Podophyllum hexandrum-Mediated Survival Protection and Restoration of Other Cellular Injuries in Lethally Irradiated Mice.

This study aims at the development of a safe and effective formulation to counter the effects of lethal irradiation. The sub-fraction (G-001M), prepared from Podophyllum hexandrum has rendered high degree of survival (>90%) at a dose of 6 mg kg(-1) body weight (intramuscular) in lethally irradiated mice. Therapeutic dose of G-001M, at about 20 times lower concentration than its LD(100), has revealed a DRF of 1.62. Comet assay studies in peripheral blood leukocytes have reflected that, treatment of G-001M before irradiation has significantly reduced DNA tail length (P < .001) and DNA damage score (P < .001), as compared to radiation-only group. Spleen cell counts in irradiated animals had declined drastically at the very first day of exposure, and the fall continued till the 5th day (P < .001). In the treated irradiated groups, there was a steep reduction in the counts initially, but this phase did not prolong. More than 60% decline in thymocytes of irradiated group animals was registered at 5 h of irradiation when compared with controls, and the fall progressed further downwards with the similar pace till 5th day of exposure (P < .001). At later intervals, thymus was found fully regressed. In G-001M pre-treated irradiated groups also, thymocytes decreased till the 5th day but thereafter rejuvenated and within 30 days of treatment the values were close to normal. Current studies have explicitly indicated that, G-001M in very small doses has not only rendered high survivability in lethally irradiated mice, but also protected their cellular DNA, besides supporting fast replenishment of the immune system.

Modulation of Th1/Th2 cytokines and inflammatory mediators by hydroxychavicol in adjuvant induced arthritic tissues.

The present study was undertaken to investigate the anti-arthritic activity of hydroxychavicol (HC) a major phenolic compound isolated from the aqueous extract leaves of plant Piper betle (Piperaceae). The compound showed significant lowering of pro-inflammatory (Th1) cytokine levels in arthritic paw tissue homogenate supernatant viz. IL-2, IFN-gamma, and TNF-alpha with maximum inhibition at higher dose levels of 2 and 4 mg/kg p.o. and enhanced the production of anti-inflammatory (Th2) cytokines IL-4 and IL-5 estimated by cytometric bead array immunoassay. Cytometric bead array uses the sensitivity of amplified fluorescence detection by flowcytometer to measure soluble analytes in a particle based immune assay. This assay can accurately quantitate five cytokines in a 50-microl sample volume. The T-helper (Th1) deviated cells produce detectable level of tumor necrosis factor (TNF-alpha), interleukin-2 (IL-2), and interferon-gamma (IFN-gamma), while the Th2 deviated cells produce significant amount of interleukin-4 (IL-4) and interleukin-5 (IL-5). HC at graded doses also significantly decreased the expression of IL-1beta, PGE(2), LTB(4), and nitric oxide levels showing significant inhibition of these parameters. Elevated levels of CD4(+) T cell specific interferon-gamma (IFN-gamma) in splenocytes of arthritic animals was also inhibited in treated animals. The oral LD(0) in both mice and rats was more than 1000 mg/kg.

Amelioration of adjuvant induced arthritis by apocynin.

The premise of the study was to investigate the antiarthritic potential of apocynin (APO) in Balb/c mice (in vivo). The experiment showed a dose-dependent decrease in oedema and showed a suppression of proinflammatory cytokines such as TNF-alpha and IL-1beta and mediators such as prostaglandin E(2) (PGE(2)) and LTB(4). At oral doses of 0.5, 1.0, 2.0 and 4.0 mg/kg once daily during the course of the experiment, APO induced an inhibition of T cell mediated immune response causing suppression of CD4+ and CD8+ T cells and of intracellular interferon-gamma (IFN-gamma) by flow cytometry in arthritic mice. In parallel there was a dose-dependent inhibition in vascular permeability causing an inhibition in the migration of leucocytes and exudate volume at the site of the inflammatory reaction. These observations validate the immunoregulatory potential of apocynin.

Immunomodulation exhibited by piperinic acid through suppression of proinflammatory cytokines.

Piper longum (PL) has been reported for its varied pharmacological activities including bio-enhancer and anti-inflammatory activities in traditional medicine. Here the premise of the study was to investigate the immunoregulatory potential of PL and piperinic acid, one of its active constituent, in Balb/C mice (in vivo) and human PBMCs (in vitro) models. Piperinic acid moderated the proinflammatory mediators and cytokines in our experiments. At doses of 10, 20, 40 and 80 mg/kg p.o. PL showed a dose dependent decrease of lymphocytes (CD4+ and CD8+ T cells) and cytokine levels in sensitized Balb/C mice with a marked inhibition at 40 mg/kg. At an in vitro dose of 20 mug/ml of PL and 5 mug/ml of piperinic acid, there was a significant inhibition of mitogen induced human PBMC proliferation, mRNA transcripts of IL-2 (ConA) and TNFalpha, IL-1beta and iNOS (LPS) respectively under stimulated conditions in time dependent (6 h, 12 h and 24 h respectively) expression studies. In parallel, induced nitric oxide production was also reduced by stimulated macrophages. Our observations rationalize the traditional use of PL and also validate the immunoregulatory potential of piperinic acid.