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 Antioxidant Activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel Leaves

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol : water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals

Investigation of the anti-inflammatory and antinociceptive activities of Hymenocardia acida Tul. (Hymenocardiaceae)

Hymenocardia acida Tul. (Hymenocardiaceae) locally called Orupa, is traditionally used for the treatment of inflammation, including arthritis, rheumatic pain and toothache. The potential antiinflammatory and antinociceptive activities of the aqueous leaf extract of this plant were evaluated in animal models. The extract (50, 100 and 200 mg/kg) significantly (P < 0.05) and dose - dependently inhibited carrageenan and egg albumin-induced rat paw oedema development compared with control group. At 3 h of post-carrageenan administration, the highest dose of the extract (200 mg/kg, p.o) inhibited oedema formation by 66.67%. The reference drug used, indomethacin (10 mg/kg, p.o), gave an inhibition of 72.22%. The inhibitory activity shown by the aqueous leaf extract of H. acida over a period of 6 h in the carrageenan and 3 h in the egg albumin-induced paw inflammation models was comparable to that exhibited by the reference drugs used, indomethacin and cyproheptadine (10 mg/kg, p.o). The extract elicited a significant analgesic activity in the tail immersion test as evidenced by the increase in latency time in seconds as compared with the control at the end of 20 min. In the acetic acid-induced writhing model, the extract showed a dose-dependent reduction in the number of writhes at 50, 100 and 200 mg/kg when compared to the control group. The 200 mg/kg dose produced a complete protective effect, as no abdominal constriction was observed. The results obtained in this study provide some justification for the folkloric uses of H. acida as a remedy for relieving pain and  inflammation.Key words: Anti-inflammatory activity, antinociceptive activity, carrageenan, egg-albumin, Hymenocardia acida

THE NOVEL ANTIHYPERGLYCAEMIC ACTION OF HUNTERIA UMBELLATA 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 alloxan-induced 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 (

Gastroprotective Effects of the Aqueous Seed Extract of Entada gigas (Linn.) Fawc. and Rendle (Fabaceae) in Ulcer Models in Rats

Background: The extract of Entada gigas Linn. (Fabaceae) is used for the treatment of ulcer in Nigerian local medicine. Objectives: This study investigated the gastroprotective effects of the aqueous seed extract of E. gigas on gastric ulcers in rats. Methodology: The ethanol- (EIU), pylorus ligation- (PLIU) and cold restraint stress (CRSIU)-induced ulcer models were used. The aqueous seed extract was administered at doses of 50-400 mg/kg p.o. Estimations of gastric content volume, pH and titratable acidity in PLIU test and ulcer score/index in all models were done. Results: In the EIU test, E. gigas produced significant reduction (p < 0.05) in ulcer scores, with peak effect elicited at 100 mg/kg (2.30 ± 0.99; 87.22% inhibition), compared with control (10.80 ± 0.80). This effect was comparable to that of misoprostol (3.00 ± 1.31; 83.33% inhibition). In the PLIU test, the extract caused significant reduction (p < 0.05) in the ulcer score compared with control (6.30 ± 0.70). Peak effect was elicited at the dose of 200 mg/kg (ulcer score 2.90 ± 0.83; 63.17%). This effect was comparable to that of cimetidine (2.60 ± 0.93; 66.98%). Also, the extract at 50 and 200 mg/kg, and cimetidine 100 mg/kg (0.24 ± 0.07, 1.06 ± 0.22 and 1.02 ± 0.16 mL/4 h, respectively) significantly reduced (p < 0.05) the volume of gastric content relative to control (2.32 ± 0.33 mL/4 h). In the CRSIU test, E. gigas caused significant reduction (p < 0.05) in the ulcer score, with the greatest effect produced at the dose of 50 mg/kg (0.80 ± 0.49; 92.38% inhibition), relative to control (4.20 ± 0.64). This effect was comparable to that of misoprostol (1.40 ± 0.60; 80% inhibition). Conclusion: The aqueous seed extract of E. gigas possess significant antiulcer activity mediated via cytoprotective and anti-secretory mechanisms. Keywords: Entada gigas, Fabaceae, ulcer, gastroprotective effect, cytoprotective, anti-secretory

Evaluation of Antioxidant Activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel Leaves

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol : water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals

The use of plants in the traditional management of diabetes in Nigeria: Pharmacological and toxicological considerations

Ethnopharmacological relevance: The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system. Materials and methods: Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. ‘Diabetes’ and ‘Nigeria’ were used as keywords for the primary searches; and then ‘Plant name – accepted or synonyms’, ‘Constituents’, ‘Drug interaction’ and/or ‘Toxicity’ for the secondary searches. Results: The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs. Conclusion: This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb–drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided

Antinociceptive and antiulcer activities of Pycnanthus angolensis

AbstractPycnanthus angolensis (Welw) Warb., Myristicaceae, is used in Nigeria folk medicine to treat complaints such as toothache, headache, sore throat, ulcers and wounds. The aim of the study was to investigate the antinociceptive and antiulcer activities of the stem bark extract of Pycnanthus angolensis. Acute toxicity was conducted with a single oral dose of 5 g/kg. Antinociceptive activity was evaluated in acetic acid-induced writhing, formalin and tail immersion tests in mice while antiulcer activity was evaluated in ethanol and indomethacin-induced models in rats. In acetic acid-induced writhing test, the extract (50, 100 and 150 mg/kg, p.o.), significantly reduced the number of writhes (46.75%, 57.28% and 75.69%) respectively, compared to control. The extract significantly (p < 0.001) reduced the time spent in licking the hind paw at both phases, in formalin test. In tail immersion test, significant antinociceptive effect was only observed with the dose of 150 mg/kg, with peak effect at 90 min (43.38%). There is no significant change in the spontaneous locomotor activity of animals in the open field. The extract prevented the gastric ulceration caused by ethanol and indomethacin treatments compared to control. The results showed that P. angolensis extract possesses antinociceptive and antiulcer activities supporting the traditional use for relieving pain and ulcers

Phytochemistry, anti-inflammatory and analgesic activities of the aqueous leaf extract of Lagenaria breviflora (Cucurbitaceae) in laboratory animals

The plant, and especially the fruit of Lagenaria breviflora is widely used in folklore medicine in West Africa as a herbal remedy for the treatment of human measles, digestive disorders, and as wound antiseptics (e.g. umbilical incision wound), while livestock farmers use it for Newcastle disease and coccidiosis treatment in various animal species, especially poultry. The purpose of this study was to contribute with new information on this plant leaves extract effect, as few studies have considered their effects. We collected fresh leaves of Lagenaria breviflora from the school farm of the University of Ibadan, Nigeria in May 2011. Dried leaves were ground and a 200g sample was used to prepare the extract. The grounded leaves material was allowed to shake in 1 000mL distilled water for 48h, in an orbital shaker at room temperature of 24°C. The obtained extract was filtered and concentrated to dryness under reduced pressure at 40ºC, and the thick solution was lyophilized, for a final extract yield of 12.6%. Standard phytochemical methods were used to test the presence of saponins, alkaloids, tannins, anthraquinones, cardiac glycosides, cyanogenetic glycosides and flavonoids. The anti-inflammatory activity of the aqueous leaf extract of the plant was assessed using carrageenan-induced paw edema and histamine-induced paw edema in rats. The analgesic effect was determined using the acetic acid writhing method as well as formalin test in mice. Our results showed that the extract at 100 and 200mg/ kg body weight significantly reduced the formation of the oedema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by reduction in the number of writhes when compared to the control. The extract caused dose-dependent decrease of licking time and licking frequency in rats injected with 2.5% formalin, signifying its analgesic effect. These results were however less than those of indomethacin, the reference drug used in this study. Since the plant extract reduced significantly the formation of oedema induced by carrageenan and histamine, as well as reduced the number of writhes in acetic acid-induced writhing models and dose-dependent decrease of licking frequency in rats injected with 2.5% formalin, the results have validated the basis for the traditional use of Lagenaria breviflora against inflamed purulent wounds, swellings, and bruises seen in some infectious diseases such as New Castle disease.La planta, y sobre todo el fruto de Lagenaria breviflora es ampliamente utilizada en medicina tradicional en África occidental como un remedio herbal para el tratamiento del sarampión humano, trastornos digestivos y como antiséptico de la herida umbilical (por ejemplo, herida de incisión), mientras que los ganaderos la utilizan para tratar la enfermedad de Newcastle y la coccidiosis en varias especies animales, especialmente aves de corral. El propósito de este estudio fue analizar el efecto del extracto de esta planta, ya que hay pocos estudios sobre la temática. Se recolectaron hojas frescas de Lagenaria breviflora en la finca demostrativa de enseñanza de la Universidad de Iba- dan, Nigeria, en mayo 2011. Las hojas secas se trituraron y una muestra de 200g fue utilizada para preparar el extracto. El material se mezcló en 1 000ml de agua destilada durante 48 horas, en un agitador orbital a temperatura ambiente de 24 C. El extracto obtenido se filtró y se concentró hasta sequedad a una presión baja y a 40 C, la solución espesa se liofilizó, para un rendimiento de extracto final de 12.6. Para probar la presencia de saponinas, alcaloides, taninos, antraquinonas, glucósidos cardíacos, glucósidos cianogénicos y flavonoides se utilizaron los métodos fitoquímicos estándares. La actividad anti-inflamatoria del extracto acuoso de hojas de la planta se evaluó mediante la inducción de un edema por carragenina e histamina en la pata de las ratas. El efecto analgésico se determinó utilizando el método de contorsiones inducidas por ácido acético y la prueba de formalina en ratones. Nuestros resultados mostraron que el extracto de 100 y 200mg/kg de peso corporal redujo significativamente la formación de edema inducido por la carragenina e histamina. En el modelo de contorsiones inducidas por ácido acético, el extracto mostró un buen efecto analgésico caracterizado por una reducción en el número de retortijones en comparación con el control. El extracto causó una disminución dependiente de la dosis en el tiempo y frecuencia de lameo en ratas inyectadas con 2.5% de formalina, demostrando su efecto analgésico. Estos resultados sin embargo fueron menores que los de la indometacina, fármaco de referencia utilizado en este estudio. El extracto de la planta redujo significativamente la formación de edema inducido por carragenina e histamina, así como la baja en el número de retortijones por ácido acético y una disminución de la dosis-dependiente de la frecuencia de lameo en ratas inyectadas con formalina al 2.5%, los resultados validan el uso tradicional de Lagenaria breviflora contra la inflamación de las heridas purulentas, inflamaciones y contusiones que se dan en algunas enfermedades infecciosas como la enfermedad de New Castle