Hitoshi Yoshimitsu

Onionin A from Allium cepa inhibits macrophage activation.

Onionin A (1), a new, stable, sulfur-containing compound, was isolated from acetone extracts of bulbs of onion (Allium cepa), and its structure was characterized as 3,4-dimethyl-5-(1E-propenyl)-tetrahydrothiophen-2-sulfoxide-S-oxide, on the basis of the results of spectroscopic analysis. This compound showed the potential to suppress tumor-cell proliferation by inhibiting the polarization of M2 alternatively activated macrophages.

Physiological functions of solanaceous and tomato steroidal glycosides

Solanaceous plants are widely distributed. They are used as food and in folk medicine. Our studies focused on these plants, starting with Solanum lyratum and S. nigrum, which are used as anti-cancer and anti-herpes agents. Extensive investigations in 45 Solanum plant species revealed that a considerable amount of glycosides such as spirosolane, solanidane, spirostane and furostane is in these plants, and some of the isolated glycosides showed strong anti-proliferative activity against various cancer cell lines and anti-herpes activity. Furthermore, we have discovered a few new hypothetical biosynthetic routes in which the pathways for the biosynthesis of 16-acyl-pregnane and pregnane glycosides were the most interesting. The occurrence of these pregnane compounds indicates that they might be internally biosynthesized in the plant from furostanol glycosides by a reaction that is similar to Marker degradation. Furthermore, this may imply that the administration of steroidal glycosides may result in their metabolization into pregnane derivatives possessing various activities. In order to perform metabolic experiments using the steroidal glycosides, we recently isolated tomato glycosides from ripe tomato fruits for the first time. For this experiment, we examined the metabolites in urine obtained from persons that consumed tomatoes. We obtained androstane derivatives that were probably metabolized via pregnane derivatives from tomato glycoside. Hence, when a steroidal glycoside is administered, it may be metabolized into a type of steroidal hormone with various physiological activities.

26-AMINOCHOLESTANOL DERIVATIVE, A NOVEL KEY INTERMEDIATE OF STEROIDAL ALKALOIDS, FROM SOLANUM ABUTILOIDES

Abstract A novel 26-aminocholestanol derivative which is regarded as an important key intermediate to spirosolane and solanidane derivatives has been isolated from the roots of Solanum abutiloides .

A new diterpenoid and a new triterpenoid glucosyl ester from the leaves of Callicarpa japonica Thunb. var. luxurians Rehd.

A new abietane-type diterpenoid and a new oleanane-type triterpenoid glucosyl ester were isolated from the leaves of Callicarpa japonica Thunb. var. luxurians Rehd. (Verbenaceae) along with 11 known compounds, comprising seven triterpenoids, two sterols, a flavonoid, and an aliphatic glycoside. Their chemical structures were determined on the basis of spectroscopic data.

Chromone and flavonol glycosides from Delphinium hybridum cv. “Belladonna Casablanca”

One new chromone and six known flavonol glycosides were isolated from the stems and leaves of Delphinium hybridum cv. “Belladonna Casablanca” (Ranunculaceae). The new chromone glycoside was elucidated as 2-methyl-chromone-5,7-diol 7-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (1). The six known flavonol glycosides were designated as compounds 2–5, being kaempferol-type glycosides, and compounds 6 and 7, being quercetin-type glycosides. The structures of these glycosides were determined by two-dimensional nuclear magnetic resonance (2D NMR) spectroscopic analysis and chemical evidence.

Three new cycloartane glycosides from Thalictrum thunbergii D.C.

Abstract Three new cycloartane glycosides possessing a five-membered ring, which is constructed by a C–C bond, at the side chain have been isolated from the aerial parts of Thalictrum thunbergii D.C. Their structures were determined by the use of 2D NMR techniques and chemical evidence.

Cycloartane-type glycosides from Aquilegia flabellata.

Two new cycloartane-type glycosides, named aquilegiosides A and B, were isolated from the dried aerial parts of Aquilegia flabellata Sieb.et Zucc.var flabellata (Ranunculaceae). Their chemical structures have been characterized as 22S-3beta,16alpha,29-trihydroxy-cycloart-24-en-26,22-olid e 3-O-beta-D-glucopyranosyl-(1--->6)-beta-D-glucopyranosyl-(1--->2)-alpha- L-arabinopyranoside and 3-O-beta-D-glucopyranosyl-(1--->2)-alpha-L-arabinopyranoside, by chemical and spectroscopic evidence.

Three new aromatic glycosides from the ripe fruit of cherry tomato

Three new aromatic glycosides were isolated from the ripe fruit of cherry tomato [Lycopersicon esculentum var. cerasiforme (Dunal) Alef. (Solanaceae)] along with six known aromatic glycosides and one known steroidal alkaloid glycoside. Their chemical structures were determined on the basis of spectroscopic data as well as chemical evidence.

TWO NEW CYCLOARTANE GLYCOSIDES FROM THALICTRUM THUNBERGII D.C.

Abstract Two new cycloartane glycosides possessing a five-membered ring, which is constructed by a CC bond, at the side chain have been isolated from the aerial parts of Thalictrum thunbergii D.C.

Cycloartane-type glycosides from Thalictri Herba

Two new cycloartane-type glycosides, designated as thalictosides V and IX, were isolated from the methanolic extract of Thalictri Herba (Takatogusa), the dried aerial parts of Thalictrum sp. plants. Their chemical structures have been characterized as 3-O-monodesmoside and the 3,21-di-O-bisdesmoside of 3 beta,22 zeta,30-trihydroxycycloart-24-en-21-oic acid, by chemical and spectroscopic evidence.