Secophragmalin-Type Limonoids from Trichilia connaroides: Isolation, Semisynthesis, and Their Cytotoxic Activities.

Two new secophragmalin-type limonoids, secotrichagmalins B (1) and C (2) along with two known compounds, were isolated from the fruits of Trichilia connaroides. The structures of the new compounds were elucidated by analysis of spectroscopic (IR, MS, and 2D NMR) data and single crystal X-ray diffraction studies. In addition, semisynthetic derivatives (2a-2l) were efficiently synthesized and evaluated for their in vitro cytotoxicity along with the isolated limonoids against a panel of human cancer cell lines. The results indicated that new analogues 2a, 2d, and 2e showed cytotoxicity on the DU145 cell line with IC50 values of 3.6, 4.2, and 5.2 µM, respectively. Flow cytometric analysis revealed that these analogues arrested the cell cycle in the G0/G1 phase and markedly induced apoptosis.

Design, Synthesis, and Evaluation of Novel 1,2,3-Triazole-Tethered Glycolipids as Vaccine Adjuvants.

A Cu-mediated azide-alkyne click chemistry protocol was employed for the synthesis of a focused library of novel 1,2,3-triazolyl conjugates bearing various carbohydrate-steroid/triterpenoid entities. The immunogenicity of these compounds was examined initially by ex vivo assays. The lead compound 15g was further subjected to in vivo evaluation in BALB/c mice immunized with ovalbumin. These in vivo biological studies revealed an increase in B cell-mediated proliferation, higher expression levels of IL-2, TNF-α, IL-12, and IFN-γ indicating Th1 activation, together with an enhanced OVA-specific antibody (IgG) response compared to alum, affirming adjuvanticity of these glycolipids. The primary indications of response skewed toward Th1 immunity induced by the new triazoyl analogs indicate the potential of these molecules for possible application as adjuvants.