Bakuchiol (BAK) has been reported to have a diverse pharmacological property as an antibiotic, anti-cancer, antihypolipidemic, 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-kappa B by suppressing the phosphorylation of I kappa B alpha and p65. The responses were statistically significant as compared with the control (*p < 0.05, **p < 0.01).

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).

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.

This study explored the antioxidant and immunomodulatory potential of two ethno-medicinally valuable species belonging to genus Arisaema viz., Arisaema flavum and Arisaema propinquum. The arial parts and tubers of these species were subjected to polarity based extraction using different solvents. In vitro antioxidant studies were performed in terms of DPPH radical scavenging, chelation power on ferrous ions, reducing power and FRAP assays. Immunomodulatory studies were also determined by evaluating Humoral antibody response (Hab) and Delayed type hypersensitivity response (DTH). The results depicted that A. flavum exhibited relatively better antioxidant and immunomodulatory potential than A. propinquum. Methanol extract of A. flavum leaves demonstrated promising antioxidant activity with DPPH radical scavenging IC value of 0.406±0.43 mg/ml (R2 = 0.9643), FRAP value of 2176 mM of Fe2+/mg extract (R2 = 0.9962) and reducing power with EC 1.25±0.27mg/ml (R2 = 0.9948) than the extracts of A.propinquum. Chelation capacity of methanol extracts of A. flavum (55 %) leaves was found to be quite significant as compared to that of A. propinquum (51 %) at 100 µg/ml concentration. A. flavum leaf methanol extract was also found have immune enhancing effect by increasing the humoral response by 83 % and DTH response by 100 % in immune suppressed mice. The present work concludes that the antioxidative power of A. flavum surpasses that of A. propinquum whereas in case of immunomodulation, A. flavum has considerable enhancing effect on humoral response and A. propinquum demonstrated better DTH response.

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.

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.

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.

Ethnopharmacological relevance: Roots of Asparagus racemosus Willd (Shatavari in vernacular) are widely used in Ayurveda as Rasayana for immunostimulation, galactogogue as also in treatment of conditions like ulcers and cancer. Various studies have indicated immunomodulatory properties of Shatavari root extracts and formulations.Aim of the study: To study the effect of standardized Asparagus racemosus root aqueous extract (ARE) on systemic Th1/Th2 immunity of SRBC sensitized animals.Materials and methods: We used HPTLC to quantify steroidal saponins (Shatavarin IV, Immunoside (R)) and flow cytometry to study effects of ARE on Th1/Th2 immunity. SRBC specific antibody titres and DTH responses were also monitored as markers of Th2 and Th1 responses, respectively. We also studied lymphocyte proliferation. Cyclosporin, cyclophosphamide and levamisole were used as controls.Results: Treatment with ARE (100mg/(kgb.w.p.o.)) resulted in significant increase of CD3(+) and CD4/CD8(+) percentages suggesting its effect on T cell activation. ARE treated animals showed significant up-regulation of Th1 (IL-2, IFN-g) and Th2 (IL-4) cytokines suggesting its mixed Th1/Th2 adjuvant activity. Consistent to this, ARE also showed higher antibody titres and DTH responses. ARE, in combination with LPS, Con A or SRBC, produced a significant proliferation suggesting effect on activated lymphocytes.Conclusion: The study suggests mixed Th1/Th2 activity of ARE supports its immunoadjuvant potential. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

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.

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.

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.

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.

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.

The hydrosoluble fraction of Euphorbia royleana latex (AER), administered by gavage at doses of 50-200 mg/kg, showed dose-dependent anti-inflammatory and anti-arthritic effects in different acute and chronic test models in rats and mice. It reduced the exudate volume and the migration of leukocytes and showed a poor inhibitory effect on the granuloma formation induced by cotton pellets, while it had a low ulcerogenic score. The oral LD(50) was more than 1500 mg/kg in both rats and mice.

Boswellic acids, a mixture of pentacyclic triterpene acids (BA) obtained from Boswellia serrata Roxb., have been investigated for their effect on cell mediated and humoral components of the immune system and the immunotoxicological potential. A single oral administration of BA (50-200 mg/kg) inhibited the expression of the 24 h delayed type hypersensitivity (DTH) reaction and primary humoral response to SRBC in mice. The secondary response was appreciably enhanced at lower doses. In a multiple oral dose schedule BA (25, 50 and 100 mg/kg) reduced the development of the 24 h DTH reaction and complement fixing antibody titres and slightly enhanced the humoral antibody synthesis. In concentrations greater than 3.9 mu g/mL BA produced almost similar and dose related inhibition of proliferative responsiveness of splenocytes to mitogens and alloantigen. Preincubation of macrophages with different concentrations of BA enhanced the phagocytic function of adherent macrophages. Prolonged oral administration of BA (25-100 mg/kg/d X 21 days) increased the body weight, total leukocyte counts and humoral antibody titres in rats. It is not cytotoxic nor does it cause immunosuppression.

The immunomodulatory activity of some flavonoids on antigen specific humoral and cell mediated immune responses and complement-mediated hemolysis has been investigated and compared with that of levamisole. Flavanone, 6-methoxyflavanone, 7-methoxyflavanone and bavachinin enhanced the sheep erythrocyte (SRBC), induced primary and secondary humoral immune responses in mice, and 6-hydroxyflavanone, 7-hydroxyflavanone and rutin inhibited primary response. Levamisole slighly stimulated the primary and suppressed the secondary response. All the flavonoids tested decreased the manifestation of SRBC induced delayed type hypersensitivity reaction and showed no effect on classical or alternative pathway dependent hemolysis. The studies revealed the significant immunomodulatory potential of these flavonoids, methoxy derivatives having immunostimulatory activity and hydroxy derivatives immunosuppressive properties.