Microwave-assisted autohydrolysis of Prunus mume stone for extraction of polysaccharides and phenolic compounds.

Stone of Prunus mume (P. mume) is a by-product of pickled P. mume industry. Stones of native and pickled P. mume, mainly composed of holocellulose (83.8 +/- 1.8% and 65.1 +/- 0.3%, respectively) and acid-insoluble lignin (25.3 +/- 2.2% and 30.6 +/- 0.9%, respectively), were autohydrolyzed by microwave heating to extract polysaccharides and phenolic compounds. By heating at 200 to 230 degrees C, 48.0% to 60.8% of polysaccharide and 84.1% to 97.9% of phenolic compound were extracted in water along with partial degradation of hemicelluloses and lignin. The extracted liquors showed antioxidant activity against hydroxyl radical and DPPH radical originated from phenolic compounds. The pickled P. mume stone showed higher autohydrolyzability and microwave absorption capacity than the native stone due to absorbed salts and acids during pickling in fruit juice of P. mume with external addition of sodium chloride. Pickling process in salty and weak acidic juice seemed to be a kind of pretreatment for softening the stones prior to autohydrolysis induced by microwave heating.

In vitro inhibitory effects of Kampo medicines on metabolic reactions catalyzed by human liver microsomes.

BACKGROUND: Although it is well known that drug-drug interactions may lead to toxicity and therapeutic failure, little is known about the incidence and consequences of herb-drug interactions in patients receiving Kampo medicines. METHODS: We evaluated the frequency of the combined use of Kampo medicines and Western drugs at Osaka University Hospital, and investigated the effects of these formulae on the metabolic activity of different cytochrome P450 (CYP) isoforms using pooled microsomes obtained from human liver. RESULTS: Twenty-two Kampo formulae were used together with 40 Western drugs catalyzed by the CYP isoforms CYP3A4, CYP2C9, CYP2D6 and CYP1A2. Among the Kampo medicines, HOCHUEKKI-TO, SHOSAIKO-TO, NINJINYOUEI-TO, SAIREI-TO and KAKKON-TO were most frequently used during the study period (1996-2000). These were co-administered with 11 categories of drugs, which are substrates for CYP3A4. HOCHUEKKI-TO and SAIREI-TO were competitive inhibitors of CYP3A4 with Ki values of 0.65 and 0.1 mg/mL, respectively. HOCHUEKKI-TO, SHOSAIKO-TO and SAIREI-TO inhibited the metabolic activities of CYP2C9, but had no effect on CYP2D6. HOCHUEKKI-TO and SAIREI-TO exhibited non-competitive inhibition of the metabolic activity of CYP2C9 with a similar Ki value (0.7-0.8 mg/mL). SAIRE-TO (0.25 mg/mL) was a potent inhibitor of CYP1A2 (inhibition > 68%). CONCLUSIONS: Frequently used Kampo medicines may interact with Western drugs, which are substrates for CYP3A4, CYP2C9 and CYP1A2. Their co-administration should be undertaken with care.

Protective effect of Salvia miltiorrhiza on angiotensin II-induced hypertrophic responses in neonatal rat cardiac cells.

The effect of the root of Salvia miltiorrhiza (SM) on angiotensin II (Ang II)-induced hypertrophic responses was examined in cultured neonatal rat cardiac cells (cardiomyocytes and non-cardiomyocytes). The methanol eluate fraction (SM2) of the water extract and the ethyl acetate-insoluble fraction (SM3) and its soluble fraction (SM4) partitioned from the methanol extract were prepared. Treatment with SM4 (5-80 microg/ml), not SM2 and SM3, for 24 h produced dose-dependent cytotoxicity against cardiac cells relative to the reduction in viability and the morphological injury of cardiomyocytes. SM2 or SM3 in the absence of Ang II affected neither hyperplastic nor hypertrophic growth of both cell types. However, SM3 (40 microg/ml) attenuated the positive chronotropic responsiveness of cardiomyocytes to Ang II (1 nM) stimulation, whereas Ang II-induced increase in non-cardiomyocyte number was decreased only by SM2 (40 microg/ml) treatment. Furthermore, SM3 suppressed Ang II-induced enlargement of cell size by preceding Ang II-induced induction of immediate early response gene (c-jun) expression in cardiomyocytes, while SM2 decreased Ang II-induced DNA synthesis in non-cardiomyocytes. Moreover, three phenolic compounds and tanshinone IIA that differed quantitatively among three SM fractions were identified by reverse-phase high performance liquid chromatography. Thus, the present findings indicate that the root of SM is an effective inhibitor of Ang II action and has a plural effective constituent, which possess different pharmacological activities on Ang II-induced hypertrophy and hyperplasia in cultured neonatal rat cardiac cells.

Interaction between the actions of taurine and angiotensin II.

The amino acid, taurine, is an important nutrient found in very high concentration in excitable tissue. Cellular depletion of taurine has been linked to developmental defects, retinal damage, immunodeficiency, impaired cellular growth and the development of a cardiomyopathy. These findings have encouraged the use of taurine in infant formula, nutritional supplements and energy promoting drinks. Nonetheless, the use of taurine as a drug to treat specific diseases has been limited. One disease that responds favorably to taurine therapy is congestive heart failure. In this review, we discuss three mechanisms that might underlie the beneficial effect of taurine in heart failure. First, taurine promotes natriuresis and diuresis, presumably through its osmoregulatory activity in the kidney, its modulation of atrial natriuretic factor secretion and its putative regulation of vasopressin release. However, it remains to be determined whether taurine treatment promotes salt and water excretion in humans with heart failure. Second, taurine mediates a modest positive inotropic effect by regulating [Na+]i and Na+/Ca2+ exchanger flux. Although this effect of taurine has not been examined in human tissue, it is significant that it bypasses the major calcium transport defects found in the failing human heart. Third, taurine attenuates the actions of angiotensin II on Ca2+ transport, protein synthesis and angiotensin II signaling. Through this mechanism taurine would be expected to minimize many of the adverse actions of angiotensin II, including the induction of cardiac hypertrophy, volume overload and myocardial remodeling. Since the ACE inhibitors are the mainstay in the treatment of congestive heart failure, this action of taurine is probably very important.

Renal excretory responses to saline load in the taurine-depleted and the taurine-supplemented rat.

Taurine is found in high concentrations in mammalian cells. Despite recognition of its role as an organic osmolyte in the kidney, information regarding its effects on renal fluid and electrolyte excretion is sparse. Therefore, the objective of the first series of experiments was to determine the effects of taurine depletion on renal excretory responses to a saline load. To induce taurine depletion, male Wistar-Kyoto (WKY) rats were treated with tap water containing 3% beta-alanine for 3 weeks. Taurine depletion reduced the initial rates of fluid and sodium excretion after an intravenous saline load. This effect was attributed to taurine depletion since maintenance of the taurine-depleted rats on tap water for 2 days to remove the effects of beta-alanine yielded the same pattern as the taurine-depleted rats exposed to beta-alanine at the time of the experiment. Nonetheless, rats exposed to short-term beta-alanine treatment, which has no influence on kidney taurine content, demonstrated a larger (approximately 25%) natriuretic but not diuretic response to the isotonic saline load than either the control or taurine-depleted rats. These data suggest that beta-alanine-induced inhibition of tubular reabsorption of taurine may result in subsequent excretion of taurine with attendant natriuresis early in the course of beta-alanine treatment. We also tested the hypothesis that taurine potentiates the renal excretory responses to an isotonic saline load in WKY rats. Inclusion of taurine in the infusate significantly increased natriuresis and diuresis after a saline load. This effect was greater in animals fed a basal than a high NaCl diet. Our data support a role for taurine as a natriuretic and diuretic agent.

Interaction of taurine with methionine: inhibition of myocardial phospholipid methyltransferase.

Perfusion of isolated, working rat heart with buffer containing 300 microM methionine in the presence of 2.5 U/L insulin led to a 15% decrease in cardiac work and a four-fold decrease in sarcolemmal Na(+)-Ca2+ exchange activity. These effects of methionine were largely prevented by inclusion of 10 mM taurine in the buffer supplemented with methionine and insulin. Taurine also reduced the extent of 3H-methyl group incorporation from radioactive methionine into myocardial phospholipids by approximately 45%. Assays of sarcolemmal phospholipid methyltransferase activity at catalytic sites I, II, and III revealed that taurine inhibited N-methylation activity approximately 30%. The data imply that the ability of taurine to modulate myocardial contraction and calcium transport may be related to taurine-mediated inhibition of phospholipid N-methylation.

Pharmacological study of a traditional Chinese medicine: effect of bezoar bovis on the irregular beating pattern of cultured mouse myocardial cells.

The water-extract from "Bezoar bovis", a drug used in Chinese traditional medicine, was examined for its ability to alter the beating pattern of spontaneously contracting cultured embryonic mouse myocardial cells following changes in extracellular calcium (Ca2+). Incubation of the cells with medium containing low Ca2+ concentration (0.4 mM) caused the number of beating cells and beating rate to decrease and the number of arrhythmic cells to increase. By contrast, the number of beating cells decreased while beating rate and the number of arrhythmic cells increased at high Ca2+ (20 mM). Addition of Bezoar bovis extract to the medium attenuated the response to varying Ca2+ concentration. One of the major constituents of Bezoar bovis extract, taurine, was effective in protecting against the abnormal beating pattern induced by high Ca2+. Since beta-alanine, an inhibitor of taurine transport, antagonized the protective effects of both Bezoar bovis and taurine, it is likely that the effect of Bezoar bovis is partially mediated by taurine.

Beneficial effect of taurine in rabbits with chronic congestive heart failure.

To examine the effect of daily treatment with taurine on improving the status of congestive heart failure (CHF), we used rabbits with artificially induced aortic regurgitation. Ten rabbits were treated daily with taurine (100 mg/kg by mouth) and eight with guanidinoethyl sulfonate (GES) (100 mg/kg by mouth) immediately after induction of aortic regurgitation. The cumulative mortality rate at 8 weeks in the taurine-treated CHF group was 10% (1 of 10) compared with 53% (16 of 30) in the nontreated CHF group and 75% (6 of 8) in the GES-treated CHF group (p less than 0.05). Although cardiac function (max dP/dt) in CHF rabbits was significantly decreased (p less than 0.001), taurine-treated CHF rabbits maintained the same values as control rabbits. Taurine content of the left ventricular tissue of the CHF rabbits was significantly increased (p less than 0.01). Administration of taurine and GES to control rabbits for 8 weeks affected neither the hemodynamics nor the taurine content of the heart. It was concluded that taurine slowed the rapid progression of heart failure and consequently prolonged life expectancy.

Levels of the glutamic oxaloacetic transaminase of erythrocytes of pregnant women and of cord bloods of newborn infants.

The mean basal specific activity (S.A.) of the glutamic oxaloacetic transaminase of erythrocytes (EGOT) for a group of 64 pregnant women was lower (p less than 0.001) than the value for the cord bloods of newborn infants, and lower (p less than 0.001) than the value for adults who had a top limit of S.A. of EGOT. In establishing the top limit of the S.A., it is important that the mean basal S.A. of the cord bloods from 49 newborn infants was identical to the mean basal S.A. of adults who had an adequate supplement of pyridoxine. There were no differences in the mean basal S.A.'s of the cord bloods between asymptomatic mothers and mothers who had anemia, edema, hypertension, proteinuria and glucosuria. An infant may be born with a top limit of S.A. which is non-deficient in pyridoxal 5'-phosphate, but a mother can have a low level of the transaminase, and which is deficient in the coenzyme.