Susumu Kawakami

Crotonionosides A-G: megastigmane glycosides from leaves of Croton cascarilloides Räuschel.

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Croton cascarilloides, collected in Okinawa, Japan, seven megastigmane glycosides, named crotonionosides A-G, were isolated together with three known megastigmane glucosides, dendranthemosides A and B, and citroside A. This structures were elucidated by a combination of spectroscopic analyses, HPLC analyses, and application of the modified Moshers method.

Oblongionosides A-F, megastigmane glycosides from the leaves of Croton oblongifolius Roxburgh.

From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Croton oblongifolius Roxburgh, collected in Chiang Mai, Thailand, six megastigmane glycosides, named oblongionosides A-F were isolated together with eight known compounds, and their structures elucidated on the basis of spectroscopic data. Absolute structures were determined by HPLC analyses and application of the modified Moshers method.

Chemical constituents of imported Rosae fructus.

Rosae fructus is a traditional Chinese crude drug, used for purgative purposes. It is included in the Japanese Pharmacopoeia XV, in which its origin is stated to be Rosa multiflora Thunberg. These days, some imported Rosae fructus are on the market and the pharmacological activity of the imported product is in question. The chemical constituents of Japanese Pharmacopoeial Rosae fructus, imported from the People’s Republic of China and whose plant origin is expected to be Rosa aff. multiflora, were investigated to give 2-hydroxynaringin 5-O-β-d-glucopyranoside and L(S)-pyroglutaminic acid derivative as new compounds. However, although we made every effort, the major flavonoids in R. multiflora, multiflorins A and B, and multinoside A acetate, could not be isolated.

Crotocascarins I-K: Crotofolane-Type Diterpenoids, Crotocascarin γ, Isocrotofolane Glucoside and Phenolic Glycoside from the Leaves of Croton cascarilloides.

From the 1-BuOH-soluble fraction of a methanol (MeOH) extract of the leaves of Croton cascarilloides, crotofolanes: crotocascarins I-K, nor-crotofolane: crotocascarin γ, isocrotofolane glucoside and phenolic glycoside were isolated by a combination of various separation techniques. Their structures were elucidated mainly from the NMR spectroscopic evidence. The structure of crotocascarin K was first elucidated by spectroscopic analysis and then was confirmed by X-ray crystallographic analysis. Its absolute structure was finally determined by the modified Moshers method. Isocrotofolane glucoside was found to possess a new skeleton, however, its absolute structure remains to be determined.

Two new cembranoids from the leaves of Croton longissimus Airy Shaw

Abstract Two new cembrane-type diterpenoids (1 and 2) along with five known compounds (3–7) were isolated from leaves of Croton longissimus collected in Thailand. Their structures were elucidated from spectroscopic evidence and compound 4 was found by HPLC analysis to be identical to oblongionoside B—a compound isolated from Crotonoblongifolius—including the absolute configuration at the C-9 position.

Megastigmane Glucosides and Megastigmanes from the Leaves of Meliosma lepidota ssp. squamulata

From the leaves of Meliosma lepidota ssp. squamulata, megastigmane glucosides with spiro-structures and megastigmanes were isolated. Their structures were determined by X-ray crystallographic analyses and spectroscopic investigation. The absolute structures of the megastigmanes were determined by the modified Moshers method.

Sulfated Glucosides of an Aliphatic Alcohol and Monoterpenes, and Megastigmanes from the Leaves of Meliosma pinnata spp. arnottiana

Chemical study of the leaves of Meliosma pinnata spp. arnottiana afforded five sulfated glucosides of oct-1-en-3-ol (1) and cyclic linalool derivatives (2-5), and two megastigmanes (6, 7). Their structures were elucidated by extensive investigation of one- and two-dimensional NMR spectroscopic data, and the absolute structures of the megastigmanes were determined by the modified Moshers method.

Alkylated Benzoquinones: Ardisiaquinones A–H from the Leaves of Ardisia quinquegona and Their Anti-Leishmania Activity

Eight alkylated benzoquinone derivatives, named ardisiaquinones A-H, were isolated together with four known compounds from the leaves of Ardisia quinquegona using a combination of different chromatography techniques. Their structures were elucidated by spectroscopy and by the preparation of methyl ethers. Anti-Leishmania activity and cytotoxicity of the isolated compounds were assayed. Some compounds showed moderate anti-Leishmania activity, however, always associated with cytotoxicity.

Microtropins Q–W, ent -Labdane Glucosides: Microtropiosides G–I, Ursane-Type Triterpene Diglucoside and Flavonol Glycoside from the Leaves of Microtropis japonica

Microtropins Q-W, (2S,3R)-2-ethyl-2,3-dihydroxybutyrate of various glucosides and glucose, as well as three ent-labdane diterpenoid glucosides, named microtropiosides G, H and I, an ursane-type triterpene diglucoside and a flavonoid glycoside were isolated from the MeOH extract of the leaves of Microtropis japonica. The structure of microtropioside A, also isolated from the branches of M. japonica, was elucidated spectroscopically in a previous experiment and was found to possess a rare seven-membered oxyrane ring. Its structure was confirmed by X-ray crystallographic analysis of its pentaacetate.

Dianthosaponins G–I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity

Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G–I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated.