Avicularin, a plant flavonoid, suppresses lipid accumulation through repression of C/EBPα-activated GLUT4-mediated glucose uptake in 3T3-L1 cells

Exploring the potential of phenolic and antioxidant compounds in new Rosaceae fruits

BACKGROUND

Rosaceae fruits have been used in traditional medicine for the prevention and treatment of diseases. However, these fruits have not extensively been studied regarding their phenolic composition. Thus, this research focuses on the determination of phenolic compounds by high-performance liquid chromatography electrospray ionization time-of-flight mass spectrometry, flavan-3-ols by high-performance liquid chromatography with fluorescence detection, and the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric reducing antioxidant power of the fruits of five species of genera Crataegus and Sorbus (Rosaceae).

RESULTS

We found a total of 71 phenolic compounds from which 30 were identified in these berries for the first time. Crataegus monogyna and Crataegus laciniata revealed higher total phenolic and flavan-3-ol contents than the other species and the highest antioxidant activities.

CONCLUSIONS

Therefore, the fruits evaluated have demonstrated to be important sources of bioactive compounds with huge potential for being used in nutraceutical or food scopes. Additional studies could be needed to evaluate the influence of the different production areas on the phenolic content. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The α-glucosidase inhibitory activity of avicularin and 4-O-methyl gallic acid isolated from Syzygium myrtifolium leaves

Diabetes Mellitus is the main cause of death on a global scale. In 2019, there were 463 million people with diabetes, and WHO predicts that by 2030, there will be 578 million. As an antidiabetic agent, α-glucosidase inhibitors are one of the methods employed to reduce the prevalence of diabetes. Diabetes is traditionally treated with Syzygium as a primary material, medicine, fruit, ornamental plant, and source of carpentry. This investigation aimed to examine the inhibitory effect of seven species of Syzygium against α-glucosidase enzyme using an in vitro assay and isolate active substances and ascertain their concentrations in each sample. As a solvent, ethanol was used in maceration to extract the substance. Afterward, the extract underwent a series of fractionation techniques, including liquid-liquid extraction, vacuum liquid chromatography, column chromatography, and preparative Thin Layer Chromatography (TLC) for purification and isolation. The compound's structures were elucidated using TLC, UV-Visible spectrophotometry, and nuclear magnetic resonance (NMR) spectroscopy. Based on concentrations of 100 and 200 µg/mL, Syzygium myrtifolium exhibited the most significant inhibitory effect, followed by other species of Syzygium. The proportion of ethyl acetate had the strongest activity (IC₅₀ 0.40 ± 0.02 µg/mL) contrasted to positive control acarbose (IC₅₀ 55.39 ± 0.67 g/mL) and quercitrin (IC₅₀ 6.47 ± 0.40 µg/mL). Avicularin and 4-O-methyl gallic acid were discovered in the ethyl acetate fraction of Syzygium myrtifolium with IC₅₀ values of 17.05 ± 0.75 µg/mL and 25.19 ± 0.21 µg/mL, respectively. As α-glucosidase inhibitory, the results of this study indicate Syzygium myrtifolium can be used as a dietary supplement to manage hyperglycemia.

Hepatoprotective effect of avicularin on lead-induced steatosis, oxidative stress, and inflammation in mice associated with the MAPK/HSP60/NLRP3 and SREBP1c pathway

Lead (Pb), an environmental hazard, causes severe diseases in the liver, kidney, cardiovascular system, hematopoietic system, reproductive system, and nervous system. Avicularin (AVI), the main dietary flavonoid found in many citrus fruits, exhibited potential protective properties on organs. However, the molecular mechanisms of these protective actions are currently not clear. In our study, the effects of AVI on Pb-induced hepatotoxicity were evaluated using ICR mice. Changes in oxidative stress, inflammation, lipid metabolism, and related signaling were evaluated. We found for the first time that treatment with AVI significantly reduced hepatic steatosis, inflammation, and oxidative stress induced by Pb. AVI attenuated Pb-induced liver dysfunction and lipid metabolism disorder in mice. AVI decreased the serum biochemical indicators of lipid metabolism. AVI decreased the expression levels of lipid metabolism-related protein SREBP-1c, acetyl-CoA carboxylase (ACC), and FAS. AVI suppressed Pb-induced inflammation in livers, as indicated by decreasing the TNF-α and IL-1β levels. AVI suppressed oxidative stress by increasing the activation of SOD, CAT, and GPx. Furthermore, AVI inhibited the activities of JNK, ERK, p38, and NF-κB. AVI further decreased the levels of HSP60, NLRP3, p-IκBα, and p-p65 in the livers of mice. Collectively, this study indicated that AVI mitigated Pb-induced hepatic steatosis, oxidative stress, and inflammation by regulating the SREBP-1c and MAPK/HSP60/NLRP3 signaling pathways.

Avicularin Alleviates Osteoporosis in Ovariectomized Mice by Inhibiting Osteoclastogenesis through NF-κB Pathway Inhibition

Osteoporosis (OP) is mainly manifested by bone loss and bone degeneration. OP is considered a risk factor for pathological fractures, as well as impacts the health of middle-aged and elderly individuals. Drug therapy remains the main treatment scheme for OP; however, its efficacy is limited and has been associated with serious side effects. Therefore, it is important to develop new, effective, and safe treatment methods for OP. Avicularin (AL) is a flavonoid and quercetin derivative from various plants. Our study showed that AL disrupts osteoclast activation and resorptive function via inhibition of the RANKL-induced osteoclast differentiation together with the resorption capacity of bone marrow-derived macrophages (BMMs). Hence, AL prevents the activation and resorptive activity of osteoclasts. The results of qPCR showed that genes related to osteoclasts exhibited downregulated expression after AL treatment. Furthermore, AL inhibited RANKL-induced phosphorylation as well as degradation of the inhibitor IκBα of the NF-κB pathway, together with P65 phosphorylation in BMMs. We used an OP mouse model that was established by ovariectomy (OVX). Relative to untreated OP mice, mice that received AL treatment showed a significant increase in bone mineral density; however, the expression of TRAP, NFATC1, mmp9, and CTX-1 was significantly reduced. These results indicate that AL disrupts osteoclastogenesis via inhibition of the NF-κB pathway, which in turn improves OVX-induced OP.

Taxillus chinensis (DC.) Danser: a comprehensive review on botany, traditional uses, phytochemistry, pharmacology, and toxicology

BACKGROUND

Taxillus chinensis (DC.) Danser (T. chinensis), known as "Sangjisheng" in Chinese, is a member of the family Loranthaceae, with the traditional functions of "dispelling wind dampness, strengthening bones and muscles, and preventing miscarriage". Since Eastern Han dynasty, it has been used for the treatment of rheumatoid arthritis, arthralgia, threatened abortion, and hypertension. Nowadays, T. chinensis is included in the 2020 Edition of the Chinese Pharmacopoeia as Taxilli Herba. The purpose of this review is to summarize the latest research on T. chinensis in recent years, and make critical comments, so as to provide reference for the clinical application and modern research of T. chinensis.

MAIN BODY

In this review, we summarize the botany, traditional uses, and research advances in the phytochemistry and pharmacological effects of T. chinensis. Its toxicity has also been discussed. The published literature on current pharmacological and toxicological data has also been assessed. To date, approximately 110 compounds, including flavonoids, phenolic acids, phenylpropanoids, tannins, glycosides, amino acids, and nucleosides, have been identified in T. chinensis. Flavonoids are considered the most vital bioactive ingredients in T. chinensis. Pharmacological studies have demonstrated that T. chinensis possesses anti-inflammatory, antioxidant, anticancer, antimicrobial, antiviral, diuretic, antihypertensive, antihyperglycemic, and other properties.

CONCLUSION

Currently, research on T. chinensis is in the preliminary stages, and further research is required to understand the active compounds present and mechanisms of action. We hope that this comprehensive review of T. chinensis will serve as a background for further research.

Molecular docking, simulation and binding free energy analysis of small molecules as PfHT1 inhibitors

Antimalarial drug resistance has thrown a spanner in the works of malaria elimination. New drugs are required for ancillary support of existing malaria control efforts. Plasmodium falciparum requires host glucose for survival and proliferation. On this basis, P. falciparum hexose transporter 1 (PfHT1) protein involved in hexose permeation is considered a potential drug target. In this study, we tested the antimalarial activity of some compounds against PfHT1 using computational techniques. We performed high throughput virtual screening of 21,352 small-molecule compounds against PfHT1. The stability of the lead compound complexes was evaluated via molecular dynamics (MD) simulation for 100 nanoseconds. We also investigated the pharmacodynamic, pharmacokinetic and physiological characteristics of the compounds in accordance with Lipinksi rules for drug-likeness to bind and inhibit PfHT1. Molecular docking and free binding energy analyses were carried out using Molecular Mechanics with Generalized Born and Surface Area (MMGBSA) solvation to determine the selectivity of the hit compounds for PfHT1 over the human glucose transporter (hGLUT1) orthologue. Five important PfHT1 inhibitors were identified: Hyperoside (CID5281643); avicularin (CID5490064); sylibin (CID5213); harpagoside (CID5481542) and quercetagetin (CID5281680). The compounds formed intermolecular interaction with the binding pocket of the PfHT1 target via conserved amino acid residues (Val314, Gly183, Thr49, Asn52, Gly183, Ser315, Ser317, and Asn48). The MMGBSA analysis of the complexes yielded high free binding energies. Four (CID5281643, CID5490064, CID5213, and CID5481542) of the identified compounds were found to be stable within the PfHT1 binding pocket throughout the 100 nanoseconds simulation run time. The four compounds demonstrated higher affinity for PfHT1 than the human major glucose transporter (hGLUT1). This investigation demonstrates the inhibition potential of sylibin, hyperoside, harpagoside, and avicularin against PfHT1 receptor. Robust preclinical investigations are required to validate the chemotherapeutic properties of the identified compounds.

Peroxisome proliferator-activated receptor gamma as a therapeutic target for hepatocellular carcinoma: Experimental and clinical scenarios

Hepatocellular carcinoma (HCC) is the most common type of liver cancer worldwide. Viral hepatitis is a significant risk factor for HCC, although metabolic syndrome and diabetes are more frequently associated with the HCC. With increasing prevalence, there is expected to be > 1 million cases annually by 2025. Therefore, there is an urgent need to establish potential therapeutic targets to cure this disease. Peroxisome-proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that plays a crucial role in the patho-physiology of HCC. Many synthetic agonists of PPARγ suppress HCC in experimental studies and clinical trials. These synthetic agonists have shown promising results by inducing cell cycle arrest and apoptosis in HCC cells and preventing the invasion and metastasis of HCC. However, some synthetic agonists also pose severe side effects in addition to their therapeutic efficacy. Thus natural PPARγ agonists can be an alternative to exploit this potential target for HCC treatment. In this review, the regulatory role of PPARγ in the pathogenesis of HCC is elucidated. Furthermore, the experimental and clinical scenario of both synthetic and natural PPARγ agonists against HCC is discussed. Most of the available literature advocates PPARγ as a potential therapeutic target for the treatment of HCC.

Health Benefits of Avicularin in the Medicine Against Cancerous Disorders and other Complications: Biological Importance, Therapeutic Benefit and Analytical Aspects

Background:

Herbal drugs and their derived phytochemicals have been used in medicine for the preparation of different types of pharmaceutical products. Pure phytochemicals including flavonoids, alkaloids and terpenoids have been used in medicine for the treatment of different types of human disorders including cancerous disorders. Flavonoids have been well known in medicine for their anti-viral, anti-bacterial, anti-inflammatory, anti-diabetic, anti-cancer, anti-aging and cardioprotective potential. Avicularin, also called quercetin-3-α-l-arabino furanoside, is a pure flavonoid, a class of phytochemicals, found to be present in Lindera erythrocarpa and Lespedeza cuneata. Avicularin has been well known in medicine for its anti-cancer properties.

Methods:

In the present work, scientific data of avicularin have been collected from different databases such as Google, PubMed, Science Direct, Google Scholar and Scopus and summarized with reference to medicinal importance, pharmacological activities and analytical aspects of avicularin. The present review summarized the health beneficial properties of avicularin in medicine through data analysis of various scientific research works. Further analytical progress in medicine for the qualitative and quantitative analysis of avicularin in medicine has been also discussed in the present work.

Results:

Scientific data analysis of different literature work revealed the biological importance of flavonoid class of phytochemical ‘avicularin’ in medicine. Scientific data analysis revealed that avicularin was found to be present in the Lindera erythrocarpa, Lespedeza cuneata, Rhododendron schlipenbachii and Psidium guajava. Avicularin has been well known in medicine for its anti-inflammatory, anti-allergic, anti-oxidant, anti-tumor and hepatoprotective activities. Avicularin protects cardiomyocytes and hepatocytes against oxidative stress-induced apoptosis and induces cytotoxicity in cancer lines and tumor tissues. Avicularin has positive influence on human hepatocellular carcinoma and inhibits intracellular lipid accumulation. The role of avicularin in rheumatoid arthritis has been also established with its underlying molecular mechanisms in the scientific work. Recent interest in avicularin has focused on pharmacological investigations for its anti-cancer activity in the medicine.

Conclusion:

The present work signified the biological importance of avicularin in medicine through its medicinal uses, pharmacological activities and analytical aspects in the biological system.

Natural products isolation studies of the paleoendemic plant species Nothofagus gunnii and Nothofagus cunninghamii

The first natural product isolation studies of Nothofagus gunnii (Hook.f.) Oerst and Nothofagus cunninghamii (Hook.f.) Oerst have been undertaken. A previously unreported stilbene derivative, pinosylvin monoacetate, was isolated from the leaves of N. gunnii, in addition to 14 known compounds; including the flavonoids galangin, pinobanksin, catechin and quercetin; sesquiterpenoids such as, ilicol and (+)-β-costol acetate; 2,4-dihydroxy-6-methoxychalcone and pinosylvin. Four known flavonoid natural products, catechin, quercetin, ayanin, and avicularin were isolated from the leaves of N. cunninghamii. This study reveals that N. gunnii is a rich source of flavonoid, chalcone and stilbene compounds, while primarily hydroxyflavonoid compounds are found in N. cunninghamii. The isolated phytochemicals are consistent with the evolutionary relationships suggested to exist among Nothofagus species.

Identifying new compounds with potential pharmaceutical and physiological activity in Areca catechu and Areca triandra via a non-targeted metabolomic approach

INTRODUCTION

The fruits of Areca catechu, also called areca nuts, are widely used as popular masticatory and traditional herbal medicine in Asia. Besides arecoline and related alkaloids, limited information is available about further primary and secondary metabolites and their potential biological activities.

OBJECTIVE

Here we aimed to further enhance our knowledge on phytochemical profiles of A. catechu and Areca triandra fruits. We intended to comprehensively identify metabolites in A. catechu and A. triandra fruits.

METHODOLOGY

Metabolites were identified by ultra-performance liquid chromatography triple-quadrupole tandem mass spectrometry (UPLC-MS/MS). The occurrence of 12 selected bioactive compounds in 4 different developmental stages of A. catechu and A. triandra was quantified by LC-MS/MS.

RESULTS

A total of 791 metabolites was identified. Of these, 115 metabolites could successfully be mapped to 44 Kyoto Encyclopedia of Genes and Genomes metabolic pathways, and 154 metabolites occurred at significantly different levels in A. catechu compared to A. triandra. Several components with known biological activities were identified for the first time in A. catechu and A. triandra. The abundance of many of these new components was similar in A. catechu and A. triandra, but significantly different between the pericarp and the seeds of A. catechu fruits.

CONCLUSIONS

Metabolic profiles indicate that fruits of the Areca species compared here have similar primary and secondary metabolites. Our findings provide new insights into A. catechu and A. triandra as valuable sources for traditional medicine and they pave the way for further studies to potentially improve the underlying pharmaceutical and physiological effects.

Antioxidant, Anti-Inflammatory, and Anti-Aging Potential of a Kalmia angustifolia Extract and Identification of Some Major Compounds

Skin aging is the most visible element of the aging process, giving rise to a major concern for many people. Plants from the Ericaceae family generally have antioxidant and anti-inflammatory properties, making them potential anti-aging active ingredients. This study aimed to evaluate the safety and anti-aging efficacy of a Kalmia angustifolia extract using reconstructed skin substitutes. The safety evaluation was performed using a 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, while the efficacy was determined by assessing antioxidant and anti-inflammatory activity and analyzing skin substitutes reconstructed according to the self-assembly method by histology and immunofluorescence staining (elastin, collagen-1, collagen-3, aquaporin-3). The cell viability assay established the safety of the extract at a concentration up to 200 μg/mL. The Oxygen Radical Absorbance Capacity (ORAC) assay and a cell-based assay using 2',7'-dichlorofluorescein-diacetate (DCFH-DA) revealed a strong antioxidant activity with an ORAC value of 16 µmol Trolox Equivalent/mg and a half-maximal inhibitory concentration (IC50) of 0.37 ± 0.02 μg/mL, while an interesting anti-inflammatory activity was found in the inhibition of NO production, with an inhibition percentage of NO production of 49 ± 2% at 80 µg/mL. The isolation and characterization of the extract allowed the identification of compounds that could be responsible for these biological activities, with two of them being identified for the first time in K. angustifolia: avicularin and epicatechin-(2β-O-7, 4β-6)-ent-epicatechin. Histological analyses of skin substitutes treated with the extract showed an increase in dermal thickness compared with the controls. K. angustifolia extract enhanced the expression of elastin and collagen-1, which are usually decreased with skin aging. These results suggest that K. angustifolia has promising antioxidant efficacy and anti-aging potential.

Stevia Genus: Phytochemistry and Biological Activities Update

The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana, a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana, many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.

Guava (Psidium guajava L.) Leaves: Nutritional Composition, Phytochemical Profile, and Health-Promoting Bioactivities

Psidium guajava (L.) belongs to the Myrtaceae family and it is an important fruit in tropical areas like India, Indonesia, Pakistan, Bangladesh, and South America. The leaves of the guava plant have been studied for their health benefits which are attributed to their plethora of phytochemicals, such as quercetin, avicularin, apigenin, guaijaverin, kaempferol, hyperin, myricetin, gallic acid, catechin, epicatechin, chlorogenic acid, epigallocatechin gallate, and caffeic acid. Extracts from guava leaves (GLs) have been studied for their biological activities, including anticancer, antidiabetic, antioxidant, antidiarrheal, antimicrobial, lipid-lowering, and hepatoprotection activities. In the present review, we comprehensively present the nutritional profile and phytochemical profile of GLs. Further, various bioactivities of the GL extracts are also discussed critically. Considering the phytochemical profile and beneficial effects of GLs, they can potentially be used as an ingredient in the development of functional foods and pharmaceuticals. More detailed clinical trials need to be conducted to establish the efficacy of the GL extracts.

Bilberry (Vaccinium myrtillus L.) Extracts Comparative Analysis Regarding Their Phytonutrient Profiles, Antioxidant Capacity along with the In Vivo Rescue Effects Tested on a Drosophila melanogaster High-Sugar Diet Model

Bilberries (Vaccinium myrtillus L.) have been reported to hold a plentitude of health-promoting properties beyond basic nutrition, mainly attributed to their anthocyanin content and antioxidant activity. In this article, we built the phytochemical profile of three wild bilberry fruit extract formulations (aqueous, methanolic, and hydro-methanolic) using UHPLC-ESI-MS/MS putative analysis, identifying 88 individual phytochemicals, mainly flavonoids (total content 8.41 ± 0.11 mg QE/g dw), free amino acids, polyphenols (total content 21.68 ± 0.19 mg GAE/g dw), carboxylic acids, and vitamins. Furthermore, the antioxidant activity of the extract was assessed, reaching 78.03 ± 0.16% DPPH free radical scavenging activity, comparable to literature values determined for bilberry extracts of other origin. Due to the increased prevalence of metabolic syndrome and based on the reviewed benefits of bilberries, we tested the most potent formulation of our bilberry extracts in this biological context. The in vivo rescue effect of a bilberry extract supplemented diet on Drosophila melanogaster was assessed by monitoring biochemical and genomic markers. Hemolymph trehalose levels were halved upon addition of 3% hydro-methanolic bilberry extract to a high-sugar (1.5 M sucrose) diet, as compared to the non-supplemented high-sugar diet. Noteworthy, the rescue seen for flies kept on the bilberry extract supplemented high-sugar diet appeared to parallel the trehalose levels observed in the case of the control diet (50 mM sucrose) flies. Moreover, next to the trehalose-lowering type of in vivo effects, other gene expression related rescues were also detected for genes such as InR, Akh, AstA, AstC, Irk, Npc2g, and CCHa2 upon supplementation of the high-sugar diet with our hydro-methanolic bilberry fruit extract. Our findings suggest that such a bilberry fruit extract could generate physiological and genomic type of compensatory mechanisms so that further translational approaches would advance the understanding of some human specific pathological conditions.

Natural derivatives with dual binding potential against SARS-CoV-2 main protease and human ACE2 possess low oral bioavailability: a brief computational analysis

The world is witnessing severe health meltdown due to COVID-19. Generic antiviral drug remdesivir has been found to reduce time to clinical recovery but with insignificant clinical benefits and the antimalarial drug, hydroxychloroquine has been red flagged by USFDA for use as a prophylactic measure due to its cardiotoxicity. There is an acute requirement for a drug candidate that has significant clinical benefit with minimal to no side effects. With restricted access to wet laboratory techniques, an alternative approach is to engage in computational screening of lead molecules that could inhibit SARS-CoV-2 at different stages of its infectious cycle. Several in silico studies on natural derivatives, especially that present in daily refreshments (tea and fruit juices), staple food (black rice, red onions, soy beans etc) and traditional medicines (extracts of herbs, leaves and flowers) have been identified as potential drug candidates that bind efficiently with the key viral proteins. However, oral bioavailability of these nutriments is considerably low due to either poor permeability or loss of structure and function due to digestion in the gastrointestinal tract. Here we discuss few natural secondary metabolites (Delphinidin 3,5-diglucoside, Scutellarein 7-glucoside, Avicularin and 3,5-Di-O-galloylshikimic acid) that showed encouraging binding affinity against coronavirus main protease (M^pro) and human ACE2 receptor with MM-GBSA energies up to −74.0 Kcal/mol and −79.5 Kcal/mol, respectively. However, their Abbott bioavailability score (ABS) of 0.11 or 0.17 predicts poor oral bioavailability. This study could trigger interest to engineer potential natural products in managing present or future pandemics.

Communicated by Ramaswamy H. Sarma

Avicularin Reduces the Expression of Mediators of Inflammation and Oxidative Stress in Bradykinin-Treated MG-63 Human Osteoblastic Osteosarcoma Cells

BACKGROUND Avicularin is a plant-derived flavonoid used in traditional Chinese medicine to treat conditions that include ankle fracture. Bradykinin stimulated MG-63 human osteoblastic osteosarcoma cells has previously been studied in an in vitro model. This study aimed to investigate the effects of avicularin on bradykinin-treated MG-63 human osteoblastic osteosarcoma cells in vitro. MATERIAL AND METHODS MG-63 cells were treated with increasing concentrations of avicularin for 48 hours, followed by 1 μM of bradykinin for 24 h. The MTT assay was used to measure cell viability. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to measure the expression of inflammatory mediators, interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-alpha) mRNA and protein, respectively. The expression of oxidative stress factors, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase were measured. Western blot and qRT-PCR were performed to determine p38, p65, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) protein levels and mRNA expression, respectively. RESULTS Avicularin had no cytotoxic effect on MG-63 cells. Avicularin significantly upregulated the expression levels IL-1ß, IL-6, and TNF-alpha in the bradykinin treated group in a dose-dependent manner. Avicularin reduced the level of MDA and the activity of SOD and catalase in the bradykinin treated MG-63 cells, reduced p-p38, p-p65, iNOS, and COX-2 expression, and decreased the p-p38/p38 ratio and the p-p65/p65 ratio in bradykinin treated MG-63 cells in a dose-dependent manner. CONCLUSIONS Avicularin reduced the expression of inflammatory cytokines and the levels of markers of oxidative stress in MG-63 human osteoblastic osteosarcoma cells in vitro.

Avicularin inhibits cell proliferation and induces cell apoptosis in cutaneous squamous cell carcinoma

Avicularin (AL), quercetin-3-α-L-arabinofuranoside, has various pharmacological properties such as anticancer and anti-infective effects. However, the potential molecular mechanism via which AL exerts its anticancer activity is not fully understood. Cutaneous squamous cell carcinoma (CSCC) is the second most common skin cancer, where metastasis has resulted in in effective clinical treatments. The aim of the present in vitro study was to investigate the anticancer effects and underlying mechanism of AL on human CSCC. The present results suggested that AL dose-dependently inhibited SCC13 cell viability and induced apoptosis. In addition, the present results suggested that AL induced apoptosis via repression of the mitogen-activated protein kinase kinase (MEK)/NF-κB signal pathway, thereby affecting the expression of apoptosis-related genes. Bax expression level was increased, while Bcl-2 expression level was decreased in SCC13 cells following AL treatment. In addition, the MEK/NF-κB signaling pathway-related genes p-MEK and phosphorylated-p65 were also decreased. The present results suggested that AL treatment increased the expression level of E-cadherin, but decreased the expression levels of N-cadherin, matrix metalloproteinase (MMP)-9 and vimentin in SCC13 cells. Collectively, the present results suggested that AL may have an anti-CSCC effect by inhibiting cell viability, inducing apoptosis and inhibiting epithelial-mesenchymal transition (EMT) of CSCC cells. The mechanism of these anti-CSCC effects was suggested to be via the regulation of apoptosis-related genes and EMT-related genes, and the inhibition of the MEK/NF-κB signaling pathway.

Hepatic transcriptome and proteome analyses provide new insights into the regulator mechanism of dietary avicularin in diabetic mice

Many dietary flavonoids existing as glycosides in fruits and vegetables are considered bioactive food components with various potential health benefits. Type 2 diabetes mellitus (T2DM) is a complex and polygenic disease with increasing global prevalence and economic burden. In this study, the hypoglycemic effect of avicularin (quercetin-3-O-α-arabinofuranoside), a flavonoid glycoside commonly found in natural plants and fruits, was determined in a high fat diet/streptozotocin induced type 2 diabetes mouse model. Our results demonstrated that dietary avicularin treatment reduced levels of fasting blood glucose, serum TG and LDL-C, liver AST and ALT, and increased hepatic glycogen in T2DM mice. Furthermore, we used RNA-Seq and iTRAQ to compare the gene and protein expression in the livers of the normal control mice (NC), diabetic control mice (DC) and avicularin treated mice (DA100). The differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were analyzed based on gene annotations and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Integrated analysis of the RNA-Seq and iTRAQ data indicated that the fifteen DEGs/DEPs showed the same trend in mRNA and protein expression levels in comparisons of both NC vs DC and DC vs DA100. KEGG analysis revealed that four DEGs/DEPs (PKM, PEPCK, PYG, and PLA2) in the glycolysis, gluconeogenesis, and arachidonic acid pathway, and six DEPs (Ndufb4, Ndufa6, Cox5a, Cox5b, Cox6c, and ATPSβ) in the oxidative phosphorylation signaling pathway, play important roles in avicularin's hypoglycemic effect. We also found six other DEGs/DEPs related to T2DM (CA1, Serpinb6a, AK, Pcolce, Cand2, and Atp2a3), and five related to cancer (Phgdh, Tes, Papss1, Psat1, and Fam49b). We did further verify by qRT-PCR and explored the possible binding modes of avicularin with targeted proteins with molecular docking simulations. Taken together, our results demonstrated the protective effects of avicularin against diabetes and provided a global view about the system-level hypoglycemic mechanisms of avicularin by the comprehensive analysis of transcriptomic and proteomic data in T2DM mice.

Avicularin ameliorates human hepatocellular carcinoma via the regulation of NF‑κB/COX‑2/PPAR‑γ activities

Hepatocellular carcinoma (HCC) has become a global public health problem. Therefore, the development of novel and effective therapeutic agents for the treatment of HCC is considered an emergency. Avicularin, a bio-active flavonoid from plants, has been reported to exhibit diverse pharmacological properties. The aim of the present study was to investigate the role of avicularin in HCC and the underlying mechanism of action. Huh7 cells were treated with avicularin in a concentration-dependent manner, and the cell proliferation was examined using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay kit. The cell migration and invasion abilities were detected using wounding-healing assays and Transwell assays. Flow cytometric analysis was performed to investigate the cell cycle distribution and cell apoptosis. The activity of nuclear factor (NF)-κB (p65), cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor γ (PPAR-γ) were measured by reverse transcription-quantitative polymerase chain reaction and western blot analyses, respectively. The results indicated that avicularin treatment markedly decreased cell proliferation concentration-dependently in HCC, and inhibited cell migration and invasion in Huh7 cells. It was also found that the treatment of avicularin markedly inhibited the G0/G1-phase cells and decreased the accumulation of S-phase cells in the cell cycle and induced cell apoptosis. In addition, it was confirmed that the anticancer efficacy of avicularin in HCC was dependent on the regulation of NF-κB (p65), COX-2 and PPAR-γ activities. In conclusion, the findings suggested that avicularin serves an antineoplastic role in HCC and may provide a potential therapeutic strategy for the treatment of HCC.

Avicularin Relieves Depressive-Like Behaviors Induced by Chronic Unpredictable Mild Stress in Mice

Background

Avicularin (AL, quercetin-3-α-l-arabinofuranoside), a glycoside of quercetin, has been reported to display diverse pharmacological properties. The present study aimed to investigate whether AL has an anti-depressant-like effect on a mouse model of depression induced by chronic unpredictable mild stress (CUMS).

Material/Methods

A mouse model of depression was established and treated with different concentrations of AL (1.25, 2.5 or 5.0 mg/kg/d) and fluoxetine (20 mg/kg/d). Then, behavioral tests – sucrose preference test (SPT), forced swimming test (FST), and the tail suspension test (TST) – were performed. The levels proinflammatory cytokines – interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) – in the hippocampi of mice were detected by enzyme-linked immunosorbent assay (ELISA). Apoptosis of hippocampal neuronal cells was determined using flow cytometry. Expression levels of phosphorylated (p)-MEK1/2, p-ERK1/2, p-NF-κB (p-p65), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), Caspase3, and B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) were measured by Western blot assay or/and quantitative real-time polymerase chain reaction (qRT-PCR), respectively.

Results

The results showed that AL significantly relieved CUMSinduced depressive-like behaviors. Compared with the model mice, AL treatment significantly increased the sucrose preference of the mice, and the immobility time in the FST and the TST were shortened. We also found that AL decreased CUMS-induced increases in the levels of IL-1β, IL-6, and TNF-α in the hippocampi of mice. AL significantly decreased the apoptosis rate of hippocampal neuronal cells in mice, which was increased by CUMS. Furthermore, activation of the MEK/ERK/NF-κB pathway induced by CUMS was inhibited by AL treatment.

Conclusions

Our results show the anti-depressant-like effects of AL on CUMS-induced depression in a mouse model.

Network Pharmacology and Reverse Molecular Docking-Based Prediction of the Molecular Targets and Pathways for Avicularin Against Cancer

AIM AND OBJECTIVE

Avicularin has been found to inhibit the proliferation of HepG-2 cells in vitro in the screening of our laboratory. We intended to explain the molecular mechanism of this effect. Therefore, the combined methods of reverse molecular docking and network pharmacology were used in order to illuminate the molecular mechanisms for Avicularin against cancer.

MATERIALS AND METHODS

Potential targets associated with anti-tumor effects of Avicularin were screened by reverse molecular docking, then a protein database was established through constructing the drugprotein network from literature mining data, and the protein-protein network was built through an in-depth exploration of the relationships between the proteins, and then the network topology analysis was performed. Additionally, gene function and signaling pathways were analyzed by Go bio-enrichment and KEGG Pathway.

RESULTS

The result showed that Avicularin was closely related to 16 targets associated with cancer, and it may significantly influence the pro-survival signals in MAPK signaling pathway that can activate and regulate a series of cellular activities and participate in the regulation of cell proliferation, differentiation, transformation and apoptosis.

CONCLUSION

The network pharmacology strategy used herein provided a powerful means for the mechanisms of action for bioactive ingredients.

Protective effect of avicularin on rheumatoid arthritis and its associated mechanisms

The present study aimed to investigate the effect of avicularin on rheumatoid arthritis (RA) in vitro, and additionally explore the molecular mechanism. To perform this investigation, an in vitro model of RA was established by treatment of the human RA synovial MH7A cell line with tumor necrosis factor-α (TNF-α). MH7A cells were then treated with various concentrations (10, 30, 100 and 300 µM) of avicularin. Then, the levels of inflammatory factors [interleukin (IL)-1β, IL-6, IL-8, matrix metalloproteinase (MMP)-1 and MMP-13] were measured by ELISA. Cell viability and apoptosis were detected using an MTT assay and flow cytometry, respectively. In addition, the expression levels of genes and proteins were determined reverse transcription quantitative polymerase chain reaction and western blot analysis. The results of the present study indicated that avicularin significantly decreased the levels of inflammatory factors (IL-1β, IL-6, IL-8, MMP-1 and MMP-13), previously increased by TNF-α, in a dose-dependent manner. Concurrently, avicularin inhibited the mRNA and protein expression levels of iNOS and COX-2 increased by TNF-α. It was also identified that TNF-α administration significantly promoted MH7A cell viability and inhibited cell apoptosis, and avicularin treatment dose-dependently inhibited MH7A cell viability and induced cell apoptosis. In addition, these data suggested that avicularin prevented the activation of the mitogen-activated protein kinase kinase (MEK)/nuclear factor kappa light-chain-enhancer of activated B-cells (NF-κB) pathway activated by TNF-α. Taken together, these results demonstrated that avicularin may inhibit the inflammatory response, prevent cell viability and induce apoptosis in human RA synovial cells through preventing the activation of the MEK/NF-κB pathway.

A fluorescent flavonoid for lysosome detection in live cells under "wash free" conditions

Lysosomes are vital organelles in living cells, which have acidic environments (pH 4.0-5.0) where macrobiomolecules and malfunctioning organelles are broken down into monomers by hydrolase activity. The majority of the currently reported fluorescent probes for detecting lysosomes suffer from small Stokes shifts (Δλ < 20 nm) and higher cytotoxicity due to an "alkalinizing effect". An interesting flavonoid-based lysosome probe is synthesized by introducing a morpholine moiety onto the flavonoid skeleton. This new probe has shown excellent selectivity to detect lysosomes in MO3.13 oligodendrocytes and normal human lung fibroblast cell lines. Probes 1a and 1b have shown excellent fluorescence quantum yield (φ_fl up to 0.43 in non-aqueous solvents) and large Stokes shifts (120-150 nm). These new fluorescent probes also exhibit a large quantum yield difference from an aqueous to organic environment, making them potentially useful as "wash-free" stains for visualizing lysosomes. Cell viability evaluation of these probes shows excellent biocompatibility with the median lethal concentration being LC50 ≈ 50 μM.

The Inhibitory Effects of Djulis (Chenopodium formosanum) and Its Bioactive Compounds on Adipogenesis in 3T3-L1 Adipocytes

The aim of this study was to provide new insights into the role of the ethanolic extracts of Djulis (Chenopodium formosanum, EECF) and its bioactive compounds in preventing adipogenesis in 3T3-L1 adipocytes. The results demonstrated EECF significantly inhibited oil red O-stained material (OROSM), triglyceride levels and glycerol-3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 adipocytes. The expression of the critical molecules involved in lipid synthesis such as PPARγ, C/EBPα and SREBP-1c was attenuated in EECF-treated cells. According to HPLC-DAD and HPLC-MS/MS analysis, rutin, kaempferol, betanin and another nine compounds were present in EECF. The suppression of lipid accumulation by rutin, kaempferol and betanin occurred by decreasing the gene expression of PPARγ, C/EBPα and SREBP-1c. Taken together, these findings suggest the presence of bioactive compounds in EECF may partly account for the anti-adipogenesis of EECF and EECF is therefore a potentially lipid lowering functional food.

Avicularin reversed multidrug-resistance in human gastric cancer through enhancing Bax and BOK expressions

5-Fluorouracil (5-Fu) and cisplatin (DDP) as important therapies in treatment of human gastric cancer have been widely determined. However, the therapeutic effects are usually hampered due to drug resistance or toxicity at high concentrations for application. Avicularin (AL, quercetin-3-α-l-arabinofuranoside), a bio-active flavonol isolated from a number of plants, has been reported to display diverse pharmacological properties. In this study, we explored the hypothesis by which AL reversed 5-Fu or DDP resistance in gastric cancer and the underlying molecular mechanism. Here, in vitro, the drug-resistant cancer cells were incubated to AL or DDP alone or the combination of AL and DDP. Then, MTT, colony formation, Hoechst 33258, flow cytometry and western blot analysis were used to investigate the effects of AL in the regulation of drug-resistance gastric cancer cells. The results indicated that AL treatment markedly re-sensitizes the drug resistant cells (SGC-7901/5-Fu and SGC-7901/DDP) to cytotoxicity of 5-Fu or DDP. Molecular mechanism analysis indicated that AL and DDP combination treatment enhanced apoptosis in SGC-7901/DDP cells, accompanied with the up-regulation of cleaved Caspase-3 and PARP, as well as the activation of pro-apoptotic signals, including Bax and BOK. Significantly, down regulation of Bax or BOK expressions using Bax siRNA or BOK siRNA decreased the inhibitory role of DDP in apoptosis of SGC-7901/DDP cells pretreated with AL, demonstrating that AL-reversed DDP resistance was associated with Bax and BOK expression. In vivo, AL and DDP combination significantly reduced gastric tumor growth. Immunohistochemical analysis indicated that co-treatment of AL and DDP significantly induced apoptosis, and reduced tumor cell proliferation in tumor tissue samples. Furthermore, we also found that the Bax, BOK, cleaved Caspase-3 and PARP expression in tumor tissues were highly induced by AL and DDP co-treatment. Together, our findings may provide a novel combination therapeutic strategy in treatment of human gastric cancer.

The Rosiglitazone-Like Effects of Vitexilactone, a Constituent from Vitex trifolia L. in 3T3-L1 Preadipocytes

The increased number of patients with type 2 diabetes (T2D) has become a worldwide problem, and insulin sensitizers such as thiazolidinediones (TZDs) are used as therapeutic agents. We found that extracts of Vitex trifolia L. (V. trifolia), a medicinal plant from Myanmar, induced adipogenesis similar to rosiglitazone (ROS), which is a TZD, in 3T3-L1 preadipocytes. In the present study, we attempted to isolate from V. trifolia those compounds that showed ROS-like effects. Among the extracts of hexane, ethyl acetate, and methanol obtained from V. trifolia, the ethyl acetate extract with the strongest ROS-like effects was purified by various chromatographic methods to obtain three known compounds: vitexilactone (1), vitexicarpin (2) and oleanolic acid (3). Among the isolated compounds, the ROS-like action of 1 was the strongest. The effects of 1 on 3T3-L1 cells during adipogenesis were compared with those of ROS. Both 1 and ROS increased lipid accumulation, the expression of adiponectin and GLUT4 in the cell membrane and decreased both the size of adipocytes and the phosphorylation of IRS-1, ERK1/2 and JNK in 3T3-L1 cells. In contrast, unlike ROS, the induction of proteins involved in lipogenesis was partial. ROS-like effects of 1 in 3T3-L1 cells were suppressed by the addition of bisphenol A diglycidyl ether (BADGE), one of a peroxisome proliferator-activated receptor γ (PPARγ) antagonists, suggesting that the action of 1 on adipocytes is mediated by PPARγ. From the results of the present study, it can be concluded that 1 is a novel insulin sensitizer candidate.

Effects of Flavonoids and Triterpene Analogues from Leaves of Eleutherococcus sieboldianus (Makino) Koidz. 'Himeukogi' in 3T3-L1 Preadipocytes

Eleutherococcus sieboldianus (Makino) Koidz. is a local product from the area in and around Yonezawa City in Yamagata Prefecture, Japan. It has been used as a medicinal plant for a long time. We isolated and identified four types of flavonoid glycosides [astragalin (1), isoquercetin (2), rhamnocitrin 3-O-glucoside (3), and nicotiflorin (4)], a triterpene [methyl hederagenin (5)], and three types of triterpene glycosides [δ-hederin (6), echinocystic acid 3-O-arabinoside (7), and cauloside B (8)] from the methanol extract of E. sieboldianus, which regulates lipid accumulation in 3T3-L1 preadipocytes. Among the compounds isolated, 2 and 8 up- and down-regulated lipid accumulation and insulin induced adipocyte differentiation in 3T3-L1 preadipocytes. Compound 2 induced up-regulation of lipid accumulation and decreased adipocyte size, while 8 down-regulated lipid accumulations without decreasing cell size. Additionally, 2 increased adipogenic proteins [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and fatty-acid-binding protein 4 (FABP4)]. In contrast, 8 decreased the levels of all adipogenic proteins and glucose transporter type 4 (GLUT4), but increased adiponectin.

Suppression of Very Early Stage Of Adipogenesis by Baicalein, a Plant-Derived Flavonoid through Reduced Akt-C/EBPα-GLUT4 Signaling-Mediated Glucose Uptake in 3T3-L1 Adipocytes

Baicalein has been used as a Chinese medicine, and is an abundant plant flavonoid present in fruits and vegetables. Here, we examined the effects of baicalein in adipogenesis and investigated its molecular mechanism in adipocytes. Baicalein lowered the intracellular lipid accumulation and decreased the transcription levels of the adipocyte-specific genes in mouse 3T3-L1 adipocytes. Glucose uptake mediated by glucose transporter 4 (GLUT4) was reduced, causing down-regulation of the intracellular lipid accumulation. These reductions were also observed even when baicalein was added in only early stage of adipogenesis (0-2 days) of 6-day-adipogenesis. Chromatin immunoprecipitation assay showed that baicalein decreased the binding level of C/EBPα protein to the promoter region of the GLUT4 gene. Phosphorylation of Akt at 1 h after the initiation of adipogenesis was inhibited by the treatment with baicalein. Inhibition during only the first 1.5 h after the initiation of adipogenesis by baicalein or an Akt inhibitor was enough to decrease the lipid contents in the cells undergoing adipocyte differentiation for 6 days. These results indicate that baicalein decreased the intracellular lipid accumulation by down-regulation of glucose uptake via repression of Akt-C/EBPα-GLUT4 signaling in the very early stage of adipogenesis of 3T3-L1 adipocytes.

Effects of Various 5,7-Dihydroxyflavone Analogs on Adipogenesis in 3T3-L1 Cells

We studied the effects of twelve 5,7-dihydroxyflavone analogs on adipogenesis in 3T3-L1 cells. Among the compounds, luteolin, diosmetin, and chrysoeriol partly inhibited adipogenesis by blocking the accumulation of triacylglycerol in the cells. Conversely, tricetin facilitated triacylglycerol accumulation in the cells. The induction of lipogenesis or lipolysis may depend on the number and bonding position of hydroxyl or methoxy groups on the B ring of 5,7-dihydroxyflavone. The mRNA expression levels of adipogenic and lipogenic genes were suppressed by luteolin treatment in the cells, while the mRNA levels of lipolytic genes were not affected. However, the expression levels of the adipogenic, lipogenic, and lipolytic genes, except for adipocyte protein 2 (aP2), were not affected by the addition of tricetin. Moreover, luteolin suppressed glucose transporter type 4 (GLUT4) gene and protein levels. These results indicate that luteolin decreased triacylglycerol levels in 3T3-L1 cells during adipogenesis through the suppression of adipogenic/lipogenic and GLUT4 genes and GLUT4 protein.

Arginase inhibition ameliorates adipose tissue inflammation in mice with diet-induced obesity

This study examined whether oral administration of an arginase inhibitor regulates adipose tissue macrophage infiltration and inflammation in mice with high fat diet (HFD)-induced obesity. Male C57BL/6 mice (n = 30) were randomly assigned to control (CTL, n = 10), HFD only (n = 10), and HFD with arginase inhibitor N(ω)-hydroxy-nor-l-arginine (HFD with nor-NOHA, n = 10) groups. Plasma and mRNA levels of cytokines in epididymal adipose tissues (EAT), macrophage infiltration into EAT, and macrophage phenotype polarization were measured in the animals after 12 weeks. Additionally, the effects of nor-NOHA on adipose tissue macrophage infiltration and mRNA expression of cytokines were measured in co-cultured 3T3-L1 adipocytes and RAW 264.7 macrophages. Macrophage infiltration into the adipocytes was significantly suppressed by nor-NOHA treatment in adipocyte/macrophage co-culture system and mice with HFD-induced obesity. Pro-inflammatory cytokines, including monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), were significantly downregulated, and the anti-inflammatory cytokine IL-10 was significantly upregulated in nor-NOHA-treated co-cultured cells. In the mice with HFD-induced obesity, plasma and mRNA levels of MCP-1 significantly reduced after supplementation with nor-NOHA. In addition, oral supplement of nor-NOHA modified M1/M2 phenotype ratio in the EAT. Oral supplementation of an arginase inhibitor, nor-NOHA, altered M1/M2 macrophage phenotype and macrophage infiltration into HFD-induced obese adipose tissue, thereby improved adipose tissue inflammatory response. These results may indicate that arginase inhibition ameliorates obesity-induced adipose tissue inflammation.

Fisetin Suppresses Lipid Accumulation in Mouse Adipocytic 3T3-L1 Cells by Repressing GLUT4-Mediated Glucose Uptake through Inhibition of mTOR-C/EBPα Signaling

3,7,3',4'-Tetrahydroxyflavone (fisetin) is a flavonoid found in vegetables and fruits having broad biological activities. Here the effects of fisetin on adipogenesis and its regulatory mechanism in mouse adipocytic 3T3-L1 cells are studied. Fisetin inhibited the accumulation of intracellular lipids and lowered the expression of adipogenic genes such as peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein (C/EBP) α and fatty acid-binding protein 4 (aP2) during adipogenesis. Moreover, the mRNA levels of genes such as acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase involved in the fatty acid biosynthesis (lipogenesis) were reduced by the treatment with fisetin. The expression level of the glucose transporter 4 (GLUT4) gene was also decreased by fisetin, resulting in down-regulation of glucose uptake. Furthermore, fisetin inhibited the phosphorylation of the mammalian target of rapamycin (mTOR) and that of p70 ribosomal S6 kinase, a target of the mTOR complex, the inhibition of which was followed by a decreased mRNA level of the C/EBPα gene. The results obtained from a chromatin immunoprecipitation assay demonstrated that the ability of C/EBPα to bind to the GLUT4 gene promoter was reduced by the treatment with fisetin, which agreed well with those obtained when 3T3-L1 cells were allowed to differentiate into adipocytes in medium in the presence of rapamycin, an inhibitor for mTOR. These results indicate that fisetin suppressed the accumulation of intracellular lipids by inhibiting GLUT4-mediated glucose uptake through inhibition of the mTOR-C/EBPα signaling in 3T3-L1 cells.

UPLC-MS/MS method for determination of avicularin in rat plasma and its application to a pharmacokinetic study

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of avicularin in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile-methanol (9:1, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 1.60 min and the elution of avicularin was at 1.20 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 434.1→301.3 for avicularin and m/z 237.2→194.3 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 10-3000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of avicularin in plasma was in the range of 84.2-89.5%. Intra-day and inter-day precision were both <12%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg avicularin in rats.

Synthesis of flavonoid O-pentosides by Escherichia coli through engineering of nucleotide sugar pathways and glycosyltransferase

Plants produce two flavonoid O-pentoses, flavonoid O-xyloside and flavonoid O-arabinoside. However, analyzing their biological properties is difficult because flavonoids are not naturally produced in sufficient quantities. In this study, Escherichia coli was used to synthesize the plant-specific flavonoid O-pentosides quercetin 3-O-xyloside and quercetin 3-O-arabinoside. Two strategies were used. First, E. coli was engineered to express components of the biosynthetic pathways for UDP-xylose and UDP-arabinose. For UDP-xylose biosynthesis, two genes, UXS (UDP-xylose synthase) from Arabidopsis thaliana and ugd (UDP-glucose dehydrogenase) from E. coli, were overexpressed. In addition, the gene encoding ArnA (UDP-l-Ara4N formyltransferase/UDP-GlcA C-4″-decarboxylase), which competes with UXS for UDP-glucuronic acid, was deleted. For UDP-arabinose biosynthesis, UXE (UDP-xylose epimerase) was overexpressed. Next, we engineered UDP-dependent glycosyltransferases (UGTs) to ensure specificity for UDP-xylose and UDP-arabinose. The E. coli strains thus obtained synthesized approximately 160 mg/liter of quercetin 3-O-xyloside and quercetin 3-O-arabinoside.