To provide a useful screening method for selecting probiotics, we compared the pH and bile resistance of four strains of Lactobacillus acidophilus, KCTC3140, KCTC3146, KCTC3154, and KCTC3179, isolated from a rat, pig, chicken, and human, respectively. When we compared the pH resistance of these strains at pH 2, 3, 4, 5 and 7, we found that L. acidophilus isolated from the rat, chicken, and pig showed little or no decrease in viable cell numbers, except at 240 min, whereas the numbers of L. acidophilus KCTC3179 from the human decreased significantly. All four strains were slightly suppressed over time and showed bile resistance, even at 3%. At 5% oxgall, the number of KCTC3179 rapidly decreased at 30 min. These results indicate that lactic acid bacteria selected for probiotic use should be screened at pH 2 for 120 min and/or at an oxgall concentration of 5% for 30 min.
The in vitro anti-platelet and antioxidant activities of various solvent extracts from Phellinus gilvus (PG), and the effects of hot water extract from PG (PGW) on murine cellular immunity were investigated. Chloroform extract (CE), methanol extract (ME) and butanol extract (BE) from PG could significantly inhibit platelet aggregation induced by thrombin. Ethyl acetate extract (EAE), BE, ME from PG had significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity compared with the control, and the EAE showed the highest effect with IC 50 values of 13.34 lg/ml, which is higher than that of ascorbic acid (40 lg/ml). In addition, EAE displayed the inhibition of xanthine oxidase (XO) activity with IC 50 value of 2.45 lg/ml. As to the cellular immunity activity, PGW could enhance both the lipopolysaccharide (LPS)-induced B lymphocyte proliferation and concanavalin A (Con A)-induced T lymphocyte proliferation in vitro. The phagocytosis of both peritoneal macrophages and RAW264.7 macrophage cells were also increased by the addition of PGW. Moreover, PGW was found to inhibit the nitric oxide (NO) production of RAW264.7 macrophages induced by LPS in a concentration-dependant manner.
The effect of extracellular β-(1→3), (1→6)-glucan, produced by Paenibacillus polymyxa JB115, on nitric oxide (NO) production in RAW264.7 macrophages was investigated. β-glucan induced the production of NO by RAW264.7 macrophages in a concentration- and time-dependent manner. Moreover, β-glucan stimulation increased the mRNA expression of iNOS, COX-2 and IL-6 in RAW264.7 macrophages in a concentration-dependent manner.
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