Yoshihito Okada

Isoliquiritigenin suppresses pulmonary metastasis of mouse renal cell carcinoma

Isoliquiritigenin is a chalcone isolated from licorice and shallots. The ability of isoliquiritigenin to suppress metastasis was examined in a pulmonary metastasis model of mouse renal cell carcinoma. Isoliquiritigenin significantly reduced pulmonary metastasis, without any weight loss or leukocytopenia. Isoliquiritigenin suppressed in vitro proliferation of carcinoma cells, potentiated nitric oxide production by lipopolysaccharide-stimulated macrophages, and facilitated cytotoxicity of splenic lymphocytes in vitro. These findings suggest activation of macrophages, activation of cytotoxicity of lymphocytes, and direct cytotoxicity as possible mechanisms of metastasis suppression by isoliquiritigenin. In addition, isoliquiritigenin prevented severe leukocytopenia caused by administration of 5-fluorouracil.

Antidiabetic effect of polyphenols from brown alga Ecklonia kurome in genetically diabetic KK-Ay mice

Context: Prevalence of diabetes mellitus type 2 (DM-II) is increasing in Japan. Brown alga Ecklonia kurome Okamura (Laminariaceae) (kurome in Japanese) is rich in phlorotannins, a kind of polyphenol. Phlorotannins have been reported to possess various bioactivities; however, few studies have reported its effect on DM-II. Objective: The present study was conducted to investigate the antidiabetic effect of polyphenols from E. kurome (KPP) on KK-Ay mice, the animal model for human DM-II. Materials and methods: Inhibitory activities of KPP against α-amylase and α-glucosidase in vitro, and effects on oral carbohydrate tolerance test in vivo were investigated. KK-Ay mice were fed with 0.1% KPP containing water for 5 weeks. A glucose tolerance test was conducted at week 4 of the 5-week period. At the end of experiment, blood biochemical parameters, including blood glucose, insulin, glycoalbumin, and fructosamine were determined. Furthermore, the kidneys and pancreatic islets were histologically examined. Results: KPP showed inhibitory activities on carbohydrate-hydrolyzing enzymes and decreased postprandial blood glucose levels. The body weight gain and blood glucose levels in the KPP group were lower than the control group during the experimental period. KPP improved glucose tolerance and decreased the fasting blood glucose and insulin levels, fructosamine and glycoalbumin levels compared with the control group. Furthermore, KPP contracted the pancreatic islet size and decreased renal mesangial matrix in KK-Ay mice. Discussion and conclusion: These results suggest that KPP is effective against DM-II and might provide a source of therapeutic agents for DM-II.

Two new coumarin glycosides from Peucedanum praeruptorum.

Two new coumarin glycosides, praerosides VI (1) and VII (2), were isolated from the roots of Peucedanum praeruptorum Dunn. Their structures were elucidated by chemical reaction and NMR spectroscopic methods.

New flavanone and chalcone glucosides from Bidens bipinnata Linn.

A new flavanone glucoside, bidenoside F, and a new chalcone glucoside, bidenoside G, along with the known compound iso-okanin 7-O-(4″,6″-diacetyl)-β-d-glucopyranoside have been isolated from the aerial parts of Bidens bipinnata L. The structures were determined on the basis of spectroscopic methods.

Antimicrobiological Studies on Turkish Cistus. Species

ABSTRACT The genus Cistus. L., mainly growing in the Mediterranean region, is represented by five species in Turkey: C. creticus. L., C. laurifolius. L., C. monspeliensis. L., C. parviflorus. Lam., and C. salviifolius. L. In this study, in vitro. antimicrobial activity of water, methanol, chloroform, ethyl acetate, and buthanol extracts, prepared from dried and powdered leaves and the fruits of the five Cistus. species, were investigated by the disk diffusion method against the following microorganisms: Staphylococcus aureus. (ATCC 29213 and ATCC 25923), Streptococcus faecalis. (ATCC 29212), Bacillus subtilis. (ATCC 6633), Bacillus cereus. (RSKK 1122), Pseudomonas aeruginosa. (ATCC 27853), Escherichia coli. (ATCC 25922), and Candida albicans. (ATCC 10231). Chloroform, ethyl acetate, butanol, and the remaining aqueous extracts, obtained from the fractionation of methanol extract, were also tested. All of the extracts showed some activity against B. subtilis. and B. cereus.. Lyophylized extracts showed the highest activity against Staphylococcus aureus. 25923 and 29213. Buthanol extracts of the leaves and fruits of C. creticus. showed the highest activity. Extracts of all Cistus. species did not show any activity against Pseudomonas aeruginosa. and Candida albicans..

Triterpene Glucosides from the Leaves of Aralia elata and Their Cytotoxic Activities

Three new triterpene glucosides, named congmuyenosides C–E (1–3, resp.), along with four known ones, were isolated from an EtOH extract of Aralia elata (Miq.) Seem. leaves. The structures of the new compounds were identified as 3‐O‐{β‐D‐glucopyranosyl‐(1→3)‐β‐D‐glucopyranosyl‐(1→3)‐[β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐glucopyranosyl}caulophyllogenin (1), 3‐O‐{β‐D‐glucopyranosyl‐(1→3)‐β‐D‐glucopyranosyl‐(1→3)‐[β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐glucopyranosyl}hederagenin 28‐O‐β‐D‐glucopyranosyl ester (2), 3‐O‐{β‐D‐glucopyranosyl‐(1→3)‐β‐D‐glucopyranosyl‐(1→3)‐[β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐glucopyranosyl}echinocystic acid 28‐O‐β‐D‐glucopyranosyl ester (3) on the basis of spectral analyses, including MS, 1H‐NMR, 13C‐NMR, DEPT, HSQC, HMBC, NOESY, and HSQC‐TOCSY experiments. All isolates obtained were evaluated for their cytotoxic activities against three human tumor cell lines (HepG2, SKOV3, and A549). Compound 3 showed significant cytotoxicity against A549 cell line (IC50 9.9±1.5 μM).