Effects of Antrodia camphorata extracts on anti-oxidation, anti-mutagenesis and protection of DNA against hydroxyl radical damage.

BACKGROUND: Antrodia camphorata is a geographically special fungus and is one of the precious traditional medicines of Taiwan. A lot of reports have addressed its antioxidant activities and anticancer activities. In order to understand whether these protection effects were resulted from its ability of preventing DNA against hydroxyl radical damage, the A. camphorata extract was used to examine its antioxidant, antimutagenic and DNA-protective activities. METHODS: A. camphorata extract was prepared by extracting the lyophilized powder of A. camphorata mycelium with distilled water. The antioxidative activity of this A. camphorata extract was then evaluated by 2,2-diphenyl-1-picrylhydrozyl (DPPH) radical-scavenging assay, and the antimutagenic activities of the extract against direct mutagen 4-nitroquinoline N-oxide (4NQNO) and indirect mutagen benzo[a]pyrene (B[a]P) were evaluated by Ames test. The effects of the A. camphorata extract in terms of DNA protection against hydroxyl radical damage were also investigated. RESULTS: It was found that the higher the concentration of A. camphorata extracts, the higher the DPPH radical-scavenging effect. A. camphorata extract at concentrations between 0.625 and 10 mg/ml was found to be neither toxic nor mutagenic. However, the higher A. camphorata concentration (10 mg/ml) used in the test showed higher inhibitory effects on 4NQNO in a dose-dependent manner. The A. camphorata extract also showed reducing and scavenging activities against superoxide anion radical and also exhibited protective effects on DNA against hydroxyl radical-induced damage. CONCLUSIONS: Results suggested that A. camphorata is a non-toxic and novel material with antioxidant, antimutagenic and DNA-protective activities and could be developed into health foods.

Chitosan reduces plasma adipocytokines and lipid accumulation in liver and adipose tissues and ameliorates insulin resistance in diabetic rats.

Chitosan is a natural product derived from chitin. To investigate the hypoglycemic and anti-obesity effects of chitosan, male Sprague-Dawley rats were divided into four groups: normal control, diabetic, and diabetic fed 5% or 7% chitosan. Diabetes was induced in rats by injecting streptozotocin/nicotinamide. After 10 weeks of feeding, the elevated plasma glucose, tumor necrosis factor-α, and interleukin-6 and lower adiponetin levels caused by diabetes were effectively reversed by chitosan treatment. In addition, 7% chitosan feeding also elevated plasma glucagon-like peptide-1 levels and lowered the insulin resistance index (homeostasis model assessment) in diabetic rats. Lower adipocyte granular intensities and higher lipolysis rates in adipose tissues were noted in the 7% chitosan group. Moreover, chitosan feeding reduced hepatic triglyceride and cholesterol contents and increased hepatic peroxisomal proliferator-activated receptor α expression in diabetic rats. Our results indicate that long-term administration of chitosan may reduce insulin resistance through suppression of lipid accumulation in liver and adipose tissues and amelioration of chronic inflammation in diabetic rats.

Enhancement of cutaneous nerve regeneration by 4-methylcatechol in resiniferatoxin-induced neuropathy.

To generate an experimental neuropathy model in which small-diameter sensory nerves are specifically affected and to test a potential treatment, adult mice were given a single injection (50 microg/kg, i.p.) of the capsaicin analog resiniferatoxin (RTX). On Day 7 after RTX treatment, there was a 53% reduction in unmyelinated nerve density in the medial plantar nerve (p = 0.0067) and a 66% reduction in epidermal nerve density of hind paw skin (p = 0.0004) compared with vehicle-treated controls. Substance P-immunoreactive dorsal root ganglion neurons were also markedly depleted (p = 0.0001). These effects were associated with the functional deficit of prolonged withdrawal latencies to heat stimuli (p = 0.0007) on a hot plate test. The potential therapeutic effects of 4-methylcatechol (4MC) on this neuropathy were then tested by daily injections of 4MC (10 microg/kg, i.p.) from Days 7 to 35 after neuropathy induction. On Day 35, 4MC-treated mice had an increase in unmyelinated (p = 0.014) and epidermal nerve (p = 0.0013) densities and a reduction in thermal withdrawal latency (p = 0.0091) compared with RTX-only controls. These results indicate that 4MC promoted regeneration of unmyelinated nerves in experimental RTX-induced neuropathy and enhanced function.