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.

Cytotoxic effect and antioxidant activity of pterocarpans from Millettia aboensis root.

Chemical analysis of the methanol extract of the root bark of Millettia aboensis led to the isolation of homopterocarpin (1), secundiflorol I (2), and maackain (3). The structures of these compounds were elucidated based on their MS and NMR spectra. The crude methanol root extract was screened for its cytotoxic activity on mouse lymphoma cell line (L5178Y), and the isolated compounds were tested for their antioxidant activity using a 2, 2-diphenylhydrazyl (DPPH) radical scavenging model. The crude methanol root extract gave a percentage growth inhibition of 87.5% on the mouse lymphoma cell line (L5178Y). Compound 3 gave the highest antioxidant activity with an IC50 of 83 µg/ml. These compounds can serve as leads for anticancer agents.

New amide and dioxopiperazine derivatives from leaves of Breynia nivosa.

The first chemical investigation of leaves of Breynia nivosa from Nigeria resulted in the isolation of two new amide derivatives breynivosamides A and B (1 and 2) and two new dioxopiperazine derivatives breynivosines A and B (4 and 5) together with seven known compounds (3, 6-11). The structures of the new compounds were elucidated by 1D, 2D NMR and HRESIMS data as well as by comparison with the literature. All isolated compounds were tested for the cytotoxic and antimicrobial activities. Only cristatin A (6) showed cytotoxicity against the L5178Y mouse lymphoma cell line with an IC50 value of 13.9µM while breynivosamide A (1) exhibited moderate antimicrobial activity against Mycobacterium tuberculosis with an MIC value of 25µM.

A new benzophenone glycoside from the leaves of Mitracarpus villosus.

A new benzophenone glycoside, mitraphenone A (1), together with three known compounds (2-4) were isolated from the leaves of the traditionally used medicinal plant Mitracarpus villosus (Rubiaceae) collected in Nigeria. A combination of one- and two-dimensional NMR spectroscopic and mass spectrometric measurements were carried out to identify the structure of 1. All isolated compounds (1-4) were screened for their antibacterial activity against several Gram-positive and Gram-negative bacteria. Compound 1 exhibited moderate activity against Enterococcus faecium (strains ATCC 35667 and ATCC 700221) and Staphylococcus aureus ATCC 25923 with MIC values ranging from 25 to 50 µM.

Modulation of intracellular expression of IFNγ and IL-2 in culture of splenic T lymphocytes by some flavonoid glycosides of Alchornea floribunda.

Context Alchornea floribunda Müll. Arg. (Euphorbiaceae) leaves are widely used in ethnomedicine for the management of rheumatism, arthritis and toothache. Objective In this study, flavonoid glycosides isolated from Alchornea floribunda were screened for their effect on the intracellular expression of interferon-gamma (IFNγ) and interleukin-2 (IL-2) type-1 cytokines. Materials and methods Chromatographic purification of the ethyl acetate fraction of the methanol leaf extract led to the isolation of seven flavonoid glycosides (1-7). Their structures were elucidated by 1D and 2D nuclear magnetic resonance and mass spectrometry. Splenocytes were treated with graded concentrations of the compounds (6.25-25 µg/mL) and incubated for 24 h. Thereafter, their effect on the expression of IFNγ and IL-2 by CD4(+ )and CD8(+ )T-lymphocytes was evaluated using intracellular cytokine staining and FACS analysis. Results Compounds 1-7 (6.25-25 µg/mL) caused the up-regulation of activated CD8(+ )(57.85-72.45% versus 57.85% for untreated control) and, to a lesser extent, activated CD4(+ )(3.21-7.21% versus 2.75% for the untreated control) T-lymphocytes that were both largely interferon-gamma-releasing in treated mouse T lymphocytes relative to untreated control. FACS data analysis showed that stimulation with all the compounds increased the proportion of CD8(+)/IFNγ(+ )and CD4(+)/IFNγ(+ )T lymphocytes up to two-fold when compared with the cells in untreated control wells. Intracellular IL-2 secretion by treated T cells was not detected. Conclusion This recorded T-lymphocyte-specific immune-modulatory property may contribute to explain in part the dynamics associated with the ethnomedicine of Alchornea floribunda, and may find relevance as a necessary cellular immune response precursor to infection-associated disease management.

Flavonoid glycosides from Olax mannii: Structure elucidation and effect on the nuclear factor kappa B pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Olax mannii Oliv. (Olacaceae) is among the many medicinal plants used in Nigeria for the ethnomedicinal management of both cancer and inflammation. Such plants represent potential sources of innovative therapeutic agents for the treatment of cancer and other malignant disorders. While the majority of medicinal plants exert their anticancer effects by direct cytotoxicity on tumor cells, it is important that other mechanisms through which these plants can exhibit anticancer effects are investigated. Preliminary studies indicated that Olax mannii leaves are rich sources of novel flavonoid glycosides. The detailed chemistry as well the mechanisms through which these flavonoid constituents may exert their cancer chemo-preventive and therapeutic effects are, however, not yet investigated. AIM OF THE STUDY: The aim of this study is to carry out a detailed chemical investigation of Olax mannii leaves and the effects of the isolated constituents on the nuclear factor kappa B (NF-κB) pathway. MATERIALS AND METHODS: A methanol leaf extract was subjected to various chromatographic separations to achieve isolation of flavonoid glycosides and the structures of the isolated compounds were elucidated by a combination of 1D and 2D NMR and high resolution mass spectrometry. Biological activities were assessed by measurement of cellular viability and proliferation using quantitative IncuCyte videomicroscopy, trypan blue staining and by quantification of the number of metabolically active K562 cells based on quantitation of ATP. The effect of the compounds on the inhibition of the NF-κB pathway as well as toxicity towards peripheral blood mononuclear cells to evaluate differential toxicity was also assayed. RESULTS: Chemical investigation of the methanol leaf extract of the plant material led to the isolation of three new flavonoid triglycosides, kaempferol 3-O-[α-D-apiofuranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O-α-L-rhamnopyranoside (1), kaempferol 3-O-[ß-D-glucopyranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O-α-L-rhamnopyranoside (2), kaempferol 3-O-[ß-D-arabinopyranosyl-(1→4)-α-L-rhamnopyranoside]-7-O-α-L-rhamnopyranoside (3), in addition to fourteen known flavonoid glycosides (4-17). Of all the tested compounds, only compound 9 (kaempferol 3-O-α-L-rhamnopyranoside) exhibited promising and specific antiproliferative activity on human K562 chronic myelogenous leukemia cells and dose-dependently inhibited NF-κB transactivation. CONCLUSION: The presence of this flavonoid glycoside and derivatives may account for the reported efficacy of Olax mannii leaf extract in the ethnomedicinal management of cancer and inflammation.

A new antibacterial benzophenone glycoside from Psidium guajava (Linn.) leaves.

Bioactivity-guided fractionation of methanol extract from the leaves of Psidium guajava L. (Myrtaceae) yielded a new benzophenone glycoside, Guajaphenone A (2) together with two known compounds, Garcimangosone D (1) and Guaijaverin (3). Their structures were elucidated by analysis of spectroscopic data including 1D and 2D NMR and electrospray ionisation mass spectrometry (ESI-MS). The isolated compounds were screened against standard strains of Gram-positive and Gram-negative bacteria using broth dilution assay method, and the MIC values determined and compared with reference antibiotic ceftriaxone. They were found to have significant antibacterial activities against Escherichia coli and Staphylococcus aureus with all of them showing better activities against S. aureus, but displaying weaker activities, in comparison to ceftriaxone. However, despite reduced effect of these compounds against the organisms, this work opens the perspective to use these molecules as 'leads' for the design of novel and selective drug candidates for some tropical infectious diseases.

Antioxidative polyphenols from Nigerian mistletoe Loranthus micranthus (Linn.) parasitizing on Hevea brasiliensis.

Two new phenolic glycosides, linamarin gallate (1) and walsuraside B (2), together with nine known compounds, catechin (3), epicatechin (4), epicatechin 3-O-gallate (5), epicatechin 3-O-(3-O-methyl)gallate (6), epicatechin 3-O-(3,5-O-dimethyl)gallate (7), epicatechin 3-O-(3,4,5-O-trimethyl)gallate (8), quercetin 3-O-ß-d-glucopyranoside (9), rutin (10), and peltatoside (11), were isolated from the leafy twigs of Nigerian mistletoe Loranthus micranthus (Linn.) parasitic on Hevea brasiliensis. Compound 1 was characterized as an unusual cyanogenic glycoside, while compound 8 was isolated for the first time from a natural source. This is the first report of a cyanogenic glycoside from mistletoes. The structures of the new compounds were unambiguously elucidated by 1D ((1)H, (13)C), 2D NMR (COSY, HSQC, and HMBC) and by mass spectroscopy. The antioxidant activities of the isolated compounds (1-11) were evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay.

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.

Phytochemical analysis, hepatoprotective and antioxidant activity of Alchornea cordifolia methanol leaf extract on carbon tetrachloride-induced hepatic damage in rats.

OBJECTIVE: To investigate the hepatoprotective and antioxidant activities of Alchornea cordifolia (A. cordifolia) leaf extract. METHODS: Various solvent fractions of the methanol extract of the leaf of the plant A. cordifolia Mull. Arg (Fam: Euphorbiaceae) were evaluated for hepatoprotective activity by carbon tetrachloride-induced liver damage in rats. The degree of protection was measured by using biochemical parameters such as serum glutamate oxalate transaminase (SGOT/AST), serum glutamate pyruvate transaminase (SGPT/ALT), alkaline phosphatase (ALP) and total bilirubin. The in vitro antioxidant activity of the extract was also evaluated by the 1, 1-diphenyl- 2-picrylhydrazyl (DPPH) free radical scavenging assay. The extract was subjected to preliminary phytochemical screening. RESULTS: The ethyl acetate and chloroform fractions, at a dose of 300 mg/kg, produced significant (P<0.05) hepatoprotection by decreasing the activities of the serum enzymes and bilirubin while there were marked scavenging of the DPPH free radicals by the fractions. The effects were comparable to those of the standard drugs used for the respective experiments, silymarin and ascorbic acid. Alkaloids, flavonoids, saponins and tannins were detected in the phytochemical screening. CONCLUSION: From this study, it was concluded that the plant of A. cordifolia possesses hepatoprotective as well as antioxidant activities and these activities reside mainly in the ethyl acetate and acetone fractions of methanol leaf extract.

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.

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.

Anti-inflammatory and membrane-stabilizing stigmastane steroids from Alchornea floribunda leaves.

Alchornea floribunda (Euphorbiaceae) leaves are widely used in African ethnomedicine for the management of acute and chronic inflammatory disorders. In the present study, bioactivity-guided fractionation led to the isolation of two known (1 and 3) and one new (2) stigmastane steroids from the hexane extract of Alchornea floribunda leaves. The anti-inflammatory activities of these compounds were evaluated using IN VITRO and IN VIVO animal models. The compounds 1, 2, and 3 at 50 and 100 microg/ear significantly (p < 0.05) inhibited xylene-induced ear edema in mice in a dose-dependent manner. The topical anti-inflammatory effect of 1 and 2 are significantly (p < 0.05) higher than that of indomethacin and prednisolone. At 20 mg/kg (i. p.), all the compounds significantly (p < 0.05) inhibited acute inflammation induced by subplantar injection of egg albumen in rats. Compound 1 exhibited an anti-inflammatory effect (50.9 % edema inhibition) comparable (p < 0.05) to that of prednisolone (48.0 % edema inhibition) at 3 h. Compounds 1, 2, and 3 (50 microg/mL) significantly (p < 0.05) inhibited heat-induced haemolysis of human erythrocytes in vitro, but had no effect on hypotonicity-induced hemolysis. The compounds were elucidated as (24R)-5alpha-stigmast-3,6-dione ( 1), 5alpha-stigmast - 23-ene-3,6-dione ( 2), and 3beta-hydroxy-5alpha-stigmast-24-ene ( 3) by spectral analysis. The results of this study show that these compounds may, in part, account for the anti-inflammatory effect of Alchornea floribunda leaves. This is the first report on the isolation and structure elucidation of these anti-inflammatory steroids from Alchornea floribunda leaves.

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.