Activity Of Aqueous Leaf Extract Research Articles

Antihypertensive activities of the aqueous extract of Kalanchoe pinnata (Crassulaceae) in high salt-loaded rats

Ethnopharmacological relevanceThe leaves of Kalanchoe pinnata (Crassulaceae) are used in Cameroon folk medicine to manage many diseases such as cardiovascular dysfunctions. In this work, we aimed to evaluate the activities of aqueous leaf extract of Kalanchoe pinnata on the blood pressure of normotensive rat (NTR) and salt hypertensive rats (SHR), as well as its antioxidant properties. Materials and methodsHypertension was induced in rats by oral administration of 18% NaCl for 4 weeks. For the preventive study, three groups of rats received 18% NaCl solution and the plant extract at 25mg/kg/day, 50mg/kg/day or 100mg/kg/day by gavage. Two positive control groups received 18% NaCl solution and either spironolactone (0.71mg/kg/day) or eupressyl (0.86mg/kg/day) by gavage for 4 weeks. At the end of this experimental period, systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and heart rate (HR) were measured by the invasive method. Some oxidative stress biomarkers (reduced glutathione (GSH), superoxide dismutase (SOD), nitric monoxide (NO) were evaluated in heart, aorta, liver and kidney. NO level was indirectly evaluated by measuring nitrite concentration. ResultsKalanchoe pinnata extract prevented significantly the increase of systolic and diastolic arterial pressures in high salt-loaded rats (SHR). In SHR, concomitant administration of Kalanchoe pinnata at 25, 50 and 100mg/kg/day significantly prevented the increase in blood pressure by 32%, 24% and 47% (for SAP); 35%, 33% and 56% (for DAP), respectively. No significant change was recorded in heart rate of those rats. The plant extract improved antioxidant status in various organs, but more potently in aorta. Thus, antioxidant and modulatory effects of Kalanchoe pinnata at the vasculature might be of preponderant contribution to its overall antihypertensive activity. ConclusionThe work demonstrated that the concomitant administration of high-salt and the aqueous extract of Kalanchoe pinnata elicits prevention of salt-induced hypertension in rat. This antihypertensive activity is associated with an improvement of antioxidant status. Overall, results justify and support the use of Kalanchoe pinnata as antihypertensive medicine.

Antidiabetic activity of aqueous leaf extract of Atriplex halimus L. (Chenopodiaceae) in streptozotocin–induced diabetic rats

ObjectiveTo investigate the antidiabetic effect of A. halimus leaf in streptozotocin-induced diabetic rats. MethodsThe aqueous extract of the plant leaf was tested for its efficacy in streptozotocin-induced diabetic rats. The extract was evaluated for its acute and short term general toxicity in male mice and for its antihyperglycemic activity using glucose tolerance test in rats. The aqueous extract was subjected to phytochemical screening and determination of total phenolic contents. ResultsThe statistical data indicated the significant increase in the body weight and decrease in the blood glucose and hepatic levels. The total protein level was significantly increased when treated with the extract. ConclusionsThese results suggest that the aqueous leaf extract of A. halimus has beneficial effects in reducing the elevated blood glucose level and hepatic levels in streptozotocin-induced diabetic rats.

Phytotoxicity evaluation of six fast-growing tree species in South Africa

Vachellia sieberiana, Albizia adianthifolia, Buddleja saligna, Combretum kraussii, Halleria lucida and Rapanea melanophloeos are fast-growing, indigenous tree species in South Africa. They are usually found growing alongside other plants in agricultural systems. In this study, the comparative phytotoxic activity of aqueous leaf extracts of these tree species at different concentrations was investigated using lettuce seeds (Lactuca sativa L.) in a laboratory bioassay. To simulate natural situations, seeds were germinated under 16h light/8h darkness in a growth chamber using distilled water as control. The results showed that germination, chlorophyll accumulation and growth indices (plumule and radicle lengths) were significantly inhibited with increasing concentration of plant extracts. The treated lettuce seedlings experienced lipid peroxidation at high extract concentrations (1.0% and 2.0%) as evidenced by increased concentration of malondialdehyde (MDA). In response to this, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) increased at low extract concentration but significantly dropped as concentration increased. These results suggest that aqueous extracts of the studied tree species may produce growth inhibitory substances. Thus, our study revealed that these trees possess phytotoxic activity which could be exploited in the management of weeds in agroforestry systems.

Anti-inflammatory activity of geraniin and aqueous extract of Phyllanthus muellerianus (Kuntze) Exell.

Phyllanthus muelllerianus (Kuntze) Exell. (Family Euphorbiaceae) is a tropical plant used for the management of menstrual disorders, fever and pains [1]. In this study, acute and chronic anti-inflammatory activity of aqueous leaf extract (ALE) of P. muellerianus and its isolate, geraniin, were investigated.

English

Nauclea latifolia is known to possess various therapeutic properties. The present study was designed to evaluate the anti-ulcer activity of aqueous leaf extract of N. latifolia against indomethacin-induced gastric ulcers in rats. Five groups of albino rats were pre-treated orally with: vehicle, distilled water (ulcer control), cimetidine (100 mg/kg, reference control), and 170, 340 and 510 mg/kg N. latifolia leaf extracts (experimental groups) respectively, 60 min prior to oral administration of indomethacin to generate gastric mucosal injury. Seven hours later, the animals were sacrificed by a blow on the head; their stomachs were removed and examined for ulcer index. The extract produced significant (P<0.05), and dose dependent anti-ulcer activity against indomethacin-induced ulcers in rats. These results suggest that the extract possesses significant anti-ulcer activity against experimentally induced gastric lesions and may justify its use as an anti-ulcerogenic agent. Keywords : Anti-ulcer activity, Nauclea latifolia leaf, mucosal injury, indomethacin, rats African Journal of Biotechnology Vol. 12(32), pp. 5080-5086

The acaricidal efficacy of aqueous neem extract and ivermectin against Sarcoptes scabiei var. cuniculi in experimentally infested rabbits

Sarcoptes scabiei var. cuniculi is one of the most important veterinary ectoparasites in rabbits and results in considerable loss of weight, productivity, and wool quality. The acaricidal activity of aqueous leaf extract of neem (CAN) and ivermectin (IVR) were evaluated in vitro and in vivo against S. scabiei var. cuniculi. Rabbits were classified into four groups (ten rabbits each). The first group (group 1) was designated as the negative control group. Each rabbit of the other groups was experimentally infested with 50 mites. One month post-infestation, the second group (group 2) was not treated and taken into account as the positive control group. The third group (group 3) was subcutaneously injected with 1% IVR (200μg/kg body weight, three times within a week interval). The fourth group (group 4) was treated topically with CAN (25%) every 3days for three consecutive weeks. Index scoring of lesions was described weekly. The number of live mites (larvae, nymphs, and adults) on each rabbit was counted on the 14th, 28th, and 42th day post-treatment (PT). Blood samples were taken 28 and 42days PT for estimation of some chemical parameters. The body weight and cumulative body weight gain were recoded 14, 28, and 42days PT. CAN (40%) was highly efficacious against larvae of S. scabiei var. cuniculi as 100% mortality was reached 24h PT. On the other hand, all treated mites with CAN (20%) and IVR died 48h PT. The lethal values of CAN (LC50, LC90, LC95, and LC99) were 7.496, 14.67, 17.75, and 25.37%, respectively, 48h PT. Lesion scoring in groups 3 and 4 were significantly decreased (P ≤ 0.05), reaching 0.20 and 0.40, respectively, when compared with that of group 2 (4.00), 42days PT. Twenty-eightdays PT, the reduction percentages of mites infesting rabbits were 93.38 and 93.09% for IVR and CAN, respectively. However, complete mite reduction was reached 42days PT. Rabbits treated with CAN did not show signs of restlessness or irritation, respiratory signs, or inflammation on the eye and/or skin at the time of application or afterwards. Regarding biochemical analysis, the levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and total cholesterol in rabbits treated with CAN were decreased significantly (P ≤ 0.05) than those of rabbits of the positive control group and those treated with IVR. On the other hand, the levels of total protein, albumin, and globulin of rabbits in group 4 were significantly (P ≤ 0.05) increased when compared with the corresponding values of groups 2 and 3. The body weight and cumulative body weight gain of rabbits treated with CAN were significantly increased (P ≤ 0.05) when compared with such values of groups 2 and 3, 28 and 42days PT. The present data indicated that CAN had in vitro and in vivo acaricidal efficiency similar to that of IVR and improved the performance of rabbits without inducing adverse effects on treated rabbits; consequently, CAN could be suitable as a promising alternative acaricide for veterinary use.

Phytotoxicity of leaf aqueous extract of Rapanea umbellata (Mart.) Mez (Primulaceae) on weeds

Allelopathic substances can be used to develop weed control alternatives based on natural products. The objective of this study was to compare the phytotoxic activity of aqueous leaf extracts of Rapanea umbellata with the toxicity of a synthetic herbicide on the germination and growth of weed species. The weeds species barnyard grass (Echinochloa crus-galli), wild poinsettia (Euphorbia heterophylla) and morning glory (Ipomoea grandifolia) were used. The effects of the aqueous leaf extract of R. umbellata at concentrations of 10% and 5% (g mL -1 ) were compared to the control (distilled water) and to the synthetic herbicide oxyfluorfen. The average weed germination time was significantly lower (p < 0.05) in control than in extract and herbicide treatments. The herbicide had more significant effects than the extract on the initial growth of the aerial part. However, the initial growth of the root part was significantly more affected by the leaf extract than by the herbicide. The extract also caused many disorders in weed root anatomy. Therefore, the leaf aqueous extract of R. umbellata showed important results that indicate that it should be bioprospected and that its allelochemicals should be purified for the discovery of natural-origin herbicides.

Antidiabetic Activity of Aqueous Leaf Extracts of Guazuma ulmifolia Lamk., Ethanolic Extracts of Curcuma xanthorrhiza and their Combinations in Alloxan-induced Diabetic Mice

Antidiabetic Activity of Aqueous Leaf Extracts of Guazuma ulmifolia Lamk., Ethanolic Extracts of Curcuma xanthorrhiza and their Combinations in Alloxan-induced Diabetic Mice

A study on the hematological parameters and brain acetylcholine esterase activity in immobilization induced stress and co-treatment with Centella asiatica leaves extract to wistar rats

Aim: Our aim was to evaluate the anti-stress activities of aqueous leaf extract of Centella asiatica (CA) in immobilization-induced stress in rats. The anti-stress activities of CA were assessed by monitoring the changes in the behavior, counts of red blood cells (RBCs) and white blood cells (WBCs) (Lymphocytes, Monocytes, Neutrophils, Esinophils) and change in the level of brain acetylcholine esterase (AChEs) activity in immobilization-induced stress in male albino Wistar rats. Materials and Methods: Immobilization stress was induced in rats by placing in 20 cm × 7 cm plastic tubes for 2 h/day for 21 days. Aqueous leaf extract of CA was co-administered orally to the experimental rats at a dose of 200 mg/kg body weight daily for the 21 days. Results: Stress induced by immobilization in the rats for 21 days decreased the passive avoidance behavior, total counts of RBCs, WBCs and brain AChEs activity. Upon co-administration of CA leaves extract to the stressed animals significantly reverted the changes to near normal levels when compared to control animals. Conclusion: Aqueous extract of CA leaves significantly reverted the changes due to immobilization induced stress which may be due to the anti-stress activities of CA leaves.

The effects of aqueous leaf extract of Aegle marmelos on immobilization-induced stress in male albino Wistar rats

Aim: Stress is the major problem in the modern world. Stress is one of the basic factors in the development of many diseases and has been exposed to be associated with altered homeostasis that may lead to antioxidant imbalance. Our aim was to evaluate the anti-stress activities of aqueous leaf extract of Aegle marmelos (AM) in immobilization-induced stress in rats. The anti-stress activities of AM were assessed by monitoring the change in the status of stress hormone, glucose, and non-enzymic antioxidants in immobilization-induced stress in rats. Materials and Methods: Immobilization stress was induced in rats by placing in 20 cm × 7 cm plastic tubes for 2 h/day for 21 days. Aqueous leaf extract of AM was given by gavage to the experimental rats at a dose of 100 mg/kg body weight daily for 21 days. Results: Immobilization stress induced in rats for 21 days caused increased corticosterone, glucose levels and decreased levels of non-enzymic antioxidant such as Vitamin C, vitamin E, and glutathione in plasma, liver, and kidney. AM significantly increased the non-enzymic antioxidants and decreased the levels of corticosterone at the end of experimental period as compared to control. Conclusion: Natural antioxidants strengthen the endogenous antioxidant defenses from reactive oxygen species and restore an optimal balance by neutralizing the reactive species. They are gaining immense importance by virtue of their critical role in disease prevention. In this context, AM can rightly be mentioned as a plant of considerable interest. In the present study, treatment with AM was found to reverse the oxidative stress in the hypothalamus caused by immobilization stress. So, it is concluded that AM is having high antioxidant properties and anti-stress activity.

Evaluation of leaf aqueous extract and synthesized silver nanoparticles using Nerium oleander against Anopheles stephensi (Diptera: Culicidae)

Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and ecofriendly reducing and capping agents. The present study was carried out to establish the larvicidal activity of synthesized silver nanoparticles (AgNPs) using leaf extract of Nerium oleander (Apocynaceae) against the first to fourth instar larvae and pupae of malaria vector, Anopheles stephensi (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by the aqueous extract of the plant parts to generate extremely stable silver nanoparticles in water. The results were recorded from UV-Vis spectrum, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy analysis. The production of the AgNPs synthesized using leaf extract of N. oleander was evaluated through a UV-Vis spectrophotometer in a wavelength range of 200 to 700nm. This revealed a peak at 440nm in N. oleander leaf extracts, indicating the production of AgNPs. The FTIR spectra of AgNPs exhibited prominent peaks at 509.12cm(-1) (C-H bend alkenes), 1,077.05cm(-1) (C-O stretch alcohols), 1,600.63cm(-1) (N-H bend amines), 2,736.49 and 2,479.04cm(-1) (O-H stretch carboxylic acids), and 3,415.31cm(-1) (N-H stretching due to amines group). An SEM micrograph showed 20-35-nm-size aggregates of spherical- and cubic-shaped nanoparticles. EDX showed the complete chemical composition of the synthesized nanoparticles of silver. Larvicidal activity of aqueous leaf extract of N. oleander and synthesized AgNPs was carried out against Anopheles stephensi, and the results showed that the highest larval mortality was found in the synthesized AgNPs against the first to fourth instar larvae and pupae of Anopheles stephensi with the following values: LC(50) of instar larvae 20.60, 24.90, 28.22, and 33.99ppm; LC(90) of instar larvae 41.62, 50.33, 57.78, and 68.41ppm; and LC(50) and LC(90) of pupae 39.55 and 79.10ppm, respectively. The aqueous leaf extract exhibited larval toxicity against the first to fourth instar larvae and pupae of Anopheles stephensi with the following values: LC(50) of instar larvae 232.90, 273.71, 318.94, and 369.96ppm; LC(90) of instar larvae 455.95, 563.10, 639.86, and 730.30ppm; and LC(50) and LC(90) of pupae 426.01 and 805.13ppm, respectively. The chi-square value was significant at p < 0.05 level. The possible larvicidal activity may be due to penetration of nanoparticles through a membrane. The results could suggest that the use of plant N. oleander to synthesize silver nanoparticles is a rapid, environmentally safer, and greener approach for mosquito control. This could lead us to a new possibility in vector-control strategy.

Antidiarrheal activity of aqueous leaf extract of Ceratotheca sesamoides in rats

The antidiarrheal effects of the aqueous leaf extract of C. sesamoides at 25, 50 and 100 mg/kg body weight was evaluated in female rats using gastrointestinal transit, diarrhea and enteropooling induced by castor oil models. The extract was positive for alkaloids, saponins, flavonoids and phenolics. The 25 mg/kg body weight of the extract significantly (p&lt;0.05) prolonged the onset time of diarrhea, decreased the fecal parameters (number, water content, fresh weight, total number of wet feaces) with no episode in the animals treated with 50 and 100 mg/kg body weight. The activity of small intestine Na+-K+ ATPase increased (p&lt;0.05) while the nitric oxide, volume and mass of intestinal fluid as well as the distance travelled by the charcoal meal decreased. The patterns of changes were similar to the reference drugs. Overall, the antidiarrheal activity of the aqueous leaf extract of Ceratotheca sesamoides may be due to alkaloids, phenolics, flavonoids and saponins present in the extract.

Management of finger millet (Eleusine coracana) blast under field conditions by plant extracts

Antifungal activity of aqueous leaf extracts of eight plants against the pathogen Pyricularia grisea causing blast in finger millet was evaluated under in vitro and field conditions. In the in vitro screening, extracts of A. nilagirica, latifolia, L. camara, and P. hysterophorus showed significant hyphal growth inhibition (&gt; 39.6%) over control with A. nilagirica showing highest inhibition (50.0% to 60.9%) at all concentrations. In general, the inhibitory activity of all eight extracts increased with increasing concentration. These four extracts were further evaluated as foliar sprays in field trials conducted over two crop seasons (2006 and 2007) along with the fungicide carbendazim for control of leaf, neck and finger blast of finger millet. Among the extracts, O. latifolia extract showed significantly high reduction in leaf (43.7%), neck (45.5%) and finger blast (28.1%) along with a significant yield increase (28.1%) over control in both crop seasons. Results indicate that crude aqueous extracts of O. latifolia can be used as an effective, economical and viable option for control of finger millet blast at farm level, especially under low input and/or organic farming conditions.

In vitro assays of the antibacterial and antioxidant activity of aqueous leaf extracts from different Prunus salicina Lindl. cultivars

The growing interest in the substitution of synthetic food antioxidants and antimicrobial additives by natural ones has fostered research on vegetable sources and on the screening of raw materials, for identifying new antioxidants and antimicrobial natural agents. The aim of the present study was to assess total phenolic contents and determine polyphenolic composition, related antioxidative and antimicrobial properties of plum leaves extracts from six cultivars. It was observed that the content of total phenolic compounds was cultivar dependent. High antioxidant capacity has been observed and related to the relative amounts of polyphenolic compounds with good antioxidant properties. The antimicrobial activity was confirmed against Listeria innocua and Escherichia coli, and it has found to be related with the high phenolic contents. Our results suggest that the use of plum leaf extracts is a feasible alternative as antibacterial and antioxidant agents to prevent the deterioration of stored foods by bacteria and oxidation.

Larvicidal and Adult Emergence Inhibition Effect of Crude Aqueous Leaf Extract of Jatropha curcas Against Anopheles arabiensis (Diptera: Culicidea)

This study aimed at evaluating the larvicidal and adult emergence inhibitory effects of crude aqueous leaf extract of Jatropha curcas against laboratory reared late third instar larvae of Anopheles arabiensis. For this purpose, standard larvicidal and recovery bioassays were used. At 500–1000 ppm, larvicidal activity of aqueous leaf extract of J. curcas was comparable to the larvicidal activity of 0.5 ppm Temephos (positive control). The LC50 and LC90 values of crude aqueous leaf extract of J.curcas were found to be 359 and 921. 61 ppm, respectively. More than 70% adult emergence inhibition (IE) was occurred in larvae recovered from treatments with test concentrations ranging from 125–1000 ppm. Generally, crude aqueous leaf extract of J.curcas showed dose dependent larvicidal and adult emergence inhibitory activities against the tested larvae. Future studies are recommended to identify active chromatographic fractions from the crude aqueous leaf extract of J. curcas because its larvicidal and adult emergence inhibitory activities may not be due to the synergistic effect of its bioactive fractions.

Acaricidal activity of aqueous extract and synthesized silver nanoparticles from Manilkara zapota against Rhipicephalus (Boophilus) microplus

Traditional parasite control is primarily based on the use of chemical acaricides, which unfortunately have many negative side effects. The aim of the present study was to evaluate the effect of plant synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Manilkara zapota to control Rhipicephalus (Boophilus) microplus. The synthesized AgNPs were characterized by UV–vis spectrum, scanning electron microscopy (SEM), Fourier transform infrared and X-ray diffraction. The UV–vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 421nm corresponding to the surface plasmon resonance band of AgNPs. SEM supports the biosynthesis and characterization of AgNPs with spherical and oval in shape and size of 70–140nm. Acaricidal activity of aqueous leaf extract of M. zapota and synthesized AgNPs were carried out against R. (B.) microplus and the results showed the LC50 values of 16.72 and 3.44mg/L; r2=0.856 and 0.783), respectively.

Antioxidant activities of aqueous leaf extracts of Toona sinensis on free radical-induced endothelial cell damage

In Taiwan, Toona sinensis (Toona sinensis) is well known as a traditional Chinese medicine, while the underlying pharmacological mechanisms of this drug are still a matter of debate. The purpose of this study was to evaluate the protective effects of non-cytotoxic concentrations of aqueous leaf extracts of Toona sinensis (TS extracts; 50-100 μg/mL) and gallic acid (5 μg/mL), a major component of these extracts, against AAPH-induced oxidative cell damage in human umbilical vein endothelial cells (ECs). Exposure of ECs to AAPH (15 mM) decreased cell viability from 100% to 43%. However, ECs were pre-incubated with TS extracts prior to AAPH induction resulted in increased resistance to oxidative stress and cell viability in a dose-dependent manner. An increase in ECs-derived PGI(2) and IL-1 β in response to AAPH exposure was positively correlated with cytotoxicity and negatively with TS extracts concentrations. In addition, gallic acid also suppressed PGI(2) and IL-1 β production in AAPH-induced ECs. Notably, TS extracts/gallic acid treatment significantly inhibited ROS generation, MDA formation, SOD/catalase activity, and Bax/Bcl-2 dysregulation in AAPH-stimulated ECs. Pretreatment of ECs with TS extracts/gallic acid also suppressed AAPH-induced cell surface expression and secretion of VCAM-1, ICAM-1 and E-selectin, which was associated with abridged adhesion of U937 leukocytes to ECs. Moreover, TS extracts/gallic acid treatment significantly inhibited the AAPH-mediated up regulation of PAI-1 and down regulation of t-PA in ECs, which may decrease fibrinolytic activity. Therefore, Toona sinensis may possess antioxidant properties that protect endothelial cells from oxidative stress. Our results also support the traditional use of Toona sinensis in the treatment of free radical-related diseases and atherosclerosis.

Antioxidant ability and total phenolic content of aqueous leaf extract of Stevia rebaudiana Bert

In the present study, we carried out a systematic research on relative antioxidant activity of aqueous leaf extract of Stevia rebaudiana. The DPPH activity of aqueous leaf extract (20, 40, 50, 100 and 200 μg/ml) was increased in a dose dependent manner, which was found in the range of 40.00-72.37% as compared to ascorbic acid 64.26-82.58%. The IC(50) values of aqueous extract and ascorbic acid in DPPH radical scavenging assay were obtained to be 83.45 and 26.75 μg/ml, respectively. Measurement of total phenolic content of the aqueous leaf extract of S. rebaudiana was achieved using Folin-Ciocalteau reagent containing 56.73 mg/g of phenolic content, which was found significantly potent when compared to reference standard gallic acid. The aqueous extract also inhibited the hydroxyl radical, nitric oxide and superoxide anions with IC(50) values of 100.86, 98.73 and 100.86 μg/ml, respectively. The greater amount of phenolic compounds leads to more potent radical scavenging effects as shown by the aqueous leaf extract of S. rebaudiana.

Antidiarrhoeal activity of aqueous leaf extract of Momordica charantia in rats

Momordica charantia Linn (Cucurbitaceae) is a medicinal herb, whose common name bitter melon, has been reported to possess antidiabetic property. However, its antidiarrhoeal potential is still unknown. The antidiarrhoeal activity of aqueous leaf extract of M. charantia (MC) was evaluated on castor oilinduced diarrhoea, gastrointestinal transit, intestinal fluid accumulation and gastric emptying in rats. The aqueous extract of the plant showed inhibitory activity against castor oil induced diarrhoea. A significant reduction (p< 0.05) in the gastrointestinal motility in charcoal meal test in rats was observed. The extract decreased volume of intestinal secretion induced by castor oil with a significant effect (p< 0.05) on the gastric emptying of the test animals compared to control rats. Inhibition of the gastrointestinal propulsion and fluid secretion by the extract suggest the extract might exert its antidiarrhoeal activity by antisecretory mechanism.

Antimalarial activity of Ageratum conyzoides in combination with chloroquine and artesunate

Objective To determine the suppressive and curative activity of aqueous leaf extract of Ageratum conyzoides (A. conyzoides) in combination with chloroquine and artesunate, respectively against Plasmodium berghei infection in mice. Methods Using malaria ( Plasmodium berghei) infected albino mice of both sexes, aqueous extracts of A. conyzoides in combination with chloroquine and artesunate were tested for antimalarial activity, respectively. Four-day suppressive test and Rane's curative test were carried out. Results Suppressive tests showed significant dose dependent reduction in parasitemia level produced by the extract-chloroquine and extract-artesunate combinations. Suppressive activities of both extract-drug combinations were greater than the individual drugs alone. Extract-chloroquine (100:5) produced the highest suppressive effect (98% suppression). Curative tests showed absolute survival in two extract-drug combinations. Two extract-drug combinations produced higher curative effects than the individual drugs alone. The highest dose combinations of extract-chloroquine (100:5) and extract-artesunate (100:5) produced absolute parasitemia clearance (cure) in the infected mice. Conclusions The study indicated that aqueous extract of A. conyzoides had the ability to potentiate the antimalarial activity of chloroquine and artesunate against induced plasmodiasis in mice. It contributes a lot in the malaria endemic and poverty stricken tropics.