Neurite Outgrowth-Promoting Active Constituents of the Japanese Cypress (Chamaecyparis obtusa)

Abstract

There are many severe social problems associated with aging and reduced brain function worldwide and especially in Japan due to lengthning of the average life span. There is currently no definitive treatment for such diseases. In the course of our biological test-guided screening of Japanese woody plant extracts, we condacted several tests of biological activity on isolated biologically active constituents from woody plants. We reported the isolation of antibacterial constituents, 1,2) antioxidative constituents, 3) and antitumor-promoting constituents 4) from woody plants. Neuronal PC12 cell 5) neurite outgrowth testing of methanol extracts of woody plants collected in the northern part of Hiroshima prefecture identified the methanol extract of leaves of the Japanese cypress (Chamaecyparis obtusa) as an active sample. Japanese cypress is a popular architectural wood in Japan and is cultivated all nationwide. We isolated neurite outgrowth-promoting active constituents from the leaves of the plant using biological tests to give two new compounds along with known lignan derivatives. The structures of the new compounds were determined using chemical and spectral methods including two-dimensional NMR spectrum. Some of these compounds showed potent neurite outgrowth activity. This report describes the isolation of the constituents of C. obtusa and determination of their structures. We also report their neurite outgrowth-promoting activity. Results and DiscussionThe methanol extract of the leaves of C. obtusa was fractionated to an ethyl acetate layer (AcOEt lay.), an n-butanol layer (n-BuOH lay.) and, aqueous lay. Of these, the AcOEt lay. showed the most potent neurite outgrowth-promoting activity in PC12 cells in the presence of an inactive amount of NGF, so the fraction was successively separated by means of silica gel column chromatography (SiO 2 c.c.), preparative thin layer chromatography (PLC), and HPLC using a reversephase column to give two new compounds 1 and 2 along with eleven known compounds 3-13. Structures of the known compounds were determined by means of (4) (d C 147.8, 147.7, 146.9, 145.9, 136.4, 133.6, 121.4, 119.1, 108.8, 108.2, 108.0, 106.1), three carbinyl carbons (d C 83.0, 72.6, 62.5), three alkane carbons (d C 49.1, 42.3, 33.1), and methylenedioxy groups (d C 100.9). These data show that 1 is lignan monoacetate. The HMBC spectrum shown in Fig. 2 indicates that the structure of 1 is 9-acetoxy-3,4:3Ј,4Ј-bismethylenedioxy-7,9Ј-epoxylignan. Thus 1 should be an acetate of dihydrosesamin (6). Compound 1 ([a] D ϩ20.2°) was identified as an acetate of 6 in all respects including optical rotation ([a] D ϩ17.2°). These findings indicated that the configuration of 1 is identical to that Life and Environmental Sciences, Prefectural University of Hiroshima; 562 Nanatsuka, Shobara, Hiroshima 727-0023, Japan: b School of Traditional Chinese Medicines, Shenyang Pharaceutical University; 103 Wenhua Road, Shenyang 110016, P. R. China: c Hiroshima Prefectural Forestry Research Center; 168-1 Tokaichi, Miy...

Novel Lanostane and Rearranged Lanostane-Type Triterpenoids from Abies sachalinensis-II-

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Beyerane Derivatives and a Sesquiterpene Dimer from Japanese Cypress (Chamaecyparis obtusa)

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Acyl flavonoids, biflavones, and flavonoids from Cephalotaxus harringtonia var. nana

“…Two antitumor compounds, paclitaxel and camptothecin, which are derived from woody plants, have been used clinically. In the course of our research isolating biologically active compounds from woody plants in Japan, we have reported several antioxidative compounds from Alnus japonica [1], antitumor-promoting active compounds from Chaenomeles sinensis [2], and active neurite outgrowth promoting compounds from Chamaecyparis obtuse [3]. One hundred methanol (MeOH) extracts of woody plants collected in the Hiroshima area were tested for antitumor activity, and some samples were selected for a study on the isolation of antitumor constituents.…”