In vitro modulation the Notch pathway by piperine: A therapeutic strategy for docetaxel-resistant and non-resistant prostate cancer.

Docetaxel (DTX) resistance poses a significant challenge in the treatment of prostate cancer (PCa), often leading to chemotherapy failure. This study investigates the ability of piperine, a compound derived from black pepper, to enhance the sensitivity of PCa cells to DTX and elucidates its underlying mechanism. We established a DTX-resistant PCa cell line, DU145/DTX, to conduct our experiments. Through a series of assays, including MTT for cell viability, flow cytometry for apoptosis, Transwell for cell migration and invasion, and western blot for protein expression analysis, we assessed the effects of piperine on these cellular functions and on the Notch signaling pathway components. Our results demonstrated that we successfully established the DTX-resistant PCa cell line DU145/DTX. Piperine effectively decreased the viability of both DU145 and its DTX-resistant counterpart, DU145/DTX, in a concentration and time-dependent manner when used alone and in combination with DTX. Notably, piperine also induced apoptosis and reduced the migration and invasion capabilities of these cells. At the molecular level, piperine down-regulated the Notch pathway by inhibiting Notch1 and Jagged1 signaling, as well as reducing the expression of downstream effectors Hey1 and hes family bHLH transcription factor 1. The study concludes that piperine's ability to modulate the Notch signaling pathway and induce apoptosis highlights its potential as a complementary treatment for DTX-resistant PCa, paving the way for the use of traditional Chinese medicinal compounds in modern oncology treatment strategies.

A Validated HPLC-MS/MS Method for Simultaneous Determination of Militarine and Its Three Metabolites in Rat Plasma: Application to a Pharmacokinetic Study.

A rapid, reliable, and sensitive HPLC-electrospray ionization-tandem mass spectrometry (HPLC-MS/MS) method was established and validated for simultaneous determination of militarine and its three metabolites (gastrodin, α-isobutylmalic acid, and gymnoside I) in rat plasma. Plasma was acidified with formic acid, and protein was precipitated with methanol. MS/MS with ESI and multiple reaction monitoring at m/z 725.3→457.3, 457.1→127, 304.3→107.2, 189→129, and 417.1→267.1 was used for determination of militarine, gastrodin, α-isobutylmalic acid, gymnoside I, and puerarin (internal standard), respectively. Chromatographic separation was conducted using an ACE UltraCore SuperC18 (2.1 × 100 mm, 2.5 µm) column with gradient mobile phase (0.1% formic acid in water and acetonitrile). The lower limits of quantitation for militarine, gastrodin, α-isobutylmalic acid, and gymnoside I were 1.02, 2.96, 1.64, and 0.3 ng/mL, respectively. The relative standard deviations of intra- and interday measurements were less than 15%, and the method accuracy ranged from 87.4% to 112.5%. The extraction recovery was 83.52%-105.34%, and no matrix effect was observed. The three metabolites (gastrodin, α-isobutylmalic acid, and gymnoside I) were synchronously detected at 0.83 h, suggesting that militarine was rapidly transformed to gastrodin, α-isobutylmalic acid, and gymnoside I. Moreover, the area under the curve (AUC) and Cmax of militarine were significantly lower than those of gastrodin and α-isobutylmalic acid, showing that militarine was largely metabolized to gastrodin and α-isobutylmalic acid in vivo. The studies on pharmacokinetics of militarine and its three metabolites were of great use for facilitating the clinical application of militarine and were also highly meaningful for the potential development of militarine.

[Analysis of metabolites of quercitrin in rat intestinal flora by using UPLC-ESI-Q-TOF-MS/MS].

To investigate the metabolism of quercitrin in rat intestinal flora and possible biological pathways, laying the foundation for the metabolic mechanism of traditional Chinese medicine glycosides ingredients. UPLC-Q-TOF-MS/MS method was established to detect the quercitrin and its metabolites with 0.1% formic acid solution(A)-0.1% formic acid acetonitrile(B) as the mobile phase for gradient elution at a flow rate of 0.3 mL•min⁻¹. Electrospray negative ion mode was applied to analyze the metabolites of quercitrin in rat intestinal flora. Metabolite ToolsTM, mass defect filter(MDF) and other technologies were used to screen, analyze the metabolites and infer the chemical formula of the metabolites. The results showed that quercitrin would have degalactoside, deoxygenation and acetylation reactions, and the aglycone quercetin resulted from degalactoside would have further reactions such as hydroxylation, deoxygenation, reduction, and ring opening to achieve deoxygenation metabolite kaempferol, C2-C3 double bonds hydrogenation and reduction product taxifolin, and degalactoside product quercetin. The research results showed that quercitrin can be metabolized by rat intestinal flora, which could increase their hydrophobicity and chemical diversity.

A UPLC-MS/MS Method for Simultaneous Determination of Free and Total Forms of a Phenolic Acid and Two Flavonoids in Rat Plasma and Its Application to Comparative Pharmacokinetic Studies of Polygonum capitatum Extract in Rats.

The principal active constituents of Polygonum capitatum are phenolic acids and flavonoids, such as gallic acid, quercitrin, and quercetin. The aim of this study was to develop and validate a method to determine the three constituents and the corresponding conjugated metabolites of Polygonum capitatum in vivo and to conduct pharmacokinetic studies on the herb, a well-known Miao medicinal plant in China. Gallic acid, quercitrin, and quercetin were analysed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Protein precipitation in plasma samples was performed using methanol. For the determination of total forms of analytes, an additional process of hydrolysis was conducted using ß-glucuronidase and sulphatase. The analytes were separated on a BEH C18 column (50 mm × 2.1 mm; i.d., 1.7 µm) and quantified by multiple reaction monitoring (MRM) mode. The linear regression showed high linearity over a 729-fold dynamic range for the three analytes. The relative standard deviations of intra- and inter-day measurements were less than 9.5%, and the method was accurate to within -11.1% to 12.5%. The extraction recoveries for gallic acid, quercitrin, and quercetin were 94.3%-98.8%, 88.9%-98.8%, and 95.7%-98.5%, respectively. All samples were stable under short- and long-term storage conditions. The validated method was successfully applied to a comparative pharmacokinetic study of gallic acid, quercitrin, and quercetin in their free and total forms in rat plasma. The study revealed significantly higher exposure of the constituents in total forms for gallic acid and quercetin, while quercitrin was detected mainly in its corresponding free form in vivo. The established method was rapid and sensitive for the simultaneous quantification of free and total forms of multiple constituents of Polygonum capitatum extract in plasma.

HfO2/porous anodic alumina composite films for multifunctional data storage media materials under electric field control.

New materials for achieving direct electric field control of ferromagnetism and resistance behavior are highly desirable in the development of multifunctional data storage devices. In this paper, HfO2 nanoporous films have been fabricated on porous anodic alumina (PAA) substrates by DC-reactive magnetron sputtering. Electrically induced resistive switching (RS) and modulated room temperature ferromagnetism are simultaneously found in a Ag/HfO2/PAA/Al (Ag/HP/Al) heterostructure. The switching mechanism between low resistance state and high resistance state is generally attributed to the formation/rupture of conductive filaments which may consist of oxygen vacancies. The combination of the electric field control of magnetization change and RS makes HP films possible for the multifunctional data storage media materials.