PEEK tube-based online solid-phase microextraction-high-performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study

Ultra-thin FeCoNi-LDH hollow nanoflower as solid-phase microextraction coating for targeted capture of six pesticides by electrostatic adsorption

Pesticides are common pollutants that cause detriment to the ecological environmental safety and health of human due to their toxicity, volatility and bioaccumulation. In this work, an ultra-thin polymetallic layered double hydroxide (FeCoNi-LDH) with hollow nanoflower structure composite was synthesized using ZIF-67 as a self-sacrificial template, which was used as solid-phase microextraction (SPME) coating for the targeted capture pesticides, which could be combined with high-performance liquid chromatography (HPLC) to sensitive inspection pesticides in real water samples. Orthogonal experimental design (OAD) was applied to ensure the best SPME condition. Additionally, the adsorption properties were evaluated by chemical thermodynamics and kinetics. Under the optimized conditions, high adsorption capacity was obtained (117.0-21.5 mg g-1). A wide linear range (0.020-1000.0 μg L-1), low detection limit (0.008-0.172 μg L-1) and excellent reproducibility were obtained under the established method. This research provided a new strategy for designing hollow materials with multiple cations for the adsorption of anion or organic pollutants.

Yohimbine, an α2-Adrenoceptor Antagonist, Suppresses PDGF-BB-Stimulated Vascular Smooth Muscle Cell Proliferation by Downregulating the PLCγ1 Signaling Pathway

Yohimbine (YOH) has antiproliferative effects against breast cancer and pancreatic cancer; however, its effects on vascular proliferative diseases such as atherosclerosis remain unknown. Accordingly, we investigated the inhibitory mechanisms of YOH in vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF)-BB, a major mitogenic factor in vascular diseases. YOH (5–20 μM) suppressed PDGF-BB-stimulated a mouse VSMC line (MOVAS-1 cell) proliferation without inducing cytotoxicity. YOH also exhibited antimigratory effects and downregulated matrix metalloproteinase-2 and -9 expression in PDGF-BB-stimulated MOVAS-1 cells. It also promoted cell cycle arrest in the initial gap/first gap phase by upregulating p27Kip1 and p53 expression and reducing cyclin-dependent kinase 2 and proliferating cell nuclear antigen expression. We noted phospholipase C-γ1 (PLCγ1) but not ERK1/2, AKT, or p38 kinase phosphorylation attenuation in YOH-modulated PDGF-BB-propagated signaling pathways in the MOVAS-1 cells. Furthermore, YOH still inhibited PDGF-BB-induced cell proliferation and PLCγ1 phosphorylation in MOVAS-1 cells with α2B-adrenergic receptor knockdown. YOH (5 and 10 mg/kg) substantially suppressed neointimal hyperplasia in mice subjected to CCA ligation for 21 days. Overall, our results reveal that YOH attenuates PDGF-BB-stimulated VSMC proliferation and migration by downregulating a α2B-adrenergic receptor–independent PLCγ1 pathway and reduces neointimal formation in vivo. Therefore, YOH has potential for repurposing for treating atherosclerosis and other vascular proliferative diseases.

Yohimbine hydrochloride inhibits benign prostatic hyperplasia by downregulating steroid 5α-reductase type 2

Benign prostatic hyperplasia (BPH) is a frequently encountered disease in older men that affects sexual function and is capable of causing lower urinary tract dysfunction. Unfortunately, current treatment options for BPH primarily seek to address the lower urinary tract dysfunction aspect of the disease and do not improve sexual function. Yohimbine has been effectively used for decades to treat erectile dysfunction. Therefore, the objective of this study was to evaluate the inhibitory effect of yohimbine on BPH and explore the associated underlying mechanisms. Thirty-six rats were randomly divided into the control, BPH, finasteride (1 mg/kg), and yohimbine (2, 4, and 8 mg/kg) groups. Except for the rats in the control group, those in the other groups were subcutaneously injected testosterone propionate (5 mg/kg/day) daily for a period of 4 weeks to establish BPH models. They were also administration the corresponding drug daily for a period of 6 weeks. After the treatments, in addition to determining prostate wet weight and index, the histopathological status of the prostate was observed, and the levels of testosterone, dihydrotestosterone, prostatic acid phosphatase, the prostate-specific antigen, proliferating cell nuclear antigen, and steroid 5α-reductase were determined. Specifically, the administration of 2, 4, and 8 mg/kg yohimbine inhibited prostatic index increase by 46.7, 55.1, and 69.3%, respectively, in BHP rats. Further, yohimbine significantly reduced the levels of dihydrotestosterone, prostatic acid phosphatase, prostate-specific antigen, proliferating cell nuclear antigen, and steroid 5α-reductase, suggesting that it exerts beneficial effects against BPH by modulating the steroid 5α-reductase pathway.

A Dual Ligand Sol⁻Gel Organic-Silica Hybrid Monolithic Capillary for In-Tube SPME-MS/MS to Determine Amino Acids in Plasma Samples

This work describes the direct coupling of the in-tube solid-phase microextraction (in-tube SPME) technique to a tandem mass spectrometry system (MS/MS) to determine amino acids (AA) and neurotransmitters (NT) (alanine, serine, isoleucine, leucine, aspartic acid, glutamic acid, lysine, methionine, tyrosine, and tryptophan) in plasma samples from schizophrenic patients. An innovative organic-silica hybrid monolithic capillary with bifunctional groups (amino and cyano) was developed and evaluated as an extraction device for in-tube SPME. The morphological and structural aspects of the monolithic phase were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption experiments, X-ray diffraction (XRD) analyses, and adsorption experiments. In-tube SPME-MS/MS conditions were established to remove matrix, enrich analytes (monolithic capillary) and improve the sensitivity of the MS/MS system. The proposed method was linear from 45 to 360 ng mL^-1 for alanine, from 15 to 300 ng mL^-1 for leucine and isoleucine, from 12 to 102 ng mL^-1 for methionine, from 10 to 102 ng mL^-1 for tyrosine, from 9 to 96 ng mL^-1 for tryptophan, from 12 to 210 ng mL^-1 for serine, from 12 to 90 ng mL^-1 for glutamic acid, from 12 to 102 ng mL^-1 for lysine, and from 6 to 36 ng mL^-1 for aspartic acid. The precision of intra-assays and inter-assays presented CV values ranged from 1.6% to 14.0%. The accuracy of intra-assays and inter-assays presented RSE values from -11.0% to 13.8%, with the exception of the lower limit of quantification (LLOQ) values. The in-tube SPME-MS/MS method was successfully applied to determine the target AA and NT in plasma samples from schizophrenic patients.

Utility of alkaloids as chemical and biomarkers for quality, efficacy, and safety assessment of botanical ingredients

BACKGROUND

Selecting the appropriate chemical and bio-markers for monitoring the quality, efficacy, and safety is critical for efficient and reliable assessment of traditional medicines derived from botanical sources. Chemical markers have been implicated primarily in establishing the analytical methodologies aiming at verification of the botanical sources of the raw materials, the extracts, and the finished products such as botanical dietary supplements and nutraceuticals. In addition, they have been employed in differentiation between crude or raw (unprocessed) and processed plant extracts, and identification as well as determination of potential toxicants and adulterants in herbal medicines. Additionally, these chemical markers are utilized for selection of efficient methods for extraction of plants. Further, biomarkers have been exploited in determination of the pharmacokinetic properties of bioactive herbal constituents. Alkaloids, unlike other plant constituents, are uniquely characterized by having basic properties, and possessing substantial and diverse pharmacological effects. These features make alkaloids attractive components for functioning as chemical and biomarkers in determining the quality of botanical ingredients where this class of phytochemicals prevail or is responsible for lending biological effects.

PURPOSE

The aim of the review is to exhibit the function of alkaloids as biomarkers and chemical markers in the evaluation of quality, efficacy, and safety of medicinal herbs and their commercial products.

METHODS

Literature acquisition was accomplished using the most commonly accessed scholarly search engines including SciFinder, PubMed, and Google Scholar. Secondly, the full-texts which are relevant to the topic were included in this review. This was followed by a thorough and detailed analysis of the collected information.

RESULTS

The literature search with main emphasis on the roles of alkaloids in the evaluation of quality, efficacy and safety of herbal medicines was evaluated to provide all succinct information in one place. Compilation of such critical information is expected to help the reader to appreciate alkaloids as important markers in the quality control of herbal drugs and products.

CONCLUSION

The current review article covers the fundamental roles played by alkaloids as chemical and biomarkers in assessing the essential parameters of the quality of botanical ingredients, as briefly described earlier. The utilization of alkaloids as biomarkers to determine the efficacy-linked pharmacokinetic parameters is limited to reviewing studies on human subjects.

Current direction and advances in analytical sample extraction techniques for drugs with special emphasis on bioanalysis

Analytical techniques may not be compatible or sufficiently sensitive to the analytes, unless it undergoes a specific sample extraction procedure. Sample extraction can be considered as one of the key steps in analysis. Analysis of a poorly treated sample may produce inferior quality of analytical data. Continuous advancement and development of newer sample extraction techniques such as solid phase microextraction, ultrasound, magnetically and microwave assisted magnetic extraction; electro-membrane extraction and dried blood spotting are to address the shortcomings of the existing techniques and to provide more automation, minimizing preparation time and make them high throughput. This review summarizes the suitability of application of the advanced sample preparation techniques available for chemical and bioanalysis in a comprehensive manner. This review also provides a scientific guidance for selecting the appropriate sample extraction technique based on sample type.