Five polysaccharide fractions (AB-1, AB-2, AB-3, AB-4, and AB-5) were obtained after a systemic solvent extraction and precipitation of Agaricus blazei mycelia with yields of 5.20, 9.03, 2.84, 17.47, and 0.44%, respectively. Among which, AB-1 and AB-3 demonstrated great DPPH* radical scavenging ability around 85.0 and 72.0%, respectively, at a concentration of 5 mg/mL. The ferrous ion chelating powers were even more excellent at a concentration of 1 mg/mL, reaching almost over 99.65% for fractions AB-2, AB-3, and AB-4 as compared to the reference control of citric acid (35%); at a dosage of 5 mg/mL, fraction AB-1 even showed 105% in efficiency. In terms of the absolute chelating power (ACP), the mole numbers of ferrous (Fe2+) ions chelated were inversely related with the mean molecular mass of the polysaccharides in each fraction. In addition, gel permeation chromatography analysis showed that the more potent fractions were residing in those fractions with lower molecular masses, such as fractions AB-1 (757 kDa), AB-2 (887 kDa), and AB-4 (631 kDa) etc., and surprisingly, the free radical scavenging capability was also not closely correlated with the mean molecular masses, alternately being well-associated with the solubility of polysaccharides.
Rosemary (Rosmarinus officinalis) leaves possess a variety of bioactivities. Previous studies have shown that the extract of rosemary leaves from supercritical fluid extraction inhibits the expression of inflammatory mediators with apparent dose-dependent responses. In this study, three different extraction conditions (5000 psi at 40, 60, and 80 °C) of supercritical carbon dioxide (SC-CO(2)) toward the extraction of antioxidants from rosemary were investigated. Furthermore, simultaneous comparison of the anti-inflammatory properties between rosemary extract prepared from SC-CO(2) under optimal conditions (5,000 psi and 80 °C) and its purified carnosic acid (CA) using lipopolysaccharide (LPS)-treated murine RAW 264.7 macrophage cells was also presented. Results showed that the yield of 3.92% and total phenolics of 213.5 mg/g extract obtained from the most effective extraction conditions showed a high inhibitory effect on lipid peroxidation (IC(50) 33.4 μg/mL). Both the SC-CO(2) extract and CA markedly suppressed the LPS-induced production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), phosphorylated inhibitor-kappaB (P-IκB), and nuclear factor-kappaB (NF-κB)/p65 in a dose-dependent manner. The five major compounds of verbenone, cirsimaritin, salvigenin, carnosol, and CA existing in the SC-CO(2) extract were isolated by semipreparative HPLC and identified by HPLC-MS/MS analysis. CA was the most abundant recorded compound and the most important photochemical with an anti-inflammatory effect with an IC(50) of 22.5 μM or 7.47 μg/mL presented to the best inhibitory activity on NO production better than that of the 14.50 μg/mL dosage prepared from the SC-CO(2) extract. Nevertheless, the effective inhibition of LPS-induced NF-κB signaling in RAW 264.7 cells from the SC-CO(2) extract extends the potential application of nutraceutical formulation for the prevention of inflammatory diseases.
Many phytoantioxidants have therapeutic drawbacks due to their potent prooxidant bioactivity. It is hypothesized that phytoantioxidants (PAO) are beneficial only to the early-stage diabetes mellitus (DM) and will become ineffective once renopathy occurs. Gallic acid, rutin, EGCG, ferulic acid (FA), and quercetin were tried on the streptozotocin (STZ)-induced DM rat model for a 28 week experimental period. All of these PAO were shown to be ineffective for hypoglycemic action. The incidence of cataract (50%), injured glomerules, and renal cell carcinoma (RCC) was very common, among which the most severely affected involved the quercetin- and the FA-treated groups. The tumorigenicity of ferulic acid is still unclear. However, for quercetin, this can be attributted to (i) the prooxidant effect, (ii) the insulin-secretagogue bioactivity, and (iii) the competitive and noncompetitive inhibition on the O-methyltransferase to enhance the estradiol-induced tumorigenesis. Conclusively, quercetin and FA are able to aggravate, if not induce, nephrocarcinoma. It is time to reevaluate the tumorigenic detrimental effect of PAO, especially those exhibiting prooxidant bioactivity.
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