. var.auriculato-dentata. As a new monomer compound3’-dehydroxyl-rosmarinic acid-3-O-glucoside was not detected in P. var. arguta, P. var.crispa, and P. var.acuta.(5) The removing ABTS, DPPH free radicals and reducing power study in ethanol extract showed a high antioxidant of P. var. crispa and P. var. arguta. The antioxidant research of monomer compounds showed stronger activities with rosmarinic acid, rosmarinic acid methyl ester, rosmarinic acid-3-O-glucoside, uteolin, luteolin-5-O-glucoside and caffeic acid.