Blood glucose lowering effect of aqueous extract of Graptophyllum pictum (Linn) Griff. on alloxan-induced diabetic rats and its acute toxicity in mice

This study was aimed at evaluating the claimed anti-diabetic property of the aqueous extract of Graptophyllum pictum leaf and to establish an effective dose for the extract. It also attempted to unravel if the extract could be acutely toxic to mice. The anti-diabetic study was carried out on alloxan-induced diabetic Wistar rats. After diabetic induction, the rats were divided into 5 groups. Groups 1 to 3 were orally administered 100, 150 and 200 mg/kg body weight extract by gastric probe for four weeks; group4 was administered 10 mg/kg body weight metformin, a well known hypoglycemic drug, while group 5 served as control and received the vehicle of administration (distilled water). The fasting blood glucose level (FBGL) of the rats was checked before commencement of treatment and weekly during the drug administration period using Roche Accu-chek Active Glucometer. The percentage change in FBGL before commencement of treatment and during the treatment period was calculated and expressedgraphically. The acute toxicity of the extract was studied in 4 groups of Swiss albino mice which were orally administered high doses (1 to 4 g/kg) of the extract. The results obtained from the anti-diabetic study showed a significant reduction (P < 0.05) in the mean fasting blood glucose level in all the three groups of animals treated with the plant extract when compared to the control; and it exhibited effective anti-diabetic potency when compared with metformin (a standard anti-diabetic drug); the effective dose was established at 100 mg/kg. The LD50 could not be determined as none of the treated mice died during the acute toxicity study. These findings suggest that the aqueous extract of the leaves of G.pictum possess hypoglycemic effect which is comparable to metformin and can be safely administered orally without any immediate unwanted effect. However, this calls for detailed studies to elucidate the therapeutic and long term toxicological profiles of the extract.Key words: Diabetes, Graptophyllum pictum, aqueous extract, hypoglycemic, metformin

Evaluation of acute and subchronic toxicity of Stachytarpheta angustifolia (Mill) Vahl (Fam. Verbanaceae) extract in animals

Stachytarpheta angustifolia is an important and a highly valued medicinal plant ethnobotanically used in the treatment of various diseases. The present study was carried out to evaluate acute andsubchronic toxicity in animals and also evaluate the phytochemical profiles of hydroethanolic extract of S. angustifolia (Mill) Vahl plant. S. angustifolia attracted the attention of the researchers because of itsuses as an anti-infective, antidiabetic in folkloric medicine and also as soap by local farmers. The aqueous ethanol (80%) extract of the powdered dried plant was obtained by maceration. Evaluation ofacute and subchronic toxicity and phytochemical profiles of the plant extract was performed using standard procedures. The median acute toxicity value (LD50) of the extract of S. angustifolia was determined to be 8.721g/kg body weight. The extract lowered blood plasma glucose and low density lipoprotein (LDL-cholesterol) levels but raised high density lipoprotein (HDL-cholesterol) level. The protein, creatinine, and phosphorous levels were significantly affected only by the highest dose of the extract while calcium level was not affected by all the doses used. The extract contained triterpenoid saponins as the major bioactive constituent. The LD50 value indicated the drug as being slightly toxic.The extract did not produce any toxic effect in the animals’ tissues at low and moderate doses but could cause kidney damage in higher doses. Lowering of plasma glucose level and the positive effectsof the extract on the cardiovascular risk factors were an indicator that the extract could have some good antidiabetic activity

Assessing plasma glucose and lipid levels, body weight and acute toxicity following oral administration of an aqueous ethanolic extract of Parinari curatellifolia Planch, (Chrysobalanaceae) seeds in alloxan-induced diabetes in rats

The study was aimed at evaluating the safety and hypoglycaemic effects of Parinari curatellifolia seeds used in the treatment of diabetes. The plasma glucose level and other biochemical parameters, bodyweight and liver, heart, renal and acute toxicities were assessed following oral administration of an aqueous ethanol (80%) extract of the seeds in alloxan-induced diabetes in rats. Toxicity of the extractwas evaluated in Swiss albino mice by feeding the animals with the graded doses of the extract between 1.0 to 2.0 g/kg body weight orally and observed continuously for the first 4 h and hourly fornext 24 h, then 6 hourly for 48 h (72 h, acute toxicity). Diabetes was induced in male and female Wistar rats with alloxan monohydrate (150 mg/kg) dissolved in normal saline and administered intraperitoneally (i.p). The plasma glucose levels of the induced animals were monitored with a glucometer after 72 h. The animals with plasma glucose level >300 mg/dl were classified as diabetic and were included in the study. The diabetic animals were treated with the extract and a reference drug,glibenclamide, respectively for 30 days. Their effects on plasma glucose levels and some biochemical parameters were evaluated at the end of the experiment as indices of their antidiabetic activity. Themedian acute toxicity value (LD50) of the extract was determined to be 7.27 g/Kg body weight. There was significant reduction (

Evaluation of hypoglycaemic and hypolipidaemic effects of aqueous ethanolic extracts of Treculia africana Decne and Bryophyllum pinnatum,/i> Lam. and their mixture on streptozotocin (STZ)-induced diabetic rats

The plants Treculia africana and Bryophyllum pinnatum are ethnobotanically used in the treatment of various diseases including diabetes and heart diseases. Diabetes mellitus is a disease characterized by hyperglycaemia, and hyperlipidaemia which leads to an increased risk of atherosclerosis and other cardiovascular diseases. The effects of aqueous ethanol (80%) extracts of T. africana leaves and B. pinnatum plants and their mixture, in an equal proportion, were evaluated on postprandial glycaemic status. Three groups of normal rats were treated with the extracts and their mixture (1:1), at a dose of500 mg/kg body weight and then charged with glucose (40%) at a dose of 1 ml/100 g body weight. Plasma sugar contents were analyzed from the blood collected from the tail vein at 30, 60 and 120 minintervals. Also glycaemic status and serum lipid profiles of normal and streptozotocin-induced diabetic rats were evaluated. Three groups of streptozotocin-induced diabetic (50 mg/kg ip) rats were treatedwith the extracts and the (1:1) mixture at a dose of 500 mg/kg, respectively for 21 days. A significant reduction (p0.05) in both postprandial and STZ-induced diabetes blood glucose levels, triglyceride levels, low density lipoprotein (LDL) level, and increase in high density lipoprotein (HDL) level were observed. This scientific finding supports the basis for the herbal use of T. africana and B. pinnatum in the management of diabetes and heart diseases

Evaluation of acute toxicity in mice and subchronic toxicity of hydroethanolic extract of Parinari curatellifolia Planch (Chrysobalanaceae) seeds in rats

Parinari curatellifolia seeds are ethnobotanically used in the treatment of diabetes and other diseases. The seed drug preparations are administered over a long period of time in the treatment of certaindisease conditions. The aim of this study was to evaluate the safety of the seed extract through acute toxicity study. Also subchronic toxicity in the animals was carried out by assessing the effects onbiochemical parameters, body weight and liver, heart and renal organs following oral administration of aqueous ethanolic extract of the seeds. Toxicity of the extract was evaluated in Swiss albino mice byfeeding the animals with graded doses of the extract between 1.0 to 20.0 g/kg body weight orally and observed continuously for the first 4 h and every hourly for the next 24 h, then 6 hourly for 48 h (72 h,acute toxicity). Wistar rats were also fed with different extract doses for at least 30 days and the effects on biochemical parameters evaluated (subchronic toxicity model). The median acute toxicity value(LD50) of P. curatellifolia seeds extract was found to be 7.27 g/kg body weight. The extract reduced plasma glucose and low density lipoprotein (LDL)-cholesterol levels, but increased high density lipoprotein (HDL)–cholesterol in the treated groups compared to the control. A significant increase in the body weight was observed in all the groups treated with the extract. Aspartate aminotransferases (AST), creatinine and phosphorus levels were significantly increased only in the group treated with highest dose of the extract while significant decrease in alanine aminotransferases (ALT) level was observed in all groups. The LD50 value indicated the drug to be quite safe in one dose treatment. The study also showed that the extract had good hypoglycemic effects and good reducing effects on the cardiovascular risk factors but indicated that high dose of the extract on a long term use can causeliver and kidney problems

Evaluation of antibacterial activity and acute toxicity of the hydroethanolic extract of Stachytarpheta angustifolia (Mill) Vahl.

The aim of this study was to evaluate antibacterial activity, acute toxicity in mice and phytochemical profiles of hydroethanolic extract of Stachytarpheta angustifolia plant. The plant S. angustifolia hasattracted the attention of the researchers because of its use as an anti-infection agent. The aqueous ethanol (80%) extract of the powdered dried whole plant was obtained by maceration. The bacteriaorganisms tested include Shigella dysentriae (ATCC 32412), Salmonella typhi (ATCC 213415), and the following clinical isolates: coagulase-negative Staphylococcus, Staphylococcus aureus, Proteusmirabilis, Klebsiella species and Escherichia coli. Susceptibility test, acute toxicity test and phytochemical screening of the plant extract were performed using standard procedures. The results showed that the extract had a good antibacterial activity against S. aureus, S. dysentriae, coagulasenegative Staphylococcus and Proteus mirabilis. The minimum inhibitory concentration (MIC) was foundto be between 11.6 and 14.0 mg/ml for the susceptible organisms. The extract exhibited minimum bactericidal concentration (MBC) of 150 mg/ml against S. dysentriae only while other susceptible testedbacteria strains required higher concentrations. The median acute toxicity value (LD50) of the extract was determined to be 8.721 g/kg body weight indicating the extract as being slightly toxic. The extractcontained triterpenoid saponins as the major bioactive constituent

Phytochemical evaluation and antibacterial profile of Treculia africana Decne bark extract on gastrointestinal bacterial pathogens

Treculia africana Decne (Fam. Moraceae) is a highly valued economic plant, as well as an important medicinal plant widely used in the traditional herbal medicine for the treatment of several ailments ofboth microbial and non-microbial origins. It was, therefore, investigated for activity in vitro on pathogenic bacterial isolates of gastrointestinal tract. Fresh plant materials were collected from the Forestry Division in Oyo State and the aqueous ethanol (70%) extracts of the powdered bark were obtained by maceration method. The bacterial organisms tested were Salmonella typhi (ATCC24682), Shigella dysentriae (ATCC23513), Escherichia coli (Clinical isolate), Pseudomonas aeruginosa (ATCC12462) and Staphylococcus aureus (ATCC23815). Susceptibility testing and phytochemical screening of the plant extracts were performed by standard procedures. Aqueous ethanol extract of T.africana was effective on the tested organisms. The mean Minimum Inhibition Concentration (MIC) of the extract ranged from 3.125 to 25 mg/ml for different organisms tested. The extract exhibitedminimum bactericidal concentration (MBC) of 50 mg/ml on S. dysentriae and P. aeruginosa only, while other tested bacteria strains required higher concentrations. Phytochemical screening revealed thepresence of steroidal saponin glycosides as the major component, anthraquinone glycoside and polyphenols. Our results offer a scientific basis for the traditional use of T. africana. The aqueousethanol extract of the bark was effective in vitro in this study on gastrointestinal bacteria pathogens, and thus could be explored for further pharmaceutical use

Anticonvulsant Activity of Schumanniophyton magnificum Roots Extracts in Mice

Schumanniophyton magnificum, a highly valued medicinal plant in Nigeria and West African sub-region is widely used by traditional medical practitioners in the treatment of various ailments including epilepsy and convulsion. In order to evaluate this aspect of the folkloric use of the plant, the anticonvulsant effects of the S. magnificum ethanolic root extract were studied in mice, using picrotoxin and strychnine as convulsants.The extract (1000mg/kg) administered orally, 30 minutes prior to subcutaneous administration of picrotoxin (5mg/kg body weight) was found to confer a 100% protection on the animals. Also, a dose of 800mg/kg of the extract administered 30 minutes before subcutaneous administration of strychnine (4mg/kg body weight) prolonged the latency period of the induced seizures, and increased the time to death. The results of the study indicate that the extract has a protective effect on convulsions and this may provide a rationale for its local use in the management of episodes of seizure. Key Words: Anticonvulsant activity, medicinal plants, picrotoxin, Schumanniophyton magnificum, strychnine. Résumé Schumanniophyton magnificium plante à grande valeur medicinale au Nigeria et dans la sous région Ouest- africaine. Est largement utilisé par les tradi-praticiens dans le traitement de différents maux parmis lesquels l'epilepsy et la convulsion . dans le but d'évaluer cet aspect floklorique de l'utilisation de la plante; l'effet anticonvulsant des extraits à base d'ethanol de la racine du S. magnificium ont été étudié sur des souris utilisant la picrotoxine et la strychinne comme anticonvulsant. Des extraits (1000mg/kg) administré orallement 30minutes avant l'administration sous-cutanée des pricrotoxin(5mg/kg poids corporel) conférais aux animaux une protection de 100%. Des dose 800mg/kg des extaits administré 30 minute orallement avant administration sous-cutanée du strychnine (4mg/kg poids corporel) prolongeait la période de latence des convulsions induites et augmentaient le temps de mort. Les resultats des études montre que les extraits ont un effet protecteur sur la convulsion et ceci peut être la raison de son utilisation local pour le traitement des épisode de convulsions. Mot clés: activité anticonvulsante ,plante medicinales , picrotoxine, Schumanniophyton magnificium, strychnine. West Afr. J. Pharmacol. Drug Res. Vol.19 (1&2) 2003: 33-3