Hypoglycemic evaluation of a new triterpene and other compounds isolated from Euclea undulata Thunb. var. myrtina (Ebenaceae) root bark

Aim of the study

Investigate the hypoglycaemic activity of the four isolated compounds from a crude acetone extract of the root bark of Euclea undulata var. myrtina, which is used by traditional healers in the Venda area, Limpopo Province in the treatment of diabetes.

Material and methods

The hypoglycaemic activity of the four compounds isolated from Euclea undulata was determined by in vitro screening of glucose utilization by C2C12 myocytes at a concentration of 25 μg/ml or 50 μg/ml. The inhibition of α-glucosidase was also tested at concentrations ranging from 0.02 to 200.00 μg/ml.

Results

Assay-guided isolation of the crude acetone extract of the root bark of Euclea undulata var. myrtina afforded a new triterpene, α-amyrin-3O-β-(5-hydroxy) ferulic acid (1), in addition to three known compounds; betulin (2), lupeol (3) and epicatechin (4). The in vitro results on C2C12 myocytes suggest that compound 4 may have some effect to lowers blood glucose levels, whereas compound 1 has the ability to inhibit α-glucosidase at a concentration of 200.0 μg/ml with an IC₅₀ value of 4.79 that correlates with that of the positive control acarbose IC₅₀ value 4.75.

Conclusion

The results suggest that 4 may have some ability to lower blood glucose levels, whereas 1 has the ability to inhibit α-glucosidase.

Ethnopharmacological relevance

These findings corroborate the ethnomedicinal use of Euclea undulata by traditional healers for the treatment of diabetes as two substances was isolated from the acetone plant extract that exhibit hypoglycaemic activity.     

α-Glucosidase inhibitory activity of selected Philippine plants

Ethnopharmacological relevance

Antidesma bunius Spreng. (Phyllantaceae), Averrhoa bilimbi L. (Oxalidaceae), Biophytum sensitivum (L.) DC. (Oxalidaceae), Ceriops tagal (Perr.) C.B. Rob. (Rhizophoraceae), Kyllinga monocephala Rottb. (Cyperaceae), and Rhizophora mucronata Lam. (Rhizophoraceae) are used as remedies to control diabetes. In the present study, these plants were screened for their potential α-glucosidase inhibitory activity.

Materials and methods

The 80% aqueous ethanolic extracts were screened for their α-glucosidase enzyme inhibitory activity using yeast alpha glucosidase enzyme.

Results

Except for A. bilimbi with IC₅₀ at 519.86±3.07, all manifested a significant enzyme inhibitory activity. R. mucronata manifested the highest activity with IC₅₀ at 0.08±1.82 μg mL⁻¹, followed by C. tagal with IC₅₀ at 0.85±1.46 μg mL⁻¹ and B. sensitivum with IC₅₀ at 2.24±1.58 μg mL⁻¹.

Conclusion

This is the first report on the α-glucosidase inhibitory effect of the six Philippine plants; thus, partly defining the mechanism on why these medicinal plants possess antidiabetic properties.     

In vitro and in vivo anti-diabetic activity of Swertia kouitchensis extract

Ethnopharmacological relevance

Swertia kouitchensis has long been used as a folk medicine to treat hepatitis and diabetes in central-western China. Therefore, this study was aimed to evaluate the anti-diabetic activity of the plant ethanol extract.

Materials and methods

Firstly, the extract was tested for its inhibitory activity on α-amylase and α-glucosidase in vitro. Following that, insulin secretion test in NIT-1cell was performed. Then, oral sucrose or starch tolerance test of the extract were carried out in normal mice. After that, acute effect of the extract was executed in normal and streptozotocin-induced (60 mg/kg) diabetic mice. Eventually, long term effect of the extract was performed in diabetic mice for 4 weeks. Oral glucose tolerance test and biochemical parameters were estimated at the end of the study.

Results

Swertia kouitchensis extract could remarkably inhibit the activity of α-amylase and α-glucosidase and stimulate insulin secretion in vitro. And also the extract displayed anti-hyperglycemic activity, improved antioxidant capacity, ameliorated the hyperlipidemia and carbohydrate metabolism in diabetic mice.

Conclusions

Swertia kouitchensis exhibits considerable anti-diabetic activity and metabolic alterations in diabetic mice. These results provide a rationale for the use of Swertia kouitchensis to treat diabetes mellitus.     

In vivo and in vitro antidiabetic effect of Cistus laurifolius L. and detection of major phenolic compounds by UPLC–TOF-MS analysis

Ethnopharmacological relevance

In Turkish folk medicine, various parts of Cistus laurifolius L. are used to treat gastric ulcer and various types of pains. Additionally the tea prepared from the leaves is used to decrease symptoms of diabetes.

Materials and methods

In the present study, the hypoglycemic effects of aqueous and ethanol extracts of Cistus laurifolius were investigated in normal, glucose loaded hyperglycemic and streptozocin (STZ)-induced diabetic rats. α-Glucosidase and α-amylase enzyme inhibitory effects were determined to evaluate the mechanism of action. Total phenolic content of the extracts were determined by using Folin–Ciocalteu reagent and Ultra Performance Liquid Chromatography–Time of Flight Mass Spectrometer (UPLC–TOF-MS) was used to detect the major phenolic compounds in the extract.

Results

Results indicated that blood glucose levels of the STZ-induced diabetic rats were decreased by ethanol extract at of 250 and 500 mg/kg doses as compared to control group (16%–34%). In glucose loaded animals, extracts have shown a weak hypoglycemic effect (11%–20%). Additionally, the ethanol extract of Cistus laurifolius is found to be a potent inhibitor of α-glucosidase and α-amylase, possibly due to several polyphenolic compounds present within the extract. Twelve major flavonoids (apigenin, quercetin, kaempferol, naringenin, quercitrin and their derivatives), gallic, ellagic and chlorogenic acid in chromatographic fingerprint were analyzed by the on-line UPLC–TOF-MS system.

Conclusions

Due to having inhibitory effect on blood glucose level and carbohydrate digesting enzymes (α-glucosidase and α-amylase), Cistus laurifolius leaves might be beneficial for diabetic patients.     

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.     

In vitro antiplasmodial activity of plants used in Benin in traditional medicine to treat malaria

Aim of the study

The aim of the study was to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to validate their use.

Materials and methods

For each species, dichloromethane, methanol and total aqueous extracts were tested. The antiplasmodial activity of extracts was evaluated using the measurement of the plasmodial lactate dehydrogenase activity on chloroquine-sensitive (3D7) and resistant (W2) strains of Plasmodium falciparum. The selectivity of the different extracts was evaluated using the MTT test on J774 macrophage-like murine cells and WI38 human normal fibroblasts.

Results

The best growth inhibition of both strains of Plasmodium falciparum was observed with the dichloromethane extracts of Acanthospermum hispidum DC. (Asteraceae) (IC₅₀ = 7.5 μg/ml on 3D7 and 4.8 μg/ml on W2), Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (Rubiaceae) leaves and twigs (IC₅₀ = 13.8 and 11.3 μg/ml on 3D7 and IC₅₀ = 26.5 and 15.8 μg/ml on W2, respectively), Carpolobia lutea G.Don. (Polygalaceae) (IC₅₀ = 19.4 μg/ml on 3D7 and 8.1 μg/ml on W2) and Strychnos spinosa Lam. (Loganiaceae) leaves (IC₅₀ = 15.6 μg/ml on 3D7 and 8.9 μg/ml on W2). All these extracts had a low cytotoxicity.

Conclusion

Our study gives some justifications for the traditional uses of some investigated plants.     

Serviceberry [Amelanchier alnifolia (Nutt.) Nutt. ex. M. Roem (Rosaceae)] leaf extract inhibits mammalian α-glucosidase activity and suppresses postprandial glycemic response in a mouse model of diet-induced obesity and hyperglycemia

Ethnopharmacological relevance

Serviceberry or Saskatoon berry [Amelanchier alnifolia (Nutt.) Nutt. ex. M. Roem (Rosaceae)], native to the North Glacier forests of the Rocky Mountains in Montana, has been used by the Blackfeet Indian tribe in alleviation of diabetes. Anecdotally, tea made from twigs and leaves have been used for optimum health and diabetes management. However, such traditional knowledge of the medicinal properties of Amelanchier alnifolia has not been validated by scientific studies. The goal of this study was to identify potential antidiabetic mechanisms of serviceberry.

Materials and Methods

Serviceberry plant samples consisting of leaves, twigs, and leaves with berries were extracted and fractionated. Ethyl acetate and water fractions were tested for inhibition of α-glucosidase activity in vitro. Diet-induced obese, hyperglycemic C57Bl6 mice were administered serviceberry leaf extract prior to sucrose-, starch-, or glucose-loading to test for α-glucosidase inhibition and decreased post-prandial glycemic response.

Results

In the course of screening for potential antidiabetic mechanisms, serviceberry leaf extracts and subfractions demonstrated potent inhibitory activity against mammalian intestinal α-glucosidase activity (EC 3.2.1.20). Further, in an animal model of diet-induced obesity and hyperglycemia, serviceberry leaf subfraction demonstrated significant inhibition of intestinal α-glucosidase activity, and delayed the absorption of carbohydrates, resulting in significant lowering of post-prandial blood glucose concentrations, similar to the antidiabetic drug Acarbose™.

Conclusions

These findings indicating that serviceberry leaf extract may lower post-prandial glycemic response corroborate traditional knowledge of the Blackfeet Indians of Montana, and potentially offer a complementary approach in the treatment of diabetes.     

In vitro antimicrobial activity of extracts and compounds of some selected medicinal plants from Cameroon

Aim of the study

Seven extracts and eight compounds from four selected Cameroonian medicinal plants, Solanecio mannii Hook f. (Asteraceae), Monodora myristica Dunal (Annonaceae), Albizia gummifera (J.F. Gmel) C.A. Smith (Fabaceae/Mimosoideae) and Glyphaea brevis (Spreng) Monachino (Tiliaceae), traditionally used for the treatment of hepatitis, parasites and other infectious diseases, were tested in vitro for their antimicrobial activity against Gram-positive (5 species) and Gram-negative (4 species) bacteria species and pathogenic yeasts (2 Candida species), to establish whether or not they have antimicrobial activity and to validate scientifically their use in traditional medicine.

Materials and methods

The agar disc diffusion and the microbroth dilution methods were used to determine the zone of inhibition between the edge of the filter paper and the edge of the inhibition area (IZ) and the minimal inhibitory concentration (MIC) respectively.

Results

The most active extracts against Candida albicans and Candida krusei were respectively the cyclohexane extract from the fruits of Monodora myristica and the ethyl acetate extract from the stem bark of Albizia gummifera (MIC = 6.3 μg/ml for both extracts). The lowest MIC value (1.6 μg/ml) for purified compounds was obtained on Candida albicans with a mixture of linear aliphatic primary alcohols (n-C24H50O to n-C30H62O), with n-hexacosanol (1b) as major compound and mixture of fatty acid esters of diunsaturated linear 1,2-diols (6).

Conclusion

These results afford ground informations for the potential use of the crude extracts of these species as well as of some of the isolated compounds in bacterial and fungal infections.     

Antidiabetic, anti-oxidant and antimicrobial activities of Fadogia ancylantha extracts from Malawi

Ethnopharmacological relevance

Communities in Chilumba, Malawi use herbal tea prepared from Fadogia ancylantha Schweinf (Rubiaceae) leaves for the management of diabetes, hypertension and alleviation of symptoms of gastrointestinal disorders and pneumonia. The objective of the study was to evaluate the in vitro antidiabetic, anti-oxidant and antimicrobial activities of the crude extracts of the leaves prepared by using three different extraction methods.

Materials and methods

Each of the organic, cold and hot aqueous extracts of the herbal tea was evaluated for its effect on glucose uptake in C2C12 muscle and Chang cell lines. Metformin and insulin were used as positive controls. The anti-oxidant activity, based on neutralisation of DPPH free radicals, was determined spectrophotometrically. The Agar serial dilution method was utilised to determine the minimum inhibitory concentration (MIC) of the extracts for the selected fungal and bacterial strains.

Results and discussion

The organic extract (12.5 μg/ml) exhibited the highest in vitro glucose uptake increases in Chang cells (181.24±0.29%) and C2C12 muscle cells (172.29±0.32%) while the hot and cold aqueous extracts gave lower uptakes, 145.94±0.37% and 138.70±0.52% in Chang cells respectively. At 100 μg/ml, aqueous extracts gave significantly higher (p<0.01) anti-oxidant activity (range 85.78–86.29%) than their organic counterpart (68.16%). The minimum inhibitory concentration (156 μg/ml) was obtained in the organic extract against the fungus Aspergillus fumigatus and moderate growth inhibition was observed with other test micro-organisms. The hot aqueous extract inhibited the growth of all test organisms except Pseudomonas aeruginosa. The cold aqueous extract was inactive against Pseudomonas aeruginosa and Candida albicans. The differences in the MIC values between the aqueous extracts seem to suggest that raised temperatures, as traditionally practised, facilitate the extraction of secondary bioactive metabolites.

Conclusion

These results show that Fadogia ancylantha extracts have high antidiabetic and anti-oxidant properties.     

Anti-diabetic activity of Swertia corymbosa (Griseb.) Wight ex C.B. Clarke aerial parts extract in streptozotocin induced diabetic rats

Ethnopharmacologicals relevance

Swertia corymbosa locally called as Shirattakuchi have a long history of use in Ayurveda herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim of the study

The present study aimed to investigate the effect of the methanolic extract of Swertia corymbosa (SC) in diabetic and to analyze its chemical composition by HPLC–ESI/MS that may correlate with their pharmacological activities.

Materials and methods

The in vitro anti-diabetic activity of the extracts was measured by using α-glucosidase and α-amylase enzyme inhibitory activity. The methanolic extract of Swertia corymbosa were administered orally (125, 250 and 500 mg/kg, for 28 days) to streptozotocin-induced diabetic rats. Hypoglycemic effects, oral glucose tolerance test, change in body weight and lipid profile, biochemical analysis and histopathological examination were assessed. High-performance liquid chromatography–electrospray ionization/mass spectrometry (HPLC–ESI/MS) method was also developed to analyze the chemical composition.

Results

In vitro anti-dabetic study, the methanol extract of SC is found to be a potent inhibitor of α-glucosidase and α-amylase activity. Oral administration of SC and standard drug for 28 days caused a significant decrease in the concentrations of blood glucose level, total cholesterol (TC), serum triglycerides (TGs), low-density lipoprotein-cholesterol (LDL-C), malondialdehyde (MDA) and significant increase in the concentrations of high density lipoprotein-cholesterol (HDL-C), serum insulin and body weight. Furthermore, activities of antioxidative enzymes, including SOD, GPx, GSH and CAT were enhanced dosed dependently with SC. Histopathological studies of the pancreas showed the regeneration of the β-cells by extract which were earlier necrosed by streptozotocin. Ten major compounds such as loganic acid (1), swertiamarin (2), sweroside (3), gentiopicroside (4), isovitexin (5), amoroswertin (6), amarogentin (7), gentiacaulein (8), decussatin (9) and swertianin (10) were analyzed by HPLC–ESI/MS system.

Conclusions

These results demonstrate that SC aerial parts of methanolic extract is an effective anti-diabetic and antioxidant activities which provides the scientific proof for the folklore medicine.     

Determination of the wound healing effect of Calendula extracts using the scratch assay with 3T3 fibroblasts

Pharmacological relevance

Presentation of the scratch assay as a convenient and inexpensive in vitro tool to gain first insights in the wound healing potential of plant extracts and natural compounds.

Aim of the study

The present study deals with the optimization of the scratch assay which can be used as an in vitro model for quantification of fibroblast migration to and proliferation into the wounded area. It is suitable for the first evaluation of the wound re-epithelialization potential of crude herbal extracts, isolated compounds and pharmaceutical preparations. As a proof of concept three preparations from traditional medicinal plants were investigated.

Materials and methods

Swiss 3T3 albino mouse fibroblasts were used in monolayers and platelet derived growth factor as positive control. Hexane and ethanolic extracts from Calendula officinalis and Matricaria recutita, Hypericum oil as well as the triterpenoids faradiol myristate and palmitate were studied. To differentiate between proliferation and migration antimitotic mitomycin C was added.

Results

Both extracts of Calendula officinalis stimulated proliferation and migration of fibroblasts at low concentrations, e.g. 10 μg/ml enhanced cell numbers by 64.35% and 70.53%, respectively. Inhibition of proliferation showed that this effect is mainly due to stimulation of migration. Faradiol myristate and palmitate gave comparable stimulation rates at an almost 50 μg/ml concentration, indicating that they contribute partially, but not most significantly to the wound healing effects of Calendula preparations. Extracts from Matricaria recutita were only moderately active. Hypericum oil was cytotoxic at concentrations higher than 0.5 μg/ml.

Conclusions

The scratch assay in the present form can be used as a promising scientific approach and platform to differentiate between plant extracts known for their wound healing and their anti-inflammatory properties.     

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.     

Munronia pinnata (Wall.) Theob.: Unveiling phytochemistry and dual inhibition of 5-lipoxygenase and microsomal prostaglandin E2 synthase (mPGES)-1

Ethnopharmacological relevance

Preparations from Munronia pinnata (Wall.) Theob. are extensively used in traditional medicine in Sri Lanka for the treatment of inflammatory conditions. However, neither the pharmacological features nor the phytochemistry of this plant are explored in order to understand and rationalize the reported ethnobotanical significance. As 5-lipoxygenase (5-LO) and microsomal prostaglandin E₂ synthase (mPGES)-1 are crucial enzymes in inflammatory disorders, we evaluated their inhibition by M. pinnata extracts and studied the chemical profile of the plant for the identification of relevant constituents.

Materials and methods

Cell-free and cell-based assays were employed in order to investigate the suppression of 5-LO and mPGES-1 activity. Cell viability, radical scavenger activities, and inhibition of reactive oxygen species formation (ROS) in neutrophils were studied to assess cytotoxic and antioxidant effects. Gas and liquid chromatography coupled to mass spectrometric analysis enabled the characterization of secondary metabolites.

Results

The n-hexane extract of M. pinnata efficiently suppressed 5-LO activity in stimulated human neutrophils (IC₅₀ =8.7 µg/ml) and potently inhibited isolated human recombinant 5-LO (IC₅₀ =0.48 µg/ml) and mPGES-1 (IC₅₀ =1.0 µg/ml). In contrast, no significant radical scavenging activity or suppression of ROS formation was observed, and neutrophil viability was unaffected. The phytochemistry of the plant was unveiled for the first time and phytosterols, fatty acids, sesquiterpenes and several other types of secondary metabolites were identified.

Conclusions

Together, potent inhibition of 5-LO and mPGES-1 activity, without concomitant antioxidant activity and cytotoxic effects, rationalizes the ethnopharmacological use of M. pinnata as anti-inflammatory remedy. Detailed chromatographic/mass spectrometric analysis reveals discrete chemical structures of relevant constituents.     

Inhibition of pancreatic lipase, α-glucosidase, α-amylase,and hypolipidemic effects of the total flavonoids from Nelumbo nucifera leaves

Ethnopharmacological relevance

Nelumbo nucifera Gaertn. leaves have been used as medicinal herbs in the past 1300 years, specifically utilized to cure hyperlipidemia, hyperglycemia, and obesity. It has been recorded in the most famous medicinal book in China for more than 400 years. The present study aims to identify the potential therapeutic activities of the flavonoids isolated from Nelumbo nucifera leaves.

Materials and methods

Nelumbo nucifera leaf flavonoids (NLF) were tested for the inhibition of lipase, α-glucosidase, and α-amylase activities in vitro. A single dose of NLF was administered by oral gavage in mice for acute toxicity. Wistar rats with high-fat diet-induced hyperlipidemia and two other animal models were used to evaluate the hypolipidemic effects of NLF.

Results

Our in vitro biochemistry tests revealed that the NLF showed high inhibitory activity against porcine pancreatic lipase, α-amylase, and α-glucosidase with IC₅₀ values of 0.38±0.022, 2.20±0.18, and 1.86±0.018 mg/mL, respectively. Furthermore, the NLF significantly lowered the lipid components, such as the total cholesterol, triglycerides, low-density lipoprotein cholesterol, and malondialdehyde, in various established in vivo systems and raised the high-density lipoprotein cholesterol. Moreover, the NLF alleviated high-fat diet-induced lipid accumulation in the liver.

Conclusions

The results demonstrate that NLFs can effectively ameliorate hyperlipidemia and inhibit the key enzymes related to type 2 diabetes mellitus. Our findings may provide new pharmacological basis for the treatment of hyperlipidemia, hyperglycemia, and obesity using NLFs.     

Anti-inflammatory and analgesic activities of methanolic extract of Kigelia pinnata DC flower

Ethnopharmacological relevance

Kigelia pinnata DC is extensively used in Indian traditional medicine for several diseases including inflammatory and painful disorders.

Aim of the study

The aim of the present study is to investigate the possible anti-inflammatory and analgesic activities of methanolic extract of Kigelia pinnata flower (MKFL) to support the medicinal uses claimed by folklore practitioners.

Materials and methods

MKFL is evaluated for its anti-inflammatory activity in carrageenan-induced paw edema model in rats and analgesic activity in acetic acid-induced writhing, hot plate and formalin-induced paw licking models in mice.

Results

MKFL exhibited a significant (P < 0.01) anti-inflammatory and analgesic activities with the doses of 100, 200 and 400 mg/kg b.w. in rats and mice respectively.

Conclusions

The results of the experimental study thus strongly support the traditional use of this plant for inflammatory and pain disorders.     

Evaluation of 13 selected medicinal plants from Burkina Faso for their antiplasmodial properties

Aim of the study

The aim of this study was to evaluate the antiplasmodial properties of 13 plants used against malaria in traditional medicine in Burkina Faso.

Materials and methods

In vitro antiplasmodial activity of dichloromethane, methanol and aqueous crude extracts obtained from vegetal samples collected in Burkina Faso was first evaluated on the Plasmodium falciparum 3D7 chloroquine-sensitive strain using a colorimetric method.

Results

Thirteen extracts obtained from 8 different species were found to exhibit antiplasmodial activity (IC₅₀ < 50 μg/ml). Five species demonstrated a moderate activity (15 μg/ml < IC₅₀ < 50 μg/ml): Boswellia dalzielii (leaves), Waltheria indica (roots and aerial parts), Bergia suffruticosa (whole plant), Vitellaria paradoxa (bark) and Jatropha gossypiifolia (leaves). The best results were obtained with extracts from the Dicoma tomentosa whole plant, from Psorospermum senegalense leaves and from Gardenia sokotensis leaves. These extracts found to display promising antiplasmodial activity, with IC₅₀ values ranging from 7.0 to 14.0 μg/ml.The most active plant extracts were then tested for in vitro activity on the Plasmodium falciparum W2 chloroquine-resistant strain and also for in vitro cytotoxicity on normal human fibroblasts (WI-38) in order to determine the selectivity index.

Conclusions

Dicoma tomentosa (Asteraceae) and Psorospermum senegalense (Clusiaceae) appeared to be the best candidates for further investigation of their antiplasmodial properties, reported for the first time by this study.     

Antiplasmodial activity of extracts from seven medicinal plants used in malaria treatment in Cameroon

Aim of the study

In a search for new plant-derived biologically active compounds against malaria parasites, we have carried out an ethnopharmacological study to evaluate the susceptibility of cultured Plasmodium falciparum to extracts and fractions from seven Cameroonian medicinal plants used in malaria treatment. We have also explored the inhibition of the Plasmodium falciparum cysteine protease Falcipain-2.

Materials and methods

Plant materials were extracted by maceration in organic solvents, and subsequently partitioned or fractionated to afford test fractions. The susceptibility of erythrocytes and the W2 strain of Plasmodium falciparum to plant extracts was evaluated in culture. In addition, the ability of annonaceous extracts to inhibit recombinant cysteine protease Falcipain-2 was also assessed.

Results and discussion

The extracts showed no toxicity against erythrocytes. The majority of plant extracts were highly active against Plasmodium falciparumin vitro, with IC₅₀ values lower than 5 μg/ml. Annonaceous extracts (acetogenin-rich fractions and interface precipitates) exhibited the highest potency. Some of these extracts exhibited modest inhibition of Falcipain-2.

Conclusion

These results support continued investigation of components of traditional medicines as potential new antimalarial agents.     

Anti-cancer activity of compounds from Bauhinia strychnifolia stem

Ethnopharmacological relevance

The stem and root of Bauhinia strychnifolia Craib (Fabaceae family) have been traditionally used in Thailand to treat fever, alcoholic toxication, allergy and cancer. An EtOH extract of Bauhinia strychnifolia showed good inhibitory activity against several cancer cell lines including HT-29, HeLa, MCF-7 and KB. As there has been no previous reports on chemical constituents of Bauhinia strychnifolia, this study is aimed to isolate the pure compounds with anti-cancer activity.

Materials and methods

Five pure compounds were isolated from EtOH extract of Bauhinia strychnifolia stem using silica gel, dianion HP-20 and sephadex LH-20 column chromatography and were tested for their cytotoxic effects against HT-29, HeLa, MCF-7 and KB cell lines using the Sulforhodamine B (SRB) assay.

Results

Among five compounds, 3,5,7,3′,5′-pentahydroxyflavanonol-3-O-α-l-rhamnopyranoside (2) possessed very potent activity against KB (IC₅₀=0.00054 μg/mL), HT-29 (IC₅₀=0.00217 μg/mL), MCF-7 (IC₅₀=0.0585 μg/mL) and HeLa cells (IC₅₀=0.0692 μg/mL). 3,5,7-Trihydroxychromone-3-O-α-l-rhamnopyranoside (3) also showed good activity against HT-29 (IC₅₀=0.02366 μg/mL), KB (IC₅₀=0.0412 μg/mL) and MCF-7 (IC₅₀=0.297 μg/mL), respectively. The activity of 2 (IC₅₀=0.00054 μg/mL) against KB cell was ten times higher than that of the positive control, Camptothecin (anti-cancer drug, IC₅₀=0.0057 μg/mL). All compounds did not show any cytotoxicity with normal cells at the concentration of 1 μg/mL.

Conclusion

This is the first report of compounds 2 and 3 on anti-cancer activity and based on the anti-cancer activity of extracts and pure compounds isolated from Bauhinia strychnifolia stem, it might be suggested that this plant could be useful for treatment of cancer.     

Renoprotective effects of the crude extract and solvent fractions of the leaves of Euclea divinorum Hierns against gentamicin-induced nephrotoxicity in rats

Ethnopharmacological relevance

Euclea divinorum Hierns (Ebenaceae) is used in Ethiopian folklore medicine to treat scabies, inflammation of the skin, eczema, abdominal pain, gonorrhea, and kidney problems. However, the claim has not been scientifically validated.

Aim of the study

To assess the renoprotective effects of the crude extract and solvent fractions of E. divinorum leaves against gentamicin-induced nephrotoxicity in rats.

Materials and method

Rats of either sex were divided into seven experimental groups, each comprising six animals. Group I served as control and given vehicle (Tween 80, 2%, v/v in water) and Group II were treated with gentamicin intraperitoneally (100 mg/kg/day) for eight days. Group III–V received crude extract at three different doses 100 mg/kg, 150 mg/kg and 200 mg/kg, respectively. Group VI received 100 mg/kg of the methanolic fraction and Group VII 100 mg/kg of the aqueous fraction. The extract was administered orally two days before and eight days concomitantly with gentamicin. Following treatment, blood and renal tissue were used to assess creatinine, blood urea nitrogen (BUN), malondialdehyde (MDA), antioxidant enzymes and tubular necrosis using recommended procedures. In addition, free radical scavenging activity was determined using in vitro methods.

Results

Gentamicin significantly increased serum creatinine and BUN, MDA and tubular necrosis in rats. It also decreased activity of catalase and superoxide dismutase as well as levels of gluthatione. Pre- and co-treatment with the crude extract and solvent fractions of Euclea divinorum leaves reversed gentamicin-induced alterations as evidenced by a decrease in tubular necrosis, serum and oxidant markers as well as by an increase in antioxidant molecules. Effect was found to decrease with dose when the crude extract was used and maximum protection was conferred by 100 mg/kg of the methanolic fraction in both in vivo and in vitro studies.

Conclusions

Euclea divinorum reversed gentamicin-induced nephrotoxicity, probably via its antioxidant activity. The fact that the methanol fraction conferred maximum protection suggests that semi-polar antioxidant principles might be responsible for the observed effect.     

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.