Antimicrobial activity of Mahonia aquifolium and two of its alkaloids against oral bacteria.

Extracts or alkaloids isolated from Mahonia aquifolium exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi, and protozoa. In this study the bacteriostatic and bacteriocidal activities of a M. aquifolium extract and two of its major alkaloids, berberine chloride and oxyacanthine sulphate, were tested in vitro against nine different oral bacteria.

Hypericum perforatum: which constituents may induce intestinal MDR1 and CYP3A4 mRNA expression?

In vitro and in vivo studies suggest that extracts of St John's wort (Hypericum perforatum, L .; SJWE) interact with various drugs, by enhancing their elimination, due to induction of intestinal and hepatic cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp), the gene product of multidrug resistance gene 1 (MDR1/ABCB1). The aim of our study was to identify the major constituents responsible for this induction and their relative importance.

Preserved pharmacological activity of hepatocytes-treated extracts of valerian and St. John's wort.

The two herbal extracts valerian (Valeriana officinalis L.) and St. John's wort (Hypericum perforatum L.

Antagonist effect of pseudohypericin at CRF1 receptors.

St. John's wort (Hypericum perforatum L.) is widely used for the treatment of mild to moderately severe depression.

Interference of plant extracts, phytoestrogens and antioxidants with the MTT tetrazolium assay.

The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is a widely used screening method to measure cell viability and proliferation. When testing the effects of kaempferol on breast cancer cell number (crystal violet staining) and viability (MTT tetrazolium assay) conflicting results were obtained. Cell number decreased but MTT formazan formation increased, suggesting a direct interaction of kaempferol with the MTT tetrazolium reduction.