COMPARISON OF SPASMOLYTIC ACTIVITIES OF PIPER LONGUM, P. SARMENTOSUM AND QUERCUS INFECTORIA EXTRACTS WITH LOPERAMIDE AND VERAPAMIL IN RAT AND GUINEA PIG INTESTINAL TISSUES

Autor: P. Thaina, K. Sawangjaroen, P. Poonpanang
Rok vydání: 2005
Předmět:
Zdroj: Acta Horticulturae. :183-189
ISSN: 2406-6168
0567-7572
DOI: 10.17660/actahortic.2005.680.28
Popis: Methanolic extracts from dried fruits, roots and nutgalls of Piper longum, P. sarmentosum, Quercus infectoria respectively, were examined for their spasmolytic activities using isolated rat or guinea pig ileums and compared with a reference antidiarrheal drug (loperamide) and an L-type calcium channel blocker (verapamil). Isolated rat ileums were contracted by acetylcholine (ACh, 10 μM) and serotonin (5HT, 3 μM), while guinea pig ileums were contracted by histamine (Hist, 1 μM). Prior application of P. longum, P. sarmentosum and Q. infectoria extracts into the bathing solution, the contraction-induced by ACh, 5HT and Hist were concentration-dependently inhibited with the IC50 of 91, 6, 54 μg/mL; 88, 13, 44 μg/mL and 343, 36, 377 μg/mL, respectively. Loperamide and verapamil exhibited similar pattern of inhibitions with IC50 of 0.61, 0.89, 0.42 μg/mL and 0.44, 0.15, 0.70 μg/mL respectively. All extracts and both drugs also suppressed the contractionevoked by KCl (30 mM) in rat ileums and caused the rightward shift of concentration-response curves of CaCl2-induced contractions of guinea pig ileums in a concentration-dependent manner. It is known that the contraction-induced by agonists and KCl are mainly due to calcium influx through L-type calcium channels which opened indirectly and directly by agonist-receptor activation and KCl respectively. Thus, it is concluded that the spasmolytic activities of all extracts may occur mainly through interruption of calcium influx via voltage-gated channels. The order of potency is P. longum = P. sarmentosum > Q. infectoria. However, they are less potent than loperamide and verapamil. INTRODUCTION The fruits of long pepper (Piper longum; Piperaceae), the roots of Cha-plu (Thai name for Piper sarmentosum; Piperaceae), and the nutgalls of dyer’s oak (Quercus infectoria; Fagaceae) are traditionally used for abdominal pain and as antidiarrheal and antidysentery agents. However, scientific data in support of the claimed curative properties are still lacking. The present study aimed to investigate the effects of the three plant methanolic extracts on the intestinal motility, which might contribute to their antidiarrheal and antispasmodic activities, using isolated rat or guinea pig ileums. The ileums will be induced to contract by acetylcholine (ACh), serotonin (5-HT) or histamine. These substances are chemical mediators released from intestinal mucosa or intramural nerves and have major roles during gastrointestinal disorders (Balazs et al., 1989; Baum et al., 1989; Cassuto et al., 1982; Matinole et al., 1997). The results for the plant extracts were compared with a reference antidiarrheal drug (loperamide) and their calcium channel blocking activities were evaluated by comparison with the standard calcium channel blocker, verapamil. Proc. WOCMAP III, Vol.6: Traditional Medicine & Nutraceuticals Eds. U.R. Palaniswamy, L.E. Craker and Z.E. Gardner Acta Hort. 680, ISHS 2005 184 MATERIALS AND METHODS Plant Materials and Extractions Dried fruits of long pepper and nutgalls were purchased from local medicinal plant store; Cha-plu roots were collected in the area of Prince of Songkla University, Hat Yai Campus. They were cleaned with distilled water and allowed to dry under sunlight or at 50°C in a hot air oven. Then, they were pulverized and macerated individually in absolute methanol (ratio of 1 kg of plants/3L methanol). The supernatant was collected after 7 d and evaporated (55°C) under low atmospheric pressure in rotary evaporator. The orange viscous oil (yield 22.8%), dark green semisolid (yield 4.5%) and brown powder (yield 46.7%) were obtained for long pepper fruit, Cha-plu root and nutgall respectively. Animals and Tissue Preparations All animals [Wistar rats (250-300 g) and guinea pigs (400-600 g) of either sex] were supplied by the animal house, Faculty of Science, Prince of Songkla University, Hat Yai Campus. They were sacrificed by cervical dislocation and exsanguination. The ileum was removed and put into a petri dish containing 95% O2 and 5% CO2 aerated KrebsHenseleit (Krebs) solution and cut into segments (2 cm long). The ileal segment was then set up in an organ bath filled with 25 mL of 37°C Krebs solution and aerated with 95% O2 and 5% CO2. It was loaded with 1 g tension and allowed to equilibrate for 30 min before starting the experiment. The ileal contraction was recorded isometrically with a force FT03 displacement transducer connected to a Grass Model 7H polygraph (Grass International Co., Quincy, MA, USA). Experimental Procedures 1. Inhibitory Effects on Spasmogen-induced Contractions. After 30 min equilibration period, rat ileum was induced to contract by submaximal concentration of either spasmogens 10 M ACh, or 3x10 M 5-HT. Guinea pig ileum was contracted with 10 M histamine. When stable responses to the spasmogen were obtained, the effects of the test agents (plant extracts, loperamide or verapamil) on the contractions were determined by addition into the bathing solution. Fifteen minutes later, second response to the spasmogen was obtained. This step was then repeated using higher concentrations of test agents. In parallel control experiments, the effects of spasmogen were also performed in the presence of prior addition of equal volume of vehicle. 2. Inhibitory Effects on the KCl (30 mM)-induced Contractions. The rat ileum was induced to contract by KCl 30 mM. After stable responses to KCl were reached, the plant extracts or loperamide were added in the bathing solution. Fifteen minutes later KCl 30 mM was added again. This step was then repeated 2-3 times using higher concentration of the test agents. 3. Inhibitory Effects of the Plant Extracts and Loperamide on CaCl2-induced Contractions. As described by Reynolds et al. (1984), the isolated segment of guinea pig ileum was set up in an organ bath containing a high K (KCl 80 mM) and calcium free saline solution. The tissue was allowed to equilibrate for 45 min, during which it was washed every 10 min with the fresh saline solution. Then the cumulative concentrationresponse relationship of CaCl2 was obtained by addition into the bathing solution at 2.5 min intervals. The plant extracts or loperamide were added to the bath immediately after washing the tissue and 20 min later, a cumulative dose-response curve of CaCl2 was obtained. In control experiments, pairs of concentration-response curves of CaCl2 were performed with the addition of the vehicles. Drugs and Chemicals Acetylcholine perchlorate, histamine diphosphate, 5-hydroxytryptamine hydrochloride (serotonin), loperamide hydrochloride and verapamil hydrochloride were purchased from Sigma (St. Louis, USA). Chlorpheniramine maleate for injection was purchased from A.N.B. Laboratory Co., LTD (Bangkok, Thailand). The Krebs-Henseleit
Databáze: OpenAIRE
Externí odkaz: