The Novel Antihyperglycaemic Action of Hunteria umbellate Seed Fractions Mediated Via Intestinal Glucose Uptake Inhibition

The present study evaluated the antihyperglycaemic effect and mechanism of action of fractions of the aqueous seed extract of Hunteria umbellata (K. Schum.) Hallier f. (HU) in normal and alloxan-induced hyperglycaemic rats. HU was partitioned in chloroform, acetyl acetate and butan-1-ol to give chloroform fraction (HUc), ethyl acetate fraction (HUe), butanol fraction (HUb) and the “residue” (HUm), respectively. 200 mg/kg of each of these fraction dissolved in 5% Tween 20 in distilled water was investigated for its acute oral hypoglycaemic effects in normal rats over 6 hours while its repeated dose antihyperglycaemic effect was evaluated in alloxan-induced hyperglycaemic rats over 5 days. In addition, 50 mg/kg of the crude alkaloid fraction (HUAf) extracted from HU was evaluated for its possible antihyperglycaemic activity in alloxaninduced hyperglycaemic rats using oral glucose tolerance test (OGTT) over 6 hours. Using the solvent system, distilled water-butanol-ammonium hydroxide (2:15:1, v/v/v), HUb was chromatographed and stained with Dragendorff’s reagent for confirmatory qualitative analysis for alkaloids. Results showed that oral pre-treatment with 200 mg/kg of HUe, HUb and HUm resulted in a significant (p<0.05, p<0.001) time dependent hypoglycaemic effect, with the butan-1-ol fraction HU causing the most significant (p<0.001) hypoglycaemic effect. In the alloxan-induced hyperglycaemic rats,  repeated oral treatment with 200 mg/kg of same HU fractions for 5 days resulted in significant (p<0.05) decreases in the fasting blood glucose concentrations with the most significant (p<0.01) antihyperglycaemic effect also recorded for HUb. Similarly, oral pretreatment with 50 mg/kg of HUAf significantly (p<0.05, p<0.01 and p<0.001) attenuated an increase in the post-absorptive glucose concentration at 1st -6th h in the alloxan-induced hyperglycaemic OGTT model. In addition, alkaloid was present in most of the separated spots on the TLC plate. In conclusion, results of this study showed that HU contains a relative high amount of alkaloids which could have accounted for the antihyperglycaemic action of HU that was mediated via intestinal glucose uptake inhibition.Key words: Hunteria umbellata aqueous seed extract, Alkaloid fraction, Intestinal glucose uptake inhibition, Normal and alloxan-induced hyperglycaemic rat

Evaluation of hypoglycemic activities of hydroethanolic leaf extract of Nicotiana tabacum (Solanaceae)

The aim of this study was to evaluate the hypoglycemic activities of hydroethanolic leaf extract of Nicotiana tabacum. Acute toxicity was evaluated in Swiss albino mice using graded oral doses of the extract. Hypoglycemic properties of Nicotiana tabacum was assessed using oral glucose tolerance test and on normoglycemic rats that received single doses of the extract at 40 and 80 mg/kg body weight and blood glucose levels estimated at 2, 4 and 6 hours (single dose study). Phytochemical screening of the extract for the presence of secondary metabolites was performed with standard methods. Acute toxicity study revealed a median lethal dose (LD50) of 5.82g/Kg. the single-dose study showed that 40mg/Kg and 80mg/Kg body weight of the extract significantly (p<0.05) reduced blood glucose levels at 2h compared to control (27.35% and 28.37% respectively), while 80mg/kg body weight of the extract significantly (p<0.05) reduced blood glucose level at 6h compared to control (75.40%). The oral glucose tolerance test results also showed a significant reduction (p<0.05) in blood glucose levels. These findings suggest that the extract of Nicotiana tabacum has hypoglycemic properties which may be accounted for by the presence of secondary metabolites in the extracts -flavonoids, alkaloids, phenols and terpenoids.Key words: Nicotiana tabacum, Diabetes mellitus, Hypoglycemia, Oral glucose toleranc

Antihyperglycemic profile of erinidine isolated from Hunteria umbellate seed

Water decoction made from the seed of Hunteria umbellata is widely used in the traditional management of diabetes mellitus by Nigerian herbalists, particularly, in the southwest region of the country. Recently, a new bisindole alkaloid, erinidine, was isolated but its antihyperglycemic profile remains largely un-investigated scientifically. This forms the basis for the current study which is primarily designed at investigating the antihyperglycemic profile of erinidine and other fractions in both in vitro and in vivo models of diabetes mellitus. In the present study, erinidine was isolated and purified using the earlier described methods and its antihyperglycemic potentials tested in in vitro models such as dipeptidylpeptidase (IV), glycogen phosphorylase, HIT-T15 cell insulin secretion, glucose uptake activity, aldose reductase assays and ƒ¿-glucosidase inhibition assay testings. In addition, 50 mg/kg of erinidine and that of other fractions were evaluated in in vivo models of normal and chemically-induced hyperglycemic rats. Results showed that erinidine was a light yellow, amorphous solid with UV (CHCl3) ƒÉmax 256 nm, HRESIMSm/z 382.1881 [(M+H)+] (calculated for C22H26N4O2, 382.1876) and melting point of 230 oC. The in vitro study showed the antihyperglycemic action of erinidine to be weakly mediated via ƒ¿-glucosidase inhibition mechanism as the results for other in vitro tests such as dipeptidylpeptidase (IV), glycogen phosphorylase, HIT-T15 cell insulin secretion, glucose uptake activity and aldose reductase assays were all negative. However, the in vivo results showed 50 mg/kg erinidine given per os to normal and alloxan-induced hyperglycemic rats to significantly (p<0.05, p<0.001) attenuate an increase in their post-absorptive blood glucose concentrations after 3 g/kg glucose loading in the rats, suggesting its antihyperglycemic mechanism to be via ƒ¿-glucosidase inhibition. This result, although, further corroborated the in vitro findings but also suggests that erinidine needs to be biotransformed in vivo for its inhibitory activity on intestinal glucose absorption to become evident. Thus, the present study suggests erinidine to be the possible antihyperglycemic agent in Hunteria umbellata seed extract mediating its antihyperglycemic action via intestinal glucose uptake inhibition

Gastrointestnal effects of Syzigium Aromaticum (L) Merr. & Perry(Myrtaceae) in animal models

No Abstract

Relaxant effect of Enantia clorantha on the gastrointestinal smooth muscle of rodents

The effects of aqueous boiled and evaporated extract of Enantia chlorantha (0.8 and 1.5g kg-1) were studied on certain functions of the gastrointestinal tract (GIT) vis-a-vis, gastrointestinal fluid accumulation and motility as well as castor oil induced diarrhoea, using adult rats and mice that have been starved 14-20h prior to experiment. The extract was found to exert inhibitory action on the GIT, which resulted in reduced percentage transit in the herbal-drug-treated animals, when compared with controls (

ANALGESIC AND ANTIPYRETIC ACTIONS OF ENANTIA CHLORANTHA EXTRACT IN SOME LABORATORY ANIMALS

Aqueous extract of the bark of Enantia chlorantha administered intraperitoneally (i.p) into healthy adult albino mice at does of 1.0 and 5.0g/kg resulted in elevation of pain threshold. The action of E. chlorantha was found to be about 20 times less potent than morphine. On the other hand, a dose if 15.0g/kg of the extract given orally to rabbits infected with Klebsiella sp was able to relieve the pyrogenic induced fever whereas no such effect was observed in the control group that was given ordinary water. Key Words: Enantia chlorantha, Anonaceae, malaria, fever, pain, Klesbsiella sp., mice and rabbits Nig. J. Nat. Prod. And Med. Vol.2 1998: 24-2

Gastroprotective effects of the ethanolic extract of Enantia chlorantha in rats

The bark of Enantia chloranthahas several medicinal properties and has been used by traditional medical practitioners in Nigeria for the treatment of skin, gastric and duodenal ulcers, and as an antimalarial. The aim of this study is to demonstrate the gastroprotective effects of E. chloranthaagainst known ulcerogenic agents in rats. Gastric ulcers were first induced by administering 1ml of absolute ethanol and 30mg/kg of indomethacin, separately, intragastrically, via an inflexible oral cannula to two groups of rats. Two other groups of rats were then pretreated with 300mg/kg of the ethanolic extract of E. chlorantha, administered by the same route, 30 minutes before the ulcerogenic agents and the ulcer indices compared. The extract protected against the ulcerogenic effects of absolute ethanol and indomethacininduced ulcers following its pretreatment of rats 30 minutes before the administration of these agents. The inhibition of indomethacin-induced ulcers is however not as effective as that of ethanol-induced ulcers (mean ulcer indices 30.21 ± 4.34 and 2.2 ± 2.65, respectively). We postulate that the extract may be acting mainly as a cytoprotective agent but perhaps also by inhibiting gastric acid secretion.Keywords: Enantia chlorantha, prophylaxis, ethanol, indomethacin, gastric ulcers Rsum L\'corse de Enantia chloranthaa plusieur proprite mdicinales et a t utilis par les tradi-praticients du Nigeria pour le traitement de l\'ulcer de la peau, gastrique et duodenal, et aussi commme un anti-malarial. Le but de cette tud est de montrer l\'effet protecttif de Enantia chloranthacontre les agent ulcerogeniques chez les souris. Les ulcer gastriques on t premirement t induite en administrant sparement et intragastrique 1ml d\'thanol absolute et 30mg/kg d\'indomethacine chez deux groups de souris en utilisant des cannules oral non flexible. Deux autre groupes ont t pr-traite avec 300mg/k d\'extrait ethanolique Enantia chloranthaadministr par la mme route.Ce 30minute avant l\'administration d\'agent ulcerognique. Ensuite leur indice d\'ulcer compar. Les extraits ont proteg contre l\'effet ulcerognique induite par l\'ethanol absolut et l\'indomethacine resultant du pr-traitement des souris 30minute avant l\'administration de ces agents . l\'inhibition de l\'ulcer induite par l\'indomethacine n\'est pas aussi effective que c\'elle induite par l\'ethanol absolute (l\'indice moyen d\'ulcer:30.24 ±4.34 et 2.2 ±2.65 respectivement) nous postulons que l\'extrait agirait principalement comme un agent cytoprotecteur mais peut tre aussi par inhibition de la scretion d\'acid gastrique.Mots cls: D\' Enanatia chlorantha, prophylaxie, ethanol, indomethacine, ulcer gastriqueWest African Journal of Pharmacology and Drug Research Vol. 20(1&2) 2005: 35-3

Possible mechanisms for the anti-ulcer effects of the ethanolic extract of Enantia chlorantha in rats

An alkaloid derived from Enantia chloranthahas been reported to have antiulcer properties and our unpublished data demonstrate the antiulcer properties of the crude ethanolic extract of E. chlorantha. This study is aimed at identifying a possible mechanism(s) for the antiulcer action of the crude ethanolic extract of E. chlorantha. Indomethacin- and ethanol-induced gastric ulcers were treated prophylactically by administering 300mg/kg of the crude ethanolic extract of E. chlorantha, intragastrically through an inflexible oral cannula. The response obtained was then compared with the effect of 200mg/kg of misoprostol- and 50mg/kg of ranitidine-pretreatment, both administered in the same manner but separately to the experimental animals. The effect of the extract in organ bath concentrations ranging from 0.1 to 6.4mg/ml was also tested on several segments of isolated rabbit ileum tissue. It was found that the extract completely protected against the ulcerogenic effects of absolute ethanol and was more efficacious in this regard, than misoprostol, which conferred 69.95% protection. It however, had about the same protective ability as misoprostol against indomethacin-induced ulcers (Ulcer indices of 30.21% and 31.75%, respectively). In addition, it inhibited the spontaneous contractions of isolated rabbit ileum smooth muscle in a dose-dependent manner. The extract appears to act in a manner very similar to misoprostol (inhibition of acid secretion and enhanced cytoprotection by stimulation of mucus secretion), in addition to inhibiting the spontaneous contractions of rabbit ileal smooth muscle by an as yet unclear mechanism.Keywords: Enantia chlorantha, antiulcer, mechanism, acid secretion, cytoprotection RésuméUn dérivé alkaloid d\' Enantia chloranthaa été reporté avoir des propriété anti-ulcéreux. Et nos données non encore publiées montre cette propriété anti-ulcéreux d\'extrait brute d\' Enantia chloranthacette étude a pour but d\' indendentifier les possible mecanismes d\'action anti-ulcéreux de l\'extrait ethanolique brute d\' Enantia chlorantha. L\'ulcer induite par l\'indomethacine et l\'ethanol ont été traitées prophylactiquement en administrant 300mg/kg d\'extrait ethanolique brute d\' Enantia chlorantha intragstriquement en utilisant des cannules oral non flexible. Les réponses obtenues ont été en suite comparées avec l\'effet du pré-traitement de 200mg/kg de Misoprostol et 50mg/kg de Ranitidine. Tous administrés de la même manière mais séparément aux animaux experimenté l\'effet de L\'extrait sur des bains d\'organe à concentration allant de 0.1 a 6.4mg/ml ont été aussi testé sur different segment de tissue d\'ilieum isolés de lapin. Il en est resulté que l\'extrait protégait completement contre les effet ulcerogénique d\'ethanol absolute et était plus efficace à ce regards que le misoprostol, qui conferait une protection de 69.95%. Ce pendent il eu la même abilité protective que le Misoprostol contre l\'ulcer induite par l\'indomethacine.(l\'indice d\'ulcer de 30.21% et 31.75% respectivement) en plus il inhibait la contraction spontanée des muscles blanc d\'ilieum isolée de lapin et ce à dose dépendent. L\'extrait apparait agir de manière similaire au misoprostol (inhibition de la sécretion d\'acide et augmentation de la cytoprotection par stimulation de la secretion du mucus), en plus l\'inhibait de la contraction spontanée des muscles blanc d\'ilieum isolées de lapin mais par un mécanisme non élucidée.Mots clés: d\' Enanatia chlorantha, anti-ulcereux, mecanisme, secretion d\'acid, cytoprotection West African Journal of Pharmacology and Drug Research Vol. 20(1&2) 2005: 39-4

Effects of Enantia chlorantha extracts in Laboratory-Induced Convulsion and Inflammation

Objective: It was decided to investigate the effect of boiled and evaporated extracts of enantia chlorantha in reversing bicucculine-induced convulsions and carrageenan-induced inflammation in rodents. Methods: For the anticonvulsant study, intra-peritoneal doses of 130.0 – 550.0mg/kg of the herbal preparation, or 2 -6mg/kg of phenobarbitone, or distilled water were administered to groups of the animals (15 – 20g, n = 10) prior to the injection of 7.5mg/kg bicucculine 30minutes later. The latent period before the onset of convulsions in each group of animals was determined. For the anti-inflammatory study, intra-peritoneal doses of either 50.0 – 250.0mg/kg of various extracts of the herbal preparation or 30 – 100mg/kg aspirin or distilled water was administered to groups of rats of either sex (200 – 250g, n = 10). Each of the groups of rats then received 0.1ml of 1% of carrageen into the plantar tissue of the right hand paw. The resultant inflammatory oedema was assessed by measuring the percentage increase in the paw diameter. Results: While the evaporated aqueous herbal drug increased the latency of convulsion in all the treated animals, the aqueous extract did not, behaving rather similar to the control mice given distilled water. E. chlorantha did not compare well with phenobarbitone (2.0 – 6.0mg/kg) which protected all the animals from seizure. On the other hand, a dose dependent anti-inflammatory action of evaporated extract of E. Chlorantha (50.0 – 250.0mg/kg) in carrageenan induced inflammation was obtained showing a better efficacy than the boiled aqueous preparation and compared favorably with aspirin. E. chlorantha showed statistically significant activity at doses of 100.0 and 250.0mg/kg, exhibiting 67% and 90% inhibition respectively post 6h induction of inflammation. No inhibition was observed in the control group. Conclusion: E. chlorantha, especially the evaporated extract, exhibited significant anti-inflammatory effect on carrageenan-induced inflammatory oedema in rats. This effect is more gradual and more sustained than a similar effect of aspirin. E. chlorantha also prolonged the latency of bicucculine-induced convulsions in rats. Key Words: Inflammation, Convulsion, Enantia-Chlorantha extract Orient Journal of Medicine Vol.15(1&2) 2003: 68-7