Simultaneous Ultra Performance Liquid Chromatography Determination and Antioxidant Activity of Linarin, Luteolin, Chlorogenic Acid and Apigenin in Different Parts of Compositae Species

Linarin Ameliorates Restenosis After Vascular Injury in Type 2 Diabetes Mellitus via Regulating ADAM10-Mediated Notch Signaling Pathway

Vascular lesions frequently arise as complication in patients diagnosed with diabetes mellitus (DM). Presently, percutaneous coronary intervention (PCI) and antithrombotic therapy serve as primary treatments. However, in-stent restenosis persists as a challenging clinical issue following PCI, lacking sustained and effective treatment. Linarin (LN) exhibits diverse pharmacological activities and is regarded as a potential drug for treating various diseases, including DM. But its specific role in restenosis after vascular injury in DM patients remains unclear. A rat model of diabetes-related restenosis was established to evaluate the role of LN on neointimal hyperplasia. Vascular smooth muscle cells (VSMCs) stimulated by high glucose (HG, 30 mM) underwent LN treatment. Additionally, an overexpression plasmid of A disintegrin and metalloproteinases (ADAM10) was constructed to transfect VSMCs. We employed CCK-8, Brdu, wound-healing scratch, and transwell migration assays to evaluate the proliferation and migration of VSMCs. Furthermore, western blot and immunofluorescence assays were utilized to investigate the expressions of ADAM10 and the downstream Notch signaling pathway in vivo and in vitro models. LN notably alleviated intimal hyperplasia after vascular injury in DM rats and reduced the protein expression of ADAM10, alongside its downstream Notch1 signaling pathway-related proteins (Notch1, NICD and Hes1) in rat carotid artery tissues. LN effectively suppressed the proliferation and migration of VSMCs induced by HG, downregulating the protein expression of ADAM10, Notch1, NICD and Hes1. Moreover, our findings indicated that ADAM10 overexpression significantly reversed LN's effects on proliferation, migration, and the expression of Notch1 signaling pathway-related proteins in HG-treated VSMCs. LN demonstrates potential therapeutic efficacy in addressing restenosis after diabetic-related vascular injury, with the ADAM10 mediated Notch signaling pathway playing a pivotal role.

Determination of Luteolin and Apigenin in Herbal Teas by Online In-Tube Solid-Phase Microextraction Coupled with LC-MS/MS

Herbal teas have attracted attention as functional beverages containing luteolin and apigenin, which exhibit antioxidant and anti-inflammatory effects. The objective of this study was to develop a sensitive online automated method to determine these flavones' contents in herbal teas using in-tube solid-phase microextraction (IT-SPME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). These compounds were extracted and concentrated by IT-SPME using a Supel Q PLOT capillary column and then separated and detected within 6 min using a CAPCELL PAK C18 MG III analytical column and a negative electrospray ionization-mode multiple-reaction monitoring system by LC-MS/MS. The detection limits (S/N = 3) for luteolin and apigenin were 0.4 and 0.8 pg mL-1, respectively, and the calibration curves were linear in the range of 2-2000 pg mL-1 with correlation coefficients above 0.9995, and intra-day and inter-day precisions with relative standard deviations below 2.9 and 3.6% (n = 6), respectively. The luteolin and apigenin in herbal tea were quantified using IT-SPME/LC-MS/MS following the acid hydrolysis of their glycosides. Among the 10 herbal teas tested, luteolin was detected in peppermint and sage at concentrations of 375 and 99 µg mL-1, respectively, while apigenin was detected in German chamomile at 110 µg mL-1, which were higher than in the other herbal teas. The method is expected to be a useful method for evaluating the efficacy of luteolin and apigenin in herbal teas as functional beverages.

Phytochemistry, Pharmacology and Quality Control of Xiasangju: A Traditional Chinese Medicine Formula

As a traditional Chinese herbal formula, Xiasangju (XSJ) is widely used in China for antipyresis and influenza treatment. However, XSJ still fails to have a comprehensive summary of the research progress in the last decade. This review summarizes the advanced research on the extraction process, phytochemistry, pharmacological activity, and quality control of XSJ. Current research mainly focuses on quality control and the pharmacological effects of single herbs and active ingredients, but many pharmacological mechanisms of the formula are unclear. The development of active ingredients reflects the active characteristics of triterpenes, phenolic acids and flavonoids, but the hepatotoxicity of Prunella vulgaris L. has not been taken into account. XSJ has extensive historical practical experiences, while systematic clinical trials remain lacking. Therefore, it is necessary to study the active ingredients and define the mechanisms of XSJ to develop multiple applications, and further studies on the dose range between its hepatoprotective activity and hepatotoxicity are necessary to improve the safety of the clinical application. In this review, the current problems are discussed to facilitate the reference basis for the subsequent research on the development of XSJ and future application directions.

Fabrication of Stable Apigenin Nanosuspension with PEG 400 as Antisolvent for Enhancing the Solubility and Bioavailability

The purpose of this paper is to prepare a stable apigenin nanosuspension with a drug concentration of 1.11 mg/mL through green and efficient antisolvent method. Compared with the traditional preparation process that may use toxic reagents, in this study, a green and effective strategy was applied for the preparation of stable apigenin nanosuspension by using an antisolvent method with PEG 400 as antisolvent to improve the solubility and bioavailability. It was found that the particle size of apigenin nanosuspension was about 280 nm, and the solubility and dissolution of the nanosuspension were 33 and 3 times higher than that of the apigenin, respectively. Pharmacokinetic study showed that the C_max and AUC 0-8 h values of the nanosuspension in fasting rats achieved about 6- and 2.5-fold enhancement than that of the apigenin, respectively. Stability test showed that the apigenin nanosuspension could be stored stably for 12 months at 25℃. Taken together, the antisolvent method with PEG 400 was proven to be a green and effective method to prepare the stable nanosuspension of poorly soluble drugs.

Linarin, a Glycosylated Flavonoid, with Potential Therapeutic Attributes: A Comprehensive Review

Many flavonoids, as eminent phenolic compounds, have been commercialized and consumed as dietary supplements due to their incredible human health benefits. In the present study, a bioactive flavone glycoside linarin (LN) was designated to comprehensively overview its phytochemical and biological properties. LN has been characterized abundantly in the Cirsium, Micromeria, and Buddleja species belonging to Asteraceae, Lamiaceae, and Scrophulariaceae families, respectively. Biological assessments exhibited promising activities of LN, particularly, the remedial effects on central nervous system (CNS) disorders, whereas the remarkable sleep enhancing and sedative effects as well as AChE (acetylcholinesterase) inhibitory activity were highlighted. Of note, LN has indicated promising anti osteoblast proliferation and differentiation, thus a bone formation effect. Further biological and pharmacological assessments of LN and its optimized semi-synthetic derivatives, specifically its therapeutic characteristics on osteoarthritis and osteoporosis, might lead to uncovering potential drug candidates.

Analytical determinations of luteolin

Plants, through the photosynthesis process, produce the substances necessary for all the life cycles of nature, which are called "primary metabolites." Moreover, there are some plants that synthesize, in addition to these, other substances with more specific functions, which are known as "secondary metabolites." It is inside this group that flavonoids are located, whose main function is to protect organisms from damage caused by different oxidizing agents. Luteolin (3,4,5,7-tetrahydroxy-flavone) belongs to the sub-class of flavonoids known as flavones and is one of 10,000 flavonoids currently known, being one of the most bio-active flavonoids. Its various beneficial properties for health, together with the increasing reduction in the use of synthetic antioxidants, make the study of luteolin a very active field. Within this, the quantification of this molecule has become a subject of very special interest given that it is transversal to all fields. In this review article, we aim to give the reader a broad and deep vision of this topic, focusing on the events reported in the last 5 years and covering all possible techniques related to analytical determinations. We will discuss in terms of advantages and disadvantages between techniques, selectivity, sensitivity, costs, time consumption, and reagents as well as in the complexity of operations.

Phenolic and Carotenoid Profile of Lamb's Lettuce and Improvement of the Bioactive Content by Preharvest Conditions

This study characterizes the phenolic, carotenoid and chlorophyll profile of lamb's lettuce, a vegetable whose consumption in salads and ready-to-eat products is constantly growing. The MS/MS analysis allowed the identification of thirty-five phenolic compounds including hydroxybenzoic and hydroxycinnamic acids, flavanones, flavanols and flavanones, many of which are reported here in lamb's lettuce for the first time. Chlorogenic acid was the principal phenolic compound found (57.1% of the total phenolic concentration) followed by its isomer cis-5-caffeoylquinic. Other major phenolic compounds were also hydroxycinnamic acids (coumaroylquinic, dicaffeoylquinic and feruloylquinic acids) as well as the flavones luteolin-7-rutinoside, diosmetin-apiosylglucoside and diosmin. Regarding carotenoids, seven xanthophyll and four carotenes, among which β-carotene and lutein were the major compounds, were detected from their UV-Vis absorption spectrum. In addition, chlorophylls a and b, their isomers and derivatives (pheophytin) were identified. Preharvest factors such as reduced fertilization levels or salinity increased some secondary metabolites, highlighting the importance of these factors on the final nutritional value of plant foods. Lamb's lettuce was seen to be a good potential source of bioactive compounds, and fertilization management might be considered a useful tool for increasing its nutritional interest.

Comparison of Phenolic Compounds and the Antioxidant Activities of Fifteen Chrysanthemum morifolium Ramat cv. 'Hangbaiju' in China

This study investigated the phenolic compounds of 15 Chrysanthemum morifolium Ramat cv. ‘Hangbaiju’, including 6 ‘Duoju’ and 9 ‘Taiju’, using high performance liquid chromatography (HPLC). The antioxidant activities of these ‘Hangbaiju’ were estimated by DPPH, ABTS and FRAP assays. Results show that a total of 14 phenolic compounds were detected in these flowers, including 3 mono-caffeoylquinic acids, 3 di-caffeoylquinic acids, 1 phenolic acid and 7 flavonoids. ‘Duoju’ and ‘Taiju’ possess different concentrations of phenolic compounds, and ‘Taiju’ exhibits higher caffeoylquinic acids and stronger antioxidant activities than ‘Duoju’. Caffeoylquinic acids show a strong correlation with the antioxidant activities of the samples. Principal component analysis (PCA) reveals an obvious separation between ‘Duoju’ and ‘Taiju’, using phenolic compounds as variables. Apigenin-7-O-glucoside, 3,5-di-O-caffeoylquinic acid, luteolin and acacetin were found to be the key phenolic compounds to differentiate ‘Duoju’ from ‘Taiju’.

Isochlorogenic acid C prevents enterovirus 71 infection via modulating redox homeostasis of glutathione

Enterovirus 71 (EV71) is a key pathogen of hand, foot and mouth disease (HFMD) in children under 6 years of age. The antiviral potency of antioxidant isochlorogenic acid C (ICAC) extracted from foods was evaluated in cellular and animal models. First, the cytotoxicity of ICAC on Vero cells was investigated. The viral plaques, cytopathic effects and yield induced by EV71 infection were obviously reduced by ICAC, which was consistent with the investigation of VP1 transcripts and protein expression. Moreover, the mortality, weight loss and limb paralysis of mice caused by EV71 challenge were remarkably relieved by ICAC injection, which was achieved through decreases in the viral load and cytokine secretion in the mouse brain. Further biochemical assays showed that ICAC modulated several antioxidant enzymes involved in reduced and oxidized glutathione (GSH and GSSG) homeostasis, including glutathione reductase (GR), glutathione peroxidase (GPX), and glucose-6-phosphate dehydrogenase (G6PD), resulting in restoration of the GSH/GSSG ratio and reactive oxygen species (ROS) level. Finally, the antiviral effects of ICAC were dose-dependently disrupted by BSO, a biosynthesis inhibitor of GSH. This study indicated that ICAC acted as an antioxidant and prevented EV71 infection by modulating the redox homeostasis of glutathione.

Rapid High Performance Liquid Chromatography Determination and Optimization of Extraction Parameters of the α-Asarone Isolated from Perilla frutescens L

Response surface methodology (RSM), based on a central composite design, was used to determine the best liquid-to-raw material ratio (10:3–15 mL/g), extraction time (1–3 h), and ethanol concentration (50%–100%) for maximum content of α-asarone from Perilla frutescens (PF) extract. Experimental values of α-asarone were 9.51–46.36 mg/g; the results fitted a second-order quadratic polynomial model and correlated with the proposed model (R² > 0.9354). The best conditions were obtained with extraction time of 1.76 h, liquid-to-raw material ratio of 10:13.5 mL/g, and ethanol concentration of 90.37%. Under these conditions, the model predicted extraction content of 40.56 mg/g, while experimental PF content of α-asarone was 43.84 mg/g dried plant. Optimized conditions determined for maximum content of α-asarone were similar to the experimental range. Experimental values agreed with those predicted, thus validating and indicating suitability of both the model and the RSM approach for optimizing extraction conditions. In addition, a reliable, reproducible and accurate method for the quantitative determination of α-asarone by High Performance Liquid Chromatography (HPLC) analysis was developed with limit of detection (LOD), limit of quantitation (LOQ) values of 0.10 and 0.29 µg/mL and excellent linearity (R² > 0.9999).