A convenient synthesis of novel thiazolidin-4-one-linked pseudodisaccharides by tandem Staudinger/aza-Wittig/cyclization and their biological evaluation

Novel immunostimulators with a thiazolidin-4-one ring promote the immunostimulatory effect of human iNKT cells on the stimulation of Th2-like immune responsiveness via GATA3 activation in vitro

Invariant natural killer T cells (iNKTs) are important innate immune cells which get involved in various immune responses in both mice and humans. These immune reactions range from self-tolerance to development of autoimmunity and responses to pathogens and tumor development. In this study, we aimed to explore the effects of the novel immunostimulators (CH1b and CH2b) containing thiazolidin-4-one on the functions of human invariant natural killer T cells (iNKTs). First of all, iNKTs in peripheral blood mononuclear cells were expanded with α-Galactosylceramide (α-Galcer) in vitro. Then, the highly purified iNKTs were isolated from PBMCs using magnetic cells sorting (MACS). Next, we investigated the impacts of CH1b and CH2b on proliferation, cytokines production, cytotoxicity, and the associated signaling pathways in iNKT cells. Finally, we found that CH2b could significantly promote the activated iNKTs proliferation, increase the production of Th2 cytokines, and induce Th0 differentiation into Th2 subset via GATA 3 signaling pathway. Besides, CH2b could markedly enhance the cytotoxic ability of the activated iNKTs. Therefore, we concluded that CH2b, a promising candidate immunostimulator, might be used for the treatment of infections, tumors, autoimmune and allergic diseases, and for the correction of Th1/Th2 balance disorders in future.

Glycosylation of ent-kaurene derivatives and an evaluation of their cytotoxic activities

AIM

To discover more active and water-soluble derivatives of tetracyclic diterpenoids containing an exo-methylene cyclopentanone or an α-methylenelactone moiety.

METHODS

All of the key intermediates were synthesized from stevioside, and the target compounds were obtained through glycosylation of the 4-carboxyl group. The cytotoxicity of the target compounds against six human cancer cell lines, HepG2, Bel-7402, A549, U251, MCF-7 and MDA-MB-231, were evaluated by the MTT assay.

RESULTS

Compound 1b was more effective than the positive control adriamycin against the HepG2, Bel-7402, A549, MCF-7, and MDA-MB-231 cell lines with IC50 values of 0.12, 0.91, 0.35, 0.08, and 0.07 μmol·L(-1), respectively. Moreover, compound 3c exhibited the most potent and selective cytotoxic activity against the HepG2 cell line (IC50, 0.01 μmol·L(-1)).

CONCLUSION

Compounds 1b and 3c could be considered as potential anticancer candidates for further study.

A convenient synthesis of N-linked diglycose derivatives based on one-pot tandem Staudinger/aza-Wittig/reduction and biological evaluation

A series of novel N-linked diglycose derivatives 9 and 10 were conveniently and directly synthesized based on the key step of one-pot tandem Staudinger/aza-Wittig/reduction reaction from the azido sugar and sugar-derived aldehyde followed by deprotection. The biological activities against glycosidases (α-amylase, α-glucosidase, and β-glucosidase) and HIV-RT and antitumor activity of these compounds were preliminarily evaluated.

Synthesis of C-Pseudonucleosides Bearing Thiazolidin-4-one as a Novel Potential Immunostimulating Agent

Several novel C-pseudonucleosides bearing thiazolidin-4-one were synthesized by one-pot three-component condensation using unprotected sugar aldehyde at room temperature, and their effects on T cells, B cells, the cytokine secretion of IL-2, IL-4, and IFN-γ, T cell-associated molecules (CD3, CD4, CD8), and B cell-associated molecules (CD19) were first evaluated. The experimental data demonstrated that such thiazolidin-4-one C-pseudonucleosides hold potential as immunostimulating agents.