P-38 マメ科紅木紫檀(Pterocarpus santalinus)中のSantalin類の構造 : ならびにそれらの生合成仮説及び抗酸化活性について(ポスター発表の部)

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The colourant of red sandalwood (Pterocarpus santalinus) is going to be applied to the foodstuffs. Its main pigments were characterized as santalins A and B by chemical degradation. In order to standardize the colourlant of sandalwood in the series of our studies on the leguminous plants, we re-examined the constituents of this plant by means of modern chromatographies. We obtained a novel yellow pigment named santalin Y (10), a light yellow 3-arylcoumarin derivative named santalin AC (8), and its methyl ether (9) together with santalins A (1), B (2), (-)-fisetinidol (6) and marsupsin (7). We also isolated three acetone adducts (3〜5) from the same source. These adducts were not obtained from another lot and isolation procedure without acetone. Compounds 1 and 2 were characterized by the combination of various NMR techniques (^1H-^1H COSY, ^<13>C-^1H COSY, NOESY and HMBC) enabled to assign all carbon and proton signals. Compounds 8 and 9 were determined in the similar manner as above and by comparison of NMR data with the authentic data of 3-arylcoumarin. The structure of 10 was mainly determined by X-ray analysis. In regard to the biogenesis of 1, 8 and 10, a hypothesis could be provided as shown in scheme 1 taking into account the Whalley' s report. Since the units composed of 1 and 10 were quite similar, the biogenesis of both compounds was assumed to correlate with each other. Compound 8 might be generated from the coupling with water as a nucleophile. The acetone adducts were determined to be 3〜5 which have acetyl methyl group at C-4 by comparison of NMR data with 1 and 2. Two other acetone adducts 2a and 2b which have hydroxy group at C-7 were prepared from 2 and 80% acetone with HCOONH_4. Since these compounds were identified to be conformers by NOE experiment, conformational analysis by CAChe system (MM2) was carried out. The result gave two minimum values (31.878 and 33.049kcal/mol) which were corresponding to 2b and 2a, respectively. The MeOH ext. showed anti-oxidative activities. The obtained compounds except for 10 were higher than the reference compounds (α-tocopherol and BHA). Especially, compound 4 inhibited completely even at 6th day. These data showed that a guaiacol derivative is active more than a catechol derivative.
天然有機化合物討論会の論文
1995-09-01

P-38 マメ科紅木紫檀(Pterocarpus santalinus)中のSantalin類の構造 : ならびにそれらの生合成仮説及び抗酸化活性について(ポスター発表の部)

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