Antibacterial and cytotoxic activity of isoprenylated coumarin mammea A/AA isolated from Mammea africana

Ethnopharmacological relevance

The stem bark of Mammea africana is widely distributed in tropical Africa and commonly used in traditional medicine. This study aims to identify the active compound in Mammea africana and to evaluate its antimicrobial and antiproliferative activity.

Materials and methods

Methanol extract from the bark of the Mammea africana was separated by liquid–liquid extraction, followed by open column chromatography. A principal antimicrobial compound was purified by high performance liquid chromatography (HPLC) and its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The antibacterial activity of the purified compound was determined using the broth microdilution method against 7 common pathogenic bacteria. The compound was also evaluated for cytotoxicity by cell proliferation assay (MTS) using the mouse embryonic fibroblast cell line NIH 3T3 and the non-small cell lung cancer cell line A549.

Results

The purified active compound was determined to be mammea A/AA and was found to be highly active against Campylobacter jejuni (MIC=0.5 μg/ml), Streptococcus pneumoniae (MIC=0.25 μg/ml), and Clostridium difficile (MIC=0.25 μg/ml). The compound exhibited significant antiproliferative activities against both NIH 3T3 and A549 cell lines.

Conclusion

Mammea A/AA isolated from Mammea africana exerts specific inhibitory activity against Campylobacter jejuni, Streptococcus pneumoniae, and Campylobacter difficile. Mammea A/AA was also found to exhibit significant cytotoxicity against both cancer and normal cell lines.     

Antidiabetic activity of Ficus amplissima Smith. bark extract in streptozotocin induced diabetic rats

Ethnopharmacological relevance

Ficus amplissima commonly known as kal-itchchi have a long history of use in Ayurveda, Siddha and Unani herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim

The aim of the present study was to evaluate the effect of methanolic extract of the bark of Ficus amplissima (FAB) in streptozotocin-induced diabetic rats.

Materials and methods

Oral administration of FAB bark at the doses of 50 mg/kg, 100 mg/kg and 150 mg/kg was studied in normal, glucose-loaded and STZ—induced diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 mg/kg and 100 mg/kg than 150 mg/kg. FAB also showed significant increase in serum insulin and body weight. The glycogen content in liver, skeletal muscle, total protein contents were markedly increased and marker enzymes of hepatic function of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FAB also showed significant anti-lipid peroxidative effect in the pancreas of STZ-induced diabetic rats. The anti-diabetic effect of FAB was compared with glibenclamide, a well known hypoglycemic drug. Histological analysis showed the regenerative effect of FAB on the β-cells of diabetic rats.

Conclusion

Results of this experimental study indicated that FAB possessed anti-diabetic and antioxidant activities. Hence it could be used as a natural source of antidiabetic (Type-I) and antioxidant drug.     

Antidiabetic effect of Ficus religiosa extract in streptozotocin-induced diabetic rats

Aims of study

In Indian traditional system of medicine, Ficus religiosa (Family Moraceae) is prescribed for the treatment of diabetes mellitus. In the present study, the antidiabetic effect of aqueous extract of Ficus religiosa bark (FRAE) was investigated in normal, glucose-loaded hyperglycemic and streptozotocin (STZ)-induced diabetic rats.

Materials and methods

Oral administration of FRAE at the doses of 25, 50 and 100 mg/kg was studied in normal, glucose-loaded and STZ-diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 and 100 mg/kg than 25 mg/kg. FRAE also showed significant increase in serum insulin, body weight and glycogen content in liver and skeletal muscle of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FRAE also showed significant antilipidperoxidative effect in the pancreas of STZ-induced diabetic rats. The antidiabetic effect of Ficus religiosa was compared with glibenclamide, a well-known hypoglycemic drug.

Conclusion

The results indicate that aqueous extract of Ficus religiosa bark possesses significant antidiabetic activity.     

Hypoglycemic effects of Cecropia pachystachya in normal and alloxan-induced diabetic rats

Ethnopharmacological relevance

Leaves of Cecropia pachystachya are described in the folk medicine as possessing antitusive, expectorant, antiasthmatic and hypoglycemic effects.

Aim of the study

To investigate the hypoglycemic and antioxidant effects of methanolic extract from the leaves of Cecropia pachystachya. The total amount of phenolic and flavonoids compounds was determined and the qualitative composition of the extract was analyzed.

Materials and methods

The hypoglycemic effect of the extract was tested in normal, glucose loading and alloxan-induced diabetic rats. The antioxidant activity was assessed by DPPH free radical scavenging and reduction power assays. The total amount of phenolic and flavonoids compounds was determined by Folin-Denis and AlCl₃ reagent method, respectively. The qualitative composition of the extract was analyzed using a HPLC-DAD system.

Results

The glucose tolerance test showed that in diabetic rats, the extract caused a significant hypoglycemic effect with a blood glucose reduction of 68% after 12 h. The administration of the extract in alloxan-induced diabetic rats also produced a significant reduction in the blood glucose levels at all points being more pronounced at 90 min (reduction of 60%). After 120 min, no significant difference was observed between the blood levels of the rats treated with the extract and those treated with the standard drugs (metformin and glibenclamide). The extract also presented relevant antioxidant activity with IC₅₀ = 3.1 μg/ml (DPPH assay) and EC₅₀ = 10.8 μg/ml (reduction power). Results were compared with the reference antioxidants quercetin, rutin, and ascorbic acid. The content of flavonoids was 83 mg/g plant and that of phenolics was 326 mg/g plant. Chlorogenic acid and the C-glycosylated flavones, orientin and isoorientin, were identified in the extract.

Conclusions

In conclusion, the findings showed that the folk medicinal plant Cecropia pachystachya possesses hypoglycemic and antioxidant effects which confirmed the traditional use of the plant in the treatment of diabetes. Chlorogenic acid and the C-glycosylated flavonoids may explain these activities.     

Antidiabetic and antioxidant effect of various fractions of Phyllanthus simplex in alloxan diabetic rats

Aim of the study

To evaluate the antidiabetic and antioxidant effects of various fractions of Phyllanthus simplex on alloxan induced diabetes in rats.

Materials and methods

Hypoglycemic effect of Phyllanthus simplex fractions was evaluated in normal and diabetic rats. Diabetes was induced by intraperitoneal injection of alloxan monohydrate (120 mg/kg). Normal and diabetic rats were divided into different groups (six rats each group) and orally administered with petroleum ether (P.E.) (200 and 400 mg/kg), ethyl acetate (EtOAc) (100 and 200 mg/kg), methanol (125 and 250 mg/kg), water fraction (150 and 300 mg/kg) and glibenclamide (10 mg/kg) for 21 days. Blood samples were collected from overnight fasted normal rats on day 21, from overnight fasted diabetic rats at 7, 14 and 21 days of treatment and analyzed for blood glucose level. On day 22 blood samples were collected from diabetic rats to estimate biochemical parameters, rats were sacrificed by single stunning and tissues were excised to measure their antioxidant and glycogen status.

Results

In the normoglycemic rats, MeOH (125 and 250 mg/kg) and aqueous fractions (150 and 300 mg/kg) showed a significant (P < 0.05) hypoglycemic effect on day 21. In diabetic control rats, MeOH (125 and 250 mg/kg) and aqueous fractions (150 and 300 mg/kg) showed significant antihyperglycemic effect (P < 0.001). The active fractions (MeOH and aqueous) of Phyllanthus simplex also increased the body weight of diabetic rats significantly compared to the control group. The active fractions were able to normalize the marked alterations in antioxidant enzymes and antioxidant parameters levels in liver and kidney. Treatment with the active fractions also normalized the diabetic induced hyperlipidemia and liver glycogen.

Conclusions

These results demonstrate the antidiabetic and antioxidant potential of fractions of Phyllanthus simplex and suggests that the plant may have therapeutic value in diabetes and related complications.     

Further evaluation of antihyperglycaemic activity of Hunteria umbellata (K. Schum) Hallier f. seed extract in experimental diabetes

Ethnopharmacological relevance

In African traditional medicine, water decoction made from the dry seeds of Hunteria umbellata (K. Schum) Hallier f. is highly valued in the management of diabetes mellitus.

Aim

In the present study, the antihyperglycaemic activity of the seed aqueous extract of Hunteria umbellate (K. Schum) Hallier f. (HU) was investigated in alloxan-induced, high fructose- and dexamethasone-induced hyperglycaemic rats.

Materials and methods

Alloxan-induced, dexamethasone-induced and high fructose-induced hyperglycaemic rats were treated with single, daily oral administration of 1 mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg and 200 mg/kg of HU in Groups III, IV, V and VI, for 14 days, 21 days and 8 weeks, respectively. The effects of these drugs on FBG, free plasma insulin levels, HbA_1c, serum TG and TC, and insulin resistance indices were investigated.

Results

Data generated in the current study showed that glibenclamide and graded oral doses of HU caused significant dose related (p < 0.05, <0.01 and <0.001) reductions in FBG when compared to the values obtained for the model control (Group II) rats. Similarly, daily oral administration of 66.7 g/kg fructose to rats for 8 weeks was associated with significant (p < 0.001) hyperglycaemia, elevations in plasma HbA_1c, free insulin, fasting insulin resistance indices, serum TG, and cholesterol. However, concomitant oral treatments with 1 mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg, and 200 mg/kg of HU extract significantly and dose dependently (p < 0.05, <0.01 and <0.001) attenuated development of hyperglycaemia, decreased levels of plasma HbA_1c, free insulin, and serum triglyceride and cholesterol, in the Groups III, IV, V and VI rats, respectively, when compared to fructose-induced hyperglycaemic (Group II) rats. Similar effect was also recorded in the dexamethasone-induced hyperglycaemic rats.

Conclusion

Results of this study suggest that the hypoglycaemic and antihyperlipidaemic effects of HU are mediated via enhanced peripheral glucose uptake and improvements in hyperinsulinaemia.     

Leucas cephalotes regulates carbohydrate and lipid metabolism and improves antioxidant status in IDDM and NIDDM rats

Ethnopharmacological relevance

Leucas cephalotes (Roth.) Spreng. (Laminaceae) is an ayurvedic traditional medicinal plant used in India, Nepal and Pakistan to treat several ailments including diabetes.

Aim of the study

The aim of the present study is to investigate the antidiabetic, antihyperlipaemic and antioxidant activities of Leucas cephalotes for its purported use in diabetes.

Materials and methods

The ethanol extract of leaves of Leucas cephalotes was administered (150, 300 and 450 mg kg⁻¹ bw) to diabetes induced (IDDM and NIDDM) rats and carbohydrate, lipid, antioxidant, urea and creatinine profiles were assessed.

Results

All the three doses of extract decreased plasma glucose and lipid profiles and, improved the antioxidant status of both types of diabetic rats. The extract administration improved hepatic glycogen content and hexokinase activity, decreased glucose-6-phosphatase activity, blood urea, creatinine contents and decreased lipid peroxidation in diabetic rats. Of the three doses used, 450 mg kg⁻¹ bw dose was found to be more potent in its effects comparable to those of glibenclamide and metformin.

Conclusion

Leucas cephalotes regulates both carbohydrate and lipid metabolism and, improves body antioxidant defense systems in both types of diabetes.     

Effect of Tectona grandis Linn. on dexamethasone-induced insulin resistance in mice

Ethnopharmacological relevance

The bark of Tectona grandis Linn. is traditionally used in the treatment of diabetes.

Aim

The present study was undertaken to investigate the effect of ethanolic extract of bark of Tectona grandis Linn. (TG) in dexamethasone-induced insulin resistance in mice.

Materials and methods

Mice were treated with prestandardised dose of dexamethasone for 22 days and effect of TG at the doses of 50, 100 and 200 mg/kg, p.o. on plasma blood glucose level, serum triglyceride level, glucose uptake in skeletal muscle, levels of hepatic antioxidant enzymes (GSH, SOD, catalase and LPO), and body weight were observed.

Results

TG showed significant decrease in plasma glucose and serum triglyceride levels (p < 0.01) at the dose of 100 and 200 mg/kg, p.o. and also stimulated glucose uptake in skeletal muscle. The levels of antioxidant enzymes GSH, SOD, and catalase were significantly increased (p < 0.01) and there was significant decrease (p < 0.01) in level of LPO.

Conclusion

Hence it can be concluded that Tectona grandis may prove to be effective in the treatment of Type-II Diabetes mellitus owing to its ability to decrease insulin resistance.     

Hypoglycemic effect of quassinoids from Brucea javanica (L.) Merr (Simaroubaceae) seeds

Ethnopharmacological relevance

The seeds of Brucea javanica (L.) Merr (Simaroubaceae) are recommended by traditional practitioners for the treatment of diabetes mellitus.

Aim of the study

To identify the compounds responsible for blood glucose lowering effect and evaluate the acute toxicity of the compounds.

Materials and methods

Extracts, fractions and subfractions were administered to normoglycemic mice and the blood glucose concentration was monitored for 8 h. Bioactive compounds isolated through column chromatography were administered to normoglycemic mice and streptozotocin (STZ) rats with monitoring of blood glucose concentration at 0–8 h. The acute toxicity was evaluated in mice.

Results

Bioactivity-guided fractionation led to the isolation of bruceines E (1) and D (2). Normoglycemic mice administered with 1 mg/kg of 1 and 2 exhibited significant blood glucose concentration reduction of 40.07 ± 11.45% and 48.82 ± 13.34%, respectively. STZ induced diabetic rats administered with 1 and 2 exhibited significant blood glucose concentration reduction of 73.57 ± 13.64% and 87.99 ± 2.91%, respectively.

Conclusion

The reduction of blood glucose concentration by both bruceines was comparable to glibenclamide and they might act as an insulin secretagogue. The presence of a hydroxyl moiety at C₂ in 1 reduced the toxic effect by 9-fold compared to 2.     

Alpha-amylase inhibitory activity of two Anthocleista species and in vivo rat model anti-diabetic activities of Anthocleista djalonensis extracts and fractions

Ethnopharmacological relevance

Anthocleista djalonensis (A. Chev) and Anthocleista vogelii Planch are plants being used in West Africa traditionally to treat various diseases such as malaria, hernia, hypertension, stomach aches, hemorrhoids, syphilis, and diabetes. Diabetes causes about 5% of all deaths globally each year. Chemotherapeutic agents such as biguanides, sulfonylureas, and thiozolidinediones are available for the treatment of diabetes, however, they have undesirable side effects. The need for newer, more effective and less toxic drugs is imperative and the biodiversity of Nigeria has a high potential for drug discovery based on plants used in the ethnomedicine.

Aim of the study

To investigate the leaves, stem bark and roots of these plants for their probable alpha-amylase inhibitory activities and establish their anti-diabetic activities. The overall goal is do bioassay-guided fractionation and isolation of active anti-diabetic compounds.

Materials and methods

Powdered samples (leaves, stem bark and roots) macerated with 80% aqueous methanol were evaluated in vitro using alpha-amylase inhibitory assay while in vivo investigations were carried out on hyperglycemic rats. Diabetes was induced in albino rats by an intraperitoneal injection of alloxan monohydrate (80 mg/kg). Plant extracts (1 g/kg) were given orally for 7 days, while blood glucose levels were monitored using a one touch glucometer. The crude methanol extracts found to be most active were further partitioned into hexane and ethyl acetate fractions which were also tested in vivo on the diabetic animals.

Results

The leaves and stem bark crude methanol extracts of Anthocleista djalonensis gave comparable α-amylase inhibition of 73.66% and 72.90%, respectively which were quite higher than the 38.93% and 22.90% of the same plant parts given by Anthocleista vogelii. The crude stem bark extract of Anthocleista djalonensis exhibited significant peak blood glucose reduction on day 6 (72.59%, p<0.05) which was higher than the leaves or roots which gave 45.73% and 47.46% (p<0.05), respectively The stem bark ethyl acetate fraction of Anthocleista djalonensis gave reduction in blood glucose level of 60.86% (p<0.05).

Conclusion

From our results, the leaves, stem bark and whole root of both plants exhibited α-amylase inhibitory activities with Anthocleista djalonensis also showing good anti-diabetic activities in vivo indicating that they contain active principles for the management of diabetes. There is justification for the use of the plants traditionally to manage diabetes.     

Antihyperglycemic effects of total flavonoids from Polygonatum odoratum in STZ and alloxan-induced diabetic rats

Aim of the study

Total flavonids of Polygonatum(P) odoratum (TFP) were tested for anti-diabetic activity in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats.

Materials and methods

Rhizoma Polygonati Odorati, well-known Chinese traditional medicine, is widely used for treatment of diverse diseases for example diabetes. In our study, TFP was extracted by 70% ethanol and purified by macroreticular resin. The experiments were designed to detect the anti-diabetic activity of TFP by determination of blood glucose (BG) using one touch gluco-meter and insulin levels by using a radioimmunoassay kit in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats and alpha-amylase inhibitory activity by alpha-amylase inhibition assay in vitro.

Results

TFP had beneficial effects on regulation of blood glucose. Daily administration with 50–200 mg/kg body weight of TFP for 9 days can reduce significantly hyperglycemia in STZ-induced diabetic mice. Thirtieth day administration with TFP (50–200 mg/kg body weight) also decreased significantly fasting blood glucose in alloxan-induced diabetic rats. The hypoglycemic effect of TFP at 50 and 100 mg/kg is less than that of acarbose 20 mg/kg and gliclazide 15 mg/kg. The hypoglycemic effects of TFP at 200 mg/kg is similar to that of acarbose 20 mg/kg and gliclazide 15 mg/kg. TFP also could increase significantly the insulin level in alloxan-induced type 2 diabetic rats (P < 0.05) compared with control. Alpha-amylase inhibition assay in vitro showed that TFP inhibited significantly alpha-amylase activity in a dose-dependent manner.

Conclusions

TFP possess significant dose-dependent anti-diabetic activity. TFP is one of the primary hypoglycemic active compounds of Polygonatum odoratum which would worth further study and development.     

Anti-hyperglycemic effect,inhibition of inflammatory cytokines expression,and histopathology profile in streptozotocin-induced diabetic rats treated with Arracacia tolucensis aerial-parts extracts

Ethopharmacological relevance

Arracacia tolucensis is a medicinal plant used in northeast of Mexico as a remedy to treat people with Diabetes mellitus (DM); however, there are no scientific studies that support this information. Thus, we evaluated the anti-hyperglycemic effect of the hexane, ethyl acetate and ethanol extracts from aerial parts in streptozotocin-induced diabetic rats.

Materials and methods

DM was induced in Wistar male rats by single intraperitoneal injection of streptozotocin (STZ 50 mg/kg). After STZ-induction, hyperglycemic rats were treated with all three extracts orally at a single dose (250 mg/kg) each 48 h for 21 days. Glibenclamide (1 mg/kg) was used as a reference drug. The fasting blood glucose levels, the hematic biometry and biochemical profiles, and the inhibition of inflammatory cytokines expression were estimated. Histopathology analysis of pancreas, liver, spleen, and kidney tissue was carried out.

Results

Ours results showed that ethyl acetate extract decreased blood glucose levels significantly (75%, p< 0.05) when compared to diabetic rats and controlled the body weight loss; the lipids level did not change, but the enzyme levels of aspartate aminotransferase and alanine aminotransferase decreased significantly (60.83% and 66.16%, respectively, p< 0.05) and inhibited the expression of inflammatory cytokines,with respect to diabetic rats. Histopathology injury was not observed; by contrast repair of islet of Langerhans was exhibited.

Conclusion

These results validate the use of Arracacia tolucensis as a treatment against DM and suggests it is suitable to continue studies for its safe therapeutic use.     

Hypoglycemic effect of a leaf extract of Pseuderanthemum palatiferum (Nees) Radlk. in normal and streptozotocin-induced diabetic rats

Ethnopharmacological relevance

Pseuderanthemum palatiferum (Nees) Radlk (Acanthaceae) was first found in Northern Vietnam and expanded throughout the country including the Mekong Delta region. The leaves of this plant are recommended in folk medicine of Vietnam and Thailand for promoting and treating various diseases including hypertension, diarrhea, arthritis, hemorrhoids, stomachache, tumors, colitis, bleeding, wounds, constipation, flu, colon cancer, nephritis, and diabetes.

Aim of the study

The hypoglycemic effect of an 80% ethanolic leaf extract from the leaves of Pseuderanthemum palatiferum (PPE) was investigated in normal and streptozotocin (STZ)-induced diabetic rats.

Materials and methods

The PPE was administered daily and orally to the rats at the doses of 250, 500, and 1000 mg/kg body weight (b.w.) for 14 days. The levels of fasting plasma glucose (FPG), serum insulin, and biochemical data such as blood urea nitrogen (BUN), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and alkaline phosphatase (ALP) were evaluated. The hypoglycemic effect of PPE was compared to that of the known anti-diabetic drug glibenclamide (0.25 mg/kg b.w.).

Results

FPG and serum insulin in normal rats were not significantly different from the control and test groups in all dosages. The treated diabetic rats which had received PPE and glibenclamide showed significantly (p < 0.05) decreased FPG and increased serum insulin levels at the end of the experiment. The hypoglycemic effect of PPE at the dose of 250 mg/kg b.w. was significantly (p < 0.05) more effective than that of glibenclamide. The serum insulin in PPE fed diabetic rats at the dose of 250 mg/kg b.w. was not different from those which had received glibenclamide, and this dose was significantly (p < 0.05) more effective than PPE at the doses of 500 and 1000 mg/kg b.w. while PPE increased HDL and decreased TC, TG, LDL, BUN and ALP in the diabetic rats.

Conclusions

PPE has a beneficial effect in hyperglycemic rats and may prevent the complication of diabetes.     

A fraction of stem bark extract of Entada africana suppresses lipopolysaccharide-induced inflammation in RAW 264.7 cells

Ethnopharmacological relevance

Entada africana is a plant used in African traditional medicine for the treatment of stomachache, fever, liver related diseases, wound healing, cataract and dysentery.

Aims of the study

This study aimed at evaluating the anti-inflammatory activity of fractions of the stem bark extract of the plant using lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages model.

Materials and methods

The crude extract was prepared using the mixture CH₂Cl₂/MeOH (1:1, v/v) and fractionated by flash chromatography using solvents of increasing polarity to obtain five different fractions. The effects of the fractions on the cells viability were studied by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and their inhibitory activity against LPS-induced nitric oxide (NO) production screened by Griess test. The most active fraction was further investigated for its effects on reactive oxygen species (ROS) production using flux cytometry, the expression of inducible nitric oxide synthase (iNOS), pro-and anti-inflammatory cytokines (IL1β, TNFα, IL6, IL10 and IL13) by RT-PCR, and the activity of the enzyme p38 MAPK kinase by enzyme-linked immunosorbent assay (ELISA).

Results

The fractions presented no significant effect on the viability of macrophages at 100 μg/ml after 24 h incubation. The CH₂Cl₂/MeOH 5% (Ea5) fraction was found to be the most potent in inhibiting NO production with a half inhibition concentration (IC₅₀)=18.36 μg/ml, and showed the highest inhibition percentage (89.068%) in comparison with Baicalin (63.34%), an external standard at 50 μg/ml. Ea5, as well as Baicalin significantly (P<0.05) inhibited the expression of TNFα, IL6 and IL1β mRNA, attenuated mRNA expression of inducible NO synthase in a concentration-dependent manner, stimulated the expression of anti-inflammatory cytokines (IL10 and IL13), and showed a 30% inhibition of the activity of p38 MAPK kinase.

Conclusion

The results of the present study indicate that the fraction Ea5 of Entada africana possesses most potent in vitro anti-inflammatory activity and may contain compounds useful as a therapeutic agent in the treatment of inflammatory related diseases cause by over-activation of macrophages.     

Evaluation of antidiabetic and antihyperlipidemic activity of Artemisia indica linn (aeriel parts) in Streptozotocin induced diabetic rats

Ethnopharmacological relevance

Diabetes mellitus is a major metabolic disorder affecting a huge population all over the world. Artemisia species have been extensively used for the management of diabetes in folkloric medicine. The present study is designed to investigate the antidiabetic and antihyperlipidemic effects of aeriel parts of Artemisia indica.

Materials and methods

Hydromethanolic crude extracts, chloroform, ethyl acetate and n-butanol fractions of aerial parts of Artemisia indica were tested for their antidiabetic potential in Streptozotocin (STZ) (50 mg/kg, i.p.) induced diabetic Sprague-Dawley rats. Blood glucose level, body weight, serum lipid profile and activities of liver enzymes were determined. The extracts were further subjected to preliminary phytochemical analysis.

Results

A daily oral dose of hydromethanolic crude extracts (200 and 400 mg/kg b.w.) and chloroform fraction (200 mg/kg b.w.) of Artemisia indica for 15 days showed a significant reduction in blood glucose level which was comparable to that of the standard antidiabetic drug, glibenclamide (500 μg/kg, p.o.). Artemisia indica extracts also showed reduction in total cholesterol, triglycerides and low density lipoproteins as well as serum creatinine level, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and alkaline phosphatase (ALP) in diabetic rats.

Conclusion

According to the results Artemisia indica possesses hypoglycemic, antihyperlipidemic and valuable effects on liver and renal functions in diabetic rats, which seems to validate its traditional usage.     

Screening of the topical anti-inflammatory activity of the bark of Acacia cornigera Willdenow, Byrsonima crassifolia Kunth, Sweetia panamensis Yakovlev and the leaves of Sphagneticola trilobata Hitchcock

Ethnopharmacological relevance

An investigation of topical anti-inflammatory activity was undertaken on plants used in Central America traditional medicine.

Aim of study

Four herbal drugs used in the folk medicine of Central America to treat inflammatory skin affections (Acacia cornigera bark, Byrsonima crassifolia bark, Sphagneticola trilobata leaves and Sweetia panamensis bark) were evaluated for their topical anti-inflammatory activity.

Materials and methods

Petroleum ether, chloroform and methanol extracts were obtained for herbal medicines and then extracts were tested on Croton oil-induced ear dermatitis model in mice.

Results

Almost all the extracts reduced the Croton oil-induced ear dermatitis in mice and the chloroform ones showed the highest activity, with ID₅₀ (dose giving 50% oedema inhibition) values ranging from 112 μg/cm² (Byrsonima crassifolia) to 183 μg/cm² (Sphagneticola trilobata). As reference, ID₅₀ of the non-steroidal anti-inflammatory drug indomethacin was 93 μg/cm².

Conclusions

Lipophilic extracts from these species can be regarded as potential sources of anti-inflammatory principles.     

Sesquiterpenoids from antidiabetic Psacalium decompositum block ATP sensitive potassium channels

Ethnopharmacological relevance

The hypoglycemic effect of root and rhizome aqueous decoction of Psacalium decompositum (Asteraceae), a medicinal herb from Mexico, has been experimentally demonstrated, leading to the identification of several hypoglycemic sesquiterpenoids, such as cacalol, and the mixture of 3-hydroxycacalolide, and epi-3-hydroxycacalolide; however, the mechanism of action of these compounds is unknown.

Aim of the study

To establish whether cacalol, cacalone epimer mixture and cacalol acetate may block adenosine triphosphate-sensitive potassium channels (K_ATP channels) in a similar way to the antidiabetic drug glibenclamide.

Materials and methods

Cacalol, cacalone epimer mixture, and cacalol acetate were tested on the diazoxide-induced relaxation of male rat aortic rings precontracted with phenylephrine (3.2 × 10⁻⁶ M).

Results

Cacalol (10⁻⁵ M), cacalol acetate and the cacalone epimer mixture (10⁻⁴ M) inhibited the diazoxide effect, in a similar manner and concentration as glibenclamide (10⁻⁵ M). Cacalone epimer mixture exerted this effect in a concentration-dependent manner (P < 0.01). Cacalol (10⁻⁴ M), irreversibly inhibited the diazoxide-induced relaxation, and displayed activity at a lower concentration (10⁻⁵ M) than cacalone epimer mixture and cacalol acetate.

Conclusions

These results suggest that the studied compounds block K_ATP channels in a similar way to glibenclamide in rat aorta. However, controversial data indicate that Psacalium decompositum sesquiterpenoids are less effective than glibenclamide in lowering plasma glucose levels, suggesting that cacalol and cacalone epimer mixture, as well as cacalol acetate, may display a higher affinity to SUR2 subunit of K_ATP channels in aortic smooth muscle than to SUR1 subunit in pancreatic β-cells.     

Investigation of antihyperglycaemic activity of aqueous and petroleum ether extract of stem bark of Pongamia pinnata on serum glucose level in diabetic mice

Aim of the study

The aim of the study was to evaluate the antihyperglycaemic activity of aqueous (PPSB-AQE) and petroleum ether (PPSB-PEE) extract of stem bark Pongamia pinnata in alloxan induced diabetic mice.

Materials and methods

Diabetes was induced in mice by alloxan (80 mg/kg, i.v.). After acute and subacute treatment serum glucose was determined. OGTT was performed in PPSB-PEE pretreated animals.

Results

PPSB-PEE (25, 50, 100, 200 and 400 mg/kg) showed significant reduction in serum glucose level in acute and subacute studies. The antihyperglycaemic effects of PPSBPE (100, 200 and 400 mg/kg) showed onset at 2 h and peak effect at 6 h and the effect was sustained until 24th h with 400 mg/kg. In subacute study, antihyperglycaemic effect was observed on 21st day. In PPSBPE treated mice the body weight was not reduced in contrast to that in vehicle group. In OGTT, increased glucose utilization was observed.

Conclusions

It is concluded that PPSB-PEE but not PPSB-AQE showed antihyperglycaemic activity.     

Antidiabetic and antioxidant effects of Annona muricata (Annonaceae), aqueous extract on streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Annona muricata are used in Cameroon to manage diabetes and its complications. The aim of this study was to evaluate the antidiabetic, antioxidant activities and the potential toxicity of aqueous extract of Annona muricata in streptozotocin-induced diabetic rats.

Material and methods

Oral administration of Annona muricata aqueous extract (100 mg/kg or 200 mg/kg) was studied in normal and streptozotocin-induced diabetic rats. In long term treatment, 2 weeks after streptozotocin-induced diabetic rats, animals received plant extract during 28 consecutive days. For a protective effect, extract was administered 3 days prior to streptozotocin exposure and animals were observed 2 weeks without treatment.

Results

The plant extract was not effective in normal rats. In diabetic rats, single administration of the extract significantly reduced blood glucose levels by 75% and 58.22% respectively at the dose of 100 mg/kg and 200 mg/kg as compared to the initial value. Treatment of normal rats 3 days prior to diabetes induction showed that, Annona muricata extract has no effect within 72 h following STZ injection. However, after 14 days post-treatment, the extract at the dose of 100 mg/kg significantly reduced blood glucose levels as compared with initial value and diabetic control rats. Immunohistochemical staining of pancreatic β-cells of diabetic rats treated with the dose of 100 mg/kg expressed strong staining for β-cell compared to diabetic control. In a long-term study daily administration of Annona muricata aqueous extract for 28 days to diabetic rats, reduced blood glucose levels, serum creatinine, MDA, AST, ALT activity, and nitrite levels LDL-cholesterol. Total cholesterol, triglycerides, SOD, and CAT activity contents were restored.

Conclusion

These different results show that the antidiabetic activity of Annona muricata aqueous extract can be explained by its hypolipidaemic effect, its antioxidant and protective action on pancreatic β-cells, which in turn improve glucose metabolism.     

Metabolic intervention of aflatoxin B1 toxicity by curcumin

Ethno pharmacological relevance

Curcumin, bioactive principle of turmeric (Curcuma longa Linn) is an important constituent of Indian traditional medicine. Turmeric has been known to possess several therapeutic properties.

Aim of the study

The modulatory effect of dietary curcumin (0.05%, w/w) on drug metabolizing and general marker enzymes of liver and formation of AFB₁-adducts (DNA and protein) due to dietary AFB₁ exposure for a period of 6 weeks in a rodent model, have been evaluated.

Materials and methods

Drug metabolizing enzymes CYP1A1, GSHT, UGT1A and general marker enzymes (LDH, ALT, AST, ALP and γ-GT) of liver were estimated by standardized methods. Aflatoxin adducts (DNA and protein) were quantitated by indirect competitive ELISA.

Results

Dietary curcumin enhanced GSHT (p < 0.001) and UGT1A1 (p < 0.05) activity and significantly reduced the activity of CYP1A1 (p < 0.001), in rats exposed to aflatoxin B₁. Supplementation of curcumin in the diet normalized the altered activities of LDH and ALT. At molecular level, curcumin significantly reduced AFB₁–N⁷-guanine adduct (p < 0.001) excretion in the urine, DNA adduct (p < 0.05) in the liver and albumin adduct (p < 0.001) in the serum.

Conclusion

The experimental results substantiates that curcumin intervention ameliorates the AFB₁ induced toxicity.