Bioprospecting targeted for domestic higher plant resource in search of anti-microbial chemical leads

点击翻译按钮获取中文摘要

1.Collection of plant samples at Iriomote IslandMore than 200 specie of plant samples were collected in the field survey at Iriomote Island, Okinawa Prefecture. Those collected in the field were separated into parts for convenience in case of extraction as much as possible, and herbarium specimens of each plant species were also prepared. These works were undertaken at Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus.2.Identification of plant specimensDue to insufficient data available on plants of subtropical origin in domestic herbariums, some plant specimens were identified at Philippine National Herbarium, Manila, Philippines, in collaboration with Dr.Domingo M.Madulid. This overseas research revealed that the one previously identified as Adenophora affine was found to be Ecdysanthera utilis, a rare species in the flora of Japan. During the course of writing a scientific paper on chemical constituents of Caesalpinia crista L. (Nantenkazura), a search … More of literatures led to the finding of a paper that regarded C. crista L. as a synonym of Shirotsubu, a plant belonging to the same Caesalpinia species. Therefore, the author inspected specimens of Caesalpinia plants preserved at Philippine National Herbarium, and investigated their synonym-homonym relations. It was apparent from the results of this investigation carried out overseas that a name of C. crista L. given to Shirotsubu was mostly derived from erroneous identification of plant samples and to a lesser extent from homonym. The confused use of scientific names was also found in other Caesalpinia species, in particular, Shirotsubu and Hasunomikazura. Both species are often called C. bonduc in shortened forms, and thus cannot be distinguished from one to another unless the former name is written in full as C. bonduc (L.) Roxb. emend. Dandy et Exell and the latter as C. bonduc Roxb., non L.. This would be the reason that forces many of phytochemists to use improper names of Caesalpinia species mentioned above. It was also found that the identification of Shirotsubu and its allied Caesalpinia species should not be carried out from specimens without either flowers or fruits.3.Anti-microbial activity of plant samplesAll samples of the plant extract library that counts 2000 samples in total including those collected at Iriomote Island were subjected to anti-microbial assay against Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae and Aspergillus niger. The results were that 124, 4, 28 and 24 samples exhibited significant activities against those microorganisms, respectively.4.Isolation and structure elucidation of anti-fungus principlesPricarps of Styrax obassia (Styracaceae) and Barks of Camelliaceous plant OK1588 furnished new constituents as potent anti-fungus principles by repeated chromatographic separations. Their structures were elucidated as oleanane-type acyl saponins on the spectroscopic basis.5.Isolation and structure elucidation of new constituents of phytochemical significanceBesides chemical research on plants directed toward isolation of anti-microbial seed chemicals, phytochemical research was also undertaken on plants for which lesser chemical information was available. Novel types of constituents of phytochemical significance were obtained from barks of Styrax obassia, leaves of Caesalpinia crista and fruits of Coriaria japonica, and their structures were elucidated spectroscopically. Less