M3 muscarinic receptor- and Ca2+ influx-mediated muscle contractions induced by croton oil in isolated rabbit jejunum.

AIM OF STUDY: Croton oil is the fruit oil of Croton tiglium L., which is well known in folk medicine for the treatment of gastrointestinal (GI) diseases, including constipation, abdominal pain, peptic ulcer, and intestinal inflammation for a long period. This study was to investigate the pharmacological effect of croton oil on GI tract. MATERIALS AND METHODS: The effect of croton oil on the smooth muscle contractions was investigated in vitro using the isolated rabbit jejunum model. RESULTS: Croton oil has a biphasic action contracting and relaxing intestinal tissue. At the concentrations of 20-80 microg/mL, croton oil produced a concentration-dependent increase in the amplitude and tension of muscle contractions, whereas at high concentrations (>200 microg/mL) it decreased the contractile amplitude and had no impact on the tension. Moreover, croton oil was less effective in increasing muscle amplitude and tension than Ach, confirming that the effect of croton oil on muscle contractions is not a simply stimulatory or inhibitory action, but a unique modulatory process depending on the concentration of croton oil. In addition, croton oil concentration-dependently suppressed the frequency of muscle contractions. On the other hand, atropine (10 microM) and 4-DAMP (10 microM) produced a significant inhibition of contractions caused by croton oil, while either hexamethonium (10 microM) or methoctramine (10 microM) was inactive, implying that the regulatory effects of croton oil on GI motility are mediated via the activation of M3 muscarinic receptor. Furthermore, muscle contractions induced by croton oil were dramatically reduced by verapamil (0.1 microM) but not by NE (1 microM), suggesting that the action of croton oil on GI motility is also mediated by Ca(2+) influx through L-type Ca(2+) channel. CONCLUSIONS: The results suggest that croton oil possesses spasmogenic and spasmolytic properties and the regulatory effects of croton oil on GI motility are mediated via the activation of M3 muscarinic receptor and Ca(2+) influx through L-type Ca(2+) channel.

Antidiarrhoeal and intestinal modulatory activities of Wei-Chang-An-Wan extract.

AIM OF THE STUDY: Wei-Chang-An-Wan (WCAW), a traditional pharmaceutical preparation, has been used for treating various gastrointestinal (GI) diseases for several decades, but it is still poorly understood how it works on those disorders. This study was to investigate the effects of WCAW extract on GI tract. MATERIALS AND METHODS: The activities of the methanol extract (ME) of WCAW on castor oil-induced diarrhoea, gastrointestinal transit (GIT) in mice, and contractions of isolated rabbit jejunum were investigated. We further assessed the safety of ME in vivo. Additionally, a HPLC fingerprint of ME was appraised to ensure its chemical consistency. RESULTS: Ten peaks were identified in the HPLC fingerprint of ME. At the doses of 400 and 800 mg/kg, ME significantly protected mice against castor oil-induced diarrhoea as well as the number of faeces and wet faeces. Interestingly, administration of ME significantly accelerated GIT in normal mice and reduced stimulated GIT induced by neostigmine. ME also dose-dependently attenuated spontaneous contractions of the isolated rabbit jejunum, and those induced by acetylcholine (Ach) and neostigmine. Moreover, oral administration of ME up to 5 g/kg did not produce any toxic effects. Taken together, ME is able to inhibit diarrhoea, increase normal GIT, and decrease GIT induced by neostigmine, which indicate that ME might play a bidirectional role in GI tract. CONCLUSIONS: Our study provides a scientific basis for the clinical use of WCAW.

[Measurement of borneol based on near infrared spectroscopy].

Infrared spectroscopy can provide integrated information of samples, and is easy to be applied to on-line control. So quality control specification of Chinese drugs can be improved by utilizing this method for the production of Chinese drugs. This method can accelerate the modernization process of Chinese drugs. Borneol is an effective constituent in lots of active Chinese drugs. The spectral characteristics of borneol in near infrared region were investigated in this paper. The characteristic absorption peaks of bomeol were found by measuring its spectra in near infrared band. There are five absorption peaks of borneol close to 4828, 5003, 5736, 7044 and 8387 cm(-1), respectively. Establishing a partial least square (PLS) model can get optimal results in model building experiment. The predictive results show that the linear relationship between twenty-five samples' predicted values and real values is good with regard to the content of borneol. In calibration model, the root mean square error of prediction (RMSEP) of the content of borneol is 0.28 mg x mL(-1) and the number of the principal components is equal to two. The experimental results show that infrared spectroscopy can be used as a means in the field of quality control of Chinese drugs and the measurement of effective constituents of Chinese drugs.