Pierre Kamtchouing

Protective role of Anacardium occidentale extract against streptozotocin-induced diabetes in rats

The protective effect of Anacardium occidentale aqueous extract against streptozotocin-induced diabetes was evaluated in rats. The rats were treated with 175 mg/kg of the extract per os, twice daily; beginning 2 days before streptozotocin (STZ) injection. A total of 3 days after STZ administration, there was a 48% increase in blood glucose level in pretreated rats, compared with a 208% increase in diabetic control rats treated with STZ alone. Furthermore, these pretreated animals presented no glycosuria, a normal weight gain and a non significant increase in food and fluid intake at the end of the treatment compared with the normal control. Diabetic control animals showed a positive glycosuria, body weight loss, a real polyphagia and polydypsia. These results indicate the protective role of Anacardium occidentale extract against the diabetogenic action of STZ.

Effets hypotensifs de l'extrait au méthanol de Bidens pilosa Linn chez les rats hypertendus

Abstract Bidens pilosa Linn is highly regarded in some parts of Cameroon in traditional folk medical pratices. The hypotensive effects of the leaf methanol extract from Bidens pilosa Linn (Asteraceae) were evaluated in spontaneously hypertensive rats (SHR), salt-loading hypertensive rats (SLHR) and normotensive Wistar rats (NTR) using the indirect (tail-cuff) method. Acute changes in urine volume and urinary excretion of Na + and K + were also studied. The hypotensive effect of the extract was more remarkable in hypertensive than in normotensive rats. Bidens pilosa did not provoke significant changes in the heart rate and urine volume. Urinary excretion of Na + was decreased by 36 % in spontaneously hypertensive rats and the excretion of K + increased by 35 % in normotensive rats but the effects were not statistically significant. These results suggest that the extract is a useful antihypertensive drug which has no effect on the heart frequency. The hypotensive effects of the extract may be induced by vasodilation.

Hydro‐ethanolic extract of cashew tree (Anacardium occidentale) nut and its principal compound, anacardic acid, stimulate glucose uptake in C2C12 muscle cells

SCOPEnProducts of cashew tree (Anacardium occidentale) are used in traditional medicine for various ailments, including diabetes.nnnMETHODS AND RESULTSnThe anti-diabetic properties of cashew plant parts were studied using differentiated C2C12 myoblasts (myotubes) and rat liver mitochondria. Hydroethanolic extract of cashew seed (CSE) and its active component, anacardic acid (AA), stimulated glucose transport into C2C12 myotubes in a concentration-dependent manner. Extracts of other parts (leaves, bark and apple) of cashew plant were inactive. Significant synergistic effect on glucose uptake with insulin was noticed at 100u2009μg/mL CSE. CSE and AA caused activation of adenosine monophosphate-activated protein kinase in C2C12 myotubes after 6u2009h of incubation. No significant effect was noticed on Akt and insulin receptor phosphorylation. Both CSE and AA exerted significant uncoupling of succinate-stimulated respiration in rat liver mitochondria.nnnCONCLUSIONnActivation of adenosine monophosphate-activated protein kinase by CSE and AA likely increases plasma membrane glucose transporters, resulting in elevated glucose uptake. In addition, the dysfunction of mitochondrial oxidative phosphorylation may enhance glycolysis and contribute to increased glucose uptake. These results collectively suggest that CSE may be a potential anti-diabetic nutraceutical.

Hypoglycaemic effects of Mammea africana (Guttiferae) in diabetic rats.

AIM OF THE STUDYnThe stem bark of Mammea africana Sabine (Guttiferae) is used in African rain forest to treat various diseases, including diabetes mellitus. We investigated whether Mammea africana extract induced hypoglycaemic activity in rats.nnnMATERIALS AND METHODSnWe tested the effects of acute (5h) and sub-acute (21 days) oral administrations of the CH(2)Cl(2)-MeOH stem bark extract of Mammea africana (19-300 mg/kg body weight) on blood glucose levels of normal and streptozotocin (STZ)-induced type 1 diabetic rats. The effects were compared with those of glibenclamide.nnnRESULTSnAcute administration reduced blood glucose in the diabetic rats only (33.87%, P<0.01). Sub-acute treatment for 21 days also reduced blood glucose level in diabetic rats (73.29%, P<0.01). A reduction or stabilization in total serum protein, triglyceride, cholesterol and alanine amino transferase levels was also observed. No effect was observed on body weight loss but food and water intakes were significantly reduced (P<0.01) in diabetic rats. The maximal anti-diabetic effect was obtained with the dose of 75 mg/kg and was more important than that of glibenclamide.nnnCONCLUSIONnIt can be concluded that extracts of Mammea africana exhibited a significant anti-hyperglycaemic activity and improved the metabolic alterations in STZ-diabetic rats. These results provide a rationale for the use of Mammea africana to treat diabetes mellitus and hypercholesterolemia.

Acute and sub-chronic oral toxicity studies of an aqueous stem bark extract of Pterocarpus soyauxii Taub (Papilionaceae) in rodents.

UNLABELLEDnPterocarpus soyauxii Taub (Papilionaceae) is used in Cameroonian traditional medicine and pharmacopoeia to treat hypertension, diabetes, gastrointestinal parasitizes and cutaneous diseases.nnnAIM OF THE STUDYnThe present investigation was carried out to evaluate the safety of an aqueous stem bark extract of Pterocarpus soyauxii by determining toxicity after acute and sub-chronic oral administration in male and female rodents.nnnMATERIALS AND METHODSnThe acute toxicity test was conducted in mice. An aqueous extract of barks was administrated by gavage in single doses of 2.5-12.5 g/kg. General behaviour and mortality were examined for up to 7 days. The sub-chronic toxicity test was performed in rats. The plant extract was administered by daily gavage of 150-600 mg/kg for 42 days. Body weight, food and water intakes were followed weekly. Haematological, biochemical and organ parameters were determined at the end of the 42-day administration.nnnRESULTSnIn the acute study in mice, oral administration of the aqueous extract of Pterocarpus soyauxii caused dose-dependent general behaviour adverse effects and mortality. The no-observed adverse effect level (NOAEL) of the extract was 5.0 g/kg. The lowest-observed adverse effect level (LOAEL) was 7.5 mg/kg. Mortality increased with the dose, LD(50) was>10.75 g/kg for the mouse. In the sub-chronic study in rats, daily oral administration of the aqueous extract of Pterocarpus soyauxii did not result in death or significant changes in haematological or biochemical parameters, excepted increased hepatic catalase activity (P<0.05) at the dose of 600 mg/kg. No alteration was observed in body weight, food and water intake. Liver, kidney, lung and pancreas histopathology did not reveal morphological alteration.nnnCONCLUSIONSnThe results showed that the aqueous stem bark extract of Pterocarpus soyauxii Taub had very low toxicity in oral acute high dose administration and no toxicity in oral sub-chronic low dose administration and indicate that the plant could be considered safe for oral medication.

Maternal and developmental toxicity evaluation of Acanthus montanus leaves extract administered orally to Wistar pregnant rats during organogenesis.

Acanthus montanus is a plant used in Cameroon to treat pains and threatened abortion. The aim of this study was to evaluate the influence of methanol/methylene chlorides leaves extract from Acanthus montanus on Wistar pregnant rats and identify the substance(s) essential for these actions. Dams were treated orally from days 6 to 15 of the pregnancy at the dose levels of 0, 250, 500 and 1000 mg/(kgday). They were sacrificed on day 20 or allowed to deliver and wean. Various parameters were assessed. The F(1) generation offsprings were allowed to give birth to F(2) generation and a number of parameters assessed. The results showed that there was no maternal or organs toxicity. Embryotoxicity was observed during organogenesis manifested by reduction in foetal body weight, crown-rump and tail lengths and reduced ossification of extremities bones. However after delivery, these signs of growth retardation were seen before day 5, and henceforth, the treated pups regained all their parameters to normality. All others parameters for F(1) and F(2) generations were insignificant. beta-Sitosterol was the major chemical component of the extract and its role on these results could not be ignored. The MeOH/CH(2)Cl(2) extract of this plant is embryotoxic peri-natally at high doses but this failed to manifest after 5 days of post-natal survival. beta-Sitosterol may be central in the observed effects of the extract. This extract can be tolerated by pregnant patients.

Ethanol extract of Peperomia pellucida (Piperaceae) promotes fracture healing by an anabolic effect on osteoblasts.

ETHNOPHARMACOLOGICAL RELEVANCEnThe whole plant or some part of Peperomia pellucida (L.) HBK is used in some parts of Cameroon as a treatment for fracture healing.nnnAIM OF THE STUDYnTo evaluate the effect of ethanolic extracts of Peperomia pellucida (L.), a Cameroonian medicinal plant on bone regeneration following bone and marrow injury, and determine the mode of action.nnnMATERIALS AND METHODSnEthanol extract of Peperomia pellucida was administered at 100 and 200mg/kg doses orally to adult female Sprague-Dawley rats having a drill hole injury (0.8mm) in the femur diaphysis. Vehicle (gum-acacia in distilled water) was given to the control group. After 12 days of treatment, animals were euthanized and femur bones collected. Confocal microscopy of calcein labeling at the drill hole site was performed to evaluate bone regeneration. 3-D microarchitecture of drill hole site was analyzed by micorocomputed tomography. Osteogenic effects of the extract were evaluated by assessing mineralized nodule formation of bone marrow stromal cells and expression of osteogenic genes (mRNA level of type-1 collagen, bone morphogenetic protein-2 and osteocalcin genes) in the femur.nnnRESULTSnEthanol extract from Peperomia Pellucida (L.) dose-dependently induced bone regeneration at the fracture site. At 200mg/kg dose, the extract significantly increased mineral deposition compared to controls. The extract also improved microarchitecture of the regenerating bone evident from increased bone volume fraction, trabecular thickness, trabecular number, and decreased trabecular separation and structure model index. In addition, the extract increased the formation of mineralized nodules from the bone marrow stromal cells. Furthermore, the extract induced the expression of osteogenic genes in the femur including type 1 collagen, osteocalcin and BMP-2, compared to control.nnnCONCLUSIONnEthanolic extract of P. pellucid (L.) accelerates fracture repair in rats via stimulatory effects on osteoblast differentiation and mineralization, thereby justifying its traditional use.

Efficacy of spot-spray application of Metarhizium anisopliae formulated in emulsifiable extract of Calpurnia aurea in attracting and infecting adult Rhipicephalus appendiculatus ticks in semi-field experiments

The efficacy of spot-spray application of conidia of Metarhizium anisopliae (Metsch.) Sorok. conidia formulated in an emulsifiable extract of Calpurnia aurea (Ait.) Benth in attracting and infecting Rhipicephalus appendiculatus Neumann, 1901 ticks was evaluated in semi-field experiments. Formulation was applied on a 900-cm² spot and ticks released from various distances. Attracted ticks were individually placed in glass vials to determine the number of M. anisopliae conidia picked by a single tick. Infected ticks were either transferred in glass vials or maintained in the laboratory until death or exposed to rabbits in order to investigate the effects of fungal infection on feeding and potential reproduction parameters. Data showed that individual ticks picked between 3.2 and 4.1xa0×xa0105 conidia. Mortality of 83xa0% was observed among ticks maintained in the laboratory conditions. The engorgement period of fungus-infected ticks significantly increased by 16xa0% compared to the control. A significant reduction (Pxa0<xa00.0001) was recorded in body weight, egg-mass and egg hatchability from fungus-infected females. It is therefore possible to use M. anisopliae formulated in C. aurea extract for an integrated pest management approach. This study showed that conidia of M. anisopliae formulated in C. aurea extract are effective in attracting, infecting and causing mortalities of R. appendiculatus ticks. Moreover, the reproduction performance of fungus-infected females was significantly reduced.

Ejaculatory activities of Allanblackia floribunda stem bark in spinal male rats

Abstract Context: Medicinal plants have become a great source of relief for more 70% of the population in developing countries where access to modern medicine is very limited. Some of these plants are used as aphrodisiac agents. The stem bark of Allanblackia floribunda Oliver (Clusiacea) has been used in Cameroon as an aphrodisiac. Objective: This study was designed to assess the effects of Allanblackia floribunda aqueous and ethanol extracts and their potential mechanism on fictive ejaculation in spinal male rats. Materials and methods: Electromyographic activities of the bulbospongiosus muscles were recorded in 24 groups of spinal rats after intravenous administration of aqueous and ethanol extracts (2.5, 10, 20, 40 or 60u2009mg/kg) from the stem bark of A. floribunda in the presence or absence of dopamine (60u2009mg/kg). Furthermore, electromyographic activities of the bulbospongiosus muscles were recorded in five groups of spinal rats pre-treated orally during 8u2009d with extracts (150 and 300u2009mg/kg) in the presence of dopamine. Results: Sequential treatments of rats with extracts significantly decreased the occurrence of ejaculation induced by dopamine up to 88.94% inhibition. The oral pre-treatment with both extracts significantly decreased the ejaculation induced by dopamine with the highest inhibition of 89.79%. Discussion and conclusion: Two extracts of A. floribunda used in this study had inhibitory activities on ejaculation. The inhibitory effect of A. floribunda extracts on fictive ejaculation in rat may be directly mediated through dopaminergic pathways. Inhibition of ejaculation caused by these extracts could support its use in patients suffering from rapid ejaculation.

Acute and sub-acute toxicity of a lyophilised aqueous extract of the aerial part of Spilanthes africana Delile in rats.

ETHNOPHARMACOLOGICAL RELEVANCEnSpilanthes africana is a plant used in several countries for the treatment of toothache, malaria, fracture, pneumonia, and dysentery. In order to establish the safety of aerial part of the plant extract, the acute and sub-acute toxicity of the aqueous extract of this plant has been evaluated in male and female young rats.nnnMATERIAL AND METHODSnIn acute toxicity, the effects of a single oral dose (2,000 mg/kg and 5,000 mg/kg) of the lyophilised aqueous extract have been determined. General behaviour, adverse effects and mortality were determined for up to 14 days. In sub-acute treatment, the effects of the extract in daily single oral administration at the doses of 250, 500 and 1,000 mg/kg during 28 days were evaluated. One group treated at the dose of 1,000 mg/kg for 28 days was let without treatment during 14 days to assess the possible reversibility of the harmful effects of the extract. Body weight, food and water intakes, biochemical and haematological parameters were recorded. Histopathological examination of liver, kidney and lungs were assessed.nnnRESULTSnIn acute study, a single administration of the aqueous extract at the doses of 2,000 mg/kg or 5,000 mg/kg did not induce mortality. Thus, the LD50 of the aqueous extract of S. africana has been estimated higher than 5,000 mg/kg. Four hours after administration of the extract, a reduction of the mobility, sensitivity to the noise and to touch has been observed. In sub-acute study, the administration of the extract during 28 days at all doses did not significantly modify the body weight. On the haematological analysis, a decrease of the rate of monocytes and a rise of lymphocytes counts were observed among the male group. In both sexes, it appeared a decrease of the rate of granulocytes two weeks after stopping the treatment. It has also been observed in different groups among the females, an increase of the mean corpuscular content and the mean concentration in haemoglobin as well as an increase of platelets. A significant decrease of transaminases, alkaline phosphatase, triglycerides, and a significant increase of total bilirubin compared to the normal group has been observed. There was a significant decrease in renal catalase in both sexes compared with different control groups. Besides, a significant increase of the kidney rates of glutathione and malondialdehyde have also been observed in the female treated at the doses of 1,000 mg/kg. Histopathological analysis has shown vascular congestion and leucocyte infiltrations in the liver of animals treated at the dose of 1,000 mg/kg. This congestion has been marked in satellite group. In the kidney female satellite group, tubular clarifications have been observed and disappear when stopping the treatment.nnnCONCLUSIONnThese results show that the aqueous extract of S. africana given by the oral route is slightly toxic. However in sub-acute treatment, higher doses could provoke functional and structural changes in the organism which could in part reversible. Thus the extract should be used with caution.