Evaluation of the antimalarial and CD4+ T-cell modulatory effects of leaf methanol extract of Phyllanthus muellerianus (Kuntze) Exell (Phyllanthaceae) in Plasmodium berghei-infected mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Phyllanthus muellerianus (Kunze) Exell, a member of the Phyllanthaceae family, is a medicinal plant widely distributed in Africa. Decoctions from the leaves are used in Nigeria to treat fevers, convulsions, some neurological disorders and malaria. AIM OF THE STUDY: This study is to evaluate the anti-malarial properties of methanol extract of Phyllanthus muellerianus (MEPM) leaves and its ethyl acetate fraction using a murine malaria model infected with Plasmodium berghei. Additionally, we seek to investigate the potential modulatory effects of this extract and fraction on CD4+ T-cell populations in the context of malaria infection. MATERIALS AND METHODS: The anti-malarial effects of the leaf methanol extract of Phyllanthus muellerianus (MEPM) were screened using three established in vivo models of anti-plasmodial screening namely the curative, suppressive and prophylactic models. The methanol extract (MEPM) was afterwards fractionated into hexane (HFPM), ethyl acetate (EAFPM), and methanol (MFPM) fractions. In the pilot anti-malarial screening of the fractions, EAFPM exhibited the best antiparasitic activity. Subsequently, EAFPM was screened for anti-malarial activity using the three models above. The effects of the MEPM and EAFPM on haematological indices (Hb and PCV) of the inoculated animals were further screened and the mean survival time (MST) of the animals was monitored. CD4+ T cells of various groups were counted before and after treatment using a flow cytometer. The EAFPM was further subjected to HPLC analysis for identification of its major compounds. RESULTS: The EAFPM (100 and 200 mg/kg) elicited 88% and 93% cure respectively in the curative model, while artesunate (5 mg/kg,- the positive control) gave 87% protection. The MEPM and EAFPM also gave significant suppression of parasitemia in the suppressive model. The treated groups survived beyond 28 days as against 11 days by the control group (infected but not treated). The treated groups also prevented anaemia seen in the negative control. The EAFPM group significantly modulated the CD4+ T cell. Compounds identified were Gallocatechin, Quercetin -3-O-gallate, Ellagic acid, and Methylellagic acid rhamnoside). CONCLUSION: The study established that the leaf of Phyllanthus muellerianus possesses antimalarial activity, thus lending support to its use in the folkloric treatment of malaria.

Mitigating potential public health risks and challenges from hazardous materials contained in electronic waste items in a developing country setting.

Sustainable Development Goals (SDGs) Targets 12.4 and 3.9 aim to reduce deaths and illnesses from hazardous chemicals and to achieve environmentally friendly management of chemical and wastes. Electronic wastes, which contain hazardous chemicals, are rapidly generated in poor countries due to demand for affordable near-end-of-life internet-enabled gadgets that soon wear out and are improperly disposed due to ignorance, throw-away mentality and dearth of waste management infrastructure. This study identified hazardous chemicals contained in significant quantities in e-waste items, described their public health challenges and suggested mitigation measures. Results showed that mercury, polychlorinated biphenyls (PCBs), cadmium, lead and beryllium oxide were hazardous chemicals contained in significant quantities in e-waste items. The study recommended the formulation of appropriate environmental health education technology policy (AEHETP) to guide stakeholders to design education, preventive, therapeutic and decontamination plans for awareness creation and raising to address the toxic effects of e-waste items on users in poor countries.

Immunomodulatory and immunorestorative activities of ß-D-glucan-rich extract and polysaccharide fraction of mushroom, Pleurutus tuberregium.

CONTEXT: Some edible mushrooms are reputed to possess useful medicinal properties which are related to their ability to modulate the protective responses of the immune system. OBJECTIVE: This study explored the immunomodulatory and immunorestorative properties of a hot aqueous extract (APTR) and of a ß-d-glucan-enriched polysaccharide fraction (BGP) of a local oyster mushroom Pleurutus tuberregium (Fr.) Singer (Pleurotaceae). MATERIALS AND METHODS: Immunomodulatory activities were investigated by assessing specific and none-specific immune responses in immunocompetent and immunosuppressed mice; as well as in vitro in culture of RAW264.7 macrophages stimulated with BGP. RESULTS: In a homologous prime-boost immunization schedule, oral supplementation with APTR (100, 200, or 400 mg/kg) and BGP (100 or 200 mg/kg) resulted in significantly higher titers of total IgG, IgG1, and IgG2a by as much as 2-4-folds compared with the levels in untreated control mice. The mean hemagglutination (HA) titer in immunized mice that were treated with dexamethasone (DEX; 5 mg/kg) was significantly (p < 0.05) lower than the titer in groups that did not receive dexamethasone; however, short-term alternate day administration of APTR (200 mg/kg) to mice that had been immunosuppressed with 5 mg DEX/kg produced significant increases in secondary anti-SRBC antibody compared with the mean titer of mice immunized and treated with DEX alone. In in vitro studies, stimulation of RAW264.7 macrophages with BGP caused significant increases in iNO and TNF-α expression, and phagocytic functions of the cell. CONCLUSION: Taken together, the results of these studies showed that P. tuberregium imparts immunostimulatory and immunorestorative effects that could be explained, in part, by the actions of its ß-d-glucan constituent(s) on macrophages.

Hepato- and nephroprotective activities of a Nigerian local king tuber oyster mushroom, Pleurotus tuberregium (higher Basidiomycetes), in chemically induced organ toxicities in rats.

Chronic kidney disease, end-stage renal failure, and liver diseases are increasing worldwide and constitute a huge burden on health care costs, with attendant high morbidity and debility. Despite advances in modern medicine, there are still no licensed drugs that satisfactorily restore lost kidney or hepatic functions. In this study the chemoprotective effects of the hot aqueous extract of a local edible oyster mushroom, Pleurotus tuberregium (APTR), was evaluated in experimental liver and kidney toxicities. The effect of APTR on carbon tetrachloride (CCl4)- and paracetamol (PCM)-induced hepatotoxicity in rats was investigated by determining serum concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Short-term oral treatment with APTR (100 and 250 mg/kg) significantly reduced (P < 0.05) the increased concentrations of AST, ALT, and ALP induced in both PCM and CCl4 models of liver toxicity. APTR (100 and 250 mg/kg) decreased the mean serum AST concentrations by as much as 73.00% and 99.37%, respectively, in PCM-treated rats. Nephroprotection was assessed by determining the serum concentrations of creatinine and urea, as well as antioxidant enzymes, in kidney tissue homogenates after a repeated high dose of gentamicin. APTR (100 and 250 mg/kg) produced a significant decrease (P < 0.05) in the escalated serum concentrations of creatinine and urea by as much as 48.36% and 41.53%, respectively, compared to control. Similarly, levels of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase in kidney tissue were increased in a dose-related manner in groups that received oral APTR supplementation. The results of this study suggest that the consumption of our local edible mushroom, P. tuberregium, could, in addition to its high nutritive value, protect the liver and kidneys from oxidative damage caused by drugs and toxicants such as CCl4 and high doses of gentamicin and PCM.

Immunomodulatory effects of Stachytarpheta cayennensis leaf extract and its synergistic effect with artesunate.

BACKGROUND: The leaves of Stachytarpheta cayennensis C. Rich. (Verbenaceae) have been reported to possess potent anti-inflammatory and anti-malarial activities. Due to close association between inflammatory and immune responses, we evaluated the immunomodulatory activity of leaves extract of S. cayennensis. The combined effects of the leaves extract and artesunate, a standard antimalarial agent with immunomodulatory effects, were also evaluated. METHODS: The immunomodulatory activity of the methanol extract of the leaves of S. cayennensis (MESC) was evaluated in mice using the Delayed-Type hypersensitivity response (DTHR), primary and secondary humoral immune responses and the in vivo leucocyte mobilization tests. The immunomodulatory effect of artesunate and the combined effects of MESC and artesunate were evaluated using the phagocytic activity of polymorphonuclear neutrophils. Acute toxicity and lethality test in addition to the preliminary phytochemical studies of MESC were also performed. RESULTS: The MESC exhibited 64.21% inhibition of DTHR at 500 mg/kg dose and evoked 139.64% of phagocytic stimulation at 100 µg/ml dose. Also MESC significantly (p < 0.05) showed dose related stimulation of humoral immunity and a highest percentage leucocyte mobilization of 10.15% at 250 mg/kg dose. Artesunate offered a non-significant (p > 0.05) percentage phagocytic stimulation (PPS) while the combined effect of artesunate and MESC exhibited a significant (p < 0.05) dose dependent PPS with highest PPS of 393.77% at 100 µg/ml. The LD50 of the MESC was estimated to be greater than 5000 mg/kg since there were no lethality and signs of acute intoxication after 48 h observation. Preliminary phytochemical analysis revealed the presence of carbohydrates, glycosides, flavonoids, saponins, alkaloids, terpenoids and steroids. CONCLUSIONS: The results of this study indicated that MESC possesses immunostimulatory action with significant synergistic effects with artesunate, and can therefore, offer immune boosting activities in disorders of immune suppression.

Inhibition of inflammatory mediators and reactive oxygen and nitrogen species by some depsidones and diaryl ether derivatives isolated from Corynespora cassiicola, an endophytic fungus of Gongronema latifolium leaves.

In this study, some depsidones and diaryl ether derivatives isolated from Corynespora cassicola, a fungi endophyte of Gongronema latifolium, were assessed for their anti-inflammatory potentials. The isolated metabolites corynesidone A (1), corynesidone C (2), corynesidone D (3) and corynether A (4) were screened for their effects on tumour necrosis factor-α (TNF-α), inducible nitric oxide (iNO), and reactive oxygen species (ROS) and reactive nitrogen species (RNS) production by stimulated RAW264.7 macrophages. Concentration of 1, 2, 3 and 4 up to 100 µM did not remarkably affect the viability of treated macrophages. The compounds were found to cause a concentration-dependent decrease in lipopolysaccharide-induced TNF-α and iNO in RAW264.7 cells. Pre-treatment with 100 µM of 1, 2, 3 and 4 suppressed iNO by as much as 96.28%, 95.71%, 78.14% and 73.28%; with IC(50) of 8.16, 9.49, 15.29 and 26.52 µM, respectively. Similarly, pre-treatment with 100 µM of 1, 2, 3 and 4 caused an inhibition of 99.17%, 99.59%, 95.02% and 74.07% in the formation of iNO production, respectively, with IC(50) of 1.88, 3.99, 7.48 and 37.22 µM. Treatment of with compounds 1-4 (10, 30 and 100 µM) followed by stimulation with phorbol 12-myristate 13-acetate (1 µM) caused significant (p < 0.05) suppression of ROS/RNS-evoked chemiluminescence of luminol by as much as 100.96 ± 1.88%, 98.59 ± 1.38%, 87.35 ± 1.41% and 79.22 ± 0.30%, respectively at 100 µM. The depsidone derivatives (1-4) showed more potent inhibition of TNF-α and NO production and better scavenging ROS/RNS than the diaryl ether derivative (4). These chemical scaffolds can serve as suitable lead molecules for further development into novel anti-inflammatory and/or anti-cancer agents.

Anticonvulsant effect of kaurenoic acid isolated from the root bark of Annona senegalensis.

CONTEXT: The herbal preparations of Annona senegalensis Pers. (Annonaceae) root bark are used in Nigerian ethnomedicine for the treatment of epilepsy and febrile seizures. The scientific evidence for this effect has been reported. OBJECTIVE: The aim of this study was to identify and characterize the active constituent responsible for the anticonvulsant effect. MATERIALS AND METHODS: Bioactive-guided fractionation of the methanol-methylene chloride root bark extract (MME) of A. senegalensis using pentylenetetrazole (PTZ)-induced seizures in mice, afforded a potent anticonvulsant ethyl-acetate fraction (EF). Further fractionation of the EF yielded eight sub-fractions (F1-F8) which were tested for anticonvulsant activity. The sub-fraction F2 yielded white crystals that were purified to obtain A. senegalensis crystals, AS2. The AS2, which exhibited potent anticonvulsant effects, was characterized by 1D and 2D NMR spectroscopy, mass spectroscopy and X-ray crystallography. RESULTS: The AS2 was characterized as kaur-16-en-19-oic acid (KA), a diterpenoid. The AS2 indicated an oral LD50 of 3800 mg/kg. The results showed that the MME, EF and AS2 significantly (P<0.05) and dose-dependently delayed the onset of myoclonic spasms and tonic-clonic phases of seizures induced by PTZ and maximal electroshock seizures (MES). DISCUSSION AND CONCLUSION: Kaurenoic acid was identified as the anticonvulsant principle in the root bark extract of A. senegalensis. The anticonvulsant effect of the MME, EF and AS2 is most likely being mediated through central inhibitory mechanisms.

Extracts of Ficus exasperata leaf inhibit topical and systemic inflammation in rodents and suppress LPS-induced expression of mediators of inflammation in macrophages.

The leaves of Ficus exasperata are mashed and prepared as poultices that are placed on swellings, wounds, and arthritic joints to relieve swelling and pains by the Igede tribal community of Nigeria. The leaf and stalk are also squeezed and used to mitigate itching or inflammation. These claimed benefits inspired this study in which topical and systemic (acute, chronic) anti-inflammatory activities of a methanol/methylene chloride leaf extract of F. exasperata (MFE) were assessed in rodents. Effects of an aqueous leaf extract (AFE) on lipopolysaccharide-induced expression of interleukin-1ß (IL-1ß), tumor necrosis factor (TNF)-α, and inducible nitric oxide (iNO) were also investigated in murine bone marrow-derived macrophage (BMDM) cultures. Treatment of rats with MFE (200 and 400 mg/kg) led to significant inhibition of acute and chronic inflammation induced by, respectively, agar and formaldehyde in the paws. Topically, pre-application of mice with MFE (5 µg/ear) also significantly inhibited (by up to 21%) ear edema induced by xylene. In vitro, pre-treatment of BMDM with 5-100 µg AFE/ml significantly inhibited IL-1ß, TNFα, and iNO production in a dose-related manner. BMDM viability was not significantly affected AFE at concentrations up to 200 µg/ml. Initial studies showed that flavonoids, alkaloids, and terpenoids were the predominant phytoconstituents in each extract. In conclusion, the results of the various investigations indicated that F. exasperata leaf extracts possess anti-inflammatory properties that could underlie the benefits associated with the folklore use of the plant. The results also show that the extracts may be acting through a suppression of mediators of inflammation, such as IL-1ß, TNFα, and iNO.

Supplementation with aqueous leaf extract of Morinda lucida enhances immunorestoration and upregulates the expression of cytokines and immunostimulatory markers.

Morinda lucida Benth (Rubiaceae) is a versatile plant used in traditional medicine of many countries for the treatment of a variety of ailments and the claims of efficacy are particularly remarkable in the treatment of infections and immuno-inflammatory disorders. In this study, we investigated the immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida (AML) in cultures of murine splenic lymphocytes and in cyclophosphamide-induced immunosupression models, respectively. Administration of AML (100 and 250 mg/kg; per os) in alternate days significantly (P < 0.05) increased specific total IgG, IgG1, and IgG2a responses to ovalbumin by as much as 2-10 fold when compared to untreated controls. In cyclophophamide treated mice, the rate of wound healing, leukopoiesis , and body weight recovery were all enhanced by oral supplementation with AML (100 and 250 mg/kg) in a dose-dependent manner. In vitro cultures of BALB/C splenocytes treated with AML (12.5 and 50 µg/ml) for 24 h resulted in 5-10 fold increase in IFNγ and IL-4 measured by cytokine capture ELISA. Surface expression of immunostimulatory markers, CD69 and CD25, measured flow cytometrically by FACS analyis, were also significantly (P < 0.05) upregulated on splenic T and B cells by as much as 8-20 fold. Taken together, the results of these studies show the potent immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida, which may explain some of the beneficial effects of the plant in the treatment of infections and immuno-inflammatory disorders.

Inhibition of pro-inflammatory cytokines and inducible nitric oxide by extract of Emilia sonchifolia L. aerial parts.

Emilia sonchifolia L. (Asteraceae) is used in ethnomedicine for the treatment of a wide array of inflammatory disorders. This practice has also been supported by scientific reports which showed that extracts of E. sonchifolia possess anti-inflammatory effects in rodents. However, the mechanism(s) through which the extracts produce these effects is not known. In this study, the effect of a methanol/methylene chloride extract of E. sonchifolia (ES) on the levels of IL-1ß and TNF-α after an intraperitoneal lipopolysaccharide (LPS; 1 mg/kg) challenge was investigated in mice. The effect of ES on TNF-α and inducible nitric oxide (iNO) production by LPS-stimulated bone marrow-derived macrophages (BMMDM) was also investigated in vitro. BMMDM were pre-incubated for 2 h with ES (20, and 100 µg/mL) or with Pyrrolidine dithiocarbamate, PDTC (100 µM) and then activated with LPS, and then the IL-1ß, TNF-α and NO production measured in the cell-free conditioned culture supernatant after 24 h of incubation. In groups of mice pre-treated with ES, the systemic levels of IL-1ß and TNF-α induced by LPS were found to be significantly (p < 0.05) lower. In vitro, ES treatment caused a concentration-dependent decrease in LPS-inducible IL-1ß, TNF-α, and NO production by BMDM compared to the effects of treatment of the cells with LPS alone without affecting the viability of the cells. The results of these studies suggest that treatment with ES alleviated inflammatory responses possibly through a suppression of pro-inflammatory mediators and cytokines such as IL-1ß, TNF-α, and iNO.

Evaluation of the acute and sub acute toxicity of Annona senegalensis root bark extracts.

OBJECTIVE: To investigate the safety profile of Annona senegalensis (A. senegalensis). METHODS: Dried powdered root-bark of A. senegalensis was prepared by Sohxlet extraction using methanol-methylene chloride (1:1) solution and concentrated to obtain the methanol-methylene chloride extract (MME). MME was fractionated to obtain the n-hexane (HF), ethylacetate (EF) and methanol (MF) fractions. Acute toxicity (LD(50)) test was performed with MME, HF, EF and MF in mice by oral route. The sub acute toxicity studies were performed in rats after 14 days of MME administration while haematological and biochemical parameters were monitored. RESULTS: Medium lethal (LD(50)) values of 1,296, 3,808, 1,265 and 2,154 mg/kg were obtained for the MME, MF, HF and EF, respectively. The sub-acute toxicity studies indicated a significant (P<0.05) increase in the body weight of both the treated rats and the control. The haematological tests indicated no change in the packed cell volume values but a significant (P<0.05) increase in the total WBC count at 100 and 400 mg/kg doses. The differential analysis showed a decrease in the nutrophils and a non-significant increase in the lymphocyte counts. The liver transaminase enzymes, alanin transaminase and aspartate transaminase showed no significant increase compared to the control. Histopathological examination of the liver sections also indicted no obvious signs of hepatotoxicity except with the 400 mg/kg dose that showed degeneration and necrosis of the hepatocytes. CONCLUSIONS: These results indicated that the root bark extracts of A. Senegalensis are safe at the lower doses tested, and calls for caution in use at higher doses in treatment.

The leaf extract of Spondias mombin L. displays an anti-inflammatory effect and suppresses inducible formation of tumor necrosis factor-α and nitric oxide (NO).

Extracts of Spondias mombin L. (Anacardiacea) is used in the traditional medicine of Africa and Latin America to treat many inflammatory conditions, with repeated claims of efficacy. However, there are no scientific data yet to support these claims and the mechanism through which the extract may be acting is still unknown. This study was undertaken to investigate the effects of the methanolic extract of the leaf of S. mombin (SM) on inflammation and to uncover some of the possible mechanisms that could explain any observed changes. The anti-inflammatory activity of the extract was investigated in Wistar rats using intraplantar injection of carrageenan as an in vivo model of inflammation. The effect of oral supplementation of the SM extract on tumor necrosis factor (TNF)-α levels after an intraperitoneal lipopolysaccharide (LPS; 1 mg/kg) challenge was investigated in mice. The effect of SM on TNF-α and inducible nitric oxide (iNO) production by LPS-stimulated bone marrow-derived macrophages (BM-MØ) was also investigated in vitro. BM-MØ were preincubated for 2 h with SM (0-100 µg/ml), activated with LPS, and then TNF-α and NO production measured in the cell-free conditioned culture supernatant after 24 h of incubation. The study showed that pre-treatment of rats with the SM extract (at 100, 200, and 400 mg/kg, per os) caused a significant dose-related inhibition of carrageenan-induced paw edema over a 4-h period. In treated mice, LPS-inducible (systemic) TNF-α levels were found to be significantly lower as a result of their receiving the SM extract. In vitro, SM treatment caused a dose-dependent decrease in LPS-inducible TNF-α and NO production by BM-MØ compared to the effects of treatment of the cells with LPS alone. Taken together, the results of these studies suggest that supplementation with SM extract can alleviate inflammatory responses and that this could possibly be via a suppression of the production of pro-inflammatory mediators and cytokines such as TNF-α and iNO.

Efficacy and safety assessment of T. Angelica herbal tonic, a phytomedicinal product popularly used in Nigeria.

T. Angelica Herbal Tonic (TAHT) is a herbal product indicated for indigestion and constipation and highly patronized in Nigeria. In this study, the efficacy and safety of the herbal tonic in relation to the label claims were assessed. The effect on peristalsis in mice was evaluated by the charcoal meal model and in vitro using guinea pig ileum. The effects of TAHT on behavior, fertility, birth and organ weights were also determined. Teratogenic potential and reproductive toxicity were studied in pregnant rats. Acute toxicity studies showed that at doses above 5000 mg kg(-1), the herbal tonic did not cause lethality and produced no signs of intoxication in mice. The study did not show any gross behavioral changes in mice treated with 1000 mg kg(-1) of TAHT as compared with the negative control treatment. TAHT (400 mg kg(-1)) exhibited a dose-dependent enhancement in the gastrointestinal tract motility in mice when compared with the negative control. At concentrations up to 300 µg mL(-1), TAHT did not cause any significant effect on acetylcholine, histamine and nicotine-evoked contractions of guinea pig ileum preparation. It took an average of 31.25 ± 4.52 days for the TAHT-treated animals to litter, which is significantly (P < .05) different from the 55 ± 4.51 days recorded for the control treatment group. TAHT exhibited a modest fertility-promoting effect and showed lack of abortifacient and teratogenic properties in the study. Generally, the results of this study showed some favorable pharmacological effects of TAHT in animals which may authenticate some of the label claims.

Anticonvulsant activity of ethanol leaf extract of Spathodea campanulata P. Beauv (Bignoniaceae).

The anticonvulsant properties of ethanol leaf extract of Spathodea campanulata, a plant used in traditional medicine to treat convulsion and epilepsy, were studied in mice using pentylenetetrazole-, picrotoxin-, and electroshock-induced models in mice. Other central nervous system effects and anticonvulsant-related activities such as the effects on position sense, righting reflex, Rota-Rod performance, phenobarbital sleep time, and amphetamine-induced stereotypy were also investigated. The acute toxicity potential in mice was determined by the oral route. The results showed that the administration of S. campanulata extract (250-1,000 mg/kg, p.o.) 30 minutes prior to intraperitoneal administration of pentylenetetrazole (70 mg/kg) or picrotoxin (5 mg/kg) protected the treated mice against the respective pentylenetetrazole- and picrotoxin-induced convulsion in a dose-dependent manner, offering 100% protection at the maximum dose of 1,000 mg/kg. The extract increased the threshold of maximum electroshock and reduced duration of convulsive episodes, dose-dependently. Oral administration of S. campanulata ethanol extract did not significantly (P > .05) affect other centrally coordinated behaviors and convulsion-related properties such as position sense, righting reflex, Rota-Rod performance, phenobarbital sleep time, and amphetamine-induced stereotypy in treated animals. The oral median lethal dose of the extract was estimated as 4.5 g/kg. These results show that the ethanol leaf extracts of S. campanulata possess anticonvulsant activity. The results also show that S. campanulata extract is nonsedating, has no antipsychotic properties, and may not affect motor coordination when used as an anticonvulsant.

Aqueous extract of Phyllanthus niruri (Euphorbiaceae) enhances the phenotypic and functional maturation of bone marrow-derived dendritic cells and their antigen-presentation function.

Decoctions of Phyllanthus niruri (PN) (Fam. Euphorbiaceae) is promoted in traditional medicine of Africa, Asia, and South America as beneficial supplement for different infectious diseases, especially for viral hepatitis, tumor, and for immune compromised patients. This stimulated the interest in understanding the mechanisms by which the whole extract of the plant could stimulate the immune system. Dendritic cells (DCs) are professional antigen-presenting cells and provide a link between the innate and the adaptive immune responses. In the present study, the effects of lyophilized aqueous extract of PN on structural and functional maturation of murine bone marrow-derived DCs (BM-DCs) were investigated. Bone marrow cells were cultured in the presence of granulocyte macrophage-colony stimulating factor and interleukin-4 (IL-4) and the generated immature DCs were stimulated with PN (25, 50, and 100 microg/mL) or lipopolysaccharide (10 microg/mL) for 48 h. Results showed that treatment with PN increased the expression of major histocompatibility complex-II and the various makers for DCs maturation (CD40), activation (CD83), and costimulation (CD86) in a concentration-dependent manner. Consistent with the increase in phenotypic makers, functional maturation assay showed that treatment of BM-DCs with PN caused a decrease in fluorescein isothiocyanate-dextran pinocytosis and an increase in IL-12 in the supernatant. In a transgenic T-cell activation model, PN-treated BM-DCs presented Ova antigen to Ova-specific CD8(+) T cells from OT-1 mice more efficiently as demonstrated by increased T-cells proliferation and IL-2 production. Therefore, PN enhances the structural and functional maturation of BM-DCs and their antigen-presenting function. These effects are relevant in immunodeficient conditions, tumor control, and in infectious diseases.

Activation of murine lymphocytes and modulation of macrophage functions by fractions of Alchornea cordifolia (Euphorbiaceae) leaf extract.

The immune system is highly complex, intricately regulated group of cells whose integrated function is essential to health. Modulating the functions of these cells offers important pharmacological and therapeutic approaches in many disease conditions.This study reports on the in vitro immunostimulant activities of two flavonoid-rich fractions of Alchornea cordifolia (Euphorbiaceae) leaf extract: EAC and AAC, obtained by fractionating the methanol extract into ethylacetate and acetone soluble fractions, respectively.The lymphoproliferative effect of the fractions on naïve murine splenocytes and thymocytes as well as the modulatory effects on the phagocytic and lysosomal enzyme activities of elicited murine macrophages was investigated. A. cordifolia fractions, EAC and AAC, produced significant (P<0.05) and concentration-related (10-250 microg/ml) increases in the proliferation of splenocytes and thymocytes cultures which were comparable to the mitogenic effects of lipopolysaccharide, LPS (10 microg/ml) and concanavalin A, ConA (2 microg/ml) used as standard mitogens. EAC and AAC (15.6-250 microg/ml) significantly (P<0.05) increased phagocytosis and intracellular killing capacity measured as percentage increase in nitroblue tetrazolium (NBT) dye reduction. Lysosomal phosphatase activity of peritoneal macrophages, measured by p-nitrophenyl phosphate (p-NPP) hydrolysis, was also increased significantly (P<0.05) by EAC and AAC (15.6-250 microg/ml). Treatment of macrophage cultures with EAC and AAC (15.6-250 microg/ml) decreased the expression of nitric oxide significantly (P<0.05) in the supernatant. This study demonstrates strong immunomodulatory activities of A. cordifolia leaf extracts which could explain some of the therapeutic benefits attributed to the plant in traditional medicine and could also be exploited as a source of novel immunoregulating substances.

Experimental evidence for the antidiabetic activity of cajanus cajan leaves in rats.

The antidiabetic activity of methanol leaves extract of Cajanus cajan (L.) Millsp. (Fabaceae) was studied in alloxan-diabetic and in oral glucose loaded rats. The acute toxicity and lethality (LD50) and the phytochemical analysis of the extract were also evaluated. The results showed that the extract (400 and 600 mg/kg) significantly (P<0.05) reduced fasting blood sugar of alloxan diabetic rats in a dose-related manner, with maximum hypoglycemic effect at 4 - 6 h. The extract (400 and 600 mg/kg) also significantly (P<0.05) suppressed the peak postprandial rise in blood glucose of normal rats by 101.8 and 57.40% respectively. Acute toxicity and lethality test of the extract in rats gave an oral LD50 greater than 5 g/kg. The findings indicate that the leaves of C. cajan may be beneficial as an antidiabetic therapy.

Acanthus montanus: an experimental evaluation of the antimicrobial, anti-inflammatory and immunological properties of a traditional remedy for furuncles.

BACKGROUND: Acanthus montanus (Nees) T. Anderson (Acanthaceae) is a shrub widespread in Africa, the Balkans, Romania, Greece and Eastern Mediterranean. It is used in African traditional medicine for the treatment of urogenital infections, urethral pain, endometritis, urinary disease, cystitis, leucorrhoea, aches and pains. In southeastern Nigeria, the root is popular and acclaimed highly effective in the treatment of furuncles. This study was undertaken to experimentally evaluate the antimicrobial and anti-inflammatory properties of the root extract as well as its effect on phagocytosis and specific cell-mediated immune response which may underlie the usefulness of the roots in treatment of furuncles. METHODS: The aqueous root extract (obtained by hot water maceration of the root powder) was studied for effects on the growth of clinically isolated strains of Pseudomonas aeruginosa and Staphylococcus aureus. The anti-inflammatory activity was investigated using acute topical edema of the mouse ear induced by xylene, acute paw edema induced by agar in rats, formaldehyde arthritis in rats, vascular permeability induced by acetic acid in mice and heat- and hypotonicity-induced haemolysis of ox red blood cells (RBCs). Also evaluated were the effects on in vivo leukocyte migration induced by agar, phagocytic activity of macrophages on Candida albicans and specific cell-mediated immune responses (delayed type hypersensitivity reaction (DTHR) induced by sheep red blood cell (SRBC)). The acute toxicity and lethality (LD50) in mice and phytochemical constituents of the extract were also determined. RESULTS: The extract moderately inhibited the growth of the test organisms and significantly (P < 0.05) inhibited (57%) topical acute edema in the mouse ear. It significantly (P < 0.05) suppressed the development of acute edema of the rat paw in a non-dose-related manner and was not effective in inhibiting the global edematous response to formaldehyde arthritis. It also inhibited vascular permeability induced by acetic acid in mice and the haemolysis of ox RBCs induced by heat- and hypotonicity. The extract increased total leukocyte and neutrophil counts and caused a significant (P < 0.05) dose-related increase in the total number of macrophages at the 800 mg/kg dose. On phagocytic activity, the extract evoked a significant (P < 0.05) increase in the number of macrophages with ingested C. albicans at 800 mg/kg dose, and significantly (P < 0.05) inhibited DTHR in a dose-related manner. Phytochemical tests on the extract revealed an abundant presence of alkaloids and carbohydrates while saponins, glycosides, and terpenoids occurred in trace amounts. Acute toxicity test established an oral and intraperitoneal LD50 greater than 5,000 mg/kg. CONCLUSION: The effectiveness of the root of A. montanus in the treatment of furuncles may largely derive from mobilization of leukocytes to the site of the infection and activation of phagocytic activity as well as suppression of exacerbated immune responses by its constituents. Antimicrobial and anti-inflammatory activities are likely contributory mechanisms. Phytochemical constituents such as alkaloids and carbohydrates may be responsible for these pharmacological activities.

Mechanisms of the anti-inflammatory activity of the leaf extracts of Culcasia scandens P. Beauv (Araceae).

The mechanisms of the anti-inflammatory activity of the leaf extracts of Culcasia scandens P. Beauv were evaluated. The methanol leaf extract (CE) of C. scandens was subjected to bioactivity-guided separation to obtain fraction C as the most active anti-inflammatory fraction. Further activity-guided fractionation of fraction C led to the isolation of an anti-inflammatory principle, CS-1, identified as sitosterol. Phytochemical analysis of CE indicated the presence of carbohydrates, glycosides, alkaloids, saponins, flavonoids, tannins, sterols and terpenoids. Fraction C tested positive for flavonoids, sterols and terpenoids while CS-1 tested positive for sterols. Acute toxicity test on CE in mice established an intraperitoneal (i.p.) and oral (p.o.) LD50 of >5 g/kg. The isolated compound, CS-1, inhibited topical edema in the mouse ear while CE and fraction C were devoid of any such activity. The methanol extract (CE), fraction C and CS-1 suppressed paw edema in rats with inhibitory order of magnitude: CS-1>fraction C>CE. The methanol extract (CE), fraction C and CS-1 caused gastrointestinal irritation in rats to varying extents and reduced neutrophil and lymphocyte counts while CE and fraction C reduced total leukocyte count (TLC). The methanol extract (CE) was effective in inhibiting heat-induced hemolysis of human red blood cells (RBCs) but exhibited no inhibitory effect on hypotonicity-induced hemolysis. However, fraction C and CS-1 inhibited both heat- and hypotonicity-induced hemolysis. These results suggest that the leaf extract of C. scandens has a good anti-inflammatory profile, indicating a nonspecific mechanism of action.

Behavioural effect of Pavetta crassipes extract on rodents.

The effects of the ethanol extract of Pavetta crassipes on the central nervous system (CNS) and on actions of some selected centrally acting drugs were studied in mice and rats. These studies were carried out using the spontaneous motor activity (SMA), amphetamine-induced hyperactivity and stereotyped behaviour, pentobarbital-induced hypnosis and exploratory activity, apomorphine-induced climbing and haloperidol-induced catalepsy in rats. The results demonstrated that the extract of P. crassipes dose-dependently decreased SMA in mice and attenuated amphetamine-induced hyperactivity and the different episodes of stereotypic behavioural patterns induced by amphetamine. In addition, the extract decreased the number of head dips in the exploratory activity test and potentiated pentobarbital-induced sleeping time in rats. Furthermore, the extract inhibited apomorphine-induced climbing in mice and potentiated haloperidol-induced catalepsy in rats. Our results suggest that the extract of P. crassipes contains biologically active substance(s) that might be acting centrally through the inhibition of dopaminergic pathway or a system linked to this pathway to mediate the observed pharmacological effects.