Masayuki Yoshikawa

Hepatoprotective amide constituents from the fruit of Piper chaba: Structural requirements, mode of action, and new amides.

The 80% aqueous acetone extract from the fruit of Piper chaba (Piperaceae) was found to have hepatoprotective effects on D-galactosamine (D-GalN)/lipopolysaccharide-induced liver injury in mice. From the ethyl acetate-soluble fraction, three new amides, piperchabamides E, G, and H, 33 amides, and four aromatic constituents were isolated. Among the isolates, several amide constituents inhibited D-GalN/tumor necrosis factor-alpha (TNF-alpha)-induced death of hepatocytes, and the following structural requirements were suggested: (i) the amide moiety is essential for potent activity; and (ii) the 1,9-decadiene structure between the benzene ring and the amide moiety tended to enhance the activity. Moreover, a principal constituent, piperine, exhibited strong in vivo hepatoprotective effects at doses of 5 and 10 mg/kg, po and its mode of action was suggested to depend on the reduced sensitivity of hepatocytes to TNF-alpha.

Oleanane-type triterpene oligoglycosides with pancreatic lipase inhibitory activity from the pericarps of Sapindus rarak

The methanolic extract from the pericarps of Sapindus rarak DC. was found to show pancreatic lipase inhibitory activity (IC50=ca. 614 microg/mL). From the extract, oleanane-type triterpene oligoglycosides, rarasaponins I-III (1-3), and raraoside A (4), were isolated together with 13 known saponins and four known sesquiterpene glycosides. Among them, several saponin constituents including rarasaponins I (1, IC50=131microM) and II (2, 172microM), and raraoside A (4, 151microM) inhibited pancreatic lipase activity, which were stronger than that of theasaponin E(1) (270microM).

Structures of New Cucurbitane-Type Triterpenes and Glycosides, Karavilagenins D and E, and Karavilosides VI, VII, VIII, IX, X, and XI, from the Fruit of Momordica charantia

Two new cucurbitane-type triterpenes, karavilagenins D and E, and six new cucurbitane-type triterpene glycosides, karavilosides VI, VII, VIII, IX, X, and XI, were isolated from the fruit of Momordica charantia L. (Cucurbitaceae) cultivated in Sri Lanka. Their structures were elucidated on the basis of chemical and physicochemical evidence.

Comparative evaluation of cultivars of Chrysanthemum morifolium flowers by HPLC-DAD-ESI/MS analysis and antiallergic assay.

A multicomponent quantification fingerprint based on HPLC coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MS) technique has been established for the analysis of phenolic compounds in 12 samples originated from 5 different cultivars of Chrysanthemum morifolium flowers in China. Four caffeoylquinic acids and 15 flavonoids in the capitulum were identified by comparing the retention times and ultraviolet spectra as well as the mass spectrum and/or matching the empirical molecular formula with that of reference compounds, and the contents of these compounds have been determined simultaneously. The samples from three medicinal cultivars significantly differed in the quality and quantity of flavonoid aglycones and glycosides compared with those from two edible cultivars, which allows the possibility of showing the chemical distinctness of these cultivars and may be useful in their standardization. Moreover, the antiallergic effects of these cultivars were comparatively assayed for the first time. A representative medicinal cultivar, huaiju, showed potential activity on the inhibition of antigen-induced degranulation from RBL-2H3 cells and compound 48/80-induced scratching in mice, whereas the in vitro and in vivo antiallergic activities of two edible cultivars were weak. The results suggested that the quality and quantity of some active flavonoid aglycones should be responsible for the pharmacological profiles of these cultivars.

Perennisosides I-VII, Acylated Triterpene Saponins with Antihyperlipidemic Activities from the Flowers of Bellis perennis

The methanolic extract and its saponin fraction (methanol-eluted fraction) of the flowers of Bellis perennis were found to suppress serum triglyceride elevation in olive oil-treated mice. From the saponin fraction, seven new triterpene saponins, perennisosides I (1), II (2), III (3), IV (4), V (5), VI (6), and VII (7), were isolated together with four known saponins, bellidioside A (8), asterbatanoside D (9), bernardioside B 2 (10), and bellissaponin BS6 (11). The stereostructures of 1- 7 were elucidated on the basis of chemical and spectroscopic evidence. Among these saponins, perennisosides I (1) and II (2) showed inhibitory effects on serum triglyceride elevation at doses of 25-50 mg/kg, po.

Structures of dammarane-type triterpene triglycosides from the flower buds of Panax ginseng

New dammarane-type triterpene triglycosides, floralginsenosides G, H, I, J, K, La, and Lb, were isolated from the flower buds of Panax ginseng C. A. MEYER together with ten known dammarane-type triterpene oligoglycosides. The structures of new compounds were elucidated on the basis of chemical and physicochemical evidence.

Steroidal saponins and pseudoalkaloid oligoglycoside from Brazilian natural medicine, “fruta do lobo” (fruit of Solanum lycocarpum) ☆

Steroidal saponins, lyconosides Ia, Ib, II, III, and IV and a steroidal pseudoalkaloid oligoglycoside, lobofrutoside, were isolated from a Brazilian natural medicine, fruta do lobo (the fruit of Solanum lycocarpum St. Hil.). The chemical structures of these compounds were elucidated on the basis of analysis of chemical and physicochemical evidence.

Medicinal foodstuffs. XXXII. Novel sesquiterpene glycoside sulfate, fukinoside a, with antiallergic activity from Japanese butterbur (Petasites japonicus)

Novel sesquiterpene glycoside sulfate, fukinoside A, was isolated as the potassium salt from the aerial parts of Petasites japonicus. The absolute sterostructure of fukinoside A was elucidated on the basis of chemical and physicochemical evidence. In addition, fukinoside A was found to inhibit release of β-hexosaminidase, as a marker of antigen-induced degranulation, in RBL-2H3 cells.