Previous studies on natural products had mainly dealt with their antimicrobial activity and studies on the interference of these bioactive compounds with host-bacterial interaction is limited. The present study was undertaken to investigate the effect of the sterols and fatty acids present in the chloroform fraction of crude methanol extract of Hemidesmus indicus root (CHI) on Salmonella enterica serovar Typhimurium (S. Typhimurium) mediated apoptosis in a murine macrophage cell line (P388D1).
Bacterial sensitivity test was carried out with different concentrations of CHI and the optimum dose was fixed as 100 mug/ml for CHI, which was safe on host cells as the CD(50) (50% of cell death) dose of CHI was determined to be 500 mug/ml in the P388D1 cell line.
The CHI-treated bacteria had negligible cytotoxicity and were less potent to invade and proliferate intracellularly. Murine macrophages infected with wild bacteria, stained with Hoechst 33258, had swollen and damaged morphology with characteristic apoptotic bodies whereas macrophages infected with treated bacteria had comparative normal architecture. Immunofluorescence and transmission electron micrographs both confirmed that CHI-treated bacteria were defective and smaller than the wild bacteria. Ultrastructures of P388D1 cells infected with wild bacteria showed many ingested bacteria and characteristic Salmonella-containing vacuoles (SCV). Some cells had condensed or fragmented nuclei with swollen mitochondria, whereas most of the cells infected with treated bacteria were normal in morphology and a few had internalized bacteria, but the typical bacteria laden SCV was not observed in cells infected with CHI-treated S. Typhimurium.
Our results showed that the choloroform fraction of H. indicus root blocked the cytotoxic activity of S. Typhimurium in a macrophage cell line. More studies need to be done to elaborate and confirm our findings.
[Show abstract][Hide abstract] ABSTRACT: pR(ST98) is a chimeric plasmid isolated from Salmonella enterica serovar Typhi (S. typhi) that mediates the functions of drug resistance and virulence. Previously, we reported that Salmonella plasmid virulence (spv) genes were present in S. typhi. In our current study, we investigated whether plasmid pR(ST98) exhibits significant cytotoxicity in macrophages. pR(ST98) was transferred into the avirulent Salmonella enterica serovar Typhimurium (S. typhimurium) strain RIA to create the transconjugant pR(ST98)/RIA. The standard S. typhimurium virulent strain SR-11, which carries a 100-kb virulence plasmid, was used as a positive control. The bacterial strains were incubated with a murine macrophage-like cell line (J774A.1) in vitro. Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling, and the survival of Salmonella strains in J774A.1 cells was determined. Results showed that macrophages infected with strain pR(ST98)/RIA displayed greater levels of apoptosis than those infected with RIA and that pR(ST98 )may increase bacterial survival in macrophages. Further studies showed that the pR(ST98)-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pR(ST98 )may activate caspase-9 and then caspase-3. The research data indicate that the virulence of bacteria that contain the pR(ST98) plasmid is enhanced; the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.
[Show abstract][Hide abstract] ABSTRACT: The Ayurvedic herb anantamul (Hemidesmus indicus) has been growing in popularity in the U.S. consumer marketplace. While several freely available herbal resources describe anantamul’s traditional benefits and supportive Ayurvedic theory, the current status of biomedical research on this herb is not well known. Literature searches using the terms [“anantamul” OR “anantmul” OR “Hemidesmus indicus” OR “Indian sarsaparilla”] were conducted in various databases including PubMed, Academic Search Complete, and others. Secondary searches were conducted using Google and Google Scholar and scoured for additional information regarding anantamul. A review of the literature revealed a lack of formal clinical trials. However, more than 100 animal and laboratory studies have been conducted since the 1960s, and taken together, these studies corroborate several traditional medical actions of anantamul. A table of popular anantamul-containing products, including pricing, is also included in this report. Additional modern reports of anantamul’s use in humans, including dosing, safety, and efficacy, would be helpful additions to the literature.
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