Evaluation of Anticancer Potential of Flavones from Rhamnus alaternus against B16F10 Melanoma Cells.

Melanoma has become an important health problem and new treatment have become an imperative medical need. Therefore, the finding and identification of natural product with less toxic effects, capable of promoting melanoma cell death have become an important goal of research in oncotherapy. In this study, we want to investigate the anticancer activity of an enriched total oligomers flavonoids (TOF) extract of R. alaternus in melanoma cells. First, TOF was exhibited to be rich in flavones. We revealed that this extract reduced proliferation and increased of sub-G1 and S phase cells built-up in B16-F10 cells in a dose-related manner. Moreover, In Vivo, TOF reduced tumor volume and weight with percentages of inhibition of 92.4% and 92.9%, respectively. R. alaternus was also found to be effective in reducing the level of pro-inflammatory cytokine IL-6 during metastasis. Level of TH1 cytokine, such as IL-2, was significantly enhanced by TOF treatment. Indeed, the histological examination of the tumor revealed the absence of mitoses and the presence of numerous melanin pigmented macrophage cells in the R. alaternus extract-treated group that could be explained by the induction of macrophage activation and by the arrest of the cell cycle in the Sub-G1 and S phases.

Antitumor Effect of Bryonia dioïca Methanol Extract: In Vitro and In Vivo Study.

Aim: A large number of plant-derived products have been approved for the treatment of numerous types of cancer, and these products have also shown to reduce the effects of metastatic cancer. The aim of this study is to evaluate the anticancer effects of a methanolic extract of Bryonia dioïca root (M extract) against B16F10 melanoma cancer cells in vitro as well as in vivo.Results: It was shown to induce apoptosis, in vitro, and to inhibit cell growth by arresting cell cycle progression in SubG1 phase. Mice bearing the melanoma cells were used to confirm any in vivo effectiveness of the M extract as an antitumor promoting agent. In mice dosed with 50 mg M/kg/d (for 28 days), tumor weight was inhibited by 65.03% compared to that in mice that did not receive the product. Our results demonstrate on the one hand, that this inhibition was accompanied by a drastic decrease regulation of complex FAK, Src, ERK, p130Cas and paxillin. On the other hand, it was marked by a measurable decrease of the metastatic descent in the lungs.Conclusions: These effects could be ascribed to the presence of bryoniosides and cucurbitacins such as cucurbitacin A and cucurbitacin G in M extract.

Immunomodulatory and cellular anti-oxidant activities of caffeic, ferulic, and p-coumaric phenolic acids: a structure-activity relationship study.

Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses and to reduce damage to the human body. To determine whether phenolic compounds (caffeic, ferulic, and p-coumaric acids) have immunomodulatory effects and clarify which types of immune effector cells are stimulated in vitro, we evaluated their effect on splenocyte proliferation and lysosomal enzyme activity. We also investigated the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL). In addition, induction of the cellular antioxidant activity in splenocytes, macrophages, and red blood cells was determined by measuring the fluorescence of the DCF product. The study first results indicated that caffeic, ferulic, and p-coumaric acids significantly promote LPS-stimulated splenocyte proliferation, suggesting a potential activation of B cells, and enhanced humoral immune response in hosts treated by the tested natural products. Phenolic acids significantly enhanced the killing activity of isolated NK and CTL cells but had negligible effects on mitogen-induced proliferation of splenic T cells. We showed that caffeic acid enhances lysosomal enzyme activity in murine peritoneal macrophages, suggesting a potential role in activating such cells. Immunomodulatory activity was concomitant with the cellular antioxidant effect in macrophages and splenocytes of caffeic and ferulic acids. We conclude from this study that caffeic, ferulic, and p-coumaric acids exhibited an immunomodulatory effect which could be ascribed, in part, to their cytoprotective effect via their antioxidant capacity. Furthermore, these results suggest that these natural products could be potentially used to modulate immune cell functions in physiological and pathological conditions.

In Vitro and In Vivo Anti-Melanoma Effects of Pituranthos tortuosus Essential Oil Via Inhibition of FAK and Src Activities.

A large number of plants used in traditional medicines have been shown to possess antitumor activities. The aims of this study were to evaluate any anticancer effect of the essential oil (EO) extracted from P. tortuosus against B16F10 melanoma cancer cells in vitro as well as in vivo. In vitro, EO was shown to induce apoptosis and to inhibit migration and invasion processes. Further investigation revealed that EO decreased focal adhesion and invadopodia formation which was accompanied by a drastic downregulation of FAK, Src, ERK, p130Cas and paxillin. Moreover, EO treatment decreased the expression level of p190RhoGAP, and Grb2, which impair cell migration and actin assembly. Mice bearing the melanoma cells were used to confirm any in vivo effectiveness of the EO as an anti-tumor promoting agent. In mice dosed with 100 mg EO/kg/d (for 27 days), tumor weight was inhibited by 98% compared to that in mice that did not receive the product. In conclusion, these data suggested to us that an EO of P. tortuosus could evolve to be a potential medicinal resource for use in the treatment of cancers.

Immunomodulatory and cellular antioxidant activities of pure compounds from Teucrium ramosissimum Desf.

Evaluation of the immunomodulatory activity of plant compounds is an interesting and growing area of research. Teucrium ramosissimum Desf. is a native and endemic medicinal plant from the South of Tunisia traditionally used for the treatment of many diseases. The anti-inflammatory activity of apigenin-7-glucoside, genkwanin, and naringenin isolated from T. ramosissimum were assayed. The phagocytic activities of macrophage and lymphocyte proliferation were investigated in the absence and presence of mitogens (lipopolysaccharide [LPS] or lectin). Depending on the concentrations, the compounds affect macrophage functions by modulating their lysosomal enzyme activity and nitric oxide (NO) release. The tested compounds enhance significantly splenocyte proliferation, either with or without mitogen stimulation. In studies to assess any potential effects of apigenin-7-glucoside, genkwanin, and naringenin on innate immunity, the results showed that these compounds significantly enhanced the killing activity of natural killer (NK) cells and cytotoxic activity of the T lymphocyte (CTL) isolated from splenocytes. These results suggest that T. ramosissimum compounds such as apigenin-7-glucoside, genkwanin, and naringenin may be potentially useful for modulating immune cell functions in physiological and pathological conditions.

In vitro and in vivo anti-melanoma effects of Daphne gnidium aqueous extract via activation of the immune system.

The purpose of this study was to assess the antitumor and immunomodulatory effects of the aqueous extract from Daphne gnidium in mice-bearing melanoma tumor. Balb/C mice were subcutaneously implanted with B16-F10 cells and treated intraperitoneally with the aqueous extract at 200 mg/Kg b.w for 21 days. After euthanization on day 22, the tumors were weighed; lymphocyte proliferation, cytotoxic T lymphocyte (CTL), and natural killer (NK) cell activities were evaluated using the MTT assay. Macrophage phagocytosis was studied by measuring the lysosomal activity. In addition to its potential to inhibit the growth of the transplantable tumor, the aqueous extract remarkably induced splenocyte proliferation and both NK and CTL activities in tumor-bearing mice. The aqueous extract was also seen to have promoted lysosomal activity of host macrophages.

Immunomodulatory and anticancer effects of Pituranthos tortuosus essential oil.

Many studies have been performed to assess potential utility of natural products as immunomodulants to enhance antitumor activity in situ. In this study, an essential oil (EO) from the aerial parts of Pituranthos tortuosus was prepared using hydrodistillation, its composition was characterized, and its immunomodulatory potential was assessed. The results indicated that the EO contained sabinene, α-pinene, limonene, and terpinen-4-ol as major constituents. EO was also found to be able to significantly promote lipopolysaccharide (LPS)-stimulated splenocyte proliferation, suggestive of a potential for activation of B cells and enhanced humoral immune responses in hosts given this product. Effects of EO on cell proliferation and apoptosis were also investigated in B16F10 melanoma cells. EO-induced tumor cell growth inhibition was associated with characteristic apoptotic changes in the cells, including nuclear condensation. In conclusion, these data suggested to us that an EO of P. tortuosus could evolve to be a potential medicinal resource for use in the treatment of cancers.

Limoniastrum guyonianum methanol extract induces immunomodulatory and anti-inflammatory effects by activating cellular anti-oxidant activity.

Evaluation of the immunomodulatory activity of plant extracts is an interesting and growing area of research. In this study, effects of a methanolic extract of Limoniastrum guyonianum stems (M extract) on mice immune cell function in vitro were investigated. These studies showed that mitogen-induced lymphocyte proliferation was dose-dependently inhibited by the extract. Further, the lectin-induced response appeared to be more sensitive to the suppressive effects of the extract than were LPS-stimulated responses. In studies to assess any potential effects of extract on innate immunity, the results showed that the extract significantly enhanced the killing activity of isolated NK cells. In addition, studies here demonstrated that the extract could enhance lysosomal enzyme activity and inhibit nitrite oxide (NO) production by murine peritoneal macrophages ex vivo, suggesting a potential anti-inflammatory effect in situ. The anti-inflammatory activity was concomitant with the cellular anti-oxidant effect in macrophages and splenocytes.

Limoniastrum guyonianum aqueous gall extract induces apoptosis in colorectal cancer cells by inhibiting calpain activity.

Several studies have reported that plant-derived natural products have cancer chemopreventive and chemotherapeutic properties. The aim of the present study was to determine the antiproliferative and pro-apoptotic potential of Limoniastrum guyonianum aqueous gall extract (G extract) on human colorectal cancer BE cell line and, if so, to characterize the mechanism involved. The G extract-induced growth inhibitory effect was associated with an arrest of cell cycle progression in G2/M phase as shown by the cell phase distribution. In addition, G extract promoted in a concentration-dependent manner these cells towards apoptosis as indicated by the presence of cleaved poly(ADP-ribose) polymerase (PARP). In order to characterize the mechanism involved in the antiproliferative and pro-apoptotic signaling pathway activated by G extract, calpain activity and the expression of the cell cycle inhibitor p16(INK4A) were determined. The present findings indicated that G extract exhibited significant inhibitory activity against calpain and caused a marked and concentration-dependent upregulation of p16(INK4A). These effects could be ascribed to the presence of condensed tannins and polyphenols such as epicatechin and epigallocatechin gallate in G extract.

In vitro antileukaemic activity of extracts from Daphne gnidium leaves against sensitive and multidrug resistant K562/R7 cells.

The antiproliferative potential of extracts of Daphne gnidium L. (Thymelaeaceae) on K562 cells was assessed, and the capacity of these extracts to disturb the cell cycle of K562 cells and to inhibit human P-glycoprotein was evaluated. The antiproliferative activity was evaluated using the MTT assay. The cell cycle analysis and the inhibition of P-glycoprotein were tested by flow cytometry. All the tested extracts exhibited significant anti-proliferative effects. Ethyl acetate extract has the strongest cytotoxic effect with an IC50 of 18.5 µg/ml. Furthermore, cell cycle analysis revealed that cells treated with chloroform, butanol and aqueous extracts were arrested predominantly in G2-M phase. Butanol extract was the most active extract. Percentage of cells arrested in G2-M was 34 %, 36.67 % and 42.63 % respectively, after treatment with 25, 75 and 100 µg/ml of the extract, versus 19 % in the cells treated with the vehicle solvent. In addition, chloroform extract had the ability to inhibit human P-glycoprotein-mediated daunorubicin in K562/R7 leukaemic cells in a dose-dependent manner compared to the positive control, cyclosporin A. These findings demonstrate that extracts from D. gnidium leaves have antileukaemic activity by perturbing the cell cycle of K562 and inhibiting human P-glycoprotein in K562/R7 cell line.

Luteolin induces apoptosis in BE colorectal cancer cells by downregulating calpain, UHRF1, and DNMT1 expressions.

In this study, we have investigated the effects of luteolin on colorectal cancer cells. Our results demonstrate that luteolin is able to induce cytotoxicity and cell cycle perturbation in a dose-dependent manner. By triggering poly(ADP-ribose) polymerase (PARP) cleavage, this molecule is able to induce the apoptosis of BE colorectal cancer cells. We have also studied the potential involvement of calpains in the proapoptotic effects of luteolin. Our data show that luteolin exhibits moderate inhibitory activity against calpain. Thus, treatment of these cells with both luteolin and the calpain inhibitor MDL 28170 causes an increase in the luteolin-induced apoptosis as proved by the enhancement of 89- and 26-kDa PARP fragments. This effect is concomitant with the downregulation of the DNA methyltransferase 1 (DNMT1) expression and the epigenetic integrator ubiquitin-like containing PHD Finger 1 (UHRF1). As a result, luteolin induces an upregulation of a tumor suppressor gene: p16(INK4A). This study further proposes that calpain might be involved in the epigenetic code inheritance by regulating the epigenetic integrator UHRF1. We conclude from these results that targeting calpain, UHRF1, and DNMT1 using luteolin could be an interesting way to prevent and/or treat colorectal cancers.

Antioxidant, mutagenic and antimutagenic activities of an aqueous extract of Limoniastrum guyonianum gall.

An aqueous extract of Limoniastrum guyonianum gall (G extract) was tested on Salmonella typhimurium to assess its mutagenic and antimutagenic effects. This extract showed no mutagenicity when tested with S. typhimurium strain TA104 either with or without exogenous metabolic activation mixture (S9), whereas our findings revealed that the aqueous gall extract induced a mutagenic effect in S. typhimurium TA1538 when tested in the presence, as well as in the absence, of S9 activation mixture at the concentration of 500 µg/mL. Thus, the same concentration produced a mutagenic effect, when incubated with S. typhimurium TA100 in the presence of metabolic activation mixture. In contrast, our results showed a weak antimutagenic potential of the same extract against sodium azide in the presence of S. typhimurium TA100 and S. typhimurium TA1538 without metabolic activation (S9), whereas, in the presence of S. typhimurium TA104, we obtained a significant inhibition percentage (76.39%) toward 3.25 µg/plate of methylmethanesulfonate. Antimutagenicity against aflatoxin B1, 4-nitro-o-phenylene-diamine and 2-aminoanthracène was significant, with an inhibition percentage of, respectively, 70.63, 99.3 and 63.37% in the presence of, respectively, S. typhimurium TA100, S. typhimurium TA1538 and S. typhimurium TA104 strains at a concentration of 250 µg/plate after metabolic activation (S9). Antioxidant capacity of the tested extract was evaluated using the enzymatic (xanthine/xanthine oxidase assay) and the nonenzymatic (2,2-diphenyl-1-picrylhydrazyl) system. G extract exhibited high antioxidant activity.

Assessment of Rhamnus alaternus Leaves Extract: Phytochemical Characterization and Antimelanoma Activity.

Rhamnus alaternus (Rhamnaceae) has been used as a laxative, purgative, diuretic, antihypertensive, and depurative. However, few scientific research studies on its antimelanoma activity have been reported. This study aimed to investigate the in vitro antimelanoma effect of an enriched total oligomer flavonoid (TOF) extract, from R. alaternus, and to identify its phytochemical compounds. The chemical composition of TOF extract was assessed by HPLC-electrospray ionization tandem mass spectrometry (HPLC/ESI-MS2) analysis. Antimelanoma activity was determined on cultured tumor cell B16F10 by the crystal violet assay, the alkaline comet assay, acridine orange/ethidium bromide (AO/EB), annexin V-fluorescein isothiocyanate/ propidium iodide (V-FITC/PI) staining, the cell cycle distribution, and the wound healing assay. Regarding chemical composition, a mixture of quercetin diglucoside, quercetin-3-O-neohesperidoside, kaempferol-3-O-(2G-α-L-rhamnosyl)-rutinoside, rhamnetin hexoside, kaempferol-3-O-rutinoside, rhamnocitrin hexoside, pilosin hexoside, apigenin glucoside, and kaempferol-3-O-glucoside was identified as major phytochemical compounds of the extracts. TOF extract inhibits melanoma B16F10 cell proliferation in dose-dependent manner. The induction of apoptosis was confirmed by comet assay, AO/EB, and annexin V-FITC/PI test. TOF extract could also induce S phase cell cycle, inhibit, and delay the cell migration of B16F10 cells. The findings showed that TOF extract from R. alaternus could be a potentially good candidate for future use in alternative antimelanoma treatments.

Tannin extract from maritime pine bark exhibits anticancer properties by targeting the epigenetic UHRF1/DNMT1 tandem leading to the re-expression of TP73.

Maritime pine bark is a rich source of polyphenolic compounds and is commonly employed as a herbal supplement worldwide. This study was designed to check the potential of maritime pine tannin extract (MPTE) in anticancer therapy and to determine the underlying mechanism of action. Our results showed that MPTE, containing procyanidin oligomers and lanostane type terpenoids, has an inhibitory effect on cancer cell proliferation through cell cycle arrest in the G2/M phase. Treatment with MPTE also induced apoptosis in a concentration-dependent manner in human cancer cell lines (HeLa and U2OS), as evidenced by the enhanced activation of caspase 3 and the cleavage of PARP along with the downregulation of the antiapoptotic protein Bcl-2. Interestingly, human non-cancerous fibroblasts are much less sensitive to MPTE, suggesting that it preferentially targets cancer cells. MPTE played a pro-oxidant role in cancer cells and promoted the expression of the p73 tumor suppressor gene in p53-deficient cells. It also downregulated the protooncogenic proteins UHRF1 and DNMT1, mediators of the DNA methylation machinery, and reduced the global methylation levels in HeLa cells. Overall, our results show that maritime pine tannin extract can play a favorable role in cancer treatment, and can be further explored by the pharmaceutical industry.

Anti-inflammatory and antiulcerogenic activities of leaf extracts and sesquiterpene from Teucrium ramosissimum (Lamiaceae).

Teucrium ramosissimum (Lamiaceae) is a native and endemic medicinal plant from South of Tunisia traditionally used for the treatment of many diseases. The anti-inflammatory and antiulcerogenic activities of sesquiterpene (ß-eudesmol), chloroform, and ethyl acetate leaf extracts from T. ramosissimum were assayed. Macrophage phagocytic activity and lymphocyte proliferation in the absence and presence of mitogens (lipopolysaccharide [LPS] or lectin) were investigated. Depending on the concentrations, the extracts affect macrophage functions by modulating their lysosomal enzyme activity and nitric oxide (NO) release. For lymphocyte proliferation assay, tested extracts enhance significantly cell proliferation either with or without mitogen stimulation. These results suggest that leaf extracts from T. ramosissimum contain potent components such as flavonoids that may be potentially useful for modulating immune cell functions in physiological and pathological conditions. Antiulcerogenic activity was examined on rat ethanol-induced ulcerogenic model. Compared with control (cimetidine), leaf extracts from T. ramosissimum exert different protective effects against ethanol-induced ulcerogenesis.

Heat treatment and protective potentials of luteolin-7-O-glucoside against cisplatin genotoxic and cytotoxic effects.

Cisplatin is an effective chemotherapeutic agent that has pronounced adverse effects. Using flavonoids is currently eliciting considerable interest. During extraction and conditioning, they usually undergo several physical treatments such as heat treatment, although it is not known whether thermal treatment might influence the pharmacological effects of flavonoids such as luteolin-7-O-glucoside (L7G). This study was undertaken to explore the protective role of native and heated L7G against DNA damage and oxidative stress induced by cisplatin. Balb/c mice were administered L7G before a single intraperitoneal injection of cisplatin (10 mg/kg). Animals were sacrificed 24 h after treatment with drugs. The geno-protective role of native and heated L7G was evaluated by comet assay. In addition to monitoring the activities of antioxidant enzymes, levels of malondialdehyde and reduced glutathione were assessed in the liver, kidney, brain, and spleen tissues. The results of the present study demonstrate that both heated and native L7G, at a dose of 40 mg/kg b.w, were able to reduce the genotoxicity of cisplatin. They attenuate the oxidative stress (malondialdehyde, catalase, GPx, SOD, and GSH) and tissue damage (creatinine, IFNγ). Heat treatment did not alter the antigenotoxic effect observed for native L7G and showed similar effects to those of native L7G for all of the evaluated parameters. Our study reveals that L7G attenuates the side effects of anticancer drug and heat treatment did not alter his antigenotoxic and antioxidant the potential.

In situ genotoxicity assessment in freshwater zooplankton and sediments from different dams, ponds, and temporary rivers in Tunisia.

Tunisia water resources are limited. The country currently has 29 large dams, more than 1000 hill lakes, and 220 small dams which are essential for economic and social development given their contribution to irrigation, drinking water consumption, flooding protection, production of electrical energy, groundwater recharge, and industrial uses. Given the scarcity of these resources, it is crucial to be able to ensure the quality of freshwater environments, particularly those intended for human consumption. In this study, we meant to assess the health status of various freshwater ecosystems in different regions of Tunisia (north and center west) in order to detect genotoxic components in sediments and their potential effect on zooplankton (cladocerans). Sediment and cladoceran species were collected from dams, ponds, and temporary rivers in Tunisia. For each collection site, micronucleus (MN) assay was performed, in triplicates, using a pool of ten specimens of the same cladoceran species. MN occurrence in cladocerans varied from one site to another and MN frequencies varied between 0.67 and 22‰, suggesting the presence of genotoxic substances in certain sites. Sediment genotoxicity and mutagenicity were assessed using the SOS Chromotest and the Ames test. Sediment results showed that genotoxicity varies from one site to another displaying a quantitative and a qualitative variation of pollutant among the sites. These results suggest an urgent need for continuous monitoring of freshwater environments in Tunisia, particularly those intended for drinking water.

An aqueous extract of Limoniastrum guyonianum gall induces anti-tumor effects in melanoma-injected mice via modulation of the immune response.

The objectives of this study were to evaluate the in vitro and in vivo anti-tumor potential of the aqueous gall extract (G extract) from Limoniastrum guyonianum and to elucidate its immunological mechanisms, in part, by assessing its effects on the growth of transplanted tumors and the immune response in these tumor-bearing mice. Here, mice were inoculated with B16F10 mouse tumor cells and then treated intraperitoneally with G extract at 25 or 50 mg extract/kg BW for 7, 14, or 21 days. At each timepoint, effects of the extract on the tumor growth, splenocytes proliferation, NK cell activity, and CTL activity among splenocytes isolated from the mice were measured. G extract-induced tumor growth inhibition was associated with characteristic apoptotic changes in the tumor cells, like nuclear condensation. In addition, the extract inhibited melanin synthesis and tyrosinase activity among melanoma cells in a concentration-related manner. G extract did not only significantly inhibit the growth of the transplantable tumor, but also remarkably increased splenocytes proliferation and both NK and CTL activities in tumor-bearing mice. The extract was also seen to have promoted lysosomal activity of host macrophages and gave rise to enhanced cellular anti-oxidant activity in several cell types in mice.

Increasing role of UHRF1 in the reading and inheritance of the epigenetic code as well as in tumorogenesis.

Epigenetic mechanisms such as DNA methylation and histone posttranslational modifications, allow cells to maintain the phenotype throughout successive mitosis. UHRF1 plays a major role in the inheritance of some epigenetic marks from mother cells to daughter cells due to its particular structural domains. The originality of UHRF1 lies in the fact that it can read epigenetic marks and recruit the enzymes that catalyze the same epigenetic mark. The SRA domain senses the presence of a methylated cytosine on one DNA strand allowing the recruitment of DNMT1, which methylates the cytosine on the newly synthesized DNA. The recently identified tudor domain of UHRF1 senses the presence of methylated histone H3 conducting UHRF1 to recruit histone methyltransferases. Recent studies deciphering the relationships between some of the structural domains of UHRF1 provides new insights on the reading of the epigenetic code over a larger portion of histone tail than usually expected. Furthermore, latest developments highlights that UHRF1 is one of the proteins which is able to directly connect DNA methylation to histone epigenetic marks. This paper reviews the principles how UHRF1 acts as an epigenetic reader and discusses the properties of UHRF1 to be a biomarker as well as a therapeutic target.

Immunomodulatory and cellular anti-oxidant activities of an aqueous extract of Limoniastrum guyonianum gall.

ETHNOPHARMACOLOGICAL RELEVANCE: Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses to disease/infection/etc. or to ameliorate immune based pathologies (i.e., inflammation, autoimmune associated diseases, etc.). In this particular study, the immunomodulatory potential of gall aqueous extract from Limoniastrum guyonianum Boiss. (Zita) was assessed in vitro. MATERIALS AND METHODS: The effect of G extract on splenocytes proliferation and NK activity were assessed by MTT test. The induction of NO production and the phagocytic activity of macrophages were evaluated in vitro. Activation of the cellular anti-oxidant activity in splenocytes was determined by measuring the fluorescence of the DCF product. RESULTS: The studies first demonstrated that the extract could enhance lysosomal enzyme activity and nitrite oxide production in murine peritoneal macrophages, suggesting a potential role in activation of these cells. In studies to assess potential effects on humoral immunity, the results indicated that the extract could significantly promote LPS-stimulated splenocyte proliferation implying a potential activation of B-cells and enhanced humoral immune responses in hosts given this natural product. In studies to assess any effects of extract on cellular immunity, the results showed that the extract significantly enhanced the killing activity of isolated NK cells but had negligible effects on mitogen-induced proliferation of splenic T-cells. Considerable effects were also observed on the cellular anti-oxidant activity. CONCLUSION: We conclude from these studies that aqueous extract from L. guyonianum gall exhibited an immunomodulator effect which could be ascribed, in part, to its cytoprotective effect via its anti-oxidant capacity. Furthermore, these results suggest that L. guyonianum gall extract contains potent components such as flavonoids which should be potentially used to modulate immune cell functions in physiological and pathological conditions.