Synthesis and Biological Evaluation of Scutellaria Flavone Cyclaneaminol Mannich Base Derivatives as Novel CDK1 Inhibitors.

Cyclin-dependent kinase 1 (CDK1) is the only necessary CDK in the cell proliferation process and a new target in the research and development of anti-cancer drugs. Natural flavones are selective CDK1 inhibitors which can suppress the proliferation of cancer cells. However, their bioavailability is poor. To solve these problems, 6 Scutellaria flavones were isolated from hydrolyzed products of Scutellaria baicalensis and used as lead compounds, 18 Scutellaria flavones cyclane-aminol Mannich base derivatives were semi-synthesized and their biological activity as novel CDK1 inhibitors was evaluated. Results indicated that the biological activity of 8-Hydroxypiperidinemethyl-baicalein (BA-j) is the highest among these compounds. BA-j is a selective CDK1 inhibitor, and has broad-spectrum anti-proliferative activity in human cancer cells (IC50 12.3µM). BA-j can capture oxygen free radicals (.O2(-)) and selectively increase intracellular H2O2 level in cancer cells and activated lymphocytes, thus inducing their apoptosis rather than in normal cells. These findings suggest that BA-j selectively induces apoptosis in cancer and activated lymphocyte by controlling intracellular H2O2 level, and can be developed into a novel anti-proliferative agent for the treatment of cancer, AIDS, and some immune diseases.

Metabolism and pharmacokinetics of 8-hydroxypiperidinylmethyl-baicalein (BA-j) as a novel selective CDK1 inhibitor in monkey.

Cyclin-dependent kinase 1 (CDK1) is the only necessary CDK in the cell proliferation process and a new target in the research and development of anti-cancer drugs. 8-Hydroxypiperidinemethyl-baicalein (BA-j) is a Mannich base derivative of baicalein (BA) isolated from Scutellaria baicalensis, as a novel selective CDK1 inhibitor. 12 metabolites of BA-j in the monkey urine were identified by LC-MS-MS and (1)H NMR. The major metabolic pathways of BA-j, by capturing oxygen free radicals ((.)O2(-)) and releasing peroxides (H2O2), are degraded into active intermediate metabolite dihydroflavonol, then into main metabolite M179 by Shiff reaction, second metabolite M264 by sulfation, trace amount of metabolite M559 by glucuronidation UGT1A9, and without metabolism by CYP3A4. The metabolic process of BA-j by regulating intracellular reactive oxygen species (ROS) was related with BA-j selectively inducing apoptosis in cancer cells. Pharmacokinetics of 10mg/kg oral BA-j in monkey by HPLC-UV was best fitted to a two-compartment open model, with t1/2(ß) of 4.2h, Cmax 25.4µM at 2h, and Vd 12.6L, meaning the drug distributing widely in body fluids with no special selectivity to certain tissues, and being able to permeate through the blood-brain barrier. The protein binding rate of BA-j was 91.8%. BA-j has excellent druggability for oral administration or injection, and it may be developed into a novel anti-cancer drug as a selective CDK1 inhibitor.

BA-j as a novel CDK1 inhibitor selectively induces apoptosis in cancer cells by regulating ROS.

Cyclin-dependent kinase 1 (CDK1) is the only necessary CDK in cell proliferation and a novel target in the development of anticancer drugs. 8-Hydroxypiperidinemethyl-baicalein (BA-j) is a novel selective CDK1 inhibitor with broad spectrum anti-cancer activity (IC50 12.3 µM) and 2 tumor xenografts. Because of the differential mechanisms controlling redox-states in normal and cancer cells, BA-j can capture oxygen free radicals ((·)O2(-)) and selectively increase the level of H2O2 in cancer cells, thereby specifically oxidize and activate the intrinsic apoptosis pathway bypassing the extrinsic death receptor pathway, thus inducing apoptosis in cancer cells rather than in normal cells. BA-j is different from cytotoxic anticancer drugs which can activate both the intrinsic apoptosis pathway and the extrinsic death receptor pathway, and therefore harm normal cells while killing cancer cells. The molecular and biochemical mechanisms of reactive oxygen species (ROS) regulation suggest that BA-j may be developed into a novel anticancer agent.

Preparation and stability of diallyl trisulfide self-assembled micellar injection.

Diallyl trisulfide (DATS) has shown various biological activities, such as antimicrobial, antihyperlipidemic, antithrombotic, and anticancer effects. It is a highly water insoluble thioether compound, which irritates blood vessels and degrades rapidly under normal conditions. Hence, a suitable DATS delivery system and the related stability studies are both valuable for the clinical use of DATS. The DATS micellar injection in the present study was prepared using propylene glycol, alcohol, Tween 80, and water by the self-assembling micellar method, which effectively avoided irritation and degradation of DATS. The high-pressure liquid chromatography-UV assay method was established and validated for the quantitative determination of DATS micellar injection. The major degraded compounds were identified as diallyl disulfide and diallyl tetrasulfide by gas chromatography-mass spectrometry. 3-ethenyl-3,6-dihydro-1,2-dithiin and 3-ethenyl-3,4-dihydro-1,2-dithiin might be the thermal decomposed products of DATS in process of gas chromatography-flame ionization detector analysis. The main factor influencing stability in DATS micellar injection was ascertained to be temperature. This investigation might be a beneficial contribution to further identification of DATS-degraded products and exploration of the delivery system of DATS.

Evaluation of poly(D,L-lactide-co-glycolide) microspheres for the lung-targeting of yuanhuacine, a novel DNA topoisomerase I inhibitor.

The present study was intended to develop poly(D,L-lactide-co-glycolide) (PLGA; 50:50, 0.15 dL/g) microspheres (MS) loaded with yuanhuacine (YHC) for passive targeting in lung as well as providing a simple evaluation method for the targeting efficiency of MS. A kind of photochromic spiropyran dye was applied to label MS to clearly demonstrate the in vivo distribution characteristics through intravenous injection into mice and rabbits. Sections of 10-microm thickness from different organs were cut using a microtome, and fluorescent microscopy was used to determine the biodistribution of the MS. The average particle size of MS was 9.0 microm, and the glass transition temperature was 37-40 degrees C. In vitro, the cumulative release achieved 50.8% in 24 h. Histological sections from different organs indicated that the amount of MS in lung achieved maximum in 6 h, as about 8 times as in liver and 70 times higher than the average concentration of other organs. In vivo, MS were gradually swelled and drug concentration remained just 10% in 12 h, which would not result in long time embolization in the lung. This evaluation method supplies a simple and visualized channel in focus for the targeting efficiency of PLGA MS.