Evaluation of the immunomodulatory and anti-inflammatory activity of Bakuchiol using RAW 264.7 macrophage cell lines and in animal models stimulated by lipopolysaccharide (LPS).

Bakuchiol (BAK) has been reported to have a diverse pharmacological property as an antibiotic, anti-cancer, anti-hypolipidemic, anti-inflammatory and anti-convulsant agent. This study aimed to elucidate the immunomodulation and anti-inflammatory mechanism of bakuchiol using lipopolysaccharide stimulated RAW 264.7 macrophages and various animal models. The present study has shown that BAK significantly suppressed the pro-inflammatory cytokine expression in a dose-dependent manner and its oral administration significantly decreased delayed hypersensitivity responses as compared to control group. The assessment of immunomodulatory activity was carried out by the testing Hemagglutinating antibody (HA) titer, delayed type hypersensitivity (DTH) responses and phagocytic index by carbon clearance test. On the other hand, it showed significant decrease in circulating antibody titer and carbon clearance assay in a concentration-dependent manner. BAK has significantly potentiated the cellular immunity as well as humoral immunity by facilitating the footpad thickness responses in sheep RBCs in sensitized mice by significantly decreasing circulating antibody titer. Molecular studies revealed that BAK inhibited the activation of upstream mediator nuclear factor-κB by suppressing the phosphorylation of IκBα and p65. The responses were statistically significant as compared with the control (*p < 0.05, **p < 0.01).

Immunostimulatory activity of plumieride an iridoid in augmenting immune system by targeting Th-1 pathway in balb/c mice.

Plumieride, an iridoid glucoside isolated from Plumieria acutifolia leaves was investigated for its immunostimulatory activity on humoral, cell mediated and intracellular cytokine levels in sensitized and unsensitised balb/c mice. Plumieride restores the suppressed cell mediated, humoral immune response and also enhances the release of TNF- α, IFN-γ, and IL-2 (Th-1) in immune compromised cyclosporine and cyclophosphamide treated balb/c mice. It does not stimulate the IL-4 (Th-2) expression. Plumieride demonstrates significant augmentation of Th-1 response in immunosuppressed balb/c mice. Results of the present study suggested that plumieride can be developed as an immunostimulatory adjuvant to treat the immune suppression in various disease condition(s).

Synthesis of α-santonin derived acetyl santonous acid triazole derivatives and their bioevaluation for T and B-cell proliferation.

A new series of α-santonin derived acetyl santonous acid 1,2,3-triazole derivatives were synthesised using Huisgen 1,3-dipolar cyclo-addition reaction (click chemistry approach) and evaluated for their in vitro inhibition activity on concanavalin A (ConA) induced T cell proliferation and lipopolysaccharide (LPS) induced B cell proliferation. Among the synthesised series, compounds 2-10 and 19 exhibited significant inhibition against ConA and LPS stimulated T-cell and B-cell proliferation in a dose dependent manner. More significantly compounds 4, 9-10 and 19 exhibited potent inhibition activity with remarkably lower cytotoxicity on the mitogen-induced T cell and B cell proliferation at 1 µM concentration. The compound 6 displayed potent immunosuppressive effects with ∼89% against LPS induced B-cell and ∼83% against ConA stimulated T-cell proliferation at 100 µM concentration without cytotoxicity. Compound 10 was more selective against B cell proliferation and exhibited 81% and 69% suppression at 100 and 1 µM concentration respectively. The present study led to the identification of several santonin analogs with reduced cytotoxicity and strong inhibition activity against the cell proliferation induced by the mitogens.

Immunosuppressive effects of Euphorbia hirta in experimental animals.

Euphorbia hirta L. (Euphorbiaceae) (E. hirta) is a tree locally used as a traditional medicine in Africa and Australia to treat numerous diseases such as hypertension, respiratory ailments, tumors, wounds, antipyretic, anti-inflammatory activities, etc. Therefore, we undertook to investigate their immunomodulatory effect on T lymphocytes (CD3+, CD4+ and CD8+ receptors) and Th1 cytokines (IL-2, TNF-α, IFN-γ) in a dose-dependent manner. E. hirta ethanol extract at 25, 50, 100 and 200 mg/kg doses was given orally for 7 days from the day of immunization. E. hirta maximum inhibition at 100 and 200 mg/kg p.o. was found to significantly block the production of the cell-mediated immune response, (CD3+, CD4+ and CD8+ receptors) and (IL-2, TNF-α, IFN-γ) and also prolongs graft rejection. E. hirta also showed a decrease of delayed hypersensitivity (DTH) response and dose-related decrease in the primary antibody response, respectively. Based on the data, it can be suggested that E. hirta is a potent and non-toxic immunosuppressor, which can be further explored for the development of potent immunosuppressor.

Immunosuppressive properties of Pluchea lanceolata leaves.

OBJECTIVE: To investigate the immunosuppressive potential of Pluchea lanceolata 50% ethanolic extract (PL) and its bioactive chloroform fraction (PLC). MATERIALS AND METHODS: Preliminary screening of the Pluchea lanceolata 50% ethanolic extract (PL) was carried out with basic models of immunomodulation, such as, the humoral antibody response (hemagglutination antibody titers), cell-mediated immune response (delayed-type hypersensitivity), skin allograft rejection test, in vitro (C. albicans method), and in vivo phagocytosis (carbon clearance test). The extract was then fractionated with chloroform, n-butanol, and water to receive the respective fractions by partitioning. These fractions were employed for flow cytometry to study the T-cell specific immunosuppressive potential of these fractions. RESULTS: Oral administration of PL at doses of 50 to 800 mg/kg in mice, with sheep red blood cells (SRBC) as an antigen, inhibited both humoral and cell-mediated immune responses, as evidenced by the production of the circulating antibody titer and delayed-type hypersensitiviy reaction results, respectively, and the immune suppression was statistically significant (P < 0.01) in Balb/C mice. PL also decreased the process of phagocytosis both in vitro (31.23%) and ex vivo (32.81%) and delayed the graft rejection time (30.76%). To study the T-cell-specific activities, chloroform, n-butanol, and water fractions from P. lanceolata were tested for T-cell specific immunosuppressive evaluation, wherein only the chloroform fraction (PLC) showed significant (P < 0.01) suppression of CD8+ / CD4+ T-cell surface markers and intracellular Th1 (IL-2 and IFN-(Y)) cytokines at 25 - 200 mg/kg p.o. doses. PLC, however, did not show significant suppression of the Th2 (IL-4) cytokine. CONCLUSION: The findings from the present investigation reveal that P. lanceolata causes immunosuppression by inhibiting Th1 cytokines.

Immune up regulatory response of a non-caloric natural sweetener, stevioside.

Immunomodulation is a process, which alters the immune system of an organism by interfering with its functions. This interference results in either immunostimulation or immunosuppression. An immunomodulator is any substance that helps to regulate the immune system. This "regulation" is a normalization process, so that an immunomodulator helps to optimise immune response. Immunomodulators are becoming very popular in the worldwide natural health industry as these do not tend to boost immunity, but to normalize it. Keeping this in view, major efforts have to be directed to modulate the immune responses, to permit effective treatment of various ailments associated with immune system and thus the development of a safe and effective immunomodulator for clinical us. Leaves of Stevia rebaudiana are a source of several sweet glycosides of steviol. The major glycoside, stevioside, diterpenoid glycoside--is used in oriental countries as a food sweetener. Its medical use is also reported as a heart tonic. Besides, it is used against obesity, hypertension, and stomach burn and to lower uric acid levels. Here in this study, stevioside was tested for its immunomodulatory activity on different parameters of the immune system at three different doses (6.25, 12.5 and 25 mg/kg p.o.) on normal as well as cyclophosphamide treated mice. Stevioside was found effective in increasing phagocytic activity, haemagglutination antibody titre and delayed type hypersensitivity. In parallel, stevioside substantially increase proliferation in the LPS and Con A stimulated B and T cells, respectively. Present study, therefore, reveals that the drug holds promise as immunomodulating agent, which acts by stimulating both humoral as well as cellular immunity and phagocytic function.

Anti-arthritic activity of a biopolymeric fraction from Euphorbia tirucalli.

The present study was undertaken to investigate the anti-arthritic activity of a biopolymeric fraction (BET) from plant Euphorbia tirucalli Boiss (Euphorbiaceae). The fraction showed dose dependent anti-arthritic activity and also showed in vivo immunomodulatory capacity being a major component in inhibiting arthritis. It caused suppression of CD4(+) and CD8(+) T cells, inhibition of intracellular Interleukin-2 (IL-2) and Interferon-gamma (IFN-gamma) by flowcytometry. It inhibited vascular permeability and the migration of leucocytes at the site of the insult. The oral LD(0) in both rats and mice was more than 2000 mg/kg.

Augmentation and proliferation of T lymphocytes and Th-1 cytokines by Withania somnifera in stressed mice.

Stress has been associated with reports of both greater severity and prolongation of diseases in patients with the infectious origin as well as other immune-mediated diseases. Withania somnifera, an Indian medicinal plant used widely in the treatment of many clinical conditions in India, was investigated for its anti-stress properties using BALB/c mice subjected to chronic stress. The study aimed to investigate chronic stress-induced alterations on Th1 lymphocyte subset distribution and corresponding cytokine secretion patterns. Oral administration of chemically standardized and identified aqueous fraction of W. somnifera root (WS) at the graded doses of 25, 50, 100 and 200 mg/kg p.o. caused significant increase in the stress-induced depleted T-cell population and increased the expression of Th1 cytokines in chronically stressed mice.

Suppression of T lymphocyte activity by lupeol isolated from Crataeva religiosa.

Lupeol has been shown to possess antiarthritic activity through possible suppression of the immune system. As seen in the following studies, it was found to suppress various immune factors such as the phagocytic (cell-killing) activity of macrophages, T-lymphocyte activity that included CD4+T cell mediated cytokine generation. Assessment of T cells and their intracellular content of cytokines was carried out by flow cytometric analysis in Balb/c mice. Oral administration of lupeol at doses of 12.5-200 mg/kg p.o. inhibited CD4+ T and CD8+ T cell counts and cytokines IL-2, IFN-gamma (Th1) and IL-4 (Th2). Cytometric bead array (CBA) technology was applied to carry out simultaneous measurement of multiple serum cytokines. The oral LD(0) in mice was more than 2 g/kg body weight.

Immunosuppressive properties of an ethyl acetate fraction from Euphorbia royleana.

The objective of the study was to investigate the activity of the ethyl acetate (EA) fraction of Euphorbia royleana latex on cellular and humoral-mediated immune responses and phagocytic function of the cells of the reticuloendothelial system in mice. Oral administration of EA at doses of 50, 100 and 200 mg/kg p.o. in mice with sheep red blood cells (SRBC) as an antigen-inhibited both the delayed-type hypersensitivity reaction and the production of circulating antibody titre. Reduction of CD4+ T cell counts in the peripheral whole blood and the neutrophil counts in pleural exudates of the animals treated with EA was observed by flowcytometric analysis. Process of phagocytosis was also inhibited in in vivo and in vitro experimental test models. The oral LD50 in both rats and mice was more than 2.5 g/kg body weight.

Immunopotentiating properties of Cryptolepis buchanani root extract.

The ethanol extract (95%) of the root of the plant Cryptolepis buchanani (EECB) was investigated for immunomodulatory activity in mice and rats. The oral administration of EECB caused significant stimulation of the delayed type hypersensitivity (DTH) reaction and humoral antibody production. The oral LD50 was found to be more than 3 g/kg in both rats and mice.