PADMA-28, a traditional tibetan herbal preparation inhibits the respiratory burst in human neutrophils, the killing of epithelial cells by mixtures of oxidants and pro-inflammatory agonists and peroxidation of lipids.

Both aqueous and methanolic fractions derived from the Tibetan preparation PADMA-28 (a mixture of 22 plants) used as an anti-atherosclerotic agent, and which is non-cytolytic to a variety of mammalian cells, were found to strongly inhibit (1) the killing of epithelial cells in culture induced by 'cocktails' comprising oxidants, membrane perforating agents and proteinases; (2) the generation of luminol-dependent chemiluminescence in human neutrophils stimulated by opsonized bacteria; (3) the peroxidation of intralipid (a preparation rich in phopholipids) induced in the presence of copper; and (4) the activity of neutrophil elastase. It is proposed that PADMA-28 might prove beneficial for the prevention of cell damage induced by synergism among pro-inflammatory agonists which is central in the initiation of tissue destruction in inflammatory and infectious conditions.

The hemolytic activity of citral--II. Glutathione depletion in citral treated erythrocytes.

The role of glutathione in citral induced hemolysis was investigated. The concentration of intracellular glutathione diminished in citral treated erythrocytes. GSH disappeared before hemolysis started. Glucose inhibited citral induced hemolysis and restored the depleted cellular stores of GSH. The results presented confirm the previous suggestion that a free radical-peroxide mechanism is involved in citral induced hemolysis.

The hemolytic activity of citral: evidence for free radical participation.

In the present investigation the hemolytic properties of citral were examined. Tests with different concentrations of citral showed that hemolysis of rat erythrocytes commenced after a lag period the length of which depended on the concentration of the hemolysin and tended to 100% hemolysis. Comparison of the characteristics of the hemolysis induced by high and low citral concentrations, indicated that two mechanisms are involved--a non specific steroid--terpenoid or glutathione depletion mechanism dominating at high citral concentrations and a free radical mechanism dominating at low citral concentrations. Experiments performed with various free radical scavengers indicate that 1O2 might be involved.

Hemolysis caused by cetomacrogol 1000: evidence for hydroxyl radical participation.

The mechanism of cetomacrogol 1000-induced hemolysis was investigated. Previous conclusions that peroxides are involved in the hemolytic process were confirmed. The possibility that hydrogen peroxide, superoxide, hydroxyl radical, or singlet oxygen, which are known to induce hemolysis, are involved in cetomacrogol 1000-induced hemolysis was tested by using specific inhibitors and inactivators. The hydroxyl radical (OH.) was shown to be the only apparent oxygen species involved in cetomacrogol 1000-induced hemolysis. Its contribution to the hemolytic potency of the surfactant is approximately 30%.

Trichothecene-induced hemolysis. I. The hemolytic activity of T-2 toxin.

In the present investigation, the hemolytic properties of T-2 toxin were examined. Tests with different concentrations of T-2 toxin showed that essentially complete hemolysis of rat erythrocytes commenced after a lag period, the length of which depended on the concentration of toxin. Comparison of the characteristics of hemolysis caused by T-2 toxin, saponins, H2O2, and polyoxyethylene surfactants showed great similarity between T-2 toxin and the latter two which proceed by a free radical mechanism. The same mechanism was suggested for hemolysis caused by T-2 toxin on the basis of the additional following observations: (1) darkness inhibited hemolysis; (2) specific free radical scavengers, i.e., vitamin E, mannitol, and histidine, inhibited hemolysis caused by T-2 toxin.

Hemolysis caused by polyoxyethylene-derived surfactants. Evidence for peroxide participation.

The hemolytic properties of nonionic surfactants of the series CH3(CH2)15-17-O-(CH2CH2O)nCH2CH2OH were investigated and compared to those of saponins, sapogenins and H2O2. Antioxidants and anaerobic conditions were shown to inhibit the hemolysis, while glycyrrhizin was found to enhance it. Similar effects were obtained for H2O2 hemolysis, but not for saponin and sapogenin hemolysis. It is proposed that peroxides and free radicals are mainly responsible for the polyoxyethylene derived surfactants induced hemolysis.

Hemolytic properties of synthetic glycosides.

Cholesteryl alpha-L-rhamnopyranoside, tigogenyl alpha-L-rhamnopyranoside, tigogenyl beta-D-fucopyranoside, smilagenyl beta-D-fucopyranoside, cholesteryl beta-maltoside, tigogenyl beta-maltoside, and smilagenyl beta-maltoside were synthesized and characterized. The rhamnosides and fucosides, as well as some other steroid monoglycosides, proved to be extremely insoluble in water. The concentration giving 50% hemolysis, H50, was of the same order of magnitude for all synthetic glycosides. Ghost cells collected from blood hemolyzed by smilagenyl maltoside and tigogenyl maltoside had appreciable amounts of absorbed aglycones. All results are in accordance with previous investigations on the mechanism of saponin and sapogenin hemolysis.

The susceptibility of cholesterol-depleted erythrocytes to saponin and sapogenin hemolysis.

The assumption that complex formation between erythrocyte membrane cholesterol and saponins or sapogenins is the cause for their hemolytic activity, was tested by measuring the susceptibility of cholesterol-depleted erythrocytes towards these hemolysins. For some of the hemolysins cholesterol depletion caused inhibition of hemolysis, for others an augmentation. The results suggest that cholesterol does not serve as a specific binding site for these hemolysins.

Solasodine stability under conditions of saponin hydrolysis.

The extent of formation of solasodiene from solasodine upon treatment with hydrochloric acid under various conditions was determined. The diene formed was assayed by using the characteristic extinction at 236 nm. Diene formation was effected by the acid concentration and the boiling point of the solvent used. Optimal conditions for the hydrolysis of solasodine glycosides are suggested.