Mitsuko Makino

Flavanones from Baeckea frutescens

Abstract Three novel flavanones, named BF-4, BF-5 and BF-6, were isolated from the leaves of Baeckea frutescens . The structures of these flavanones were determined by their mass, 1 H and 13 C NMR spectral data. BF-4 and BF-5 showed strong cytotoxic activity (IC 50 =0.2–0.5 μg/ml) against leukemia cells (L1210) in tissue culture.

Phloroglucinols from Baeckea frutescens

Two new phloroglucinols, named BF-1 and BF-2, were isolated from the dried leaves of Baeckea frutescens. Their structures were determined by their 1H and 13C NMR and mass spectral data. BF-2 exhibited strong cytotoxic activity (IC50 = 5.0 micrograms ml-1) against leukaemia cells (L 1210) in tissue culture.

Syntheses and estrogenic activity of 4-nonylphenol isomers☆

Eight branched 4-nonylphenol (NP) isomers, which were identified from commercially available NP reagent, 4-(1-ethyl-1,4-dimethylpentyl)phenol (NP-C), 4-(1,1-dimethyl-3-ethylpentyl)phenol (NP-D), 4-(1,3-dimethyl-1-ethylpentyl)phenol (NP-E(G)), diastereomeric mixture), 4-(1,1,4-trimethylhexyl)phenol (NP-F), 4-(1-methyl-1-n-propylpentyl)phenol (NP-H), 4-(1,1-dimethyl-2-ethylpentyl)phenol (NP-I), 4-(1,1,2-trimethylhexyl)phenol (NP-M), and 4-(1-ethyl-1-methylhexyl)phenol (NP-N), were synthesized by two different synthetic methods starting from 4-benzyloxyacetophenone or phenol. The chemical structures of the synthesized compounds were confirmed by MS and NMR spectroscopy. The estrogenic activities of these synthetic NP isomers were tested and exhibited different activities on the recombinant yeast screen system. NP-I was found to exhibit three times greater estrogenic activity than the commercial NP mixture.

Oxyfunctionalization of unactivated C–H bonds in triterpenoids with tert-butylhydroperoxide catalyzed by meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex

A system consisting of meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex [Os(TMP)CO] as a precatalyst and tert-butylhydroperoxide (TBHP) as an oxygen donor is shown to be an efficient, regioselective oxidant system for the allylic oxidation, ketonization and hydroxylation of unactivated C-H bonds in a series of the peracetate derivatives of penta- and tetracyclic triterpenoids. Treatment of the substrates with this oxidant system afforded a variety of novel or scarce oxygenated derivatives in one-step. Structures of the isolated components, after chromatographic separation, were determined by spectroscopic methods including GC-MS and shift-correlated 2D-NMR techniques. Factors governing the regioselectivity and the possible mechanism for the oxyfunctionalization of the unactivated carbons are also discussed.

Pharmacological Profile of Novel Acid Pump Antagonist 7-(4-Fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methyl cyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526)

The pharmacological profiles of the novel acid pump antagonist 7-(4-fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methylcyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526) were investigated in terms of hog gastric H+,K+-ATPase activity, gastric acid secretion, and acute gastroesophageal lesions in comparison with other proton pump inhibitors (PPIs). CS-526 inhibited H+,K+-ATPase activity in a concentration-dependent manner, with an IC50 value of 61 nM. The inhibitory effect of CS-526 on H+,K+-ATPase activity was more potent than that of any of the other PPIs examined. The inhibitory mechanism of CS-526 on H+,K+-ATPase was a competitive antagonism to the K+ binding site of H+,K+-ATPase, and it was also a reversible inhibition. In pylorus-ligated rats, intraduodenal or oral administration of CS-526 inhibited gastric acid secretion in a dose-dependent manner, and the ID50 values were 2.8 or 0.7 mg/kg, respectively. In Heidenhain pouch dogs, intrapouch administration of CS-526 inhibited histamine-stimulated gastric acid secretion in a dose- and retention time-dependent manner. In a reflux esophagitis model, intraduodenal and oral administration of CS-526 prevented esophageal lesions with ID50 values of 5.4 and 1.9 mg/kg, respectively. Lansoprazole prevented esophagitis only by intraduodenal administration (ID50 = 2.2 mg/kg). Furthermore, CS-526 inhibited acute gastric mucosal lesions. These data demonstrate that the novel acid pump antagonist CS-526 has potent antisecretory and antiulcer effects. These findings indicate that CS-526 would have a curative effect on gastroesophageal reflux disease via its potent antisecretory and antiulcer actions.

Separation, synthesis and estrogenic activity of 4-nonylphenols: two sets of new diastereomeric isomers in a commercial mixture.

Two sets of new diastereomeric 4-nonylphenol (NP) isomers [4-(3,4-dimethylheptan-4-yl)phenol (344NP, NP-J, L) and 4-(3,4-dimethylheptan-3-yl)phenol (343NP, NP-K, P)] were separated from a commercial NP mixture. The mixture of these diastereomers was synthesized at the same time by a single Friedel-Crafts reaction of 3,4-dimethyl-4-heptanol and phenol, and the mixture was separated into individual NPs by HPLC equipped with Hypercarb column. For the first time, in this study the stereostructure-estrogenic activity relationship of NP diastereomers was investigated. The NP isomers (NP-L and NP-P) having the beta-methyl group over the benzene ring were found to be 2-4 times more estrogenic than their diastereomers (NP-J and NP-K). In the case of the other set of diastereomer [4-(3,5-dimethylheptan-3-yl)phenol, (353NP, NP-E, G)] containing gamma-methyl group in the molecule, the gamma-methyl proton signal (delta 0.49) in the more estrogenic isomer (NP-G) also appeared in a higher field than the corresponding methyl signal (delta 0.76) of the less estrogenic isomer (NP-E).

seco-Adianane-type triterpenoids from Dorstenia brasiliensis (Moraceae).

Two seco-adianane-type triterpenoids, dorstenic acid A and B, were isolated, along with a known isopimarane-type diterpenoid and six coumarins, from the roots of Dorstenia brasiliensis. Their structures were elucidated on the basis of their spectral data. The two triterpenoids showed moderate cytotoxicity against leukemia cells (L-1210 and HL-60).

Terpenoids and phenethyl glucosides from Hyssopus cuspidatus (Labiatae)

Monoterpenoids (3 and 4), sesquiterpenoid (2), diterpenoid (1) and four phenethyl glucosides (5-8), together with fourteen known compounds, were isolated from the whole herb of Hyssopus cuspidatus. Their structures were determined by spectroscopic means. The abietane-type diterpenoids (1, 9, 10), rosmarinic acid (15) and salvigenin (17) inhibited leukotriene (LT) C(4) secretion from primary alveolar cells of Wistar rats.

Sesquiterpene pyridine alkaloids from Hippocratea excelsa

Nineteen sesquiterpene pyridine alkaloids including 17 new compounds have been isolated from the 70% aq. EtOH extract of stem barks of Hippocratea excelsa. The structures of these compounds were elucidated by various spectroscopic means.

Delayed healing of chronic gastric ulcer after Helicobacter pylori infection in mice

It has been suggested that there is a close relationship between Helicobacter pylori and the onset or recurrence of gastroduodenal disease. The aim of this study was to examine the effect of H. pylori on the healing of chronic gastric ulcers induced in mice.