Considering the importance of ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (UPLC-ESI-QTOF-MS/MS) hyphenated techniques for analysis of secondary metabolites from crude extracts, the present study was aimed at identification of secondary metabolites in acetone extract of the lichen Usnea longissima. From our study, 19 compounds were tentatively identified through comparison of exact molecular masses from their MS/MS spectra, mass fragmentation studies and comparison with literature data. In addition, potent cytotoxic activity of U. longissima extract prompted us to isolate four compounds, 18R-hydroxy-dihydroalloprotolichesterinic acid (19), neuropogolic acid (20), barbatic acid (21), and usnic acid (22) from this extract which were adequately identified through mass spectrometry and NMR spectroscopy. All four compounds displayed cytotoxic activity. Barbatic acid (21) manifested doxorubicin equivalent activity against A549 lung cancer cell line with IC50 of 1.78 µM and strong G0/G1 accumulation of cells. Poly ADP-ribose polymerase (PARP) cleavage confirmed that it induced cytotoxic activity via apoptosis. Finally, our work has discerned the depside, barbatic acid (21) from crude extract as a candidate anti-cancer molecule, which induces cell death by stepping up apoptosis.
Emulsions play an important role in present-day subunit vaccine delivery. Squalane-based emulsion was formulated using surfactants viz., Pluronic F68, Span 85 along with Murabutide (MB) as immunepotentiator. Particle size and zetapotential of the final optimized emulsion was found to be 134 nm and -13 mV, respectively. The in vitro cellular uptake studies performed using fluorescein isothiocyanate (FITC)-labeled ovalbumin (OVA) clearly revealed the rapid uptake of antigen in the presence of emulsion. The in vivo subcutaneous studies involving measurement of OVA-specific IgG antibody titers, Th1/Th2 cytokines were performed and a marked up regulation in IL-2, IL-12 and IFN-γ cytokines indicate Th1 immune response. Results supported that the squalane-based delivery system enhanced the uptake of the antigen by immune cells and elicited humoral as well as cell-mediated immune response in mice. These results indicate the promising application of the new squalane based oil-in-water (O/W) emulsion as capable vaccine delivery system useful for vaccine development.
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.
Research on amalgamation of an antigen with a delivery system for developing a potent mucosal vaccine that elicits both cellular and humoral response has captured immense attention these days. Cationic delivery systems being the first choice for mucosal antigen delivery, despite being effective, are associated with inherent problems like cytotoxicity. Therefore, the quest for developing a precise system that can effectively deliver antigen to immune cells without adverse toxic effect has led to the use of partial cationic systems which are mostly humoral immune mediators. The art of fine-tuning cationic nature, avoiding side effects, and being immune responsive are the needs of the hour. Herein, we try to optimize the cationic nature of polycaprolactone (USFDA approved) by conjugating it with hydrazine. The polymer was modified using two stoichiometry ratios (5 and 10 equiv) of hydrazine monohydrate and characterized using FTIR and XRD. Free amine quantification of the modified polymers concluded that both the modified polymers had 232 and 457 μM/mg amine groups, respectively. A cytotoxicity assay performed using RAW 264.7 macrophages proved the safety of cationic polymers. In vitro assays for antigen colocalization and cross-presentation have revealed that the modified polymers could effectively execute the anticipated function. In vivo evaluation in BALB/c mice using recombinant dengue antigen for intranasal immunization affirmed that the modified polymer having 457 μM/mg of free amine groups effectively stimulated humoral and potent cellular immune response. The overall data suggests that the modified polymeric nanoparticleswith their cationic, pH-responsive, and adjuvanting characteristicsproved to be a versatile system for effective mucosal antigen delivery.
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