qs-21 and Hemolysis

A new cycloartane sapogenol and a new cycloartane xyloside were isolated from Astragalus karjaginii BORISS along with thirteen known compounds. The structures of the new compounds were established as 3-oxo-6α,16β,24(S),25-tetrahydroxycycloartane (1) and 6-O-β-d-xylopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane (2) by 1D- and 2D-NMR experiments as well as ESIMS and HRMS analyses. The presence of the keto function at position 3 was reported for the first time for cyclocanthogenol sapogenin of Astragalus genus. In vitro immunomodulatory effects of the new compounds (1 and 2) along with the n-BuOH and MeOH extracts of A. karjaginii at two different doses (3 and 6μg) were tested on human whole blood for in vitro cytokine release (IL-2, IL-17A and IFN-γ) and hemolytic activities. The results confirmed that compound 2, a monodesmosidic saponin, had the strongest effect on the induction of both IL-2 (6μg, 6345.41±0.12pg/mL (×5), P<0.001) and a slight effect upon IL-17A (3μg, 5217.85±0.72pg/mL, P<0.05) cytokines compared to the other test compounds and positive controls (AST VII: Astragaloside VII; and QS-21: Quillaja saponin 21). All tested extracts and molecules also induced release of IFN-γ remarkably ranging between 5031.95±0.05pg/mL, P<0.001 for MeOH extract (6μg) and 5877.08±0.06pg/mL, P<0.001 for compound 1 (6μg) compared to QS-21 (6μg, 5924.87±0.1pg/mL, P<0.001). Administration of AST VII and other test compounds did not cause any hemolytic activity, whereas QS-21 resulted a noteworthy hemolysis.

Topics: Astragalus Plant; Erythrocytes; Hemolysis; Humans; Interferon-gamma; Interleukin-17; Interleukin-2; Molecular Structure; Plant Extracts; Plant Roots; Saponins; Triterpenes

Liposomes containing cholesterol (Chol) have long been used as an important membrane system for modeling the complex interactions of Chol with adjacent phospholipids or other lipids in a membrane environment. In this study we utilize a probe composed of QS-21, a saponin molecule that recognizes liposomal Chol and causes hemolysis of erythrocytes. The interaction of QS-21 with liposomal Chol results in a stable formulation which, after injection into the tissues of an animal, lacks toxic effects of QS-21 on neighboring cells that contain Chol, such as erythrocytes. Here we have used liposomes containing different saturated phospholipid fatty acyl groups and Chol, with or without monophosphoryl lipid A (MPLA), as model membranes. QS-21 is then employed as a probe to study the interactions of liposomal lipids on the visibility of membrane Chol. We demonstrate that changes either in the mole fraction of Chol in liposomes, or with different chain lengths of phospholipid fatty acyl groups, can have a substantial impact on the detection of Chol by the QS-21. We further show that liposomal MPLA can partially inhibit detection of the liposomal Chol by QS-21. The Limulus amebocyte lysate assay is used for binding to and detection of MPLA. Previous work has demonstrated that sequestration of MPLA into the liposomal lipid bilayer can block detection by the Limulus assay, but the binding site on the MPLA to which the Limulus protein binds is unknown. Changes in liposomal Chol concentration and phospholipid fatty acyl chain length influenced the detection of the liposome-embedded MPLA.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Adjuvants, Immunologic; Animals; Cell Extracts; Cholesterol; Dimyristoylphosphatidylcholine; Dose-Response Relationship, Drug; Hemolysis; Horseshoe Crabs; Humans; Lipid A; Liposomes; Phosphatidylcholines; Phosphatidylglycerols; Saponins

Ginsenoside Rh(4) (1), a saponin isolated from the roots of Panax notoginseng (Burk.) F. H. Chen, was evaluated for its haemolytic activity and adjuvant potential on specific antibody and cellular response to ovalbumin (OVA) in mice. Compound 1 showed a slight haemolytic effect, its concentration inducing 50% of the maximum haemolysis (HD(50) value) being 407+/-12 microg/ml using a 0.5% suspension of red blood cells. Compound 1 significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in OVA-immunized mice especially at a dose of 25 microg (P<0.05, P<0.01, or P<0.001). The OVA-specific serum IgG, IgG1, and IgG2b antibody levels were also significantly enhanced by 1 at a dose of 25 microg compared to the OVA control group (P<0.05 or P<0.01). Moreover, the enhancing effect of 1 on the OVA-specific IgG2b antibody responses to OVA in mice was more significant than that of Alum (Al(OH)(3) gel; P<0.01). These results suggest that 1 could be safely used as adjuvant with low or non-haemolytic effect.

Topics: Adjuvants, Immunologic; Animals; Dose-Response Relationship, Drug; Female; Ginsenosides; Hemolysis; Immunoglobulin G; Lymphocyte Activation; Mice; Mice, Inbred ICR; Ovalbumin; Panax notoginseng; Quillaja Saponins; Saponins