Scutellarein from Scutellaria barbata induces apoptosis of human colon cancer HCT116 cells through the ROS-mediated mitochondria-dependent pathway

Scutellarein Ameliorated Chondrocyte Inflammation and Osteoarthritis in Rats

OBJECTIVE

Osteoarthritis (OA) is a degenerative joint disorder characterized by the gradual degradation of joint cartilage and local inflammation. This study aimed to investigate the anti-OA effect of scutellarein (SCU), a single-unit flavonoid compound obtained from Scutellaria barbata D. Don, in rats.

METHODS

The extracted rat chondrocytes were treated with SCU and IL-1β. The chondrocytes were divided into control group, IL-1β group, IL-1β+SCU 50 µmol/L group, and IL-1β+SCU 100 µmol/L group. Morphology of rat chondrocytes was observed by toluidine blue and safranin O staining. CCK-8 method was used to detect the cytotoxicity of SCU. ELISA, qRT-PCR, Western blotting, immunofluorescence, SAβ-gal staining, flow cytometry, and bioinformatics analysis were applied to evaluate the effect of SCU on rat chondrocytes under IL-1β intervention. Additionally, anterior cruciate ligament transection (ACL-T) was used to establish a rat OA model. Histological changes were detected by safranin O/fast green, hematoxylin-eosin (HE) staining, and immunohistochemistry.

RESULTS

SCU protected cartilage and exhibited anti-inflammatory effects via multiple mechanisms. Specifically, it could enhance the synthesis of extracellular matrix in cartilage cells and inhibit its degradation. In addition, SCU partially inhibited the nuclear factor kappa-B/mitogen-activated protein kinase (NF-κB/MAPK) pathway, thereby reducing inflammatory cytokine production in the joint cartilage. Furthermore, SCU significantly reduced IL-1β-induced apoptosis and senescence in rat chondrocytes, further highlighting its potential role in OA treatment. In vivo experiments revealed that SCU (at a dose of 50 mg/kg) administered for 2 months could significantly delay the progression of cartilage damage, which was reflected in a lower Osteoarthritis Research Society International (OARSI) score, and reduced expression of matrix metalloproteinase 13 (MMP13) in cartilage.

CONCLUSION

SCU is effective in the therapeutic management of OA and could serve as a potential candidate for future clinical drug therapy for OA.

Comprehensive transcriptomic profiling of liver cancer identifies that histone and PTEN are major regulators of SCU‑induced antitumor activity

Worldwide, liver cancer is the most frequent fatal malignancy. Liver cancer prognosis is poor because patients frequently receive advanced-stage diagnoses. The current study aimed to establish the potential pharmacological targets and the biological networks of scutellarein (SCU) in liver cancer, a natural product known to have low toxicity and side effects. To identify the differentially expressed genes between SCU-treated and SCU-untreated HepG2 cells, RNA sequencing (RNA-seq) was carried out. A total of 463 genes were revealed to have differential expression, of which 288 were upregulated and 175 were downregulated in the group that had received SCU treatment compared with a control group. Gene Ontology (GO) enrichment analysis of associated biological process terms revealed they were mostly involved in the regulation of protein heterodimerization activity and nucleosomes. Interaction of protein-protein network analysis using Search Tool for the Retrieval of Interacting Genes/Proteins resulted in two crucial interacting hub targets; namely, histone H1-4 and protein tyrosine phosphatase receptor type C. Additionally, the crucial targets were validated using western blotting. Overall, the present study demonstrated that the use of RNA-seq data, with bioinformatics tools, can provide a valuable resource to identify the pharmacological targets that could have important biological roles in liver cancer.

Virtual screening of natural products targeting ubiquitin-specific protease 7

Ubiquitin-specific protease 7 (USP7) is a promising prognostic and druggable target for cancer therapy. Inhibition of USP7 can activate the MDM2-P53 signaling pathway, thereby promoting cancer cell apoptosis. This study based on watvina molecular docking of virtual screening method and biological evaluation found the new USP7 inhibitors targeting catalytic active site. Three hits were screened from 3760 natural products and validated as USP7 inhibitors by enzymatic and kinetic assays. The IC50 values of scutellarein (Scu), semethylzeylastera (DML) and salvianolic acid C (SAC) were 3.017, 6.865 and 8.495 μM, respectively. Further, we reported that the hits could downregulate MDM2 and activate p53 signal pathway in HCT116 cells. Molecular dynamics simulation was used to investigate the binding mechanism of USP7 to Scu, the compound with the best performance, which formed stable contact with Val296, Gln297, Phe409, Tyr465 and Tyr514. These interactions are essential for maintaining the biological activity of Scu. Three natural products are suitable as lead compounds for the development of novel USP7 inhibitors, especially anti-colon cancer drugs.Communicated by Ramaswamy H. Sarma.

Exploring the bacterial community succession and metabolic profiles of Lonicera japonica Thunb. residues during anaerobic fermentation

Discarding Lonicera japonica Thunb. (LJT) residues containing many active metabolites create tremendous waste. This study aimed to effectively use LJT residues by anaerobic fermentation. Fermentation significantly decreased the pH values and reduced the abundance of undesirable bacteria (potential pathogenic and biofilm-forming) while increasing Lactobacillus abundance. Compound additive use further improved fermentation quality (significantly increased the lactic acid (LA) content and decreased the pH values and ammonia nitrogen (a-N) content) and nutrient quality (significantly decreased the acid detergent fiber (ADF) content and increased the water-soluble carbohydrate (WSC) content) and optimized the microbial community (increased the Lactobacillus abundance). Fermentation also altered the flavonoids, alkaloids and phenols contents in the residues with minor effects on the functional metabolites amounts. The LJT residues metabolic profile was mainly attributed to its epiphytic bacteria, with a small contribution from the compound additive. Thus, compound additives may improve anaerobic LJT residue fermentation without functionally impairing the metabolites.

Monosaccharide Composition and In Vitro Activity to HCT-116 Cells of Purslane Polysaccharides after a Covalent Chemical Selenylation

The anti-cancer effects of selenylated plant polysaccharides are a focus of research. As a natural plant with extensive biological effects, there have been few studies related to edible purslane (Portulaca oleracea L.). Thus, in this study, soluble P. oleracea polysaccharides (PPS) were extracted from the dried P. oleracea and then selenylated chemically using the HNO₃-Na₂SeO₃ method to obtain two selenylated products, namely, SePPS1 and SePPS2. Compared with the extracted PPS, SePPS1 and SePPS2 had much higher Se contents (840.3 and 1770.5 versus 66.0 mg/kg) while also showing lower contents in three saccharides-arabinose, fucose, and ribose-and higher contents in seven saccharides including galactose, glucose, fructose, mannose, rhamnose, galacturonic acid, and glucuronic acid, but a stable xylose content demonstrated that the performed chemical selenylation of PPS led to changes in monosaccharide composition. Moreover, SePPS1 and SePPS2 shared similar features with respect to monosaccharide composition and possessed higher bioactivity than PPS in human colon cancer HCT-116 cells. Generally, SePPS1 and SePPS2 were more active than PPS with respect to cell growth inhibition, the alteration of cell morphology, disruption of mitochondrial membrane potential, intracellular reactive oxygen species (ROS) generation, the induction of cell apoptosis, and upregulation or downregulation of five apoptosis-related genes and proteins such as Bax, Bcl-2, caspases-3/-9, and cytochrome C, that cause cell apoptosis and growth suppression via the ROS-mediated mitochondrial pathway. SePPS2 consistently showed the highest capacity to exert these observed effects on the targeted cells, suggesting that the performed chemical selenylation of PPS (in particular when higher degrees of selenylation are reached) resulted in an increase in activity in the cells. It can thus be concluded that the performed selenylation of PPS was able to incorporate inorganic Se into the final PPS products, changing their monosaccharide composition and endowing them with enhanced nutraceutical and anti-cancer effects in the colon.

Scutellarein stimulates human sperm function by increasing the levels of intracellular calcium and tyrosine phosphorylation

As a kind of flavonoid, scutellarein is widely used to protect against various human diseases. Although the protective effects of scutellarein have been well studied, its influence on human reproduction remains unknown. In this research, we evaluated the effect of scutellarein on human sperm functions in vitro. Three different concentrations of scutellarein (1, 10, 100 μM) were applied to ejaculated human sperm. Fertilisation-essential functions, as well as the intracellular calcium concentration ([Ca²⁺ ]_i ) and protein-tyrosine phosphorylation, two factors which are vital for sperm function regulation, were evaluated. The results demonstrated that all concentrations of scutellarein utilised in this study could significantly increase sperm spontaneous capacitation and acrosome reaction through the enhancement of [Ca²⁺ ]_i . Besides, the level of tyrosine phosphorylation of sperm could also be increased by scutellarein. Meanwhile, the sperm motility could be improved by 10 and 100 μM scutellarein, which also make a significant enhancement in sperm penetration ability and hyperactivation. This is one of the limited studies showing the regulation of scutellarein on human spermatozoa functions and is helpful to enrich its application.

Cancer metabolism control by natural products: Pyruvate kinase M2 targeting therapeutics

Glycolysis is the primary source of energy for cancer growth and metastasis. The shift in metabolism from mitochondrial oxidative phosphorylation to aerobic glycolysis is called the Warburg effect. Cancer progression due to aerobic glycolysis is often associated with the activation of oncogenes or the loss of tumor suppressors. Therefore, inhibition of glycolysis is one of the effective strategies in cancer control. Pyruvate kinase M2 (PKM2) is a key glycolytic enzyme overexpressed in breast, prostate, lung, colorectal, and liver cancers. Here, we discuss published studies regarding PKM2 inhibitors from natural products that are promising drug candidates for cancer therapy. We have highlighted the potential of natural PKM2 inhibitors for various cancer types. Moreover, we encourage researchers to evaluate the combinational effects between natural and synthetic PKM2 inhibitors. Also, further high-quality studies are needed to firmly establish the clinical efficacy of natural products.

Scutellarein Attenuates Atopic Dermatitis by Selectively Inhibiting Transient Receptor Potential Vanilloid 3

BACKGROUND AND PURPOSE

Atopic dermatitis (AD) is one of the most common chronic inflammatory cutaneous diseases with unmet clinical needs. As a common ingredient found in several medicinal herbs with efficacy on cutaneous inflammatory diseases, Scutellarein (Scu) has been shown to possess anti-inflammatory and anti-proliferative activities. We aimed to evaluate the therapeutic efficacy of Scu against AD and its underlying molecular mechanism.

EXPERIMENTAL APPROACH

Efficacy of Scu on AD was evaluated in 2,4-dinitrofluorobenzene (DNFB) and carvacrol-induced dermatitis mouse models. Cytokine mRNA and serum IgE levels were examined using qPCR and ELISA, respectively. Voltage clamp recordings were used to measure currents mediated by transient receptor potential (TRP) channels. In silico docking, site-direct mutagenesis, and covalent modification were used to explore the binding pocket of Scu on TRPV3.

KEY RESULTS

Subcutaneous administration of Scu efficaciously suppresses DNFB and carvacrol-induced pruritus, epidermal hyperplasia and skin inflammation in wild type mice but has no additional benefit in Trpv3 knockout mice in the carvacrol model. Scu is a potent and selective TRPV3 channel allosteric negative modulator with an apparent affinity of 1.18 μM. Molecular docking coupled with site-direct mutagenesis and covalent modification of incorporated cysteine residues demonstrate that Scu targets the cavity formed between the pore helix and transmembrane helix S6. Moreover, Scu attenuates endogenous TRPV3 activity in human keratinocytes and inhibits carvacrol-induced proliferative and proinflammatory responses.

CONCLUSIONS AND IMPLICATIONS

Collectively, these data demonstrate that Scu ameliorates carvacrol-induced skin inflammation by directly inhibiting TRPV3, and TRPV3 represents a viable therapeutic target for AD treatment.

Molecular Assessment of Scutellaria barbata D. Don in the Treatment of Nasopharyngeal Carcinoma Based on Network Pharmacology and Experimental Verification

Objective. To predict the molecular mechanisms behind the benefits of Scutellaria barbata D. Don (S. barbata) in nasopharyngeal carcinoma (NPC) by network pharmacology and experimental verification. Methods. The active ingredients and targets of S. barbata were searched in the traditional Chinese medicine system pharmacology database and analysis platform, and the disease targets of NPC were obtained by searching the GeneCards database. A common target protein-protein interaction network was constructed by STRING, and then, an active ingredients-NPC-target interaction network map was constructed by Cytoscape 3.7.2 software. The functional enrichment analyses of Gene Ontology and KEGG pathway data were carried out by R software programming. Finally, cell proliferation was assessed by CCK8, apoptosis was detected by Annexin V-FITC/PI double fluorescence staining, and protein expression was analyzed by Western blotting. Results. In this study, 29 active ingredients were found in S. barbata. Among these, the main targets for NPC were baicalein, wogonin, luteolin, and quercetin. The main molecular targets of S. barbata on NPC were EGFR, MYC, CASP3, CCND1, and ESR1. The main biological processes involved the binding of DNA-binding transcription factors, RNA polymerase II-specific DNA-binding transcription factors, ubiquitin-like protein ligases, and ubiquitin-protein ligases. S. barbata mainly affects NPC through the PI3K-Akt, p53, and MAPK signaling pathways. The experimental results showed that baicalein and wogonin could inhibit proliferation and induce apoptosis of NPC cells and downregulate the expression of PI3K, AKT, and p53, the key proteins of the PI3K/AKT and p53 signaling pathway in CNE2 cells. Conclusion. Baicalein and wogonin, the main active ingredients of S. barbata, inhibited the proliferation and induced apoptosis of NPC cells through the PI3K/AKT and p53 signaling pathways.

Bruceine D Identified as a Drug Candidate against Breast Cancer by a Novel Drug Selection Pipeline and Cell Viability Assay

The multi-target effects of natural products allow us to fight complex diseases like cancer on multiple fronts. Unlike docking techniques, network-based approaches such as genome-scale metabolic modelling can capture multi-target effects. However, the incompleteness of natural product target information reduces the prediction accuracy of in silico gene knockout strategies. Here, we present a drug selection workflow based on context-specific genome-scale metabolic models, built from the expression data of cancer cells treated with natural products, to predict cell viability. The workflow comprises four steps: first, in silico single-drug and drug combination predictions; second, the assessment of the effects of natural products on cancer metabolism via the computation of a dissimilarity score between the treated and control models; third, the identification of natural products with similar effects to the approved drugs; and fourth, the identification of drugs with the predicted effects in pathways of interest, such as the androgen and estrogen pathway. Out of the initial 101 natural products, nine candidates were tested in a 2D cell viability assay. Bruceine D, emodin, and scutellarein showed a dose-dependent inhibition of MCF-7 and Hs 578T cell proliferation with IC₅₀ values between 0.7 to 65 μM, depending on the drug and cell line. Bruceine D, extracted from Brucea javanica seeds, showed the highest potency.

Scutellarin-induced A549 cell apoptosis depends on activation of the transforming growth factor-β1/smad2/ROS/caspase-3 pathway

Scutellarin plays an anti-tumor role in A549 lung cancer cells, but the underlying mechanism is unclear. In this study, scutellarin was used to treat A549 cells for 12, 24, and 48 h, followed by the addition of Tempo, a selective scavenger of mitochondrial reactive oxygen species (ROS) and SB431542, a transforming growth factor (TGF)-β1 receptor inhibitor. A dihydroethidium fluorescence probe was used to measure the intracellular ROS level, Cell Counting Kit-8 (CCK-8) was used to detect cell viability, and flow cytometry was performed to examine apoptosis. Western blots were used to detect the total protein level of TGF-β1, p-smad2, and cleaved caspase-3 in A549 cells. The results showed that scutellarin significantly inhibited cell viability and increased apoptosis. Scutellarin also promoted intracellular ROS production, TGF-β1/smad2 signaling pathway activation, and cleaved caspase-3 expression, which was partly reversed by Tempo. Moreover, scutellarin-induced intracellular ROS production and cleaved caspase-3 expression were inhibited by blocking the TGF-β1/smad2 pathway with SB431542. In conclusion, scutellarin promoted apoptosis and intracellular ROS accumulation, which could be abrogated by Tempo and SB431542 treatment in A549 cells. Our study indicated that scutellarin induced A549 cell apoptosis via the TGF-β1/smad2/ROS/caspase-3 pathway.

Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signaling

Scutellarein, a flavone found in the perennial herb Scutellaria baicalensis, has antitumorigenic activity in multiple human cancers. However, whether scutellarein can attenuate ovarian cancer (OC) is unclear. This study investigated the effects of scutellarein in OC. In vitro cell viability was assessed using MTT assay whereas proliferation was assessed using 5-ethynyl-2'-deoxyuridine and colony formation assays. Cell apoptosis was detected by an Annexin V-fluorescein isothiocyanate/propidium iodide assay. Wound-healing and Transwell assays were used to determine cell migration and invasion. The differential expression of enhancer of zeste homolog 2 (EZH2) and forkhead box protein O1 (FOXO1) was measured by Quantitative real-time PCR and western blot analysis. We found that scutellarein inhibited viability, migration, invasion of A2780 and SKOV-3 cells, and reduced the expression of EZH2 in OC cells. In addition, FOXO1 was downregulated in OC tissues and cells and negatively regulated by EZH2. Also, scutellarein inhibited tumor growth and metastasis in vivo. In conclusion, scutellarein alleviates OC by the regulation of EZH2/FOXO1 signaling.

A comprehensive study of the metabolism of flavonoid oroxin B in vivo and in vitro by UHPLC-Q-TOF-MS/MS

Oroxin B, a flavonoid, is a major bioactive component form Oroxylum indicum (L.) Vent. with enormous anti-hepatoma effects. To data, the oroxin B metabolism studies remain underexplored. This study was designed to characterize oroxin B metabolism in vivo and in vitro by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Consequently, 30 metabolites in rats, 8 metabolites in liver microsomes and 18 metabolites in intestinal bacteria were identified, and 9 metabolites were recognized by comparison with standards. The biotransformation processes involved ketone, acetylation, loss of C₁₂H₂₀O₁₀, and loss of C₆H₁₀O₅. And baicalein and oroxin A were generated after loss of C₁₂H₂₀O₁₀, and loss of C₆H₁₀O₅, respectively, and further went through some other reactions, such as oxidation, methylation, internal hydrolysis, hydrogenation, loss of O, ketone, glycine conjugation, glucuronide conjugation and their composite reactions. The results provide valuable evidence for elucidation the potential mechanism of oroxin B pharmacological action, and offer reasonable guidelines for further investigations of oroxin B safety and efficacy.

Scutellarein alleviates the dysfunction of inner blood-retinal-barrier initiated by hyperglycemia-stimulated microglia cells

AIM

To investigate the alleviation of scutellarein (SN) against inner blood-retinal-barrier (iBRB) dysfunction in microglia cells stimulated by hyperglycemia and to elucidate the engaged mechanism.

METHODS

Microglia BV2 cells were stimulated by using 25 mmol/L D-glucose. The same concentration of mannitol (25 mmol/L) was applied as an isotonic contrast. Real-time PCR, Western-blot assay and immunofluorescence staining assay was performed. The dysfunction of iBRB in vitro was detected by using transendothelial electrical resistance (TEER) assay. Additionally, the leakage of fluorescein isothiocyanate (FITC)-conjugated dextran (70 kDa) was detected.

RESULTS

SN abrogated microglia BV2 cells activation and reduced the phosphorylated activation of extracellular signal-regulated protein kinase (ERK)1/2. SN also decreased the transcriptional activation of nuclear factor κB (NFκB) and the elevated expression of tumor necrosis factor α (TNFα), interleukin (IL)-6 and IL-1β in BV2 cells treated with D-glucose (25 mmol/L). SN attenuated iBRB dysfunction in human retinal endothelial cells (HRECs) or choroid-retinal endothelial RF/6A cells when those cells were treated with TNFα, IL-1β or IL-6, or co-cultured with microglia cells stimulated by D-glucose. Moreover, SN restored the decreased protein expression of tight junctions (TJs) in TNFα-treated HRECs and RF/6A cells.

CONCLUSION

SN not only alleviate iBRB dysfunction via directly inhibiting retinal endothelial injury caused by TNFα, IL-1β or IL-6, but also reduce the release of TNFα, IL-1β and IL-6 from microglia cells by abrogating hyperglycemia-mediated the activation of microglia cells.

An In Vitro Evaluation of the Molecular Mechanisms of Action of Medical Plants from the Lamiaceae Family as Effective Sources of Active Compounds against Human Cancer Cell Lines

It is predicted that 1.8 million new cancer cases will be diagnosed worldwide in 2020; of these, the incidence of lung, colon, breast, and prostate cancers will be 22%, 9%, 7%, and 5%, respectively according to the National Cancer Institute. As the global medical cost of cancer in 2020 will exceed about $150 billion, new approaches and novel alternative chemoprevention molecules are needed. Research indicates that the plants of the Lamiaceae family may offer such potential. The present study reviews selected species from the Lamiaceae and their active compounds that may have the potential to inhibit the growth of lung, breast, prostate, and colon cancer cells; it examines the effects of whole extracts, individual compounds, and essential oils, and it discusses their underlying molecular mechanisms of action. The studied members of the Lamiaceae are sources of crucial phytochemicals that may be important modulators of cancer-related molecular targets and can be used as effective factors to support anti-tumor treatment.

Phytotoxic neo-clerodane diterpenoids from the aerial parts of Scutellaria barbata

Bioactivity guided the isolation of extracts from the aerial parts Scutellaria barbata D. Don to discover neo-clerodane diterpenoids with potent phytotoxic activity. Of the 34 isolates, 13 neo-clerodane diterpenoids were described for the first time. The structures of these undescribed compounds were elucidated by extensive analysis of NMR spectroscopic data, and the absolute configurations of scutebarbolides A and L and scutebata W were determined by X-ray diffraction. The phytotoxic activity of all compounds against the growth of the roots and shoots of L. perenne and L. sativa seedlings were first reported, and some compounds showed considerable inhibitory effects, especially scutebarbolide K, whose inhibition rates were higher than those of the positive control at concentrations ranging from 25 to 200 μg/mL. When L. perenne and L. sativa seedlings were treated at a concentration of 200 μg/mL, scutebarbolide K caused wilting symptoms on and finally death of these two tested plant seedlings. In addition, the structure-activity relationships of these neo-clerodane diterpenoids were also discussed.

Scutellarein inhibits the development of colon cancer via CDC4‑mediated RAGE ubiquitination

Scutellarein has been identified to serve an anti-tumor function in human colon cancer, but the underlying mechanisms remain largely unclear. The present study further investigated the effect and mechanism of scutellarein, extracted from wild chrysanthemum, in the progression of colon cancer. MTT, clone formation, flow cytometry and tumor-bearing mice assays were used to detect cell viability, clone formation, apoptosis and tumorigenesis, respectively. Western blot and quantitative PCR assays were performed for protein and mRNA expression detection. The results revealed that, compared with the control group, scutellarein treatment significantly inhibited the viability and induced the apoptosis of colon cancer cells (P<0.05), with significant decreases in receptor for advanced glycosylation end products (RAGE) protein expression and stability and an increase in RAGE ubiquitination (P<0.05). However, the effects of scutellarein exerted in cell apoptosis and viability were rescued by RAGE overexpression, and accelerated by RAGE knockdown. Additionally, it was observed that scutellarein treatment induced a significant increase in the expression of cell division control protein 4 (CDC4) compared with the control group (P<0.05), which was then verified to interact with RAGE protein and mediate its ubiquitination. Overexpression of CDC4 inhibited colon cancer cell viability and promoted the apoptosis of SW480 and T84 cells, whereas this function was weakened when RAGE was overexpressed. Furthermore, CDC4 downregulation significantly neutralized scutellarein functions in promoting cell apoptosis and inhibiting cell viability and tumorigenesis in colon cancer cells compared with the scutellarein group (P<0.05). In conclusion, the present study revealed that scutellarein inhibited the development of colon cancer through upregulating CDC4-mediated RAGE ubiquitination.