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Farfugium japonicum (L.) Kitam. var. giganteum (Siebold et Zucc.) Kitam. is mainly distributed in the Kyushu and Shikoku Islands of Japan. The main aim of this study was to isolate and identify the chemical constituents of the 70% EtOH extract of the flowers of F. japonicum var. giganteum and to evaluate their tyrosinase inhibitory and free radical scavenging activities. Five phenolic compounds, namely petasiphenol (1), rosmarinic acid (2), 4,5-di-O-caffeoylquinic acid (3), 5-O-caffeoylquinic acid (4) and quercetin (5) were isolated and their structures were elucidated on the basis of NMR spectroscopic data. All these compounds were isolated for the first time from title plant. Among them, petasiphenol (1) showed potent tyrosinase inhibitory activity followed by quercetin (5) and 4,5-di-O-caffeoylquinic acid (3). All of these compounds showed potent free radical scavenging activity.

Seven flavonoids such as luteolin (1), luteolin 7-O-β-glucopyranoside (2), luteolin 3'-O-β-glucopyranoside (3), chryseriol (4), apigenin (5), apigenin 7-O-β-glucopyranoside (6) and astragalin (7) and one coumarin, scopoletin (8) were isolated from the aerial parts of Impatiens hypophylla Makino var. hypophylla (Family: Balsaminaceae). Structures of these compounds were elucidated on the basis of spectroscopic methods. All these compounds were isolated for the first time from I. hypophylla var. hypophylla.

Background : The leaves and twigs of Lindera sericea (Seibold et Zucc.) Blume var. sericea (Lauraceae) are used as traditional medicines for treating indigestion, stomachache, anxiety, etc. In recent years, there has been a growing interest in these plant materials as a source of healthy drinks and functional foods. The main aim of this study was to characterize the major phenolic compounds from the leaves and twigs and to evaluate their free radical scavenging and α -glucosidase inhibitory activities. Methods : The dried leaves and twigs were extracted with 70% methanol. The dried extract was then subjected to repeated column chromatography to isolate eight flavonoids. The compounds were then evaluated for their 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and α -glucosidase inhibitory activity. Results : The isolated compounds were identified as (-)-epicatechin ( 1 ), taxifolin 3- O -glucoside ( 2 ), quercetin ( 3 ), quercitrin ( 4 ), quercetin 3- O -neohesperidoside ( 5 ), pinocembrin ( 6 ), pinostrobin ( 7 ) and pinostrobin chalcone ( 8 ) based on their nuclear magnetic resonance (NMR), spectroscopic data and comparison with literature values. All these compounds were isolated for the first time from this plant. All flavonoids except pinocembrin ( 6 ), pinostrobin ( 7 ) and pinostrobin chalcone ( 8 ) showed potent free radical scavenging activity. In α -glucosidase inhibitory activity assay, quercetin ( 4 ), quercitrin ( 5 ) and taxifolin 3- O -glucoside ( 2 ) showed potent activity. Conclusions: Eight flavonoids were reported for the first time from the leaves and twigs of the title plant. Some of these compounds showed potent free radical scavenging and α -glucosidase inhibitory activities. Keywords: Lindera sericea var. sericea ; Lauraceae; Kekuromoji; free radical; α-glucosidase