ABSTRACT
Lactobacillus bulgaricus is one of the predominant lactic acid bacteria of dahi, conferring technological and functional attributes. In the present study thirty dahi samples were investigated for bacteriocin producing L. bulgaricus. Fourteen different isolates were obtained and five were scrutinized for antibacterial activities against food born pathogens. Amongst, a strain TLB06FT was found to have a wide array of antibacterial activities against Gram positive and negative bacteria was selected for further characterization. Growth media optimization for this strain revealed maximum bacteriocin production on MRS media supplemented with glucose [2%], sodium chloride [1%], Tween-80 [0.5%] and yeast extract [1%]. In addition, optimization of growth conditions revealed maximum bacteriocin production at pH 5.5 and temperature of 30-37[degree]C. Bacteriocin showed thermo stability at 90[degree]C and remained highly active in the pH range of 3.5-7.5, inactive by protein catalyzing enzymes and showed no change in activity [800AUmL[-1]] when treated with organic solvents and surfactants. The obtained bacteriocin was purified to 1600AU mL[-1] by ammonium sulfate precipitation [80%] by using dialyzing tubing. In the same way, a single peak was obtained by RP-HPLC having antibacterial activity of 6400AU mL[-1]. Thus, wild strains of L. bulgaricus have great potential for the production new and novel type of bacteriocins
Subject(s)
Bacteriocins/isolation & purification , MilkABSTRACT
Taraxacum officinale L is a medicinal plant, which has enormous medicinal values against various types of liver disorders and it has traditionally been used for the treatment of liver problems by people from the South East Asia. Previously we have screened the crude methanolic extract of T. officinale against cytotoxicity induced by CCl[4].Present study was designed to compare the protective effect of ethanolic and n-hexane extract of leaves in carbon tetrachloride [CCl[4]] induced liver toxicity in rats. The extract [200 mg/kg and 400mg/kg body weight] along with silymarin [100 mg/kg] a standard drug was administered to experimental animals. It was observed that ethanolic plant extract has significantly reduced the negative effect of CCl[4] as compared to n-hexane extract and effect of extract was increased with increasing dose level. Although both leaf extracts decreased the concentration of TBARS, H[2]O[2] and nitrite contents which enhance due to CCl[4] toxicity but effect was higher in ethanolic extract. The results clearly indicated that Taraxacum officinale ethanolic leaves extract has better protective effect against CCl[4] induced liver tissues toxicity. This claim was also supported by histopathological results obtained during this study and this might be due to presence of various polar phytochemicals that might be more prevent in this extract