In vivo antimalarial activities of Enantia polycarpa stem bark against Plasmodium berghei berghei in mice

Ethnopharmacological relevance

Enantia polycarpa (PC) Engl. Et Diels (Annonaceae) is used in traditional medicine as an antimalarial remedy in Southern Nigeria.

Aim of the study

The antimalarial activities of ethanolic stem bark extracts of Enantia polycarpa was studied in vivo, in mice infected with Plasmodium berghei berghei.

Materials and methods

The ethanolic stem bark extract of Enantia polycarpa was administered at doses ranging from 200 to 600 mg/kg/day to Plasmodium berghei infected mice in both early and established models of antiplasmodial studies.

Results

The extract of Enantia polycarpa exhibited promising antimalarial activity against both early and established infections. At a dose of 600 mg/kg the extract achieved a 75.8% and 72% chemosuppression of parasitaemia in the study of acute and established infections, respectively. The extract also prolonged mean survival time of Plasmodium berghei infected mice during the study of established infection. The mean survival time of mice administered Enantia polycarpa extract at 600 mg/kg/day (27 days) was significantly longer than infected/untreated control (12 days). For the acute toxicity study the extract had an intraperitoneal LD₅₀ of 186 mg/kg but caused no mortality when administered orally at doses as high as 2,000 and 4,000 mg/kg.

Conclusions

Collectively, the results indicate that Enantia polycarpa is safe when administered orally and possesses promising antimalarial activity, thus supporting its use in traditional medicine for the treatment of malaria.     

Antiplasmodial activity of root extract and fractions of Croton zambesicus

Aim of the study

Antiplasmodial activity of root extract and fractions of Croton zambesicus were evaluated to ascertain the folkloric claim of its antimalarial activity and elucidate its antiplasmodial mechanism of action.

Material and method

The crude ethanolic root extract (27–81 mg/kg) and gradient fractions ( n- hexane, chloroform, ethyl acetate and methanol; 54 mg/kg) of Croton zambesicus were investigated for antiplasmodial activity against chloroquine - sensitive Plasmodium berghei infections in mice. The antiplasmodial activity during early and established infections as well as the prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Oxidant generation potentials of the crude extract and fractions was also evaluated to elucidate their mechanism of action.

Results

The crude root extract (27 – 81 mg/kg) demonstrated significant (P < 0.01–0.001) schizonticidal activity during early and established infections and also had prophylactic activity. The activity was comparable to that of the standard drug used (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg). Methanol, ethyl acetate and chloroform fractions had comparative in vivo antiplasmodial activity and oxidant generation potentials.

Conclusion

The antiplasmodial activity of this root extract and fractions which is likely to be through peroxidation confirms the folkloric use of this plant.     

Anticonvulsant activity of Benkara malabarica (Linn.) root extract: In vitro and in vivo investigation

Aim of the study

To systematically investigate the anticonvulsant activity of methanol extract of Benkara malabarica roots and to provide a biochemical basis elucidating its mode of action.

Methods

The median lethal dose (LD₅₀) of Benkara malabarica extract was determined. The anticonvulsant activity of the extract was assessed in strychnine-induced and isoniazide-induced convulsion models; phenytoin (20 mg/kg) and diazepam (1 mg/kg) were used as standards, respectively. Percentage protection provided by the drug was accounted as decrease in the number of convulsions within 8 h of observation. Mechanism of action was studied by performing GABA transaminase (GABA-T) assay, isolated from rat brain. Active constituent was isolated and characterized from the plant extract.

Results

The median lethal dose (LD50) of Benkara malabarica was found to be more than 500 mg/kg. It demonstrated 30% and 35% protection against strychnine-induced convulsions and 60% and 80% protection against isoniazide-induced convulsions, at doses of 25 mg/kg and 50 mg/kg, respectively. Enzyme assay results revealed that Benkara malabarica extract possesses GABA-T inhibitory activity (IC50 = 0.721 mg/ml). Scopoletin which was identified as the major constituent of the extract was found to be an inhibitor of GABA-T (IC50 = 10.57 μM).

Conclusions

The anticonvulsant activity of the plant extract is predominantly GABA mediated and may be due to the action of scopoletin alone or is a result of synergy of different compounds in the extract in which scopoletin is the major constituent.     

Anti-ulcer polysaccharides from Cola cordifolia bark and leaves

Ethnopharmacological relevance

The study documented medicinal plants that are traditionally used for treatment of malaria in Shinile District, eastern Ethiopia, and evaluated selected medicinal plants for their antiplasmodial activities against Plasmodium berghei.

Materials and methods

The study was conducted in four kebeles of Shinile District, Somali Region, Ethiopia. A total of 15 traditional healers were sampled based on recommendations of local elders and administrators. Specimens of the reported antimalarial plants were collected and stored at the Mini Herbarium of the Aklilu Lemma Institute of Pathobiology, Addis Ababa University, following identification. Crude aqueous and ethanol extracts of Aloe sp., Azadirachta indica and Tamarindus indica were tested in vivo against Plasmodium berghei. The three plants were selected based on the frequency antimalarial use report by healers.

Results

The study revealed 27 antimalarial plants, the majority of which were harvested from the wild. Root was the most frequently sought plant part. Most of the remedies were used in decoction form. Aloe sp., Azadirachta indica and Tamarindus indica were the most commonly reported plants for their antimalarial use. For the in vivo test, all the plant extracts were given to mice orally. Ethanol and aqueous leaf extracts of Aloe sp. caused 73.94% and 58.10% parasitaemia suppression, respectively at dose of 650 mg/kg. Ethanol extract of Azadirachta indica leaves induced 54.79% parasitaemia suppression at the dose of 650 mg/kg and its water extract induced 21.47% parasite suppression at a similar dose. Water extract of the fruits of Tamarindus indica showed the highest parasitaemia suppression (81.09%) at the dose of 650 mg/kg. Most Plasmodium berghei infected mice treated with high dose of plant extracts survived relatively longer compared to their respective controls although the difference was not significant.

Conclusions

The result of this study may support the traditional use of Aloe sp., Azadirachta indica and Tamarindus indica in the study area against malaria. Results of this study can be used as a basis for further phytochemical and pharmacological investigations in the effort for search of new and locally affordable antimalarial agents.     

Suppression of nitric oxide production in activated murine peritoneal macrophages in vitro and ex vivo by Scrophularia striata ethanolic extract

Ethnopharmacological relevance

Scrophularia striata (Scrophulariaceae), a traditional Iranian medicine, has been used for the treatment of allergy, rheumatics and chronic inflammatory disorders.

Aim of the study

In the present study, we investigated the in vitro and ex vivo suppressive effects of Scrophularia striata ethanolic extract on nitric oxide production in mouse peritoneal macrophages.

Materials and methods

Peritoneal macrophages were harvested by lavaging with ice cold phosphate buffer saline. Macrophages obtained from mice not treated were cultured with 10 μg/mL lipopolysaccaride (LPS), 20 U/mL interferon-γ (IFN-γ), and various concentrations of Scrophularia striata extract for the in vitro experiments and those obtained from mice treated with different doses of the extract for 7 days were cultured with 10 μg/mL LPS, 20 U/mL IFN-γ for the in vivo experiments. Nitrit levels were measured by using the diazotization method based on the Griess reaction, which is an indirect assay for NO production.

Results

In vitro exposure of mouse peritoneal macrophages with various concentrations of Scrophularia striata extract (10, 50 and 100 μg/mL) significantly suppressed NO production in a dose-dependent manner. In vivo administration of Scrophularia striata extract (50 and 100 mg/kg) to Balb/c mice inhibited LPS and IFN-γ induced production of NO in the isolated mouse peritoneal macrophages ex vivo in a dose-dependent manner. Exposure to Scrophularia striata extract had no effect on cell viability.

Conclusion

The results of the study demonstrated that the Scrophularia striata extract inhibit NO production in activated murine macrophages and we suggest that Scrophularia striata may be used in treating the inflammatory diseases.     

Effects of ethanolic dried leaf extract of Lecaniodiscus cupanioides on antioxidant enzymes and biochemical parameters in rats

Ethnopharmacological relevance

Lecaniodiscus cupanioides is widely used in West African folk medicine for the treatment of inflammatory conditions, fevers and bacterial infections.

Aim of the study

To evaluate the potential toxic effects of the ethanolic dried leaf extract of Lecaniodiscus cupanioides (LC) on antioxidant enzymes in selected organs and biochemical parameters.

Materials and Methods

Crude ethanolic extract of Lecaniodiscus cupanioides dried leaves was prepared. A 90-day sub-chronic toxicity study was conducted using albino rats. Reconstituted Lecaniodiscus cupanioides was administered at a dosage of 400, 800 and 1600 mg/kg (high dose) with a control group receiving 10 ml/kg orally. Histopathological studies of major organs and blood chemistry analysis were performed on blood obtained via cardiac puncture after euthanization. Selected organs (liver, kidney and brain) were harvested for antioxidant and histopathological assessments.

Results

The extract produced significant (p<0.05) increases in the weights of liver, kidney and brain at 800 mg/kg and 1600 mg/kg compared to the control. Biochemical analysis showed significant increase in Alanine transferase (ALT) at 800 mg/kg and 1600 mg/kg. Assay for antioxidant enzymes showed a reversible decrease in the activity of Catalase (CAT), Superoxide dismutase (SOD) and Glutathione (GSH) with an increase in Malondialdehyde (MDA) at 800 mg/kg and 1600 mg/kg Lecaniodiscus cupanioides. Histopathological study showed reversible congestion in the brain, liver, and kidney at 800 mg/kg and 1600 mg/kg.

Conclusion

Findings in this study reveal that the ethanolic dried leaf extract of Lecaniodiscus cupanioides has the potential for inhibiting in vivo antioxidant enzymes activity and causing hepatotoxicity after prolonged exposure.     

Cinchonain Ib isolated from Eriobotrya japonica induces insulin secretion in vitro and in vivo

Aims of the study

Eriobotrya japonica leaves had been used traditionally for the treatment of diabetes mellitus by immersing the dried leaves in a hot water drink. Few studies have shown the hypoglycemic effect of Eriobotrya japonica using crude alcoholic extract and isolated methanolic compounds. These studies proposed that the mechanism of action could be by stimulating the β-islets of Langerhans to secrete insulin, however with no scientific evidence.

Methods

Eriobotrya japonica water extract (EJWE) and the compounds derived from it: cinchonain Ib, procyanidin B-2, chlorogenic acid and epicatechin, were tested for their effects on insulin secretion from INS-1 cells and following oral administration in rats.

Results

The present study showed that EJWE increased significantly (p < 0.05) insulin secretion from INS-1 cells in dose-dependent manner. Oral administration of EJWE at 230 mg/kg to rats, however, decreased plasma insulin level for as long as 240 min post-administration and caused a transient drop of blood glucose at 15 and 30 min post-administration. On the other hand, cinchonain Ib enhanced significantly (p < 0.05) insulin secretion from INS-1 cells, whereas epicatechin inhibited significantly (p < 0.05) insulin secretion from INS-1 cells. In addition, cinchonain Ib enhanced significantly (150%: p < 0.05) plasma insulin level in rats for as long as 240 min after 108 mg/kg oral administration but did not induce any change in blood glucose level.

Conclusion

These data indicate that cinchonain Ib has an insulinotropic effect and suggest the possible use of cinchonain Ib for managing type 2 diabetes.     

Neuroprotective effects of Dioscorea opposita on scopolamine-induced memory impairment in in vivo behavioral tests and in vitro assays

Ethnopharmacological relevance

Plants belong to the genus Dioscorea have long been used as edible tuber crops in many tropical and subtropical areas and as a traditional herbal medicine in oriental countries including China, Japan and Korea.

Aim of the study

In this study, in vivo and in vitro tests were carried out to evaluate the cognitive enhancing effects of CHCl₃-soluble extract from Dioscorea opposita against scopolamine-induced amnesic mice and glutamate- and H₂O₂-treated cortical neurons of rats.

Materials, methods and results

Acute treatment (200 mg/kg body weight, p.o.) and 10 days’ daily administration (50 mg/kg body weight, p.o.) of CHCl₃-soluble extract showed significant spatial learning and memory improvement on mice. Furthermore, the neuroprotective effects on glutamate- and H₂O₂-induced neurotoxicity in primary cultured cortical neurons of rats were assessed. Pretreatment with the extract was found to impart significant protection against neurotoxicity.

Conclusions

These in vivo and in vitro results suggest that the Dioscorea opposita has neuroprotective effects on memory impairment related neurodegenerative diseases.     

Evaluation of toxicity of Calophyllum brasiliense stem bark extract by in vivo and in vitro assays

Ethnopharmacological relevance

Calophyllum brasiliense Camb., Clusiaceae, is commonly known as “guanandi” and its stem bark is used in Brazilian traditional medicine to treat rheumatism, vein problems, hemorrhoids and gastric ulcers. The aim of this study was to evaluate the toxicity of hexane extract of Calophyllum brasiliense stem bark (HECb) using in vitro and in vivo experimental models.

Materials and methods

In vitro toxicity was evaluated by Alamar Blue cytotoxicity assay and micronucleus test, using Chinese hamster ovary (CHO-k1) epithelial cells. in vivo toxicity was evaluated by oral acute and subchronic toxicity assays. In the oral acute toxicity screening, a single dose of HECb was administered to mice at doses ranging from 250 to 1000 mg/kg. In the subchronic study, HECb was administered orally for 30 days to Wistar rats at doses of 100 mg/kg and 500 mg/kg. Phytochemical analyses were performed by HPLC/UV–vis, secondary metabolites were quantified by spectrophotometric methods.

Results

HECb presented IC₅₀=119.94±4.31 µg/mL after a 24 h cytotoxicity test using CHO-k1 cells, showing low cytotoxicity. However, when the cells were exposed to HECb for 72 h, the IC₅₀ value was 8.39±2.00 µg/mL, showing in this case, a pronounced cytotoxic effect. In the oral acute toxicity studies, doses up to 500 mg/kg of HECb did not cause any changes in both male and female mice. At 1000 mg/kg, male mice showed signs typical of depression and stimulation that were reversed at 72 h. Besides, female mice were more sensitive to the toxic effect of HECb at 1000 mg/kg, which initially presented typical agitation signals, followed by depression signals, leading to death of all the animals at 24 h. In subchronic assay with rats, HECb administered orally at doses of 100 and 500 mg/kg did not cause significant changes in all clinical parameters evaluated. Histopathological analyses showed no deleterious effect in the vital organs of rats. Preliminary phytochemical analysis revealed the presence of phenolic compounds, steroids, and volatile coumarins. Analysis by HPLC showed two major peaks characteristic of chromanones.

Conclusions

In vitro toxicological tests showed that HECb exhibited cytotoxicity especially after 72 h of exposition, and mutagenicity on the highest tested dose. The in vivo studies demonstrated that HECb produced some toxicity signs at the highest dose tested, particularly, in the acute toxicity test but showed no significant signs of toxicity in the subchronic assay. Based on these and previous pharmacological studies, it is possible to say that HECb did not exhibit significant toxicity at its effective dose. This suggests that HECb is relatively safe in humans at its effective dose.     

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves,stem bark and root bark of Alstonia congensis

Ethnopharmacological relevance

To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases.

Materials and methods

The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well.

Results

The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC₅₀ values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC₅₀ values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC₅₀ values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC₅₀>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum.

Conclusion

These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.     

Hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus Schum. and Thonn. (Connaraceae)

Ethnopharmacological relevance

The leaf decoction of Byrsocarpus coccineus (Connaraceae) is drunk for the treatment of jaundice in West African traditional medicine.

Aim of the study

To investigate the hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus in carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats.

Materials and methods

Group allotment in this study included vehicle, CCl₄, Byrsocarpus coccineus 1000 mg/kg alone, Byrsocarpus coccineus 200, 400, and 1000 mg/kg + CCl₄ and Livolin^® 20 mg/kg + CCl₄, and treatment was carried out accordingly. On the 7th day, rats were sacrificed and blood was withdrawn by cardiac puncture. The levels and activities of serum biochemical parameters and antioxidant enzymes were then assayed using standard procedures.

Results

CCl₄ significantly (P < 0.05) increased the levels of ALT and AST and reduced total protein. In CCl₄ treated animals, Byrsocarpus coccineus (200, 400, and 1000 mg/kg) dose-dependently and significantly decreased ALT, AST and ALP levels with peak effect produced at the highest dose. Conversely, Byrsocarpus coccineus produced significant increases in albumin and total protein levels. The standard drug produced significant effects in respect of ALT (↓), albumin (↑), and total protein (↑). CCl₄ also produced significant (P < 0.05) reductions in the activity of catalase, SOD, peroxidase and GSH, and conversely increased MDA level. Byrsocarpus coccineus produced significant and dose-dependent reversal of CCl₄-diminished activity of the antioxidant enzymes and reduced CCl₄-elevated level of MDA. The standard drug also significantly increased CCl₄-diminished antioxidant enzymes activity and reduced CCl₄-elevated MDA level. In general, the effects of the standard drug were comparable and not significantly different from those of Byrsocarpus coccineus.

Conclusion

The results obtained in this study suggest that the aqueous leaf extract of Byrsocarpus coccineus possesses hepatoprotective and in vivo antioxidant effects. This finding justifies the use of this preparation in West African traditional medicine for the treatment of liver disease.     

In vitro and in vivo anti-Helicobacter pylori activity of Calophyllum brasiliense Camb.

Aims of the study

Calophyllum brasiliense (Camb.) is a medicinal tree that grows particularly in the hilly and forested regions of Brazil. Preparations from its stem bark are popular remedies for the treatment of chronic ulcers. Since earlier investigations on bark extracts evidenced gastroprotective and gastric acid inhibitory properties, this study evaluated the effects of hydroethanolic extract (HEECb) and the dichloromethanic fraction (DCMF), from Calophyllum brasiliense stem bark, against Helicobacter pylori, in vitro and in vivo.

Materials and methods

The in vitro assays were performed using the disk diffusion and broth microdilution methods to determine the minimum inhibitory concentration (MIC) values. The test substances were evaluated in vivo taking into account the delay in the gastric ulcer healing in Wistar rats, infected with Helicobacter pylori.

Results

DCMF appeared the most active and potent in vitro against Helicobacter pylori growth with an MIC of 31 μg/mL. In the in vivo assays, rats ulcerated by acetic acid, and inoculated with Helicobacter pylori showed a marked delay in ulcer healing. Treatment with HEECb (50, 100 and 200 mg/kg) and DCMF (100 and 200 mg/kg) reduced the ulcerated area in a dose-dependent manner. While DCMF, at 200 mg/kg, increased the prostaglandin E₂ (PGE₂) level, both HEECb and DCMF decreased the number of urease-positive animals, as confirmed by the reduction of Helicobacter pylori presence in histopathological analysis.

Conclusion

The results suggest that the antiulcer activity of Calophyllum brasiliense is due, in part, to its anti-Helicobacter pylori action, validating the popular use of this species.     

Anxiolytic and sedative activities of Passiflora edulis f. flavicarpa

Aim of the study

Many plants in the genus Passiflora have long been used in traditional folk medicines as a remedy for many neurogenic diseases in many countries. A number of species of the genus was studied about their neuropharmacological activities, but the results were inconsistent. No literature reported neuropharmacological studies on Passiflora edulis f. flavicarpa as yet. The present study was aimed at evaluating the anxiolytic and sedative activities of Passiflora edulis f. flavicarpa.

Materials and methods

Swiss albino mice were used as experimental animals in elevated plus-maze (EPM) test and spontaneous activity (SA) test to assay the behavioral effects of ethanolic extract (EE) of the aerial part of Passiflora edulis f. flavicarpa and its fractions, viz. petrol ether extract (PEE), ethyl acetate extract (EAE), n-BuOH extract (BE) and aqueous extract (AE), together with subfractions of BE, viz. BEF-I, BEF-II, BEF-III, BEF-IV and isoorientin, a flavonoid component isolated from BEF-III.

Results

In the EPM test, single-dose oral administration of EE (300 mg/kg and 400 mg/kg), BE (125 mg/kg and 200 mg/kg), AE (200 mg/kg and 300 mg/kg), BEF-I (200 mg/kg), BEF-II (200 mg/kg), BEF-III (100 mg/kg), or isoorientin (20 mg/kg) resulted in anxiolytic-like effects, but a sedative-like activity was produced at higher doses, such as 300 mg/kg of BE, 200 mg/kg of BEF-III, or 40 mg/kg and 80 mg/kg of isoorientin. The results of the SA test manifested that treatment with 400 mg/kg of EE, 300 mg/kg of BE, or 40 mg/kg and 80 mg/kg of isoorientin compromised motor activity in mice, which are in line with the results of the EPM test.

Conclusions

The aerial part of Passiflora edulis f. flavicarpa was anxiolytic at low dose but sedative at high dose. Flavonoids are important active constituents. Since AE contained little flavonoids, it was conjectured that there were other components responsible for the anxiolytic effect of Passiflora edulis f. flavicarpa besides flavonoids.     

Analgesic and antimalarial activities of crude leaf extract and fractions of Acalypha wilkensiana

Aim of the study

Antiplasmodial and analgesic activities of leaf extract and fractions of Acalypha wilkensiana were evaluated to ascertain the folkloric claim of its antimalarial and analgesic activities.

Materials and methods

The crude leaf extract (220–659 mg/kg) and fractions (chloroform and aqueous; 440 mg/kg) of Acalypha wilkensiana were investigated for antiplasmodial activity against chloroquine sensitive Plasmodium berghei infections in mice and for analgesic activity against chemical and heat-induced pains. The antiplasmodial activity during early and established infections as well as prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Analgesic activity of the crude extract was also evaluated against acetic acid, formalin and heat-induced pains.

Results

The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine sensitive Plasmodium berghei infection in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (p < 0.001). They also improved the mean survival time (MST) from 16 to 22 days relative to control (p < 0.01–0.001). The activities of extract/fractions were incomparable to that of the standard drugs used (chloroquine and pyrimethamine). On chemically and thermally induced pains, the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice. These inhibitions were statistically significant (p < 0.001) and in a dose-dependent fashion.

Conclusion

The antiparasitaemic and analgesic effects may in part be mediated through the chemical constituents of the plant.     

Anti-tumor activity and relative mechanism of ethanolic extract of Marsdenia tenacissima (Asclepiadaceae) against human hematologic neoplasm in vitro and in vivo

Ethnopharmacological relevance

Marsdenia tenacissima, a traditional Chinese medicinal herb, endemic to Yunnan Province is widely used to treat cough, asthma, expectorant, esophageal cancer, gastric cancer, lung cancer, and hepatocellular carcinoma. The aim of this study was to evaluate in vitro and in vivo anti-hematologic neoplasm potential of the ethanolic extract of this herb (crude ethanolic extract of Marsdenia tenacissima, CME) and by using different assays to elucidate its possible mechanism of action.

Materials and methods

The cytotoxicity of CME on tumor cells and peripheral blood mononuclear cells (PBMCs) was evaluated using MTT and apoptosis assays. We also tested the effect of CME on colony formation inhibition and cell cycle distribution of tumor cells. The protein expressions of Cyclin D1, Bax, Bcl-2, caspase-3 and caspase-9 were detected through Western blotting. In vivo anti-tumor effect was evaluated by measuring tumor volume changes, measuring tumor weight, evaluation of tumor microvessel density (MVD) and TUNEL staining by using immunohistochemistry staining in tumor models of nude mice.

Results

Marsdenia tenacissima ethanolic extract exhibited effects of proliferation inhibition and induction of apoptosis on human hematologic neoplasm tumor cells in vitro, as well as hematologic neoplasm growth in vivo.

Conclusion

This study clearly indicated that the ethanolic extract of Marsdenia tenacissima displayed strong anti-tumor effects against hematologic neoplasm cells and could induce tumor cells apoptosis in vitro and in vivo, and also had a significant anti-angiogenic effect in vivo against tumor cell apoptosis. Its multi-mechanism of action might be associated with the cell cycle (G0/G1) arrest, induction of apoptosis through up-regulation protein expressions of Bax, caspase-9 and caspase-3 genes and down-regulation of the expressions of Cyclin D1 and Bcl-2 genes, a decrease in tumor microvessel density and an increase of TUNEL-positive cells in vivo. These findings provided the molecular theoretical basis of clinical application.     

Inhibitory effect of Thymus caramanicus Jalas on hyperglycemia-induced apoptosis in in vitro and in vivo models of diabetic neuropathic pain

Ethnopharmacological relevance

Since Thymus caramanicus Jalas is used as a folk medicine for the treatment of rheumatism, skin disorders, bacterial infections and diabetes and it contain antioxidant agents, we decided to investigate the possible effects of Thymus caramanicus Jalas (TCJ) extract on in vitro and in vivo models of diabetic neuropathy.

Materials and methods

The high glucose-induced cell injury in Pheochromocytoma (PC12) cells and streptozotocin-induced diabetic rats were used. Tail-flick and rotarod treadmill assessments were used to determine nociceptive threshold and motor coordination. Cell viability was determined by MTT assay test. Western blotting was performed to measurement of apoptosis markers.

Results

The data showed that elevation of glucose consecutively increases functional cell injury and apoptosis. Furthermore, diabetic rats developed thermal hyperalgesia and motor deficit. Activated caspase 3, cytochrome c release and Bax/Bcl-2 ratio were significantly increased in high glucose-treated PC12 cells and in spinal cord of diabetic animals. TCJ extract (60 and 80 µg/ml) attenuates high glucose-induced PC12 cells damage and apoptosis. In diabetic animals, TCJ extract at daily doses of 100 and 150 mg/kg ameliorated hyperalgesia and suppressed spinal apoptosis.

Conclusion

The data indicate that TCJ extract has neuroprotective effects against high glucose-induced neural damage. These protective effects are mediated, at least in part, through attenuation of neural apoptosis and suggest therapeutic potential of TCJ extract in amelioration of diabetic neuropathy.     

Attenuation of inflammatory mediators, oxidative stress and toxic risk evaluation of Aporosa lindleyana Baill bark extract

Ethnopharmacological relevance

Traditionally, Aporosa lindleyana Baill. has been used against various ailments viz. jaundice, fever, headache, seminal loss and insanity. The present study aims to evaluate the anti-inflammatory and anti-oxidant activity of the ethanolic extract of Aporosa lindleyana Baill. bark and its fractions.

Method

The anti-inflammatory activity of ethanolic extract of Aporosa lindleyana Baill. bark and its various fractions at doses of 200 mg/kg and 300 mg/kg b.w. has been carried out by a carrageenan induced hind paw edema method. To establish the probable mechanism of action, TNF-α and NO levels have been estimated by an ELISA method and the effect of active fraction on COX-2 and NF-κB expressions has been evaluated. The effect on the levels of anti-oxidative enzymes (CAT, SOD & GPX) by the ethanolic extract and its fractions has also been investigated. Furthermore, peptic ulcer and hepatotoxic risk evaluation has also been carried out at three times higher dose than that used in inflammatory in vivo model.

Results

Among the extract and its various fractions tested for anti-inflammatory activity, the methanolic fraction at a dose of 300 mg/kg showed significant inhibition in paw edema by 73% as compared to Indomethacin which showed 77% inhibition after 5 h. The same dose of methanolic fraction also caused significant reduction in TNF-α (59.27%) and NO concentration (57.12%) while Indomethacin showed inhibition of 63.91% and 60.12%. The active methanolic fraction was also found to inhibit the expression of NF-κB and COX-2 induced by carrageenan. Histological studies showed that the ethanolic extract and its fractions did not cause any damage to the stomach as well as to liver. Moreover, the active fractions also decreased lipid peroxidation levels and increased the antioxidant enzyme activities (SOD, CAT, GPX).

Conclusion

The results of present study demonstrated that significant anti-inflammatory activity of methanolic fraction of Aporosa lindleyana may be attributed to the modulation of pro-inflammatory mediators. Same fraction was also found to be effective against oxidative stress as it was found to elevate the levels of anti-oxidative enzymes. It can therefore be concluded that the methanolic fraction could be explored as a disease modifying agent against inflammation and oxidative stress.     

Substantiation of the ethnopharmacological use of Conyza sumatrensis (Retz.) E.H.Walker in the treatment of malaria through in-vivo evaluation in Plasmodium berghei infected mice

Ethnopharmacological relevance

Scientific validation of ethnopharmacologically used plants and their utilization for therapeutic interventions can be a source of affordable treatment especially for neglected diseases in endemic areas. Conyza sumatrensis is a plant which finds its use in treating malaria like fevers but lacks proper scientific validation. Our study has tried to address this gap by authenticating its traditional use for the treatment of malaria.

Aim of the study

Evaluate the antimalarial activity of extracts derived from Conyza sumatrensis for its ethnopharmacological validation.

Materials and methods

Shade dried leaves were extracted with varying concentrations of ethanol and concentrated for bio-evaluation. Swiss albino mice infected with 1×10⁶ parasitized red blood cells, were orally administered with test extracts for 7 days in two sets of experiments. The first set was used to evaluate alcoholic, hydroalcoholic and aqueous extracts while the second set was used to evaluate the dose response of alcoholic extract ranging from 500–1600 mg/kg. Mean survival time, parasitaemia and haemoglobin levels were considered to interpret the antimalarial potential. Phytochemical analysis for the presence of flavonoids, alkaloids tannins, total phenolics, riboflavin and thiamine was also carried out.

Results

Among the three extracts administered at 1000 mg/kg, chemo suppression was significantly (p<0.001) observed in the alcoholic extract (62.59±12.52%) followed by hydroalcoholic (41.81±19.04%, p<0.01) and aqueous (32.04±19.04%, P<0.05) indicating that the active constituents leach out in ethanol. The dose response study involving the ethanol extract concluded the optimum dose to be 1000 mg/kg, as also evidenced by the haemoglobin levels.

Conclusion

The plant exhibits moderate antimalarial activity which can be further prospected for active fractions or pure molecules for adjunctive therapy.     

Antimalarial and safety evaluation of extracts from Toddalia asiatica (L) Lam. (Rutaceae)

Ethnopharmacological relevance

Toddalia asiatica (L) Lam. (Rutaceae) is a medicinal plant traditionally used in Kenya by many communities for the treatment of malaria and other ailments. All parts of the plant are claimed to have medicinal value, but the root bark in particular is believed to be more potent. Decoctions or infusions of the roots are taken orally to treat malaria, fever and stomach ache.

Aim of the study

To evaluate antimalarial activity of aqueous and organic extracts prepared from Toddalia asiatica and determine in vitro and in vivo safety of the extracts.

Materials and methods

Aqueous, ethyl acetate, hexane and methanol extracts were obtained from Toddalia asiatica root bark, fruits and leaves. In vitro antiplasmodial activity was done using chloroquine-sensitive (D6) and chloroquine-resistant (W2) Plasmodium falciparum strains and the concentration causing 50% inhibition of radioisotope incorporation (IC₅₀) was determined. In vivo assay was done by administering mice infected with Plasmodium berghei four consecutive daily doses of the extracts through oral route following Peters 4-Day suppressive test. The percentage suppression of parasitaemia was calculated for each dose level by comparing the parasitaemia in untreated control with those of treated mice. Quinine hydrochloride was used as positive control while double distilled water or 20% Tween-80 was used as a negative control. In vivo acute toxicity was determined in mice using standard procedures. In vitro cytotoxicity assay was carried out using actively dividing sub-confluent Vero cells.

Results

Inhibitory concentrations of ethyl acetate extract of Toddalia asiatica fruits showed high activity against chloroquine resistant (W2) strains of Plasmodium falciparum (IC₅₀=1.87 μg/ml), followed by root bark aqueous extract (IC₅₀=2.43 μg/ml). Tested in vivo against Plasmodium berghei, the fruit ethyl acetate extract (500 mg/kg) and root bark aqueous extract (250 mg/kg) reduced malaria parasitaemia by 81.34% and 56.8% respectively. Higher doses were found to be less effective in vivo. Acute toxicity and cytotoxictiy of the tested extracts, with the exception of hexane extract from the roots, showed LD₅₀>1000 mg/kg and CC₅₀>100 μg/ml respectively.

Conclusions

The results obtained contribute to the validation of traditional use of Toddalia asiatica and provides in vivo and safety data of the plant extracts tested for the first time. Ethyl acetate extract of the fruits was active against chloroquine resistant Plasmodium falciparum as well as against Plasmodium berghei. These findings confirm the suitability of Toddalia asiatica as a good candidate for further tests to obtain a prototype for antimalarial medicine.     

Antiprotozoal activity of Khaya anthotheca, (Welv.) C.D.C. a plant used by chimpanzees for self-medication

Ethnopharmacological relevance

Khaya species, endemic to Africa and Madagascar, continues to be valuable in indigenous traditional medicine. Their bitter tasting barks are decocted to treat fevers, several febrile conditions, microbial infections and worm infestations. In the Budongo rain forest of Western Uganda, non-human primates, especially chimpanzees and baboons, have been observed to eat the bitter non-nutritious bark and occasionally the seed.

Materials and methods

Extracts were prepared by sequential fractionation with solvents of increasing polarities and assayed using standard procedures. Bioassay guided purification of the petroleum ether extract by column chromatography yielded three pure limonoids, Grandifolione (1), 7-deacetylkhivorin (2) and 1,3-deacetyldeoxyhavenensin (3). The antitrypanosomal, antileishmanial and antiplasmodial activities of pure compounds (1) and (2) were evaluated in vitro against Plasmodium falciparum K1, Trypanosoma brucei rhodesiense STIB 900, Trypanosoma cruzi trypomastigotes (Tulahuen C4), and axenic Leishmania donovani MHOMET-67/L82 and for cytotoxicity against L6 rat skeletal myoblast cells, in parallel with standard drugs.

Results

Of the four extracts tested, the petroleum ether extract showed activity against Plasmodium falciparum (IC₅₀ 0.955 μg/ml) and Trypanosoma brucei rhodesiense (IC₅₀ 5.72 μg/ml). The pure compounds (1) and (2) demonstrated activity against Plasmodium falciparum (KI strain) and marginal activities against Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania donovani.

Conclusion

The present study provides evidence justifying the use of Khaya preparations in traditional medicine to treat fevers and microbial infections. The observed antiprotozoal activity of grandifolione and 7-deacetylkhivorin from the seed of Khaya anthotheca further confirms the ethnomedicinal potential of this plant and supports the hypothesis that non-human hominids (chimpanzees and baboons) too, eat the bitter bark and seeds for self-medication and in general, the use of Khaya plant material for medication by humans in disease endemic tropical areas. The antiprotozoal activity of gradifolione, and, the antitrypanosomal and antileishmanial activities of 7-deacetylkhivorin are reported here for the first time.