Chrysophyllum albidum fruit ethanol extract ameliorates hyperglycaemia and elevated blood pressure in streptozotocin-induced diabetic rats through modulation of oxidative stress, NF-κB and PPAR-γ

Oxidative stress and inflammation arising from hyperglycaemia have been identified as important targets in mitigating hyperglycaemia-induced organ dysfunction in diabetics. Chrysophyllum albidum fruit is commonly consumed as fruit snacks because of its beneficial effects in diabetes management. This study aim to evaluate the protective mechanisms of Chrysophyllum albidum fruit extract (CAFE) in streptozotocin-induced rats involving attenuation of oxidative stress, nuclear factor-kappa B (NF-κB) and peroxisome proliferator-activated receptor-gamma (PPAR-γ). CAFE was investigated for in vitro antioxidant and alpha amylase inhibitory activity. Male Wistar rats were made diabetic by single intraperitoneal injection of streptozotocin (60 mg/kg). The rats were then treated with CAFE (100 and 200 mg/kg) and pioglitazone (10 mg/kg) for two weeks. Fasting blood sugar (FBS), blood pressure parameters, lipid profile, oxidative stress parameters, NF-κB and PPAR-γ were determined. The extract showed antioxidant and alpha amylase inhibitory activities. CAFE significantly reduced STZ-induced hyperglycaemia after 7 and 14 days of treatment. CAFE also reduced STZ-induced elevation of diastolic blood pressure and mean arterial pressure and as well reduced atherogenic index in diabetic rats. It significantly decreased lipid peroxidation but increased the enzymatic and non-enzymatic antioxidant markers in the plasma, liver, kidney and pancreas. The immunohistochemical analysis revealed that CAFE significantly decreased hepatic and renal tissues NF-κB while increasing PPAR-γ gene expressions. The results of this study collectively showed the protective effect of Chrysophyllum albidum fruit extract in streptozotocin-induced diabetic rats via modulation of oxidative stress and NF-κB/ PPAR-γ expressions.

Antihypertensive effect of Phragmanthera incana (Schum) Balle on NG-nitro-L-Arginine methyl ester (L-NAME) induced hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Phragmanthera incana (Schum) Balle is a member of the African mistletoes that has been reported to be used in ethnomedicine for the treatment of hypertension.

AIM

The aim of this study was to investigate the antihypertensive effect of Phragmanthera incana leaf ethanol extract (PILEE) in NG-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats.

MATERIALS AND METHODS

Phytochemical analysis of PILEE was determined using the Gas chromatography - Mass spectrophotometry (GC-MS) method. Antihypertensive activity was investigated in rats that received PILEE (50, 100 and 200 mg/kg) or captopril (40 mg/kg) daily for 28 days together with oral administration of L-NAME (40 mg/kg). Blood pressure parameters were measured on day 7, 14, 21 and 28. Blood was obtained for determination of serum nitrite, interleukin-6 (IL-6) and tumor necrosis factor, TNF-α. The heart, liver and kidneys were used to determine oxidative stress indices (malondialdehyde, reduced glutathione and catalase). The cardiac tissue was processed for histopathological changes.

RESULTS

The GC-MS profiling of PILEE identified 20 compounds namely fatty acid esters. Administration of PILEE (50, 100 and 200 mg/kg) dose dependently and significantly reduced systolic blood pressure and mean arterial pressure in hypertensive rats. PILEE administration significantly (p < 0.05) reversed elevated IL-6 and TNF-α in hypertensive rats. PILEE demonstrated antioxidant activity by attenuating L-NAME-induced elevated malondialdehyde and depletion of reduced glutathione and catalase activity in rat tissues. PILEE treatment demonstrated cardioprotective effect in L-NAME-induced cardiac hyperplasia and necrosis in rats.

CONCLUSION

It can be concluded that Phragmanthera incana leaf ethanol extract possess antihypertensive, antioxidant and anti-inflammatory properties, suggesting a protective role in cardiovascular diseases.

Clofibrate, a PPAR-α agonist, abrogates sodium fluoride-induced neuroinflammation, oxidative stress, and motor incoordination via modulation of GFAP/Iba-1/anti-calbindin signaling pathways

Fluoride is an environmental contaminant that is ubiquitously present in air, water, and soil. It is commonly added in minute quantity to drinking water, toothpaste, and mouth rinses to prevent tooth decay. Epidemiological findings have demonstrated that exposure to fluoride induced neurodevelopmental toxicity, developmental neurotoxicity, and motor disorders. The neuroprotective effect of clofibrate, a peroxisome proliferator-activated receptor alpha agonist, was investigated in the present study. Forty male Wistar rats were used for this study and randomly grouped into 10 rats per group as control, sodium fluoride (NaF) alone (300 ppm), NaF plus clofibrate (250 mg/kg), and NaF plus lisinopril (10 mg/kg), respectively, for 7 days. NaF was administered in drinking water while clofibrate and lisinopril were administered by oral gavage. Markers of neuronal inflammation and oxidative stress, acetylcholinesterase activity, and neurobehavioral (hanging wire and open field) tests were performed. Immunohistochemistry was performed on brain tissues, and they were probed with glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, and cerebellar Ca²⁺ -binding protein calbindin-D28k. The results showed that NaF significantly increased of oxidative stress and neuroinflammation and inhibited AChE activity. Immunostaining showed reactive astrocytes, microgliosis, loss of dendritic spines, and arborization in Purkinje cells in rats administered only NaF. Neurobehavioral results showed that cotreatment of NaF with clofibrate improved muscular strength and locomotion, reduced anxiety, and significantly reduced astrocytic count. Overall, cotreatment of NaF with either clofibrate or lisinopril showed neuroprotective effects by mitigating neuronal inflammation and oxidative and motor incoordination. Hence, clofibrate could be seen as a novel drug candidate against neurodegeneration and motor disorders.

Cobalt chloride toxicity elicited hypertension and cardiac complication via induction of oxidative stress and upregulation of COX-2/Bax signaling pathway

Cobalt is a ferromagnetic metal with extensive industrial and biological applications. To assess the toxic effects of, and mechanisms involved in cobalt chloride (CoCl₂)-induced cardio-renal dysfunctions. Male Wistar rats were exposed orally, daily through drinking water to 0 ppm (control), 150 ppm, 300 ppm, and 600 ppm of CoCl₂, respectively. Following exposure, results revealed significant ( p < 0.05) rise in markers of oxidative stress, but decreased activities of catalase, glutathione peroxidase, glutathione-S-transferase, and reduced glutathione content in cardiac and renal tissues. There were significant increases in systolic, diastolic, and mean arterial blood pressure at the 300- and 600-ppm level of CoCl₂-exposed rats relative to the control. Prolongation of QT and QTc intervals was observed in CoCl₂ alone treated rats. Also, there were significant increases in the heart rates, and reduction in P wave, and PR duration of rats administered CoCl₂. Histopathology of the kidney revealed peritubular and periglomerular inflammation, focal glomerular necrosis following CoCl₂ exposure. Further, cyclooxygenase-2 and B-cell associated protein X expressions were upregulated in the cardiac and renal tissues of CoCl₂-exposed rats relative to the control. Combining all, results from this study implicated oxidative stress, inflammation, and apoptosis as pathologic mechanisms in CoCl₂-induced hypertension and cardiovascular complications of rats.

The ethanol leaf extract of Andrographis paniculata blunts acute renal failure in cisplatin-induced injury in rats through inhibition of Kim-1 and upregulation of Nrf2 pathway

Background Cisplatin (CP) is a novel drug of choice in the treatment of cancer but its major limitation is nephrotoxicity, which is dose limiting. Andrographis paniculata (AP) is a common Indian dietary component. It is well known for its medicinal properties. This present study investigated the nephroprotective effect of ethanol leaf extract of Andrographis paniculata (EEAP) on CP-induced nephrotoxicity. Methods CP was used to induce nephrotoxicity in male Wistar rats to study the effect of EEAP on renal damages using hematological parameters, biochemical parameters, histology, and immunohistochemistry studies. Results The effects of EEAP were determined by CP-induced changes in different kidney tissue on antioxidant enzymes, markers of oxidative stress, serum creatinine, and urine parameters. Administration of EEAP (200 mL/kg and 400 mg/kg orally), prior to and following a single dose CP treatment (10 mg/kg i.p), significantly mitigated the CP-induced decrease in antioxidant enzymes, and increase in markers of oxidative stress, serum creatinine, and urinary protein. On histopathological examination of the kidney tissue, there was severe glomerular degeneration and infiltration of inflammatory cells in CP only treated rats, mild glomerular degeneration, and infiltration of inflammatory cells in EEAP pre-treated rats. Furthermore, EEAP activated Nrf2 and mitigated Kim-1 pathways in CP-induced nephrotoxicity. Conclusions The results showed the protective effect of EEAP against CP-induced nephrotoxicity.

Cardioprotective Effects of Curcumin-Nisin Based Poly Lactic Acid Nanoparticle on Myocardial Infarction in Guinea Pigs

Myocardial infarction (MI) is the most prevalent cause of cardiovascular death. A possible way of preventing MI maybe by dietary supplements. The present study was thus designed to ascertain the cardio-protective effect of a formulated curcumin and nisin based poly lactic acid nanoparticle (CurNisNp) on isoproterenol (ISO) induced MI in guinea pigs. Animals were pretreated for 7 days as follows; Groups A and B animals were given 0.5 mL/kg of normal saline, group C metoprolol (2 mg/kg), groups D and E CurNisNp 10 and 21 mg/kg respectively (n = 5). MI was induced on the 7^th day in groups B-E animals. On the 9^th day electrocardiogram (ECG) was recorded, blood samples and tissue biopsies were collected for analyses. Toxicity studies on CurNisNp were carried out. MI induction caused atrial fibrillation which was prevented by pretreatment of metoprolol or CurNisNp. MI induction was also associated with increased expressions of cardiac troponin I (CTnI) and kidney injury molecule-1 (KIM-1) which were significantly reduced in guinea pig's pretreated with metoprolol or CurNisNp (P < 0.05). The LC₅₀ of CurNisNp was 3258.2 μg/mL. This study demonstrated that the formulated curcumin-nisin based nanoparticle confers a significant level of cardio-protection in the guinea pig and is nontoxic.

Oxidative stress changes observed in selected organs of African giant rats (Cricetomys gambianus) exposed to sodium metavanadate

Vanadium is a contaminant of crude oil that released into the atmosphere through burning of fossil fuels. The mechanism by which it exerts toxic influences had not been fully elucidated in African giant rat (AGR). This study investigates the mechanisms of sodium metavanadate (SMV) induced oxidative stress in AGR. A total of 24 adult male AGR weighing 600-850 g were used. Animals were randomly divided into six groups. Groups 1, 3 and 5 served as control while groups 2, 4 and 6 were treated with intraperitoneal 3 mg/kg body weight of SMV for 3, 7 and 14 days, respectively. Serum, brain, liver, testes, kidneys, spleen and lungs were harvested for biochemical assays. SMV induced significant increase in malondialdehyde, hydrogen peroxide, sulfhydryl (total thiol) and protein carbonyl levels but decreased non-protein thiol levels in tissues accessed. A significant decrease was observed in glutathione-S-transferase (GST), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GPx) levels in SMV treated rats compared to controls. Serum myeloperoxidase, xanthine oxidase and Advanced Oxidative Protein Products (AOPP) were markedly increased while nitrous oxide levels were significantly decreased in all treated groups. SMV exposure to AGR induced oxidative stress through generation of reactive oxygen species (ROS) and depletion of the antioxidant defence system. These conditions could become severe with prolonged exposure.

Ameliorative effect of gallic acid on doxorubicin-induced cardiac dysfunction in rats

BACKGROUND

The use of doxorubicin (DOX) as an antineoplastic agent has been greatly limited because of the myriad of toxic sequelae associated with it. The aim of this study was to assess the protective effects of gallic acid (GA) on DOX-induced cardiac toxicity in rats.

METHODS

Sixty male rats (Wistar strain) were used in this study. They were divided into six groups (A-F) each containing 10 animals. Group A was the control. Rats in Groups B, C, and D were treated with DOX at the dosage of 15 mg/kg body weight i.p. Prior to this treatment, rats in Groups C and D had been treated orally with GA for 7 days at the dosage of 60 and 120 mg/kg, respectively. Animals from Groups E and F received only 60 and 120 mg/kg GA, respectively, which were administered orally for 7 days.

RESULTS

The exposure of rats to DOX led to a significant (p<0.05) decrease in the cardiac antioxidant defence system and elevation of creatine kinase myocardial band and lactate dehydrogenase. The electrocardiography results showed a significant decrease in heart rate, QRS, and QT-segment prolongation. GA alone improved the antioxidant defence system.

CONCLUSIONS

The GA pretreatment significantly alleviated GA-associated ECG abnormalities, restored the antioxidant status and prevented cardiac damage.

Effect of arsenic acid withdrawal on hepatotoxicity and disruption of erythrocyte antioxidant defense system

We investigated the effects of withdrawal from Sodium arsenite (NaAsO₂) on the hepatic and antioxidant defense system in male Wistar rats using a before and after toxicant design. Rats were orally gavaged daily with varying doses of NaAsO₂ for a period of 4 weeks. One half of the population was sacrificed and the remaining half had the toxicant withdrawn for another further 4 weeks. Biochemical and immunohistochemical techniques were used to assess the impact of withdrawal on the erythrocyte and hepatic systems. Exposure of Wistar rats to NaASO₂ led to a significant (p < 0.05) increase in hepatic and erythrocyte markers of oxidative stress (malondialdehyde, thiol contents and hydrogen peroxide generation). Concurrently, there was a significant (p < 0.05) increase in hepatic and erythrocyte antioxidant enzymes (glutathione-S-transferase, glutathione peroxidase and superoxide dismutase) following exposure. Withdrawal from NaAsO₂ exposure led to a decline in both erythrocyte and hepatic markers of oxidative stress and together with a significant improvement in antioxidant defense system. Histopathology and immunohistochemistry revealed varying degrees of recovery in hepatocyte ultrastructure alongside increased expression of the pro-survival protein Kinase B (Akt/PKB) after 4 weeks of NaAsO₂ withdrawal. Conclusively, withdrawal from exposure led to a partial recovery from oxidative stress-mediated hepatotoxicity and derangements in erythrocyte antioxidant system through Akt/PKB pathway.

The Methanol Seed Extract of Garcinia kola Attenuated Angiotensin II- and Lipopolyssacharide-Induced Vascular Smooth Muscle Cell Proliferation and Nitric Oxide Production

All over the world, cardiovascular diseases are a risk factor for poor health and early death with predisposing factors to include age, gender, tobacco use, physical inactivity, excessive alcohol consumption, unhealthy diet, obesity, family history of cardiovascular disease, hypertension, diabetes mellitus, hyperlipidemia, psychosocial factors, poverty and low educational status, and air pollution. It is envisaged that herbal products that can stem this trend would be of great benefit. Garcinia kola (GK), also known as bitter kola is one of such plants. Generally used as a social snack and offered to guests in some cultural settings, bitter kola has been indicated in the treatment of laryngitis, general inflammation, bronchitis, viral infections and diabetes. In this study, the effects of methanol seed extract of Garcinia kola on the proliferation of Vascular Smooth Muscle Cells (VSMCs) in cell culture by Angiotensin II (Ang II) and LPS-induced NO production were carried out. Confluent VSMCs were exposed to GK (25, 50 and 100 μg/ml) before or after treatment with lipopolyssacharide (100μg/ml), and Angiotensin II (10−8-10−6M). Cellular proliferation was determined by MTT assay and NO production by Griess assay. Treatment with Angiotensin II (10−8, 10−6) or LPS significantly enhanced proliferation of VSM cells while LPS significantly increased nitric oxide (NO) production. Treatment with GK (25, 50 & 100 μg/ml) attenuated VSM cell proliferation. The results indicate that GK has potential to inhibit mitogen activated vascular cell growth and possibly inhibit inflammatory responses to LPS. Thus GK may be useful in condition that is characterized by cellular proliferation and inflammatory responses.

Phytochemical screening, safety evaluation, anti-inflammatory and analgesic studies of the leaf extracts of Sterculia tragacantha

BACKGROUND

Sterculia tragacantha (Sterculiaceae) is used in the treatment of boils, diarrhea, dyspepsia, fever, gonorrhea, snake bite, syphilis, and tapeworm in some West African nations. This study is to investigate its anti-inflammatory and analgesic activities since the plant is being used to treat fever.

METHODS

Fresh leaves of the plant were collected and dried at room temperature and pulverized into powder form and 200 g of this powder was dissolved first in hexane for 72 h and the extract was filtered and the filtrate was concentrated while the substrate was further dissolved in chloroform, ethyl acetate and methanol at different times and similar procedure adopted as for the hexane. The organic solvents were used based on order of increasing polarity. Graded concentrations of the solvent extracts were prepared and used for the study. Pilot toxicity test was carried out to determine safety dose using hematology and serum chemistry as indices of toxicity. Thereafter anti-inflammatory and analgesic studies were conducted using standard tests such as carrageenan, histamine-induced-edema, tail flick test and acetic writhing test. Phytochemical screening of the plant was also conducted.

RESULTS

Phytochemical screening of the powdered material showed that alkaloid, flavonoid and reducing sugar were present while tannin, cardiac glycosides, saponins and anthraquinones were absent. Pilot toxicity test using aqueous extract at 100 mg/mL concentration showed that no mortality was recorded although the animals that received 3,000 mg/kg dose exhibited slight dullness after 48 h. No significant changes were also observed for the packed cell volume, hemoglobin, white blood cell counts, platelet counts, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, blood urea nitrogen, albumin, globulin except for the 200 and 3,000 mg/kg doses that caused significant increase in the level of total protein. The n-hexane, chloroform, ethyl acetate, and methanol extracts of S. tragacantha and indomethacin produced significant (p<0.05) inhibition of paw edema compared with the control using histamine and carrageenan methods of paw edema induction. There was significant (p<0.05) reduction in writhing movements at 100 mg/kg and 200 mg/kg of n-hexane, chloroform, and ethyl acetate leaf extracts of S. tragacantha and indomethacin (10 mg/kg) when compared to the control. This effect using tail flick test was not as effective when compared to the writhing test.

CONCLUSIONS

The different leaf extracts of S. tragacantha exhibited anti-inflammatory and analgesic properties and they are also safe for medicinal use.

Ethnomedicinal survey of some plants used for the treatment of diabetes in Ibadan, Nigeria

Objectives: A comprehensive survey with the aim of documenting traditional medicinal practices was carried out in targeted areas of Ibadan, Nigeria in order to inventory plants used by traditional healers in the area for the management of diabetes. Materials and Methods: Open-ended informal interviews were administered during series of repeated visits to the respondents consisting majorly the traditional medical practitioners (TMPs) and herb sellers. Some traditional healers who know and use medicinal plants for treating diabetes mellitus were interviewed. The inventory contains scientifi c, vernacular, common names of the plants used and methods of preparation. Results: Twenty seven plants commonly used by traditional healers in the region were identifi ed. These plants were found to be very important and useful in the treatment of diabetes based on their frequency of occurrence in the recipes obtained. Herbal remedies were either prepared from dried or freshly collected plants while traditional solvent of choice included water, lime, local gin and aqueous extract from fermented maize. Decoction and pulverization were the main methods of preparation while mode of administration varies within 1 to 3 times daily. Survey revealed that leaves form the major part of plants for herbal preparations. Residents in the study area fi nd traditional medicine cheaper as compared to orthodox medicine. Conclusion: This review focuses on the various plants that have been reported to be effective in the treatment of diabetes. The survey shows that plants from the Rubiaceae, Labiataceae, Meliaceae, Hypoxidaceae and Cucurbitaceae families are commonly used by traditional healers in Ibadan for the treatment of diabetes mellitus. DOI: http://dx.doi.org/10.3126/ajms.v6i5.10480Asian Journal of Medical Sciences Vol.6(5) 2015 36-40  

Anti-inflammatory and antinociceptive activities of the aqueous leaf extract of Phyllanthus amarus Schum (Euphorbiaceae) in some laboratory animals

BACKGROUND

Phyllanthus amarus has a history of use in Ayurvedic medicine for over 2000 years as well as a wide variety of traditional applications and has gained popularity in many continents as a herbal remedy; hence, it is being assessed for its safety potential and anti-inflammatory and analgesic properties in some laboratory animals.

METHODS

Standard phytochemical methods were used to test for the presence of phytoactive compounds in the plant. Acute toxicity testing was carried out in mice to determine safe doses for the extract. The anti-inflammatory activity of the leaf extract of this plant was assessed using carrageenan-induced and histamine-induced paw edema. The analgesic effect was determined using the acetic acid writhing method as well as formalin test.

RESULTS

The extract at 100 and 200 mg/kg body weight reduced significantly, the formation of edema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by reduction in the number of writhes when compared to the control. The extract caused dose-dependent decrease of licking time in rats injected with 2.5% formalin, signifying its analgesic effect. These results were also comparable to those of ibuprofen, the reference drug used in this study.

CONCLUSIONS

The plant extract reduced significantly the formation of edema induced by carrageenan and histamine as well as reducing the number of writhes in acetic acid-induced writhing models and dose-dependent decrease of licking time in rats injected with 2.5% formalin. The results have validated the basis for the traditional use of P. amarus as a medicinal plant.

Evaluation of antimalarial and antioxidant activities of the methanol seed extract of Adenanthera pavonina (Linn) in Plasmodium berghei infected mice

Objectives: Malaria and oxidative stress are major health problems in the world in general. The goal of the study is to investigate the antimalarial and antioxidant activities of the methanol seed extract of Adenanthera pavonina linn (ADP) in Plasmodium berghei infected mice. Methods: Thirty five mice distributed into seven groups of five animals each were used in this study. Plasmodium berghei, was inoculated into Swiss albino mice intraperitoneally with an innoculum size of 1x107 on day zero (D0). The vehicle (1% DMSO), ADP (100, 200, 400, 600 and 800 mg/kg dose) or chloroquine (10 mg/kg) were thereafter administered from D0 – D3. At the end of the antimalarial studies, the blood samples from these animals were collected through cardiac puncture for biochemical assay. The effect of the ADP on the biomakers of oxidative stress was determined in infected mice. In addition in vitro antioxidant activities of ADP were assessed using the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) based assay. Results: The percentage parasitemia decreased significantly in the parasitized treated group with the crude extract (p < 0.001) compared to the parasitized untreated control group. Also the crude extract, at a dose of 800 mg/kg exerted an antimalarial activity (92.11%) higher than that of chloroquine (88.73%). In the in vitro antioxidant studies, the extract had an IC50> 400 μg/ml which was significantly higher than the standard antioxidant drug, ascorbic acid (IC50 = 1.20 μg/ml). In the case of biochemical and in vivo assay, there was no statistical significant difference (p >0.05) in plasma total protein, malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels in all the treated groups compared to the parasite control group but, there was a statistical significant decrease (p < 0.05) in glutathione (GSH) levels at doses of 400 and 800 mg/kg compared to the parasitized untreated control group. Conclusions: Methanol seed extract of Adenanthera pavonina demonstrated a significant antimalarial activity but did not exert any antioxidant effect over the parasitized treated mice. DOI: http://dx.doi.org/10.3126/ajms.v5i4.9107 Asian Journal of Medical Sciences 2014 Vol.5(4); 44-51

The anti-diabetic activities of the methanol leaf extract of Phyllanthus amarus in some laboratory animals

Background: Phyllanthus amarus is used in Nigeria and other parts of the world as a medicinal plant. Aim and objective: The plant is being evaluated for antidiabetic potential because diabetes mellitus has assumed a worldwide dimension and plant with safe potential are being deployed as they are available all year round and are cheap for use by the rural populace. Materials and Methods: The antidiabetic effect of the methanol extract (ME) of Phyllanthus amarus was evaluated in rats. Standard phytochemical methods were used to test for the presence of phytoactive compounds in the plant. Acute toxicity was carried out in mice to determine safe doses for this plant extract. The anti-diabetic activities of the ME of the plant were assessed using some standard tests as well as histological changes in liver, kidney and pancreas. Diabetes mellitus was induced in rats using alloxan while glibenclamide at 0.2mg/kg was the reference drug used in this study. Results: The ME at 200 and 400mg/kg body weight caused a significant reduction of fasting blood glucose, significant change in the oral glucose tolerance test, marked effect in the hypoglycaemic activity test and pronounced reduction on the glucose level of diabetic rats. Histopathologically, there was no visible lesion seen in the liver, kidney and pancreas of extract-treated and glibenclamide-treated groups. Conclusion: This study may have validated the traditional basis for the use of Phyllanthus amarus as an antidiabetic agent. At the doses used, ME also appeared safer than glibenclamide even though the latter is more potent. DOI: http://dx.doi.org/10.3126/ajms.v4i3.6992 Asian Journal of Medical Sciences 4(2013) 23-34

Effects of fenofibrate, a PPAR-α ligand, on the haemodynamics of glycerol-induced renal failure in rats

The modulating effect of peroxisome proliferator-activated receptor α ligand on haemodynamic effects of phenylepherine (PE), angiotensin II (AII), endothelin 1 (ET1), acetylcholine (Ach), sodium nitroprusside (SNP) and isoproterenol (ISO) were evaluated in glycerol-induced acute kidney injury in rats. The effect of PE on fenofibrate-treated animals was a dose-dependent increase in mean arterial blood pressure (MAP). For AII and ET1, MAP was also increased for the fenofibrate group but not in a dose-dependent fashion. On the medullary blood flow (MBF), while the lower doses of PE and AII increased the perfusion unit on the fenofibrate-treated group, the higher doses decreased the perfusion unit. The ET1 increased the perfusion unit on this group but not in dose-dependent fashion. The effects of PE and AII on the cortical blood flow (CBF) of fenofibrate-treated group is similar to that of MBF for the same group but not for ET1. The effect of Ach, SNP and ISO in all the groups was the decrease in MAP. ISO caused dose-dependent increase in MBF of fenofibrate-treated group. The effect of Ach, SNP and ISO on the CBF perfusion unit was that of the increase for the fenofibrate-treated group. The study showed that fenofibrate did not attenuate increased blood pressure induced by PE, AII and ET1 but caused enhanced vasodilation by Ach, SNP and ISO.

Anti-inflammatory and analgesic activities of the aqueous extracts of Margaritaria discoidea (Euphorbiaceae) stem bark in experimental animal models

Margaritaria discoidea is a medicinal plant used for the treatment of various body pains in Central, Eastern and Southern Africa. The aqueous extract of its stem bark was investigated for its anti-inflammatory and analgesic activities in animal models. The extract at 50, 100 and 200mg/kg body weight reduced significantly the formation of oedema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract had a good analgesic effect characterized by a reduction in the number of writhes when compared to the control. Similarly, the extract caused dose-dependent decrease of licking time and licking frequency in rats injected with 2.5% formalin. These results were also comparable to those of indomethacin, the reference drug used in this study. Acute toxicity test showed that the plant may be safe for pharmacological uses. This study has provided some justification for the folkloric use of the plant in several communities for conditions such as stomachache, pain and inflammations.

Assessment of the medicinal potentials of the methanol extracts of the leaves and stems of Buddleja saligna

Background

Buddleja saligna Willd (Loganiaceae) is a small to medium-sized evergreen tree; trunk short, often gnarled and crooked; crown dense, rounded or domed-shaped; foliage greyish green. The wild olives are traditionally used to lower blood pressures in many parts of the world. In southern Africa, bark and leaf decoctions are used to treat colic, coughs, colds, sore eyes, urinary problems and as purgatives.

Methods

The antibacterial, antioxidant activities and phenolic contents of the methanol extracts of the leaves and stems of Buddleja saligna were evaluated using in vitro standard methods. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the leaves and stem extracts of Buddleja saligna were determined by ABTS, DPPH, and ferrous reducing antioxidant property (FRAP) methods. Laboratory isolates of 10 bacteria species which included five Gram-positive and five Gram-negative strains were used to assay for antibacterial activity of this plant.

Results

The antioxidant activities of the leaves as determined by the ABTS and DPPH were similar to that of the stem. The flavonoids and the flavonols contents of the leaves were higher than that of the stem but the total phenols, proanthocyanidins and FRAP activities were higher in the methanol extracts of the stem. The extracts did show activity against both Gram-positive and Gram-negative bacteria. For instance, while the methanol extract of the leaves showed good activities on all the organisms except Serratia marcescens and Pseudomonas aeruginosa at MICs of between 2.5 and 5.0 mg/ml, the extract of the stem only showed activities on Bacillus cereus, Streptococcus pyrogens and Pseudomonas aeruginosa at the same concentration.

Conclusion

The results from this study indicate that the leaves and stem extracts of Buddleja saligna possess antioxidant properties and could serve as free radical inhibitors or scavenger or, acting possibly as primary antioxidants. Although, the antibacterial properties of Buddleja saligna are not as effective as the standard drugs-Chloramphenicol and Streptomycin, they still possess some activity against bacterial strains used in this study. Buddleja saligna may therefore be a good candidate for functional foods as well as pharmaceutical plant-based products.

Safety evaluation of the aqueous extract of Leonotis leonurus shoots in rats

The aqueous extract from Leonotis leonurus (L) R.Br. (Lamiaceae) shoots was evaluated in female rats for its acute, sub acute, and chronic toxicity together with hematological, biochemical, and histopathological changes. In the acute toxicity test, the extract caused death in animals receiving 3200 mg/kg dose. The extract also caused significant ( P < 0.05) changes in red blood cells, packed cell volume, hemoglobin concentration, mean corpuscular volume, platelets, white blood cells and its differentials at doses of 1600 mg/kg in sub-acute toxicity and in as low as 200 mg/kg in chronic toxicity. In biochemical parameters, the extract caused a significant ( P < 0.05) decrease in the levels of urea and creatinine at 1600 mg/kg dose and a significant ( P < 0.05) reduction in urea, total bilirubin, total protein, albumin, globulin, glutamine transference gamma-glutamyl transferase (GGT), and alanine transminase in the 400 mg/kg dose in chronic toxicity. Changes were also noted in body weights, but no significant changes were observed in the levels of electrolytes (sodium, potassium, and chloride). Clinico-pathologically, starry hair coat, respiratory distress, and mortality were recorded. The extract also caused various histopathological changes in the organs. The study concluded that farmers need to exercise caution in the use of the plant for medicinal purposes.

Antioxidant activities and phenolic contents of the methanol extracts of the stems of Acokanthera oppositifolia and Adenia gummifera

BACKGROUND

Acokanthera oppositifolia Lam (family: Apocynaceae) is a shrub or small tree with white latex, and the leaves of this plant are used in the form of a snuff to treat headaches and in infusions for abdominal pains and convulsions and septicaemia. Adenia gummifera Harv of the family Passifloraceae is a distinctive woody climber whose infusions are used as emetics and are said to help with some forms of depression. Lipid peroxidation has gained more importance today because of its involvement in pathogenesis of many diseases. Free radicals are the main agents in lipid peroxidation. Antioxidants thus play an important role of protecting the human body against damage by the free radicals. Plants containing phenolic compounds have been reported to possess strong antioxidant properties.

METHODS

The antioxidant activities and phenolic contents of the methanol extracts of the stems of Acokanthera oppositifolia and Adenia gummifera were evaluated using in vitro standard procedures. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the stem extract of Acokanthera oppositifolia were determined by the 2,2'-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS), 1,1-Diphenyl-2-picrylhydrazyl (DPPH), and ferrous reducing antioxidant property (FRAP) methods.

RESULTS

The results from this study showed that the antioxidant activities of the stem extract of Acokanthera oppositifolia as determined by the 1,1-Diphenyl-2-picrylhydrazyl (DPPH), and ferrous reducing antioxidant property (FRAP) methods, were higher than that of Adenia gummifera. The levels of total phenols and flavonols for A. oppositifolia were also higher. On the other hand, the stem extract of Adenia gummifera had higher level of total flavonoids and proanthocyanidins than that of Acokanthera oppositifolia. The 2, 2'-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS) activities of the 2 plant extracts were similar and comparable to that of BHT.

CONCLUSION

Thus, the present results indicate clearly that the extracts of Acokanthera oppositifolia and Adenia gummifera possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. This study has to some extent validated the medicinal potential of the stems of Acokanthera oppositifolia and Adenia gummifera.

Antibacterial and antioxidant properties of the methanol extracts of the leaves and stems of Calpurnia aurea

BACKGROUND

In South Africa, Calpurnia aurea (Ait.) Benth is used to destroy lice and to relieve itches, to destroy maggots and to treat allergic rashes, particularly those caused by caterpillars. Antioxidants play an important role protecting against damage by reactive oxygen species. Plants containing flavonoids have been reported to possess strong antioxidant properties.

METHODS

The antibacterial, antioxidant activities and phenolic contents of the methanol extracts of the leaves and stems of Calpurnia aurea were evaluated using in vitro standard methods. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the stem extract of Calpurnia aurea were determined by ABTS, DPPH, and ferrous reducing antioxidant property (FRAP) methods. Laboratory isolates of 10 bacteria species which included five Gram-positive and five Gram-negative strains were used to assay for antibacterial activity of this plant.

RESULTS

The results from this study showed that the antioxidant activities of the stem extract of Calpurnia aurea as determined by the total phenol, flavonoids, and FRAP methods were higher than that of the leaves. On the other hand, the leaf extract of the plant has higher level of total flavonols and proanthocyanidins. The leaf extract also has higher radical scavenging activity as shown in 1, 1-Diphenyl-2-picrylhydrazyl (DPPH), and 2,2¿-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS) assay. The leaf extract showed activity against seven of the bacterial organisms.

CONCLUSION

The results from this study indicate that the leaves and stem extracts of Calpurnia aurea possess antioxidant properties and could serve as free radical inhibitors or scavenger or, acting possibly as primary antioxidants. Although, the antibacterial properties of Calpurnia aurea are not as effective as the standard drugs- Chloramphenicol and Streptomycin, they still possess some activity against bacterial strains used in this study. Calpurnia aurea may therefore be a good candidate for functional foods as well as pharmaceutical plant-based products.

Anti-inflammatory and analgesic activities of the aqueous extract of Acacia karroo stem bark in experimental animals

The aqueous extract of the stem bark of Acacia karroo Hayne was investigated for its anti-inflammatory and analgesic activities in animal models. The extract at 100 and 200 mg/kg reduced significantly the formation of oedema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by a significant reduction in the number of writhes with two doses (100 and 200 mg/kg) used when compared to the untreated control group. In the tail immersion test, the extract at the doses used (100 and 200 mg/kg) increased reaction time to pain after 30 min. of oral administration of the extract. Indomethacin at 10 mg/kg served as reference drug in all these tests. The results gave a scientific basis to the traditional uses of Acacia karroo mainly for wound poultices, eye treatments and cold remedies.

Evaluation of the medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida

The medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida (Scrophulariaceae) were evaluated by assessing their antibacterial and antioxidant properties in vitro using standard procedures. The antioxidant activities of methanol extract of the leaves as determined by the ABTS, DPPH, proanthocyanidins and total flavonoids were higher than that of the stem. On the other hand, the total phenols, the flavonoids and the FRAP contents of the stem were higher than that of the leaves. The extracts however showed poor activity against both Gram-positive and Gram-negative bacteria. The methanol extract of the stem showed activities against Bacillus cereus and Staphylococcus epidermidis at MIC of 1.0 mg/ml. The methanol extract of the leaves did not show activity against any of the organisms used in this study. This study has to some extent validated the medicinal potential of the leaves and stems of H. lucida.

Studies on the toxicity of an aqueous extract of the leaves of Abrus precatorius in rats

The toxic effects of an aqueous extract of Abrus precatorius were studied in 20 male white rats over a period of 18 days. The rats were divided into four groups of five rats per group. Those in Group A served as controls while the rats in Groups B, C and D were dosed per os with 400 mg/kg, 800 mg/kg and 1 600 mg/kg of the extract, respectively. Blood samples were collected for haematological and biochemical analysis and specimens of the liver, kidney and testes were taken for histopathological studies. The study showed that the extract of A. precatorius caused decreased levels of packed cell volume, haemoglobin concentration, red blood cell count, white blood cell count, mean corpuscular volume and mean corpuscular haemoglobin. The extract also resulted in increased levels of total serum protein, albumin, alanine amino transaminase, aspartate amino transferase, alkaline phosphatase and total bilirubin. Histologically, testicular degeneration characterized by decreased numbers of lining cells of the epithelium as well as reduction in sperm cells with presence of scattered Sertoli cells were noted. The study thus showed that aqueous extract of Abrus precatorius is toxic and caution should be exercised in its use for medicinal purpose.

Toxic effects of chromatographic fractions ofPhyllanthus amarus on the serum biochemistry of rats

Chromatographic fractions obtained from Phyllanthus amarus were tested for toxicity on the serum biochemistry of rats. The results revealed that some fractions of P. amarus had potentially deleterious effects on the blood and therefore caution should be exercised in the use of P. amarus as a medicinal plant.

Some clinico-pathological changes associated with the aqueous extract of the leaves ofPhyllanthus amarus in rats

The pathological changes of the aqueous crude extract of the leaves of Phyllanthus amarus were studied in 32 male rats over a period of 30 days. The animals were divided into four groups of eight animals per group. The aqueous crude extract was prepared and administered orally using a cannula to rats in three groups receiving doses of 400 mg/kg, 800 mg/kg and 1,000 mg/kg but the fourth group served as a control and received distilled water only. Blood samples were collected for haematological and serum biochemical analysis. Organs such as the liver, kidney, testes and pancreas were also assessed for histopathological changes. The study showed that the extract caused a decrease in the red blood cell (RBC) count, packed cell volume (PCV), haemoglobin concentration (Hb), but an increase in the white blood cell (WBC) count. The extract also resulted in an increase in the levels of aspartate amino transferase (AST), total and conjugated bilirubin, total protein and albumin. The study, however, caused a decrease in the level of alanine amino transferase (ALT). Histopathologically, there were cases of protein casts in the kidney tubules with tubular nephrosis, foci of lymphocytic infiltration at the portal areas of the liver as well as marked testicular degeneration with severe disorganization of seminiferous tubules, which were devoid of spermatic cells. A reduction in the weight of the experimental animals was also noted in this study. It thus shows that Phyllanthus amarus has potential toxic properties.

Morphometric and histopathological studies on the effects of some chromatographic fractions of Phyllanthus amarus and Euphorbia hirta on the male reproductive organs of rats

The aqueous crude extracts of P. amarus and E. hirta were administered to thirty eight-week old sexually mature male albino to determine the effects of these extracts on the male reproductive organs of these animals. The results from this study revealed that the aqueous crude extracts of P. amarus and E. hirta caused varying degrees of testicular degeneration as well as reduction in the mean seminiferous tubular diameter (STD) in the treated rats. It thus shows that the aqueous crude extracts of P. amarus and E. hirta have potentially deleterious effects on the testes and accessory organs of rats. Great caution should therefore be exercised in the use of these plants for medicinal purpose.