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From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Guettarda speciosa L., two new compounds (1, 2) were isolated together with six known compounds. Spectroscopic analysis of 1 and 2 established their structures to be derivatives of a glycerol α-glucuronide and a megastigmane glycoside, respectively. HPLC analysis of the hydrolyzate of 1 confirmed the presence of D-glucuronic acid in the structure, and the modified Mosher's method established the absolute structure of 2.

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 Mosher's method., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

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.

Icariside B(5) is one of the widely distributed megastigmane glucosides among plant sources. The absolute structure of icariside B(5) was reinvestigated by chemical conversion from the related compound and the application of the modified Mosher's method. As a result, the structure of icariside B(5) was revised to be (6S,9S)-6,9-dihydroxymegastigman-4-en-3-one 9-O-β-D-glucopyranoside.

From a 1-BuOH-soluble fraction of a MeOH extract of Cananga odorata var. odorata, collected at the Botanical Garden of Chiang Mai University, a new megastigmane glucoside, named canangaionoside, and an irregular monoterpene were isolated. A known compound, breyniaionoside A, which has been obtained from the leaves of Breynia officinalis, was also isolated, and its absolute structure was substantiated for the first time in this study. On this occasion, the absolute stereochemistries of structurally related megastigmane glucosides, breyniaionosides B and C, isolated from B. officinalis were examined.

From a 1-BuOH-soluble fraction of the MeOH extract of the leaves of Crotalaria zanzibarica collected in the Okinawa Islands, three new megastigmane glucosides, named crotalionosides A-C, two new pterocarpan glucosides and a chalcone C-glucoside were isolated together with two known flavonoid glycosides and one known megastigmane glucoside. The structures of the new compounds were elucidated by a combination of spectroscopic analyses. The absolute configurations of allenic megastigmane glucosides were determined by application of the modified Mosher's method. Those of the allenic moieties were determined by interpretation of the circular dichroism (CD) spectra of the reduction products derived from citrosides A and B. The aglycones of pterocarpan glucosides were found to be melilotocarpan B and the absolute structure of the chalcone C-glucoside was determined by comparison of the CD spectral behavior with the reported values.

The absolute stereochemistry of blumenol C glucoside and byzantionoside B was revised here as (6R,9S)- and (6R,9R)-9-hydroxymegastigman-4-en-3-one 9-O-beta-D-glucopyranosides, respectively, by modified Mosher's method. The empirical rules of (13)C-NMR chemical shift to determine the absolute stereochemistry of C-9 of 9-hydroxymegastigmane 9-O-beta-D-glucopyranoside were also discussed.

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.

From a 1-BuOH-soluble fraction of the MeOH extract of leaves of Euodia meliaefolia, collected in Okinawa, seven megastigmane glucosides, named euodionosides A-G, were isolated together with three known megastgmane glucosides, and two aliphatic and three phenolic compounds. Their structures were elucidated through a combination of spectroscopic analyses and application of the modified Mosher's method.

The chemical investigation of leaves of Bridelia glauca f. balansae afforded six megastigmane glucosides, named bridelionosides A-F, along with seven known megastigmane glucosides. Their structures were determined by a combination of spectroscopic analyses and by application of the modified Mosher's method.

Four new megastigmane glucosides, named macarangiosides A-D (2-5), together with mallophenol B, lauroside E, methyl brevifolin carboxylate, and hyperin and isoquercitrin as a mixture were isolated from the leaves of Macaranga tanarius (L.) MULL.-ARG. (Euphorbiaceae). Their structures were elucidated by spectroscopic and chemical analyses. Macarangioside A-C (2-4) and mallophenol B were galloylated on glucose moiety and possessed the potent 2,2-diphenyl-picrylhydrazyl (DPPH) radical-scavenging activity.

Chemical investigation of leaves of Staphylea bumalda DC., collected in the suburbs of Hiroshima City, afforded 11 new megastigmane glucosides, named staphylionosides A-K (3-13), along with two known megastigmane glucosides (1, 2). The relative structures were elucidated from spectroscopic evidence, and the absolute structures of the aglycones were determined by means of the combination of beta-D-glucosylation-induced shift-trends and the modified Mosher's method.

From the leaves of Lasianthus fordii, three megastigmane glucosides, lasianthionosides A, B and C, were isolated together with the known iridoid glucoside, asperuloside, deacetylasperuloside and methyl deacetyl-asperulosidate, and a megastigmane glucoside, citroside A. The structures have been elucidated based on spectroscopic analyses and/or X-ray crystallographic analysis.

Five megastigmane glucosides were isolated from the leaves of Glochidion zeylanicum. One of them was a known compound, blumenol C O-beta-D-glucopyranoside (1), and the structures of the four new compounds, glochidionionosides A-D (2-5), were mainly elucidated by spectroscopic methods, including a modified Mosher's method. The absolute configurations of the six-membered ring of glochidionionoside D (5) were deduced by beta-D-glucopyranosylation-induced shift trends in the (13)C-NMR spectra and confirmed by X-ray analysis as its p-bromobenzoate (5b), and the axis chirality of C-7 was determined to be R.

From Glochidion zeylanicum, two megastigmane glucosides, 3- and 9-O-beta-D-glucopyranosides of (3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetrol (1 and 2, respectively), were isolated. Their structures were different from those of kiwiionoside (3) and actinidioionoside (4), isolated from Actinidia chinensis and Actinidia polygama, respectively, in the stereochemistry at the 9-positions. Alangionosides E (5) and O (6), isolated from the leaves of Alangium premnifolium, are also megastigmane glucosides, and the latter is closely related to 1 and actinidioionoside (4). However, the absolute configurations of the 9-position remained to be determined. They were analyzed to be R by means of a modified Mosher's method. Alangionoside E (5) is identical with corchoionoside A in all aspects. The name of corchoionoside A must be retained thereafter.