DIVERSIFIED STUDIES ON DEVELOPMENT OF RARE MEDICINAL RESOURCE PLANTS IN RYUKYU ISLANDS

1.矮蛇根草细胞培养（1）愈伤组织代谢产物的研究：愈伤组织培养产生一组蒽醌类化合物，而不是预期的生物碱。鉴定了9个蒽醌类化合物的结构，其中包括2个新化合物：1-羟基-2-羟甲基-3-甲氧基蒽醌和2-丁氧基甲基-1，3-二羟基蒽醌。（2）矮蛇筋草愈伤组织分化植株的诱导：由愈伤组织分化出再生植株。对喜树碱的化学成分进行了研究，发现喜树碱、9-甲氧基喜树碱、pumiloside和3（R）-deoxypumiloside的存在，证明其具有与原植物相同的生物碱形成酶活性。2.喜树碱的生物合成模型的一步：3-epi-pumiloside tetraacetate被转化为C-7脱氧衍生物。所得产物被证明与天然脱氧番荔枝苷的乙酸酯相同;这一观察结果要求我们修正上述天然分子形式α至β的C-3立体化学。3.新喜树碱衍生物的合成：合成10-羟基喜树碱的五种酯;分别与10、12、16、18和20个碳的饱和脂肪酸的酯。哺乳动物酯酶和拓扑异构酶I的生物活性试验正在进行中。4.斑鸠菊和树斑鸠菊化学成分的研究：对灰斑鸠菊化学成分的研究因材料量少而未成功。5.寻找新的药用资源植物：冲绳或热带亚洲植物的研究（茜草科），耳草属（Rubiaceae），Glycosmis（芸香科），Murraya（芸香科），或Acalypha（大戟科），正在与东南亚国家的科学家密切联系下取得进展。

1.Cell cultivation of Ophiorrhiza pumila(1)Studies on metabolites of cultured callus : The cultured callus produced a group of anthraquinones instead of anticipated alkaloids. Structures of nine anthraquinones including two new molecules, 1-hydroxy-2-hydroxymethyl-3-methoxy anthraquinone and 2-butoxymethyl-1,3-dihydroxy anthraquinone, were elucidated.(2)Induction of differentiated plants from callus of Ophiorrhyza pumila : Regenerated plants were formed from the callus. Studies on the constituents revealed occurrences of camptothecin, 9-methoxycamptothecin, pumiloside, and 3(R)-deoxypumiloside, proving expression of the same alkaloid-forming enzyme activities as the original plant.2.A step toward biosynthesis-modeled synthesis of camptothecin : 3-epi-pumiloside tetraacetate was converted to the C-7 deoxy derivative. The resulting product proved to be identical with the acetate of natural deoxypumiloside ; an observation that required us to revise the proposed C-3 stereo chemistry of the above natural molecule form alpha to beta.3.Synthesis of new camptothecin derivatives : Synthesis of five esters of 10-hydroxycamptothecin was made ; esters with saturated fatty acids of 10,12,16,18 and 20 carbons, respectively. Biological activity tests for mammalian esterases and for topoisomerase I are under progress.4.Studies on the constituents of Vernonia cenerea and V.arborea : A study on the constituents of V.cinerea was unsuccessful because of scarece material amount. V.arborea native to South Thai gave a new lignan of unknown structure besides known 3-0-caffeoyl quinic acid.5.Search for new medicinal resource plants : Studies on some Okinawan or Tropical Asian plant species of such genera as Morrinda (Rubiaceae), Hedyotis (Rubiaceae), Glycosmis (Rutaceae), Murraya (Rutaceae), or Acalypha (Euphorbiaceae), are in progress under close contact with scientists in the countries of South East Asia.