Kazuyoshi Kawazoe

Alkyl gallates, intensifiers of beta-lactam susceptibility in methicillin-resistant Staphylococcus aureus.

ABSTRACT We found that ethyl gallate purified from a dried pod of tara (Caesalpinia spinosa) intensified β-lactam susceptibility in methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA strains, respectively). This compound and several known alkyl gallates were tested with MRSA and MSSA strains to gain new insights into their structural functions in relation to antimicrobial and β-lactam susceptibility-intensifying activities. The maximum activity of alkyl gallates against MRSA and MSSA strains occurred at 1-nonyl and 1-decyl gallate, with an MIC at which 90% of the isolates tested were inhibited of 15.6 μg/ml. At concentrations lower than the MIC, alkyl gallates synergistically elevated the susceptibility of MRSA and MSSA strains to β-lactam antibiotics. Such a synergistic activity of the alkyl gallates appears to be specific for β-lactam antibiotics, because no significant changes were observed in the MICs of other classes of antibiotics examined in this study. The length of the alkyl chain was also associated with the modifying activity of the alkyl gallates, and the optimum length was C5 to C6. The present work clearly demonstrates that the length of the alkyl chain has a key role in the elevation of susceptibility to β-lactam antibiotics.

Interrelationship of dipeptidyl peptidase IV (DPP4) with the development of diabetes, dyslipidaemia and nephropathy: a streptozotocin-induced model using wild-type and DPP4-deficient rats

We examined the role of dipeptidyl peptidase IV (DPP4) in the development of diabetes, dyslipidaemia and renal dysfunction induced by streptozotocin (STZ). F344/DuCrlCrlj rats, which lack DPP4 activity, and wild-type rats were treated with STZ. Plasma DPP4 activity and biochemical parameters were measured until 42 days after STZ treatment. At the end of the experiment, renal function and DPP4 expressions of the kidney, liver, pancreas and adipose tissues were determined. Increases in blood glucose, cholesterol and triglycerides were evoked by STZ in both rat strains; however, the onset of hyperglycaemia was delayed in DPP4-deficient rats as compared with wild-type rats. By contrast, more severe dyslipidaemia was observed in DPP4-deficient rats than in wild-type rats after STZ treatment. Plasma DPP4 activity increased progressively with time after STZ treatment in wild-type rats. The kidney of wild-type rats showed decreased DPP4 activity with increased Dpp4 mRNA after STZ treatment. In addition, kidney weight, serum creatinine and excreted amounts of urinary protein, glucose and DPP4 enzyme were enhanced by STZ. DPP4-deficient rats showed increased serum creatinine in accordance with decreased creatinine clearance as compared with wild-type rats after STZ treatment. In conclusion, plasma DPP4 activity increased after STZ treatment, positively correlating to blood glucose. DPP4-deficient rats were resistant to developing diabetes, while susceptible to dyslipidaemia and reduction of glomerular filtration rate by STZ. DPP4 activation may be responsible for hyperglycaemia, lipid metabolism and preservation of renal function.

Sesquiterpenoids from the fruits of Ferula kuhistanica and antibacterial activity of the constituents of F. kuhistanica

Ethyl acetate extracts of the air-dried fruits of Ferula kuhistanica afforded three daucane esters: kuhistanicaol H, I and J, together with nine other known compounds. Their structures were established on the basis of spectroscopic evidence. Isolated compounds in this paper and previously reported compounds from the roots and stems of F. kuhistanica were tested for antibacterial activity. Some of them were selectively toxic against Gram-positive bacteria, including methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA).

Adiponectin inhibits insulin-like growth factor-1-induced cell migration by the suppression of extracellular signal-regulated kinase 1/2 activation, but not Akt in vascular smooth muscle cells.

Adiponectin, an adipocyte-derived hormone, has been proposed to show antiatherogenic properties through the inhibitory effects against various growth factors. Insulin-like growth factor-1 (IGF-1) is one of the potent mitogens, which has been considered to play important roles in both atherogenesis and plaque stabilization in accordance to the phase of atherosclerosis. The aim of this study is to elucidate the adiponectin effects on IGF-1-induced cell migration and its intracellular signaling pathways in vascular smooth muscle cells (VSMCs). In this study, we assessed cell migration and several kinase activities in cultured rat aortic smooth muscle cells (RASMCs). Adiponectin pretreatment suppressed IGF-1-induced cell migration and extracellular signal-regulated kinase (ERK)1/2 activation, which is one of the major mediators for IGF-1-induced cell migration. In RASMCs, adiponectin and 5-aminoimidazole-4-carboxamide riboside (AICAR), a 5′-AMP-activated protein kinase (AMPK) activator, stimulated AMPK activation. AMPK activation by AICAR inhibited IGF-1-induced ERK1/2 activation and cell migration in RASMCs. On the other hand, phosphorylation of Akt and Bad, proapoptotic molecules of the Bcl-2 family, which were increased by IGF-1 stimulation, was not diminished by the pretreatment with adiponectin. It was shown that adiponectin inhibited IGF-1-induced VSMC migration through suppression of ERK1/2 activation, which might be implicated in AMPK activation. Furthermore, adiponectin selectively inhibited ERK1/2 pathway, not Akt–Bad pathway, stimulated by IGF-1. From these findings, it was implied that adiponectin suppressed IGF-1-induced VSMC migration and its signaling selectivity.

Rearranged abietane-type diterpenes from Salvia dichroantha

Abstract Three new irregular abietane-type diterpenes were isolated from the root of Salvia dichroantha. It was revealed by spectroscopic methods and chemical reaction that these compounds have a unique structure which contains a rearranged abietane skeleton. They were named dichroanal A and B and dichroanone and shown to be rel-(4aS,9R,9aS)-8-formyl-1,2,3,4,4a,9a-hexahydro-5,6,9-trihydroxy-7-isopropyl-1,1,4a-trimethylfluorene; 4aS∗-8-formyl-2,3,4,4a-tetrahydro-5,6-dihydroxy-7-isopropyl-1,1,4a-trimethyl-1H-fluorene and 4aS∗-2,3,4,4a-tetrahydro-6-hydroxy-7-isopropyl-1,1,4a-trimethyl-5,8(1H)-fluorene dione, respectively. Salvia tomentosa was found to contain seven known abietane-type diterpenes.

A novel targeting therapy of malignant mesothelioma using anti-podoplanin antibody.

Podoplanin (Aggrus), which is a type I transmembrane sialomucin-like glycoprotein, is highly expressed in malignant pleural mesothelioma (MPM). We previously reported the generation of a rat anti-human podoplanin Ab, NZ-1, which inhibited podoplanin-induced platelet aggregation and hematogenous metastasis. In this study, we examined the antitumor effector functions of NZ-1 and NZ-8, a novel rat-human chimeric Ab generated from NZ-1 including Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against MPM in vitro and in vivo. Immunostaining with NZ-1 showed the expression of podoplanin in 73% (11 out of 15) of MPM cell lines and 92% (33 out of 36) of malignant mesothelioma tissues. NZ-1 could induce potent ADCC against podoplanin-positive MPM cells mediated by rat NK (CD161a+) cells, but not murine splenocytes or human mononuclear cells. Treatment with NZ-1 significantly reduced the growth of s.c. established tumors of MPM cells (ACC-MESO-4 or podoplanin-transfected MSTO-211H) in SCID mice, only when NZ-1 was administered with rat NK cells. In in vivo imaging, NZ-1 efficiently accumulated to xenograft of MPM, and its accumulation continued for 3 wk after systemic administration. Furthermore, NZ-8 preferentially recognized podoplanin expressing in MPM, but not in normal tissues. NZ-8 could induce higher ADCC mediated by human NK cells and complement-dependent cytotoxicity as compared with NZ-1. Treatment with NZ-8 and human NK cells significantly inhibited the growth of MPM cells in vivo. These results strongly suggest that targeting therapy to podoplanin with therapeutic Abs (i.e., NZ-8) derived from NZ-1 might be useful as a novel immunotherapy against MPM.

Triterpenoid inhibitors of interleukin-1 secretion and tumour-promotion from Tripterygium wilfordii var. Regelii

Abstract Three new triterpenoids, 2,3,22β-trihydroxy-21-oxo-24, 29-nor-D:A-friedooleana-1,3,5(10)-triene, 2α, 6β-dihydroxy-3-oxo-24-nor-D:A-friedooleana-4-ene-29-oic acid and 2,3,7-trihydroxy-6-oxo-24-nor-D:A-friedooleana-1,3,5(10), 7-tetraene-29-oic acid, named regeol A, B and C, and nine known triterpenoides were isolated from T. wilfordii var. regelii . Their structures were established on the basis of the chemical reactions and spectroscopic evidence. Isolated compounds and derivatives were observed to inhibit Epstein-Barr virus early antigen activation and showed potent inhibitory activities against interleukin-1α and β release from human peripheral mononuclear cells.

Dietary doses of nitrite restore circulating nitric oxide level and improve renal injury in l-NAME-induced hypertensive rats

We have reported that pharmacological doses of oral nitrite increase circulating nitric oxide (NO) and exert hypotensive effects in Nomega-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. In this study, we examined the effect of a chronic dietary dose of nitrite on the hypertension and renal damage induced by chronic L-NAME administration in rats. The animals were administered tap water containing L-NAME (1 g/l) or L-NAME + nitrite (low dose: 0.1 mg/l, medium dose: 1 mg/l, high dose: 10 mg/l) for 8 wk. We evaluated blood NO levels as hemoglobin-NO adducts (iron-nitrosyl-hemoglobin), using an electron paramagnetic resonance method. Chronic administration of L-NAME for 8 wk induced hypertension and renal injury and reduced the blood iron-nitrosyl-hemoglobin level (control 38.8 +/- 8.9 vs. L-NAME 6.0 +/- 3.1 arbitrary units). Coadministration of a low dose of nitrite with L-NAME did not change the reduced iron-nitrosyl-hemoglobin signal and did not improve the L-NAME-induced renal injury. The blood iron-nitrosyl-hemoglobin signals of the medium dose and high dose of nitrite were significantly higher than that of L-NAME alone. Chronic administration of a medium dose of nitrite attenuated L-NAME-induced renal histological changes and proteinuria. A high dose of nitrite also attenuated L-NAME-induced renal injury. These findings suggest that dietary doses of nitrite that protect the kidney are associated with significant increase in iron-nitrosyl-hemoglobin levels. We conclude that dietary nitrite-derived NO generation may serve as a backup system when the nitric oxide synthase/L-arginine-dependent NO generation system is compromised.

Sesquiterpenoids from Ferula kuhistanica

Methanol extracts of the air-dried roots and stems of Ferula kuhistanica afforded seven daucane-type sesquiterpenes, called kuhistanicaol A-G, together with 13 known daucane esters. Their structures were established on the basis of spectroscopic evidence and the results of chemical reactions.

Phenolic diterpenes from Tripterygium wilfordii var. regelii

Abstract Seven new phenolic abietane type diterpenoids: 14, 19-dihydroxy-3-oxo-abieta-8, 11, 13-triene; 3,14-dihydroxy-abieta-8, 11, 13-triene; 14, 19-dihydroxy-3,7-dioxo-abieta-8, 11, 13-triene; 18(4 → 3)-abeo-abieta-3,8,11,13-tetraene-18-oic acid; 18(4 → 3)-abeo-14, 15-dihydroxy-abieta-3, 8, 11, 13-tetraene-18,19-olide; 18(4 → 3)-abeo-abieta-14,16-dihydroxy-abieta-3,8,11,13-tetraene-18,19-olide; 18(4 → 3)-abeo-abieta-14, 17-dihydroxy-abieta-3,8,11,13-tetraene-18,19-olide named triptobenzene A, B, C, D, E, F and G have been isolated from Tripterygium wilfordii var. regelii. Their structures have been established on the basis of spectroscopic evidence.