Mitsunori Aramoto

Euodionosides A-G: megastigmane glucosides from leaves of Euodia meliaefolia.

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 Moshers method.

Sprouting characteristics of a subtropical evergreen broad-leaved forest following clear-cutting in Okinawa, Japan

This study explores the sprouting characteristics of an evergreen broad-leaved forest after clear-cutting based on a survey of 1,893 stumps of 62 tree species in Okinawa, Japan. The sprouting capabilities of the stumps varied among tree species. The stumps of 60 species could produce sprouts, while those of the other two species could not. In 10 of the sprouting species, the mean sprout-stem number was higher than 4.0 stems per stump; nine sprouting species showed low sprouting capabilities. Additionally, Castanopsis sieboldii and Schima wallichii, the dominant species, exhibited high sprouting capabilities. Further, the sprouting capabilities varied with stump diameter at breast height (DBH). Stumps with a larger DBH tended to have a higher mean number of sprout stems per stump, higher DBH, and higher tree height than the smaller stumps. The forest stands regenerated by sprouting might recover into a tree community similar to that before clear-cutting.

Glycosidic constituents of the leaves of an Okinawan Leguminosae plant, Derris trifoliata Lour.

From the leaves of Derris trifoliata, collected in Okinawa, 15 glycosidic compounds were isolated and identified.

Characteristics of a 20-year-old evergreen broad-leaved forest restocked by natural regeneration after clearcut-burning

Abstract• To elucidate the application of natural regeneration to the restocking of evergreen broad-leaved forests in the subtropics, the characteristics of a 20-year-old evergreen broad-leaved forest restocked by natural regeneration after clearcut-burning were studied in Okinawa, Japan. Within a 0.87 ha clearcut area with four 10 m × 10 m sampling plots, two burned and two unburned ones, the tree composition, tree species diversity and vegetation changes were investigated.• The results showed that the species diversity, basal area and density of woody stems ⩾ 1.0 m in height differed significantly among phanerophyte types, while they were not significantly different between the burned and unburned treatments. A vegetation census also revealed no obvious differences between the treatments.• The primary dominant species, Castanopsis sieboldii, continued to dominate the secondary forest with a broad height distribution.• The structural complexity and high tree species diversity of the regenerating forest after clearcut-burning provides no evidence of degeneration. We can predict that the regeneration forest may gradually develop into stands similar to pre-clearcut primary forest, and that natural regeneration may restore the high tree species diversity of the evergreen broad-leaved forests in Okinawa.Résumé• Pour élucider la pertinence de la régénération naturelle pour la reconstitution des forêts feuillues dans la zone subtropicale, les caractéristiques d’une forêt feuillue sempervirente, âgée de 20 ans, reconstituée par régénération naturelle après coupe rase et feu, ont été étudiées à Okinawa au Japon. Dans une coupe rase de 0,87 ha, 4 placeaux échantillons de 10 m × 10 m ont été établis : deux après coupe rase et feu et deux après coupe rase. On a étudié la composition des arbres, la structure de la forêt, la diversité spécifique des arbres et les changements de végétation.• Les résultats montrent que la diversité spécifique, la surface terrière et la densité des troncs ligneux d’une hauteur supérieure ou égale à 1,0 m différent significativement parmi les phanérophytes, tandis qu’il n’y a pas eu de différences significatives entre les traitements brûlés et les non brûlés. Le recensement de la végétation a aussi révélé qu’il n’y avait pas de différence évidente entre les traitements.• La principale espèce dominante Castanopsis sieboldii a continué à dominer la forêt secondaire avec une large distribution des hauteurs.• La complexité structurelle et la grande diversité des espèces d’arbre de la forêt régénérée après coupe rase et feu fournissent la preuve qu’il n’y a pas eu dégénérescence. Nous pouvons prédire que ces forêts peuvent se développer graduellement en peuplements similaires à la forêt primaire existant avant la coupe et que la régénération naturelle peut rétablir la grande diversité spécifique des arbres dans les forêts feuillues sempervirentes d’Okinawa.

Rearranged ent-kauranes from the stems of Tricalysia dubia and their biological activities.

From the EtOAc-soluble fraction of an MeOH extract of the stems of Tricalysia dubia, two new rearranged ent-kaurane derivatives, named tricalysiolides H and I, were isolated, together with five known rearranged ent-kauranes, i.e. tricalysiolides A–E, stigmast-4-en-6β-ol-3-one, (+)-pinoresinol, scopoletin and syringaldehyde. Their structures were elucidated from spectroscopic evidence, and their cytotoxicity toward KB cells and P-gp inhibitory activity were assayed.

Bridelioside, a new lignan glycoside from Bridelia glauca Bl. f. balansae (Tucht.) Hatusima

A new lignan glycoside, bridelioside, has been isolated from Bridelia glauca f. balansae. The structure of bridelioside was elucidated be (+)-isolariciresinol 2a-O-α-l-arabinopyranoside on the basis of spectral data.

Tricalysiolide G and tricalysiols A and B: rearranged ent-kaurane-type and ent-kaurane-type diterpenoids from the leaves of Tricalysia dubia (Lindl.) Ohwi

Three rearranged ent-kaurane diterpenes with the cafestol-type framework have been isolated from the leaves of Tricalysia dubia. Two were found to be known diterpenoids, tricalysiolides B and C. Tricalysiolide B was isolated as colorless prisms in this experiment and its three-dimensional structure was determined by X-ray crystallography. The remaining diterpenoid was a new compound and was named tricalysiolide G. Two new ent-kaurane-type diterpenoids, given the trivial names tricalysiol A and tricalysiol B, were also isolated. The structures of the new compounds were elucidated from spectroscopic evidence.