Preliminary Mechanistic Study on the Trachea Smooth Muscle Relaxant Activity of Aqueous Leaf Extract of Tridax Procumbens in Male Wistar Rats.

Objectives: Aqueous leaf extract of Tridax procumbens (ALETP) has potent relaxant activity. However, this relaxant activity in respiratory smooth muscle remains uninvestigated. This study investigates the effect of ALETP on the contractile activity of tracheal smooth muscle (TSM) in adult male Wistar rats. Methods: Twelve male Wistar rats divided into 2 groups and were treated with either 100 mg/kg of ALETP (ALETP treatment group) or vehicle (distilled water; control group) through oral gavage for 4 weeks. Dose responses of TSM from the 2 groups to acetylcholine (10-9 to 10-5 M), phenylephrine (10-9 to 10-5 M), and potassium chloride (KCl; 10-9 to 10-4 M) were determined cumulatively. Furthermore, cumulative dose responses to acetylcholine (10-9 to 10-5 M) after pre-incubation of TSM with atropine (10-5 M), L-NAME (10-4 M), indomethacin (10-4 M), and nifedipine (10-4 M), were determined. Results: Treatment with ALETP substantially inhibited TSM contraction stimulated by cumulative doses of acetylcholine, phenylephrine, and KCl. Furthermore, preincubation of TSM from the 2 groups in atropine significantly inhibited contractility in TSM. Incubation in L-NAME and indomethacin also significantly inhibited contractility in TSM of ALETP-treated rats compared to that of controls. Contractile activity of the TSM was also inhibited significantly with incubation in nifedipine in ALETP-treated rats. Conclusion: ALETP enhanced relaxant activity in rat TSM primarily by blocking the L-type calcium channel and promoting endothelial nitric oxide release. ALETP contains agents that may be useful in disorders of the respiratory tract.

Mechanisms of inhibitory activity of root extract of Carpolobia lutea G. Don on in vitro contractile responses of rabbit corpus carvernosum.

INTRODUCTION: Carpolobia lutea root extract (CLRE) has been reported to enhance penile erection. However, the mechanism involved is poorly understood. We investigated in vitro mechanisms of CLRE action on contractile activity of rabbit corpus cavernosum (CC). METHODS: Corpus cavernosum strips from four healthy male New Zealand rabbits (2.5-3.0kg) were mounted on an organ chamber and contracted with phenylephrine (PE) (10-9 to 10-5M) and Potassium Chloride (KCl) (10-50mM) before treatment with various concentrations of CLRE (0.1-1.2mg/ml). Interactions between CLRE and a Nitric Oxide Synthase (NOS) inhibitor (N-nitro-l-arginine methyl ester - l-NAME 10-4M); guanylyl cyclase inhibitors (Oxalodiazolo 4,3-a quinoxalin-1-one - ODQ 10µM, 20µM, 30µM), and (methylene blue 10-30µM); a cyclooxygenase inhibitor (10-4M indomethacin); potassium-channel inhibitors (100µM tetraethyl ammonium TEA), (100ηM apamin) and (glibenclamide 10µM and 20µM); and a calcium-channel inhibitor (-10-4M nifedipine) were investigated. RESULTS: Maximal contractions of KCl and PE contracted CC strips were significantly reduced in a concentration-dependent manner (40.8±3.6% and 38.6±4.0% from 64.6±2.9% and 98.1±4.2% respectively). Relaxant effect of CLRE was significantly reduced by ODQ (38.6±4.0% to 6.4±1.3% and 38.6±4.0% to 7.2±1.2%), nifedipine (38.6±4.0% to 21.1±2.7%) and glibenclamide (40.8±3.6% to 31.5±3.3%). However l-NAME, indomethacin, methylene blue, TEA and apamin did not inhibit relaxation by CLRE. CONCLUSION: Concentration-dependent relaxant effect of CLRE in rabbit CC involves the soluble guanylate cyclase/cyclase Guanosine Monophosphate system, and activation of ATP-dependent K+ channels.

Evaluation of Male Fertility-Enhancing Activities of Water Seed Extract of Hunteria umbellata in Wistar Rats.

BACKGROUND: In this study, the male fertility-enhancing activity of 100, 200, and 400 mg/kg/day of Hunteria umbellata water seed extract (HU) in Wistar rats was studied for 60 days. In doing this, effect of repeated doses of HU was studied on the weight gain pattern, gonadosomatic index (GSI), serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (TS), prolactin (PRL), and estradiol (ES)} as well as testicular antioxidant status of the treated rats as a way of elucidating the mechanism(s) of action of HU. METHOD: Thirty-six (36) male Wistar rats were randomly divided into six groups (I-VI) of six rats per group. Group I rats were gavaged with 10 ml/kg/day of distilled water and served as an untreated control; Group II rats were gavaged with 0.3 mg/kg/day of clomiphene in distilled water; Groups III-V rats received 100 mg/kg/day, 200 mg/kg/day, and 400 mg/kg/day of HU, respectively, and Group VI rats received 20 mg/kg/day of Vitamin C all in distilled water. All treatments were for 60 days after which the treated rats were humanely sacrificed. Sera of blood samples were processed for the above stated hormonal profile. Similarly, testicular tissues obtained were processed for semen analysis and complete antioxidant profile of the HU-treated testicles by assaying for superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), glutathione reductase (GSR), glutathione peroxidase (GSH-Px), and Thiobarbituric Reactive Species (TBARS). RESULTS: Prolonged treatments with 100 mg/kg/day, 200 mg/kg/day, and 400 mg/kg/day of HU for 60 days induced dose dependent reductions in weight gain pattern with the most significant (p<0.001) effect recorded with the highest dose of HU. Conversely, significant (p<0.001) increase was recorded for GSI at the same HU dose. Clomiphene and HU also induced significant (p<0.01, p<0.001) dose dependent increases in the total sperm count, %live sperm, but reverse effects on %dead sperm and %abnormal sperm. On the hormonal profile, oral treatment with 100 mg/kg/day, 200 mg/kg/day, and 400 mg/kg/day of the extract induced profound (p<0.05, p<0.01, and p<0.001) dose related increases in the sera TS, LH, and FSH while it caused reverse effect on serum PRL but caused no significant alterations in the serum ES levels. Similarly, oral treatment with vitamin C and 100-400 mg/kg/day of HU induced profound (p<0.05, p<0.01, and p<0.001) increases in the antioxidant enzyme activities. CONCLUSION: Overall, prolonged oral treatment with 100-400 mg/kg body weight of HU for 60 days significantly improved sperm function which was mediated via enhanced spermatogenesis, steroidogenesis, and antioxidant mechanisms.

Effects of aqueous leaf extract of Tridax procumbens on contractile activity of corpus cavernosum in N-nitro-l-arginine methyl ester-induced hypertensive male rats.

OBJECTIVE: This study investigated the effects of aqueous leaf extract of Tridax procumbens (ALETP) on contractile activity of corpus cavernosum in N-nitro-l-arginine methyl ester (l-NAME)-induced hypertensive male rats. METHODS: Twenty normal, adult male rats (130-150 g) were divided into four groups of five rats each. Group I (control) was given normal saline (0.6 mL/kg) and group II was given l-NAME (40 mg/kg) for 6 weeks. Groups III and IV also received l-NAME (40 mg/kg) for 6 weeks but were further co-treated with 100 and 200 mg/kg of ALETP, respectively, from week 4 to week 6. All treatments were given orally. Strips of corpus cavernosum from each of the four groups were exposed to increasing concentrations of acetylcholine (ACh) and sodium nitroprusside (SNP) (10-9-10-5mol/L) after contraction with phenylephrine (10-7 mol/L) to test for a dose-response effect. Response to potassium and calcium was also measured after cumulatively adding potassium and calcium (10-50 mmol/L) to potassium- and calcium-free organ chamber. Isometric contractions were recorded through an Ugo Basile data capsule acquisition system. RESULTS: Mean arterial blood pressure was significantly reduced in the ALETP co-treated group compared to the control and l-NAME-only groups (P < 0.05). Cavernosa strips from ALETP co-treated rats exhibited significant inhibition of contraction in response to phenylephrine, potassium chloride, and calcium chloride (P < 0.05). Relaxation in response to Ach and SNP was also significantly impaired in cavernosa strips from the l-NAME-only treated group (P < 0.05), while ALETP co-treated groups showed enhanced percentage relaxation. CONCLUSION: ALETP treatment of l-NAME-induced hypertensive rats promotes a relaxant effect on isolated cavernosa strips. ALETP shows potential in correcting erectile dysfunction in hypertension.