Effects of the aqueous extract of Pittosporum mannii Hook. f. (Pittosporaceae) stem barks on spontaneous and spasmogen-induced contractile activity of isolated rat duodenum.

ETHNOPHARMACOLOGICAL RELEVANCE: Pittosporum mannii Hook. f. (Pittosporaceae) is a plant widely used in traditional medicine in Cameroon for the treatment of many gastrointestinal disorders including diarrhea. To date, no pharmacological study on the antidiarrheal and the antispasmodic properties of this plant has been reported. The aim of the present study was to evaluate in vitro the relaxant activity of the aqueous extract of stem barks of P. mannii (PMAE) on rat duodenum. MATERIALS AND METHODS: Different concentrations of PMAE were tested separately (10-80 µg/mL) or cumulatively (5-80 µg/mL) on spontaneous and spasmogen (carbachol, histamine and KCl)-induced contractions of isolated rat duodenum strips. RESULTS: At concentrations ranging from 10 to 80 µg/mL, PMAE significantly decreased the tonus and the amplitude of spontaneous contractions. However, at high concentration (80 µg/mL), the extract elicited a transient relaxation was followed by a slight increase of tonus, while the amplitude remained lower compared to the normal spontaneous activity. The relaxant effect of the extract was not significantly affected in the presence of atropine (0.713 µg/mL) and promethazine (0.5 µg/mL). In addition, PMAE (20, 40, and 80 µg/mL) partially but significantly inhibited in a concentration related manner the contractions induced by carbachol (10(-9)-10(-4)M) and histamine (10(-9)-10(-4)M) on rat duodenum. PMAE (10-80 µg/mL) also significantly induced a concentration-dependent relaxation on KCl (20mM, 50mM, 10(-3)-6.10(-3)M)-induced contraction of rat duodenum. CONCLUSIONS: These results show that the aqueous extract of P. mannii stem barks possesses antispasmodic and spasmolytic effects at lower concentrations; therefore, supporting the use of the stem barks of this plant in the folk medicine for the treatment of diarrhea. However, caution should be paid while using higher concentrations that instead might produce spasmogenic effect and might worsen the diarrheal condition. The relaxant effect of PMAE appears to be non-specific of muscarinic or histaminic receptors, but may involve at least in part a mechanism of inhibition of the Ca(2+) influx into the smooth muscle cells through voltage-operated Ca(2+) channels.

Delay of ejaculation induced by Bersama engleriana in nicotinamide/streptozotocin-induced type 2 diabetic rats

OBJECTIVE@#To evaluate the effects of aqueous and methanolic extracts of Bersama engleriana (B. engleriana) leaves on the expulsion phase of fictive ejaculation in nicotinamide/streptozotocin-induced type 2 diabetic male rats.@*METHODS@#The electromyographic activity of the bulbospongiosus muscles was recorded in urethane anaesthetized, spinal cord transected rats receiving dopamine (0.1 μmol/L/kg) intravenously, in the absence or presence of aqueous and methanolic extracts of B. engleriana (2.5, 10, 50, 60, 75 mg/kg). In another experiment, the pro-ejaculatory effect of dopamine (0.1 μmol/L/kg, i.v.) was monitored in rats orally pre-treated with the aqueous and methanolic extracts (60 mg/kg) of B. engleriana for 1 or 4 weeks.@*RESULTS@#Results of the study showed that the intravenous administration of B. engleriana did not provoke any contraction of the ejaculatory muscles whilst rhythmic and rapid contractions of the bulbospongiosus muscles accompanied sometimes by penis movement and expulsion of the urethral contents were recorded after dopamine application. The sequential treatment of animals with B. engleriana extracts (2.5-75.0 mg/kg) followed by dopamine (0.1 μmol/L/kg) resulted in a dose-dependent abolishment of the pro-ejaculatory response due to dopamine. However, in animals orally submitted to a daily gavage with B. engleriana extracts (60 mg/kg) for 1 or 4 weeks, the ejaculation stimulating effect of dopamine (0.1 μmol/L/kg) was significantly delayed (P<0.01) but not completely suppressed.@*CONCLUSIONS@#Present findings suggest the involvement of dopaminergic system in the activity of B. engleriana and further support its aphrodisiac potentials due to sterols and saponins revealed in this plant.

Delay of ejaculation induced by Bersama engleriana in nicotinamide/streptozotocin-induced type 2 diabetic rats

Objective: To evaluate the effects of aqueous and methanolic extracts of Bersama engleriana (B. engleriana) leaves on the expulsion phase of fictive ejaculation in nicotinamide/streptozotocin-induced type 2 diabetic male rats. Methods: The electromyographic activity of the bulbospongiosus muscles was recorded in urethane anaesthetized, spinal cord transected rats receiving dopamine (0.1 μmol/L/kg) intravenously, in the absence or presence of aqueous and methanolic extracts of B. engleriana (2.5, 10, 50, 60, 75 mg/kg). In another experiment, the pro-ejaculatory effect of dopamine (0.1 μmol/L/kg, i.v.) was monitored in rats orally pre-treated with the aqueous and methanolic extracts (60 mg/kg) of B. engleriana for 1 or 4 weeks. Results: Results of the study showed that the intravenous administration of B. engleriana did not provoke any contraction of the ejaculatory muscles whilst rhythmic and rapid contractions of the bulbospongiosus muscles accompanied sometimes by penis movement and expulsion of the urethral contents were recorded after dopamine application. The sequential treatment of animals with B. engleriana extracts (2.5-75.0 mg/kg) followed by dopamine (0.1 μmol/L/kg) resulted in a dose-dependent abolishment of the pro-ejaculatory response due to dopamine. However, in animals orally submitted to a daily gavage with B. engleriana extracts (60 mg/kg) for 1 or 4 weeks, the ejaculation stimulating effect of dopamine (0.1 μmol/L/kg) was significantly delayed (P<0.01) but not completely suppressed. Conclusions: Present findings suggest the involvement of dopaminergic system in the activity of B. engleriana and further support its aphrodisiac potentials due to sterols and saponins revealed in this plant.

Effects of Ficus asperifolia on normal rat estrus cyclicity

<p><b>OBJECTIVE</b>To evaluate Ficus asperifolia (Moraceae) (F. asperifolia) effecting on regular estrus cycle of Wistar rats.</p><p><b>METHODS</b>Air-dried fruits of F. asperifolia were extracted using water. Prior to the test, vaginal smear was monitored daily for a 3-week period to select females with normal (regular) estrous cycle. Those with regular estrus cycle weighing between 150-170 g were randomized into three sets of 15 animals each. Each set was then divided into three groups: Group 1 (control) was orally administered with distilled water (10 mL/kg body weight) once a day for 1 week starting from the proestrus stage. Groups 2 and 3 were respectively treated with 100 and 500 mg/kg body weight of the plant aqueous extract. The two other sets of 15 animals each were similarly treated as the first set for 3 weeks and 6 weeks respectively. Estrus cycle pattern was monitored before and during plant extract application whereas lipid profile, ovary, uterus and liver growth indices were determined at the end of each treatment.</p><p><b>RESULTS</b>F. asperifolia did not disrupt (0%) the order of appearance of normal estrus cycle stages, namely, proestrus, estrus, metestrus and diestrus. Short-term treatment (1 week duration) exhibited high frequency of appearance of proestrus and estrus stages while mid- (3 weeks) and long-term (6 weeks) treatments revealed constancy in the frequency of all stages irrespective to animal groups. The plasma and organ lipid profile, as well as ovary, uterus and liver growth remained unchanged when compared to distilled water-treated animals. Following long-term administration of plant extract (6 weeks), no adverse effect was noticed.</p><p><b>CONCLUSIONS</b>Our data partially support the use of F. asperifolia in common medicine.</p>