Free Radical Scavenging and Antioxidative Properties of ‘Silibin’ Complexes on Microsomal Lipid Peroxidation

Abstract

The antioxidant properties of silibin complexes, the water-soluble form silibin dihemisuccinate (SDH), and the lipid-soluble form, silibin phosphatidylcholine complex known as IdB 1016, were evaluated by studying their abilities to react with the superoxide radical anion (O2-.), and the hydroxyl radical (OH.). In addition, their effect on pulmonary and hepatic microsomal lipid peroxidation had been investigated. Superoxide radicals were generated by the PMS-NADH system and measured by their ability to reduce NBT. IC50 concentrations for the inhibition of the NBT reduction by SDH and IdB 1016 were found to be 25 microM and 316 microM respectively. Both silibin complexes had an inhibitory effect on xanthine oxidase activity. SDH reacted rapidly with OH radicals at approximately diffusion controlled rate and the rate constant was found to be (K = 8.2 x 10(9) M-1 s-1); it appeared to chelate Fe2+ in solution. In hepatic microsomes, when lipid peroxidation was induced by Fe2+, SDH inhibited by 39.5 per cent and IdB 1016 by 19.5 per cent, whereas when lipid peroxidation was induced by CuOOH, IdB 1016 exerted a better protective effect than SDH (29.4 per cent and 19.4 per cent inhibition, respectively). In both microsomal systems lipid peroxidation proceeded through a thiol depletion mechanism which could be restored in the presence of silibin complexes. Low levels of lipid peroxidation in pulmonary microsomes point out the differences between in-vitro lipid peroxidation occurring in microsomes of different tissues. The results support the free radical scavenger and antioxidative properties of silibin when it is complexed with a suitable molecule to increase its bioavailability.

Antibacterial and Antifungal Effects of Essential Oils from Coniferous Trees

“…5) More recently, plant extracts have been developed and proposed for use in foods as natural antioxidants. 6) In the present study, we investigated the antimicrobial and antifungal activities of several essential oils extracted from the coniferous trees Pinus densiflora, Pinus koraiensis, and Chamaecyparis obtusa against bacteria and fungi that commonly cause foot rot and other diseases. The essential oils were quantified using gas chromatography (GC) and identified in gas chromatography-mass spectrometric (GC-MS) analysis.…”

Understudied populations with hepatitis C

“…21 Silybum has hepatoprotective effects in animal models of liver disease, specifically preventing the formation of superoxide anions, nitric oxide, tumor necrosis factor (TNF)-␣, and leukotriene B4. [22][23][24] In clinical studies, milk thistle, glycyrrhiza glabra (licorice) and sho-saiko-to (a Japanese Kampo formula consisting of 7 different herbals) have been reported to decrease ALT levels, improve histological stage, and improve symptoms in patients with several liver diseases. 25,26 In a small study of the combination of glycyrrhizin and interferon for hepatitis C, 38% of treated patients became HCV RNA negative.…”

Silymarin Glyceryl Monooleate/Poloxamer 407 Liquid Crystalline Matrices: Physical Characterization and Enhanced Oral Bioavailability

“…Silymarin as well as silybin, the main active component comprising about 33% of total silymarin weight (4), is used clinically as a hepatoprotector to treat liver injuries and chronic hepatitis. However, the main problem with silymarin is its poor oral bioavailability, which is attributable to its poor solubility (5)(6)(7) and low permeability as well as degradation in the gastrointestinal tract (8). Therefore, it appears quite important to improve the solubility and/or the permeability of silymarin to achieve higher oral bioavailability.…”