Immunomodulatory activity of aqueous extract of Nyctanthes arbor-tristis flowers with particular reference to splenocytes proliferation and cytokines induction.

OBJECTIVES: To investigate the immunomodulatory activity of aqueous extract of Nyctanthes arbor-tristis flowers (NAFE) with particular reference to splenocytes proliferation and induction of cytokines. MATERIALS AND METHODS: Antibody titer was determined by tube agglutination and indirect ELISA assay in four groups of mice-control, antigen alone, and NAFE-treated (400 and 800 mg/kg for 21 days) after immunization with Salmonella antigen while cellular immunity was studied in three groups of rats (control and NAFE-treated - 400 and 800 mg/kg) following DNCB application. Splenocytes from untreated and NAFE-treated rats were stimulated using concanavalin-A (Con-A) and optical density (OD) and stimulation index were determined. Splenocytes from control rats were also treated in vitro with NAFE (50-1600 µg/ml) and Con-A to determine the effect on splenocytes proliferation. Interleukin-2 (IL-2) and IL-6 levels in splenocytes supernatant from control and NAFE-treated rats and following in vitro treatment of splenocytes with NAFE (50-1600 µg/ml) were determined using ELISA kits. RESULTS: Marked to a significant increase in antibody titer by both the methods in NAFE-treated mice and a significant increase in skin thickness in rats after challenge with DNCB, respectively suggested humoral and cell-mediated immunostimulant potential of NAFE. Significant increase in OD and stimulation index following e x vivo and in vitro exposure of splenocytes and sensitization with Con-A and significant elevation in IL-2 and IL-6 levels in splenocytes supernantant was also observed after their ex vivo and in vitro exposure to NAFE. CONCLUSION: Humoral and cell-mediated immunostimulant activity of NAFE seems to be mediated through splenocytes proliferation and increased production of cytokines, especially IL-2 and IL-6.

Withania somnifera ameliorates lead-induced augmentation of adrenergic response in rat portal vein.

OBJECTIVES: Present study was undertaken to elucidate the ameliorating potential of Withania somnifera root extract (WRE) against lead-induced augmentation of adrenergic response in rat portal vein. MATERIALS AND METHODS: In-vitro studies were conducted on effect of lead alone and lead+WRE on rat-isolated portal vein while in-vivo studies were done in three groups of 12 rats each; Group-II and III received 0.5% lead acetate and 1.0% WRE + 0.5% lead acetate, respectively, in drinking water for 12 weeks whereas group-I served as control. Adrenaline and noradrenaline levels in brain and blood were determined by HPLC assay while vascular reactivity of portal vein to lead and WRE was determined by measuring the isometric tension. RESULTS: Following in-vitro exposure, lead did not alter the contractile effect of phenylephrine. In-vivo studies revealed that contractile effect of lead on portal vein was significantly potentiated and it was antagonized by prazosin (10(-7) M) and WRE (1%). WRE treatment significantly reduced elevated blood noradrenaline (37.80%) and restored noradrenaline level in brain (39.39%) in lead-exposed animals. These values were almost comparable to the control group. But it failed to significantly affect the blood and brain adrenaline levels. CONCLUSIONS: Results suggest that following pre-exposure of rats to WRE, lead-induced augmentation of alpha 1-adrenoceptors mediated response was reversed possibly by regulating catecholamine release from nerve endings. Thus, WRE may be useful in therapeutic management of lead-induced hypertension.