Toward Use of the Leaves of Perilla frutescens (L.) Britton var. Acuta Kudo (red perilla) with Japanese Dietary Pickled Plum (Umeboshi)

Abstract

Six phenolic compounds and one steroid were isolated from the leaves of Perilla frutescens Britton var. acuta (red perilla) with Japanese dietary pickled plum (Ume). These compounds were identified based on UV, MS, 1H-NMR and 13C-NMR spectroscopic data as β-sitosterol [1], shisonin [2], kaempferol 3-O-rutinoside [3], rosmarinic acid [4], rosmarinic acid methyl ester [5], 4-glucopyranosylcinnamic acid [6], and caffeic acid methyl ester [7]. In the bioassay, remarkable superoxide scavenging activity was found in the 1-butanol extract, and 20% methanol-water eluate, 50% methanol-water eluate and methanol eluate of an Amberlite XAD-2. In addition, remarkable superoxide scavenging activity was found in rosmarinic acid and rosmarinic acid methyl ester which are those isolation compounds. Moreover, we synthesized caffeic acid derivatives which were metabolic product of citrusin C and rosmarinic acid, and pharmacological effects such as superoxide scavenging activity used metabolite (vanillic acid, 4-hydroxy cinnamic acid, ferulic acid and isoferulic acid) of the chlorogenic acid as a starting material, and synthesized glycoside. And we examined their superoxide scavenging activity and tyrosinase inhibitory activity (Step1 as L-Tyrosine substrate; Step 2 as L-DOPA substrate), and their synthesized compounds investigated for cosmetic use. As a result, for tyrosinase inhibitory activity, isoferulic acid (3,4-CA) and their methyl ester (3,4-CAM), good inhibition of 67.5 and 93.9% of Step 1 and 65.1 and 53.8% of Step 2 were noted. These compounds inhibited tyrosinase activity more than arbutin (63.0% of Step 1 and 7.7% of Step 2). For superoxide scavenging activity, ferulic acid (4,3-CA) and their methyl ester (4,3-CAM), and 4-hydroxy cinnamic acid (4-CA) were good activity of 43.6, 57.9 and 55.2%, respectively. Melanin inhibition and cytotoxicity were examined by using cultured B16 melanoma cells. More than 40% suppression was observed in 3-β-glucopyranosyl isoferulic acid methyl ester (3,4-CAGlc) and 4-hydroxy cinnamic acid methyl ester (4-CAM).