Uterotonic Effects of Aqueous and Methanolic Extracts of Lannea acida in Wistar Rats: An In Vitro Study.

Lannea acida (Anacardiaceae), commonly called Kikié in the Noun division (West-Cameroon), is a tree whose bark is used locally to facilitate delivery. This study was aimed at evaluating the in vitro uterotonic effects of aqueous and methanol extracts of L. acida in Wistar rats. Uterine strips isolated from rats pretreated with 5 µg estradiol (48 h) were mounted in a single-organ bath containing aerated and thermostated De Jalon solution (37 °C). After equilibration, non-cumulative effects of L. acida extracts were recorded after application. The effect of the methanol extract (the most active extract) was monitored in the presence of atosiban (a competitive antagonist of oxytocin receptors), atropine (a specific type 3 muscarinic receptor antagonist), nifedipine (an L-type calcium channel antagonist), and 2-Aminoethoxydiphenyl borate (2-ADB, a specific antagonist of inositol 1,4,5-triphosphate receptors type 1), and in calcium-free medium containing EGTA to elucidate its mechanism of action. L. acida induced uterine contraction in a concentration-dependent manner with the methanol extract (1.506 ± 0.032 gf) being the most effective. Administration of atosiban (2 µmol/L) and atropine (1 µmol/L) reduced the contractile effect of L. acida. Complete inhibition was observed with nifedipine, 2-APB, and calcium-free medium containing EGTA. These results suggest that L. acida possesses uterotonic effects mediated through oxytocin receptors with mobilization of extracellular calcium.

Traditional preparations used as uterotonics in Sub-Saharan Africa and their pharmacologic effects.

BACKGROUND: Little is known about the use of traditional preparations for uterotonic effects at or near delivery in Sub-Saharan Africa. OBJECTIVE: To describe (1) use of traditional preparations in Sub-Saharan Africa intended to have uterotonic effects at or near birth; and (2) results of pharmacologic investigations of the uterotonic properties of such preparations. SEARCH STRATEGY: Structured review of 13 databases. SELECTION CRITERIA: Articles describing use of traditional preparations in Sub-Saharan Africa with primary data, published in English between January 1, 1980 and June 30, 2010. DATA COLLECTION AND ANALYSIS: Full-text review using standard spreadsheet templates. MAIN RESULTS: Objective 1 analysis identified 208 plant species used for uterotonic effects at or near delivery. The most common use was labor induction/augmentation (n=185). Other uses were to expel the placenta, shorten the third stage of labor, manage retained placenta (n=61), and prevent/manage postpartum hemorrhage (n=20). Objective 2 analysis identified 82 species with uterotonic activity confirmed through pharmacologic evaluation. Studies also identified potentiating/inhibiting effects of extracts on pharmaceutical uterotonics. CONCLUSION: Numerous plants are used for uterotonic effects in Sub-Saharan Africa; uterotonic activity has been confirmed in many through pharmacologic evaluation. Such use may increase the risk of adverse outcomes. Further research is needed on the uterotonic efficacy of traditional preparations and on interventions to address use during labor.

In vitro determination of the mechanism of the uterine stimulatory effect of Newbouldia laevis.

The uterine stimulatory effect of the ethanol leaf extract of Newbouldia laevis (Beauv.) Seemann ex Bureau (Bignoniaceae) was evaluated in the presence of some antagonists in vitro in an attempt to elucidate the mechanism of action of the extract. The extract was tested in the presence and absence of phentolamine (4.09 and 40.91 nM), diphenhydramine (4.45 and 44.47 nM), atropine (1.18 and 11.91 nM), and verapamil (2.03 and 20.35 nM). The effect of the antagonists on the extract and on oxytocin used as a reference drug in this study was evaluated. The EC(50) and E(max) were determined and statistically analyzed using one way ANOVA and Dunnett's post hoc test. There was no significant difference in the EC(50) and E(max) of the extract and oxytocin in the presence of phentolamine. Diphenhydramine and atropine significantly inhibited (p <0.01) the extract but both drugs had no effect on oxytocin. However, significant differences (p <0.01) were observed in the EC(50) and E(max) of the extract and oxytocin in the presence of verapamil. These results suggest that the leaf extract of N. laevis contracts the uterus by opening voltage-operated calcium channels and/or by activation of muscarinic receptors.

Quantitative separation of oxytocin, norfloxacin and diclofenac sodium in milk samples using capillary electrophoresis.

A simple, sensitive and rapid method has been developed for simultaneous separation and quantification of three different drugs: oxytocin (OT), norfloxacin (NOR) and diclofenac (DIC) sodium in milk samples using capillary electrophoresis (CE) with UV detection at 220 nm. Factors affecting the separation were pH, concentration of buffer and applied voltage. Separation was obtained in less than 9 min with sodium tetraborate buffer of pH 10.0 and applied voltage 30 kV. The separation was carried out from uncoated fused silica capillary with effective length of 50 cm with 75 microm i.d. The carrier electrolyte gave reproducible separation with calibration plots linear over 0.15-4.0 microg/mL for OT, 5-1000 microg/mL for NOR and 3-125 microg/mL for DIC. The lower limits of detection (LOD) were found to be 50 ng/mL for OT, and 1 microg/mL for NOR and DIC. The method was validated for the analysis of drugs in milk samples and pharmaceutical preparations with recovery of drugs within the range 96-100% with RSD 0.9-2.8%.

Oxytocic properties of the aqueous extract of Globimetula braunii (loranthaceae).

The leaves of Globimetula braunii are used in ethnomedicine to augment labour. The crude aqueous extract of the plant was tested on isolated rat uteri. The agonistic activity of the aqueous extract was compared with that of a standard uterine stimulant oxytocin and uterine smooth muscle antagonists atropine and salbutamol. The extract was found to exhibit oxytocic activity on the uterine smooth muscle which was less potent than that of oxytocin. The force of contraction (3.60 +/-0.25 g) elicited by the highest concentration of the extract (640 mg/ ml) was similar to that of 2.7 x 10-4 mg / ml of oxytocin (3.61+/-0.17 g). Oxytocin was also observed to significantly (p<0.05) enhance the uterine contractile effect of the extract. The oxytocic effects of the extract was significantly (p<0.05) inhibited by both atropine and salbutamol. The oxytocic effects indicate the presence of active principle(s) which would explain the use of the leaves of Globimetula braunii to "hasten delivery" in traditional medicine practice.

Cyclic peptides from Oldenlandia affinis DC. Molecular and biological properties.

A new isolation procedure for Kalata polypeptides from the tropical plant Oldenlandia affinis DC is described. Fractions were screened by thin-layer chromatography, and Van Urk positive fractions were tested for oxytocic activity in estrogenized rat uteri. By using this procedure, we were able to isolate and characterize three macrocyclic polypeptides with uterine activity. Their amino acid sequence and biological effects have been analyzed, and their NMR spectra were compared with those of the earlier ones. All three peptides showed hemolytic activity on human blood, and were tested for antibiotic effect against E. coli, Staphylococcus aureus, and Hemophilus influenzae.

Venusol from Gunnera perpensa: structural and activity studies.

From the aqueous extract of the dry rhizomes of Gunnera perpensa the minor components pyrogallol, succinic acid, lactic acid, and the trimethyl ether of ellagic acid glucoside were isolated. The major constituent was identified as Z-venusol, a phenylpropanoid glucoside. Its structure was verified by X-ray diffraction. Tests on isolated uterine smooth muscle from rats showed that the whole extract stimulated a direct contractile response and induced a state of continuous contractility of the uterus once all additives had been removed from the organ bath. By contrast, venusol did not trigger the direct contractile response but induced the state of continuous contractility once the organ bath was flushed.

Phytochemical and pharmacological studies on Monechma ciliatum.

The leaves of Monechma ciliatum were found to contain alkaloids, glycosides, proteins, tannins and saponins. The hot methanol extract (HME) of the leaves, previously found to have potent oxytocic effect in various species was fractionated in various solvents and the fractions analysed chemically and also assayed on the rat uterus in an attempt to identify the chemical constituents present and in particular the oxytocic principle. Positive reaction with ninhydrin spray suggests that the oxytocic constituent is an amino acidic derivative.

Bioassay-directed isolation of oxytocic principles from the methanol extract of Monechma ciliatum.

The hot methanol extract (HME) of Monechma ciliatum which has been reported to have potent oxytocic activity was purified by fractionation in an attempt to isolate the oxytocic principle. Thin layer analysis indicated that the oxytocic fraction was very polar. A positive reaction with ninhydrin-spray suggested that it is an amino acid/protein. Repeated column chromatography (CC) on silica gel followed by sephadex LH-20 column, accompanied by bioassay of the fractions on the rat isolated uterus enabled partial isolation of the oxytocic principle (P3) to be achieved. Although the exact structure of P3 could not be identified from the present study, various spectral analyses suggest that it is a small peptide made up of tyrosine, leucine and a third component which is probably serine. It is interesting to note that the parent compound, oxytocin, is also a peptide with tyrosine and leucine in its structure.

Characterization of Gaddum's substance R.

1. When the isolated small intestine of the rat is perfused via the mesenteric artery, an oxytocic principle (Gaddum's substance R) is released which is detectable in the perfusate after 30 min and is present in samples collected 8 h later. 2. The oxytocic activity of substance R is lost after boiling but is unaffected by treatment with thioglycolate. Furthermore, atropine, methysergide and indomethacin failed to antagonize uterine contractions to substance R. 3. Neither substance R nor urinary kallikrein alone induce a contraction of the guinea-pig isolated ileum. However, in the presence of kininogen both substance R and urinary kallikrein produce a slow and prolonged contraction of the guinea-pig ileum. 4. The oxytocic and kininogenase properties of both substance R and urinary kallikrein are inhibited by Trasylol. 5. Soy bean trypsin inhibitor (SBTI) selectively inhibited both the oxytocic and the kininogenase activities of substance R but not those of urinary kallikrein. 6. Gel filtration of substance R resolved a single peak of oxytocic activity with an estimated molecular weight of 40 kDa. 7. We conclude that substance R is a kininogenase enzyme which may be distinguished from plasma kallikrein by its molecular weight and from urinary kallikrein by its susceptibility to SBTI. The exact nature of this enzyme remains to be elucidated.

Isolation of oxytocic peptides from Oldenlandia affinis by solvent extraction of tetraphenylborate complexes and chromatography on sephadex LH-20.

PIP: To extract the water-soluble oxytocic polypeptides in Oldenlandia af finis DC, a plant used in African folk medicine as an oral oxytocic, dried above-ground parts were soaked in boiling water for 30 minutes, filtered, and the filtrate shaken for 15 minutes with a .1 M solution of sodium tetraphenylborate (NaTPB) in n-butanol. The butanol layer was separated and shaken with hydrochloric acid for 3 minutes to convert the TPB complexes to hydrochlorides, then washed with water until the pH reached 3, and dried. Ether was added to the dried butanol fraction, fo rming a fluffy yellow precipitate, treated again, forming an almost white precipitate, then examined by chromatography. During the n-butanol and ether treatment some serotonin known to be present in the plant was coprecipitated; in reprecipitation this remained in solution. 2 polypeptides were found. Both came from the same fraction, gave the same ultraviolet spectrum, the same color reaction, and had the same biological effect. After separation with Tlc only the compound with the highest RF value was isolated in sufficient quantities for degration. The amino acid composition has been determined and further structural studies are in progress.^ieng

The pharmacology of a new oxytocic principle from ox hypothalamus.

1. An oxytocic substance has been isolated from ox hypothalamus by successive gel filtration on Sephadex G-25 and Sephadex G-50, and its pharmacology has been examined on three smooth muscle preparations.2. The substance has the same order of potency on rat uterus, guinea-pig ileum, and hen rectal caecum.3. The action of the substance on rat uterus was not abolished by thioglycollate.4. Atropine (1.0 mug/ml.), phenoxybenzamine (0.1 mug/ml.) and mepyramine (1.0 mug/ml.) did not block the smooth muscle action of the substance.5. Drug action, relative potency, and log dose-response relationships distinguish the substance from 5-hydroxytryptamine, acetylcholine, oxytocin, vasopressin, angiotensin amide, bradykinin, and purified preparations of substance P.