The role of α – and β – adrenergic receptors in the spasmolytic effects on rat ileum of Petroselinum crispum Latifolum (parsley)

Antisecretory and Spasmolytic Activities of Aqueous and Ethanolic Stem Bark Extracts of Nauclea diderrichii in Wistar Rats

Background

Diarrheal diseases are a major cause of morbidity and mortality throughout the world and particularly in developing countries. Nauclea diderrichii is a plant used in traditional medicine in the treatment of anemia, fever, gastric ulcer, malaria, abdominal pain, skin infections, and diarrhea. The present work is aimed at evaluating the antisecretory and spasmolytic activities of aqueous and ethanolic stem bark extracts of Nauclea diderrichii in Wistar rats.

Methods

The effect of aqueous and ethanolic extracts of Nauclea diderrichii was tested at doses of 100, 200, and 300 mg/kg on castor oil-induced secretory diarrhea, misoprostol-induced fluid accumulation, and the effect of pretreatment with yohimbine and glibenclamide. They were also tested on normal motility and castor oil- and carbachol-induced hypermotility.

Results

The results showed that the aqueous and ethanolic extracts of Nauclea diderrichii significantly (p < 0.001) inhibited castor oil-induced secretory diarrhea at all the doses. Both extracts significantly (p < 0.001) inhibit fluid accumulation induced by misoprostol. The pretreatment with glibenclamide reduced the antidiarrheal activity of aqueous extract of Nauclea diderrichii. The pretreatment with yohimbine did not alter the effect of the aqueous extract of Nauclea diderrichii. On intestine transit as on castor oil- and carbachol-induced motility, the aqueous and ethanolic extracts at doses of 100 and 200 mg/kg reduced significantly (p < 0.05, p < 0.01, and p < 0.001) the travelled distance by charcoal and peristaltic index.

Conclusions

The study demonstrated that the aqueous and ethanolic extracts of Nauclea diderrichii possess antisecretory and antispasmolytic properties hence its use in traditional medicine against diarrhea.

Investigation of Antibacterial and Anti-Diarrhoeal Activities of 80% Methanol Leaf and Fruit Extract of Leonotis ocymifolia (Burm. F) Iwarsson (Lamiaceae)

BACKGROUND

Leonotis ocymifolia (Burm.F) Iwarsson (Lamiaceae) is among the medicinal plants that are claimed to have various pharmacologic activities. However the leaves and fruits of L. ocymifolia have not yet been explored scientifically for antibacterial and anti-diarrhoeal activities. This study was aimed at investigating the anti-diarrhoeal and antibacterial activities of 80% methanol leaf and fruit extract of Leonotis ocymifolia in mice and selected diarrhea causing bacterial species.

METHODS

The leaves and fruits of Leonotis ocymifolia were extracted using 80% methanol through maceration technique. The anti-diarrheal activity was evaluated using a castor oil induced diarrheal model, prostaglandin induced anti-enteropooling, and castor oil induced charcoal meal test in mice of either sex. Data were analyzed using one-way analysis of variance followed by Tukey post-hoc test. The antibacterial activity was evaluated on using an agar well diffusion assay. Bacterial species used were Salmonella typhi, Salmonella paratyphi, Salmonella typhimurium, Shigella species, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. For anti-diarrhoeal activity, the extract was tested at 100, 200, and 400 mg/kg. Positive and negative control groups were treated with loperamide (3 mg/kg) and 2% tween 80 (10 mL/kg), respectively.

RESULTS

A significant (p<0.05) reduction in frequency of wet stools and watery content of diarrhea as well as in delaying onset of diarrhea as compared to controls was observed in mice at the stated doses. The extract showed a dose-dependent inhibition in all used models. L. ocymifolia leaf and fruit extract also showed antimicrobial activity against all tested organisms.

CONCLUSION

Results from this study collectively indicated that 80% methanol leaf and fruit extracts of L. ocymifolia possessed significant anti-diarrhoeal activity and antibacterial activities, hence provides the scientific base for its traditional use as a diarrhea treatment.

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.

Effect of insulin on Blattela germanica Linnacus

OBJECTIVE

To determine the sensitivity of Blattela germanica L (B. germanica L) to differenct doses of insulin.

METHODS

B. germanica were reared in laboratory conditions at (25±2) °C and (50±5)% relative humidity (RH), and exposure period of 12:12 L/D. Different concentrations, viz. 5, 10, 15, 20 and 25 µ of insulin N, R, (N+R) were prepared and injected to 10 treated cockroaches with another 10 cockroaches which were injected with normal saline as control group.

RESULTS

Insulin N with a dose of 20 µ caused more than 70% mortality of B. germanica in this study. There was a significant difference between 20 µ of insulin N with other doses of 5, 10, 15 and 25 µ, and its comparison with other forms of medication also showed obvious difference (P<0.05).

CONCLUSIONS

It can be concluded that effective drug doses of insulin which can be used as posion bait or gel against German cockroaches could be utilized in the control of B. germanica in the future field studies.