Withania somnifera chemotypes NMITLI 101R, NMITLI 118R, NMITLI 128R and withaferin A protect Mastomys coucha from Brugia malayi infection.

Withania somnifera is an ayurvedic Indian medicinal plant whose immunomodulatory activities have been widely used as a home remedy for several ailments. We recently observed immunostimulatory properties in the root extracts of chemotypes NMITLI-101, NMITLI-118, NMITLI-128 and pure withanolide, withaferin A. In the present study, we evaluated the potential immunoprophylactic efficacies of these extracts against an infective pathogen. Our results show that administration of aqueous ethanol extracts (10 mg/kg) and withaferin A (0·3 mg/kg), 7 days before and after challenge with human filarial parasite Brugia malayi, offers differential protection in Mastomys coucha with chemotype 101R offering best protection (53·57%) as compared to other chemotypes. Our findings also demonstrate that establishment of B. malayi larvae was adversely affected by pretreatment with withaferin A as evidenced by 63·6% reduction in adult worm establishment. Moreover, a large percentage of the established female worms (66·2%) also showed defective embryogenesis. While the filaria-specific immunological response induced by withaferin A and NMITLI-101 showed a mixed Th1/Th2 phenotype, 118R stimulated production of IFN-γ and 128R increased levels of IL-4. Taken together, our findings reveal potential immunoprophylactic properties of W. somnifera, and further studies are needed to ascertain the benefits of this plant against other pathogens as well.

In vitro antioxidant and radical-scavenging capacities of Citrullus colocynthes (L) and Artemisia absinthium extracts using promethazine hydrochloride radical cation and contemporary assays.

A new, quick and economical decolorization assay based upon the generation of a radical cation made from promethazine hydrochloride (PMZH) is described for screening of antioxidant activity of plants/herbal extracts. PMZH radical cations, produced through a reaction between PMZH and potassium persulfate (K(2)S(2)O(8)) in phosphoric acid medium, have maximum absorption at 515 nm in their first-order derivative spectrum. Theconcentrations of chromagen and K(2)S(2)O(8) were optimized (final concentration of PMZH and K2S2O8 were 0.166 mM and 0.11 mM, respectively) for better stability and sensitivity of the radical cation produced. Agood linear correlation was found between the percentage inhibition and the increasing amounts of standard antioxidants, with correlation coefficients ranging from 0.989 to 0.999. The newly developed assay was employed to evaluate the antioxidant capacity of Citrullus colocynthes L. and Artemisia absinthium extracts. The proposed assay involved a more stable radical cation and required only 1 h for preparation of a working solution in comparison to the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorizaion assay, which was reported to be less sensitive at low pH and almost 12-16 h were required for preparation of a working ABTS solution. Other assays employed to evaluate the antioxidant potential andradical-scavenging capacities of the extracts were the ferric-reducing antioxidant power, 2,2'-diphenyl-1-picrylhydrazyl radical scavenging, total phenolic contents assay, total flavonoid contents and metal-chelating activity assays, and the lipid peroxidation value in linoleic acid emulsion systems. The results indicate that boththe plants have potent free radical-scavenging activity and the ability to prevent lipid peroxidation and radical chain reactions.