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Further isolation work on the water-soluble fraction of a MeOH extract of Tricalysia dubia afforded one new megastigmane gentiobioside, named tricalysionoside A (1), and three sulfates, named sulfatricalysines A-C (2-4). Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of T. dubia yielded sulfatricalysines D-F (5-7) and three new ent-kaurane glucosides, named tricalysiosides X-Z (8-10). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute stereochemistry of tricalysionoside A (1) was established by modified Mosher's method.

The approximately 50 species of Tricalysia (Syn. Canthium) are found in subtropical and tropical areas of Asia and Africa. Some species are used for medicinal purposes, e.g. the roots, leaves, and stem bark of Canthium subcordatum are used as folk medicines in Africa. 1)Tricalysia dubia (LINDL.) OHWI (Rubiaceae) is an evergreen shrub or tree that grows to a height of about 2-4 m. It is distributed in the south of China, Taiwan, and Okinawa. 2)In the course of our study on Okinawa's promising resource plants, the constituents of the title plant, T. dubia, were investigated.In previous papers, the structural elucidation of seven rearranged ent-kaurane glucosides, tricalysiosides A-G, and eight ent-kaurane glucosides, named tricalysiosides H-O, from leaves of T. dubia was reported.3,4) Non-glycosidic rearranged ent-kauranes were also isolated from the same plant species. 5,6) Further extensive investigation of the same plant material afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with one megastigmane glucoside, two monoterpene glucosides (1, 2), [7][8][9] and sammangaoside B (3).10) This paper deals with their structural elucidation and revision of the stereostructure of sammangaoside B. Results and DiscussionAir-dried leaves of T. dubia were extracted with MeOH three times and the concentrated MeOH extract was partitioned with solvents of increasing polarity. The 1-BuOH-soluble fraction was separated by various chromatographic procedures including column chromatography (CC) on a highly porous synthetic resin (Diaion HP-20), normal silica gel and reversed-phase octadecyl silica gel (ODS) CC, then droplet counter-current chromatography (DCCC) to afford six diterpenoid glucosides, named tricalysiosides P-U (4-9) (Fig. 1), together with one megastigamne glucoside, two monoterpene glucosides (1, 2), [7][8][9] and summangaoside B (3).10) The details and yields are given in the Experimental section. The structures of tricalysiosides P-U (4-9) were elucidated by spectroscopic analyses and comparison with tricalysiosides previously isolated based on spectroscopic evidence. Sammangaoside B (3), [a] D Ϫ35.0°, was first isolated from Clerodendrum inerme but the stereochemistry of its six-membered ring portion remained to be determined. Phase-sensitive NOE experiments supported the previously reported relative structure of the ring system, as depicted in the literature. 10) Application of modified Mosher's method 11) to the aglycone led to revision of the absolute configuration of the 9-position to S (Fig. 2) Further extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of Tricalysia dubia afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with a known megastigmane glucoside, sammangaoside B (1), and monoterpene glucosides (2, 3). The structures of the new compounds were elucidated by analyses of one-and two-dimensional NMR spectroscopic data. The absolute configuration of the 9-position of sammangaoside B was revised to ...

From a 1-BuOH-soluble fraction of an extract of the leaves of Elaeocarpus japonicus, six megastigmane glucosides (1-6) were isolated. Five were known compounds (2-6), i.e. amelopsisionoside, citroside A, roseoside, alangionoside A and turpinionoside A, respectively. The structure of the new compound, named elaeocarpionoside, was elucidated to be (3R,4R,5S,6S,7E,9R)-megastigman-7-ene-3,4,9-triol 9-O-beta-D: -glucopyranoside by spectroscopic analyses and the modified Mosher's method.

Crotalionoside A (Ia), B (Ib), C (II), two pterocarpane glucosides (III) and a chalcone C‐glucoside (IV) are isolated from the MeOH exract of the leaves of the title herb.