Feng Wei Cao

Sprague-Dawley rats received the aqueous extract by oral gavage at 100, 500 and 1000 mg/kg per day for 28 days. There were no adverse effects on general condition, growth, feed and water intake, red cell or clotting parameters, clinical chemistry or organ weights, except slightly reduced neutrophils in males and lymphocytes in females at the top dose, and necropsy and histopathology showed no treatment-related change. The authors concluded that the herb used in the traditional oral way is likely free of toxic risk. This is a 28-day study and therefore says nothing about the long-term carcinogenicity question that hangs over the Pteridaceae.

Hyperlipidaemic Sprague-Dawley rats fed a high-cholesterol diet were given lyophilised spider brake powder, with beta-sitosterol as comparator. At 10 percent dietary substitution, liver, adipose and relative adipose weights fell by 6, 15.9 and 14.3 percent, and plasma triglycerides, LDL cholesterol, LDL/HDL ratio and liver cholesterol and triglyceride fell by 36.8, 21, 18.7, 10.2 and 14.3 percent. Wet and dry faecal weight, nitrogen compounds, neutral steroid excretion and bile acid excretion all rose, indicating increased intestinal loss of lipid.

HPLC with tandem mass spectrometry identified ten flavonoids as the key constituents of a total flavonoid extract. Given at 180 mg/kg by gavage for 60 days it clearly reduced the prostate index in mice with benign prostatic hyperplasia, with immunohistochemistry showing suppressed VEGF and activated TGF-beta1 in prostate tissue. A 90-day subchronic study in male Sprague-Dawley rats set the no-observed-adverse-effect level at 200 mg/kg body weight per day.

Two new pterosin glycosides were isolated from the roots with ten known pterosins and tested against HCT116 colorectal cancer cells. The caffeoyl glucoside of (2S,3S)-pterosin C showed moderate antiproliferative activity with an IC50 of 8.0 plus or minus 1.7 micromolar, upregulated caspase-9 and procaspase-9 on Western blot and increased the annexin V/propidium iodide-positive population.

An 80 percent methanolic extract of the roots inhibited nitric oxide production in LPS-activated BV-2 microglia. Three new ent-kaurane diterpenoids were isolated with nine known compounds; two isolates significantly inhibited nitric oxide production and reduced COX-2 protein, prostaglandin E2, TNF-alpha, IL-1beta and IL-6.

Mice infected with Salmonella Typhimurium ST21 received aqueous extracts of Pteris multifida or Cortex phellodendri, or lactic acid bacteria, for four days. Pteris multifida and Cortex phellodendri both reduced the bacterial count in blood, intestine and liver; Pteris multifida lowered serum TNF-alpha, IL-1beta and IgG. A macrophage infection model suggested TNF-alpha was only partly responsible. This is the closest published support for the traditional use in dysentery and diarrhoea.