A newly developed UPLC-MS/MS method for simultaneous quantitative analysis of ajuforrestin A, ajuforrestin B, ajugamacrin and 8-O-acetylharpagide derived from Ajuga plants in mice blood and the in vivo pharmacokinetics.

OBJECTIVE: To develop a sensitive and fast detection method via ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to assess the concentration of ajuforrestin A, ajuforrestin B, ajugamacrin and 8-O-Acetylharpagide primarily derived from Ajuga plants in mice blood and their pharmacokinetics. METHODS: Single protein precipitation with high-proportioned acetonitrile is chosen for sample clean-up. The UPLC HSS T3 (2.1 mm × 100 mm, 1.8 µm) column with a mobile phase in gradient elution mode at the flow rate of 0.4 mL/min was used for sample separation. Acetonitrile was selected as the organic phase solution and water containing 0.1% formic acid was chosen as the aqueous solution. A tandem mass spectrometer containing an electrospray ionization (ESI) source in the positive ionization mode was used to detect four compounds via multiple reaction monitoring (MRM). RESULTS: The calibration curves (5-1000 ng/mL) of four compounds were linear with correlation coefficients > 0.997. The matrix effects, accuracy, precision, and recovery were all within permissible scope. CONCLUSIONS: In this approach, the corresponding pharmacokinetic parameters were successfully clarified in mouse for the first time, which provided a theoretical basis for the improvement of the standard of Ajuga plants and the safety of clinical medication. Furthermore, this method may provide the UPLC-MS/MS evidence for the differentiation of the main close relative varieties of genus Ajuga according to these plants contain different mixtures of the four marker compounds.

High throughput-screening of native herbal compounds identifies taccaoside A as a cytotoxic compound that mediates RAS signaling in cancer stem cells.

BACKGROUND: Cancer stem cells (CSCs) are characterized by their ability to self-renew, to differentiate into multiple cell types and also drive tumor formation, altogether making them important cellular targets for therapeutic intervention. However, existing CSC-targeting drugs do not significantly improve clinical outcomes. More recently, preclinical studies of natural product-derived compounds have demonstrated their potential usefulness as a therapeutic cancer treatment through their cytotoxic actions on CSCs. PURPOSE: Here, we identify CSC-specific compounds derived from natural products and characterize their putative mechanisms of action in CSCs. METHODS: Glioblastoma stem cells (GSCs) were labeled with EGFP via homologous recombination and utilized for a high-throughput screen of 8,344 fractions from 386 herbal medicines. The fractions that extinguished EGFP fluorescence signal were then further characterized by LC-MS/MS. Next, several putative cytotoxic compounds were evaluated for their cytotoxic effects on GSCs, cancer cell lines and immortalized cells using a variety of methods to study cell proliferation (EdU incorporation assay), cell death (cleaved-Caspase-3 immunostaining), DNA damage (comet assay), mitochondrial membrane changes (JC-1 immunostaining), and tumor formation in vitro (soft agar colony forming assay). We also performed surface plasmon resonance analysis, western blotting, and immunohistochemistry to characterize the putative mechanisms underlying the cytotoxic effects of putative compounds on GSCs. Finally, we carried out xenograft tumor growth assays to study the cytotoxic potential of several candidates in vivo. RESULTS: Our high throughput screen led to the identification of the furostanol saponin taccaoside A and its two homologs from the rhizomatous geophyte Tacca. subflabellata that were cytotoxic to GSCs. Interestingly, the cytotoxic effect of taccaoside A on cell lines was significantly less compared to its homologs, owing to stereochemical differences of a carbon-carbon double bond between C-20 and C-22. Molecular studies revealed that taccaoside A binds to RAS to inhibit downstream effector signaling. Correspondingly, blockade of the interaction between taccaoside A and RAS abolished the inhibitory effect of this compound on CSCs. Furthermore, taccaoside A treatment was effective in limiting tumor cell growth in vivo. CONCLUSION: Our study yielded an effective approach to screen for CSC-specific agents. Through this approach, we identified taccaoside A from the rhizomatous geophyte Tacca. subflabellata are cytotoxic to CSCs through a molecular mechanism that involves RAS binding and suppression of its downstream signaling. Our findings indicate taccaoside A is a potential lead compound for anti-CSC drug discovery.

Achieving visible and near-infrared dual-emitting mechanoluminescence in Mn2+ single-doped magnesium aluminate spinel.

Visible (VIS) and near-infrared (NIR) mechanoluminescence (ML) materials have been developed rapidly for use in energy conversion, biological applications and mechanical sensing. The realization of visible and NIR ML in single host materials meets the dual requirements of visualization and anti-interference for high-precision mechanical sensing. In this work, Mn2+ single-doped magnesium aluminate spinel MgAl2O4 with excellent ML performance was studied in detail. Bright, visible green and NIR ML were achieved under mechanical stimulation, and the ratio between visible and NIR ML intensity can be regulated by manipulating the doping concentration of Mn2+. The generation of ML without additional pre-irradiation proved that the self-powered ML phenomenon was independent of trap. The functional relationship between mechanical parameters and ML intensity indicated that the doped spinel can be used for visualization, anti-interference and non-contact mechanical sensing. In addition, the NIR ML of MgAl2O4:Mn2+, centered at 835 nm, is located in the first NIR window (NIR-I, 650-950 nm), which effectively penetrates living tissue such as skin, fat, and lean meat, respectively, showing that it has potential applications in in vivo optical imaging.

Combination Treatment of Citral Potentiates the Efficacy of Hyperthermic Intraperitoneal Chemoperfusion with Pirarubicin for Colorectal Cancer.

Citral is a widely used penetration enhancer that has been used to assist the delivery of drugs through the skin. In this study we aimed to investigate the effectiveness of combination treatments of citral with hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal cancer and to unravel the underlying mechanism by which citral increased the efficacy of HIPEC. In vitro experiments indicated that citral increased cytoplasmic absorption of pirarubicin and potentiated the effects of pirarubicin on colorectal cancer cells to induce apoptosis. Intracellular reactive oxygen species (ROS) activity was elevated after single or combo treatments with pirarubicin, leading to compromised NF-κB signaling. Therefore, the results suggested that the effects of citral were mediated by increasing cell permeability and ROS productions. Furthermore, the colorectal xenograft model was used to evaluate the efficacy of the combo treatment at the histological and molecular levels, which showed that the cotreatment with citral for colorectal cancer increased the efficacy of HIPEC with pirarubicin with respect to both ascite control and tumor load. The results indicated that citral was an effective additive for HIPEC with pirarubicin for colorectal cancer, which warrant further effort to explore the translational application of this new treatment regimen.