Induction of apoptosis in murine leukemia by diarylheptanoids from Curcuma comosa Roxb.

Diarylheptanoids, isolated from the rhizome of Curcuma comosa Roxb., have several biological activities including anti-oxidant and anti-inflammation. The present study investigated the effect of five diarylheptanoids isolated from C. comosa rhizome on the proliferation of murine P388 leukemic cells. Compound-092, (3S)-1-(3,4-dihydroxyphenyl)-7-phenyl-(6E)-6-hepten-3-ol, bearing a catechol moiety, was the most potent diarylheptanoid (IC₅₀ of 4 μM) in inhibiting P388 leukemic cell viability by causing DNA breakage and inducing apoptosis. Apoptotic cell death was characterized by the presence of chromatin condensation, formation of apoptotic bodies, DNA fragmentation, and externalization of plasma membrane phosphatidylserine. This compound increased caspase-3 activity about fivefold above the untreated control, decreased the intracellular reduced glutathione level, and impaired mitochondrial transmembrane potential. In the presence of Cu(II) ion, the compound exhibited a pro-oxidant activity causing DNA strand breakage and enhancing the anti-proliferative activity. The results provide evidence for the pro-oxidant activity of the diarylheptanoid bearing a catechol moiety in the induction of apoptosis in murine P388 leukemia.     

Triglyceride interesterification by lipases. 3. Alcoholysis of pure triglycerides

Lipase-catalyzed alcoholysis of triolein dissolved in ethanol or isopropanol for the formation of ethyl and isopropyl esters was investigated. Of 16 lipases screened, Amano lipase from P. fluorescens was selected for investigation of the effects of basic reaction conditions on alcoholysis yields. Ethanolysis yields were only slightly affected by water additions to immobilized lipase preparations. Isopropyl ester yields decreased with water addition. Good operational stability was observed over 17 days. Changes in initial triolein concentration in the range 5–50 mM had very little effect on ester yields. The ionic strength of the phosphate buffer used in lipase immobilization affected ethanolysis and isopropanolysis yields in opposite ways. The highest ethanolysis yields were obtained with lipases immobilized from 250 mM buffer, while isopropyl ester yields were highest with lipases immobilized from water. In addition, the quantities and isomers of monoglyceride intermediates in ethanolysis were affected by the immobilization buffer strength. Larger quantities of 2-monoglycerides were formed in ethanolysis reactions with lipase preparations immobilized from water.     

Use of an alternative Archaea-specific probe for methanogen detection

An alternative 16S rRNA-targeted oligonucleotide probe specific for Archaea was developed and used for detection of methanogens in anaerobic reactors. The designed probe was checked for its specificity by computer-aided comparative sequence analysis. For in situ application, optimal stringency conditions were adjusted by performing whole cell hybridization using target and nontarget organisms. Anaerobic sludge samples were examined by in situ hybridization for methanogenic populations. The relative abundance of methanogens was monitored with epifluorescence microscopy. Individual cells could be visualized with strong fluorescence signals after hybridization with the newly developed probe.     

Synthetic analogues of durantoside I from Citharexylum spinosum L. and their cytotoxic activity

New iridoid glycoside derivatives from durantoside I, the latter from the dried flowers and leaves of Citharexylum spinosum, were synthesized by variously modifying a sugar moiety by silylation or acetylation and/or removal of cinnamate group at C-7 position and subsequent screening for comparative cytotoxicity against several cancer cell lines. Addition of alkylsilane to durantoside I and removal of cinnamate group were most effective in improving cytotoxicity.     

Synthesis of 14-deoxy-11,12-didehydroandrographolide analogues as potential cytotoxic agents for cholangiocarcinoma

A series of 14-deoxy-11,12-didehydroandrographolide analogues were synthesized from naturally occurring andrographolide and their cytotoxicity evaluated against nine cancer cell lines including cholangiocarcinoma. Analogues 5a and 5b exhibited the most potent cytotoxicity with ED₅₀s of 3.37 and 3.08?μM on KKU-M213 cell lines and 2.93 and 3.27?μM on KKU-100 cell lines, respectively. Selective cytotoxicity on cholangiocarcinoma cell lines identified in this study highlight the importance of structural modification in the development of drugs for this cancer.     

Stimulation of gastric mucus and protein secretion by cytochalasin E in rats

Effects of cytochalasin E on the secretion of mucus and protein were investigated in gastric fistula rats. Direct exposure of the gastric mucosa to cytochalasin E (5-20 micrograms/ml) significantly stimulated the secretory rate of soluble mucus and protein in pentagastrin-stimulated rats. The amount of surface mucus gel was also increased. The stimulatory effect was increased with increased concentrations of cytochalasin. Histological study suggests that the cytochalasin stimulated the release of mucus from the cell. The increase in secretory rate of protein was not due to an increase of pepsin secretion but rather was the consequence of the increase in mucus secretion.     

Bone Sparing Effect of a Novel Phytoestrogen Diarylheptanoid from Curcuma comosa Roxb. in Ovariectomized Rats

Phytoestrogens have been implicated in the prevention of bone loss in postmenopausal osteoporosis. Recently, an active phytoestrogen from Curcuma comosa Roxb, diarylheptanoid (DPHD), (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol, was found to strongly promote human osteoblast function in vitro. In the present study, we demonstrated the protective effect of DPHD on ovariectomy-induced bone loss (OVX) in adult female Sprague-Dawley rats with 17β-estradiol (E₂, 10 µg/kg Bw) as a positive control. Treatment of OVX animals with DPHD at 25, 50, and 100 mg/kg Bw for 12 weeks markedly increased bone mineral density (BMD) of tibial metaphysis as measured by peripheral Quantitative Computed Tomography (pQCT). Histomorphometric analysis of bone structure indicated that DPHD treatment retarded the ovariectomy-induced deterioration of bone microstructure. Ovariectomy resulted in a marked decrease in trabecular bone volume, number and thickness and these changes were inhibited by DPHD treatment, similar to that seen with E₂. Moreover, DPHD decreased markers of bone turnover, including osteocalcin and tartrate resistant acid phosphatase (TRAP) activity. These results suggest that DPHD has a bone sparing effect in ovariectomy-induced trabecular bone loss and prevents deterioration of bone microarchitecture by suppressing the rate of bone turnover. Therefore, DPHD appears to be a promising candidate for preserving bone mass and structure in the estrogen deficient women with a potential role in reducing postmenopausal osteoporosis.     

Regulation of asthmatic airway relaxation by estrogen and heat shock protein 90

We tested the hypothesis that asthmatic mouse airways exhibit impaired relaxation to NO donors. Mouse tracheal rings were incubated overnight in serum from asthmatic human subjects or from nonasthmatic controls. The next day, cumulative concentration-response curves (CCRC) to sodium nitroprusside (SNP) and nitroglycerine (NTG) were obtained. Both SNP and NTG relaxed the pre-constricted normal tracheal rings. Tracheal rings exposed to serum from asthmatic patients exhibited a more than a threefold increase in the EC50 of SNP and NTG. Pre-incubation of tracheal rings with heat shock protein 90 inhibitors decreased the relaxation of both normal and asthmatic tracheal rings to SNP and NTG. Pre-incubation with estradiol did not affect normal tracheal ring relaxation but exhibited an increase in asthmatic tracheal ring relaxation, which was abolished by an estrogen receptor (ER) antagonist. ER subtype-selective agonists, but not GPR30 agonists, mimicked the action of estradiol on tracheal ring relaxation. Co-incubation of rings with radicicol and estradiol produced an ER-dependent increase in the relaxation response to SNP of both normal and asthmatic ASM. Estrogen-induced relaxation of ASM was abolished by overnight incubation with radicicol and this was associated with reduced expression of ERβ. These data suggest that asthmatic ASM is considerably less responsive to NO-donors and that both estrogen and hsp90 play important roles in ASM relaxation.     

New substituted C-19-andrographolide analogues with potent cytotoxic activities

Andrographolide, the major diterpenoid lactone from Andrographis paniculata, is toxic against cancer cells. In the present study, we investigated the structure-activity relationships (SARs) of 19 andrographolide analogues which were synthesized by modification at the three hydroxyl groups. A number of the andrographolide analogues showed much higher cytotoxic activities than that of the parent compound on cancer cells including P-388, KB, COL-2, MCF-7, LU-1 and ASK cells. SAR studies of the synthetic analogues indicated that the introduction of silyl ether or triphenylmethyl ether group into C-19 of the parent compound led to increase in toxicity against the cancer cells. The 19-O-triphenylmethyl ether analogue 18 showed higher cytotoxic activity than the potent anticancer drug ellipticine, and this analogue may serve as a potential structure lead for the development of new anticancer drugs.     

Gastric mucosal lesions in streptozotocin-diabetic rats

Formation of gastric mucosal lesions by streptozotocin-induced diabetes was investigated in rats. A single intravenous administration of streptozotocin in a dose of 65 mg/kg effectively produced hyperglycemia and damaged the gastric mucosa. Incidence and severity of mucosal lesions were progressively increased with time, from one to six weeks posttreatment. Microscopic lesions of the mucosa included hyperemia, desquamation of the surface epithelium with diffuse hemorrhage, and severe hemorrhage with localized erosion. Concurrent to the hyperglycemia, the histamine stimulated gastric H+-secretion was significantly decreased whereas pepsin secretion was not affected. Both soluble mucus and surface mucus gel were increased. The result suggests that the early lesion of gastric mucosa may be associated with the direct action of streptozotocin, the severity of which may be further aggravated by diabetic state.