Mallotus philippinensis MUELL. ARG. (Euphorbiaceae) iswidely distributed in the forestes of Kelara. The Granular hairs on the surface of fruits is called Kamala. It has been used as a drug and dye. Earlier investigations on Kamala dye have afforded various flavonoides.2-5) Kamala powder is used as an anthelmintic and cathartic in traditional medicine. 6) Macrophages play an important role in non-specific host defense mechanisms. 7) In macrophages, bacterial LPS alone or in combination with cytokines like interferon-g (IFN-g) is one of the best-characterized stimuli to induce the transcription of genes encoding pro-inflammatory proteins, resulting in cytokine release and synthesis of enzymes such as cyclooxygenase-2 (COX-2) 8) and inducible nitric oxide synthase (iNOS). 9) NO is a short-lived bioactive molecule that participate in the physiology and pathophysiology of many systems.10) NO is synthesized in vivo from L-arginine by NOS with NADPH and oxygen as cosubstrates.11) Large amounts of NO may lead to tissue damage. In inflammatory disease such as rheumatoid arthritis, excessive NO production by activated macrophages has been observed. Therefore, it would be valuable to develop potent and selective inhibitors of NO for potential therapeutic use.Previously, we reported that mallotophilippens A and B, phloroglucinol derivatives from M. philippinensis, suppressed the NO production and iNOS gene expression. 3)In this work, we isolated three novel chalcone derivatives, 1, 2 and 3 ( Fig. 1), from the hexane-soluble fraction and investigated the inhibitory effects of those compounds on NO generation from activated macrophages. Results and DiscussionCompound 1 (Table 1), indicated a 2,2-dimethylpyran system.The arrangement of the substituents and the placement of the pyran at the 4aЈ/8aЈ positions were established from the results of the heteronuclear multiple bond connectivity (HMBC) experiments (Fig. 2). The chelated hydroxyl group in ring B showed the expected Kumage-gun, Kagoshima 891-3604, Japan. Received June 6, 2004; accepted August 27, 2004 Three novel chalcone derivatives, mallotophilippens C (1), D (2) and E (3) were isolated from the fruits of Mallotus philippinensis MUELL. ARG. These compounds were identified, using chemical and spectral data, as 1-[6-(3,7-dimethyl-octa-2,6-dienyl)-5,7-dihydroxy-2,2-dimethyl-2H-chromen-8-yl]-3-(4-hydroxy-phenyl)-propenone, 3- (3,4-dihydroxy-phenyl)-1-[6-(3,7-dimethyl-octa-2,6-dienyl)

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In screening experiments for rat intestinal -glucosidase (sucrase and maltase) inhibitors in 325 plants cultivated in Japan's southern island, of Tanegashima, marked inhibition against both sucrase and maltase was found in the extract of the fruit of Solanum torvum. Enzyme-assay guided fractionation of the extract led to the isolation of methyl caffeate (1) as a rat intestinal sucrase and maltase inhibitor. We examined 13 caffeoyl derivatives for sucrase-and maltase-inhibitory activities. The results showed that methyl caffeate (1) had a most favorable structure for both sucrase and maltase inhibition, except for a higher activity of methyl 3,4,5-trihydroxycinnamate (14) against sucrase. Its moderate inhibitory action against -glucosidase provides a prospect for antidiabetic usage of S. torvum fruit.Key words: Solanum torvum; -glucosidase inhibitor; methyl caffeate; Tanegashima Diabetes mellitus is one of the most serious chronic diseases. It is caused by continual hyperglycemia and develops along with increases in obesity and aging in the general population. 1) One of the therapeutic approaches to decreasing postprandial hyperglycemia is to retard absorption of glucose by inhibition of carbohydrate hydrolyzing enzymes -amylase and -glucosidase in the digestive organs.2) In recent years, many efforts have been made to search for effective -glucosidase inhibitors from natural sources in order to develop a physiological functional food or to discover lead compounds for medicinal usage against diabetes.3) In the course of our search for rat intestinal -glucosidaseinhibiting principles from various plants, we have isolated and identified several active compounds from plants grown in Asian regions, including Japan, [4][5][6][7] Thailand, 8,9) China, 10,11) and Nepal. 12) In this paper, we present the results of a screening of plants cultivated in Tanegashima, a southern island of Japan, for rat intestinal -glucosidase inhibition. In the screening experiments for rat intestinal sucrase and/or maltase inhibitors in 325 plants, potent sucrase and maltase inhibiting activity was found in extract of the fruit of Solanum torvum (Solanaceae), an edible herbaceous perennial plant. There have been several reports on the chemical constituents of this plant, which include welldocumented steroidal compounds [13][14][15] and antiviral activities, 16) but no other biologically active compounds from this plant have been reported to date. Hence, the promising screening result prompted us to isolate and elucidate the structures of active compounds in this plant. Separation of S. torvum fruit extract using various column chromatographic techniques lead to the isolation of methyl caffeate (1) as one of active principles. Some -glucosidase inhibitors previously isolated from plants contain the caffeoyl moiety as the part of their structure and have been found to be important in exerting inhibitory activity, 3,7) but the contribution of an ester part to the -glucosidase-inhibitory activity of caffeic esters has not been studied. Hence ...

The composition and contents of neutral and acidic saponins of Chinese and Japanese wild