OBJECTIVE: The study aims to investigate the role and underlying mechanisms of tricetin in regulating hepatic stellate cells (HSCs) activation.
METHODS: We treated human hepatic stellate cells line LX-2 and freshly isolated primary mouse hepatic stellate cells (mHSCs) with tricetin, pharmacological inhibitors and siRNAs, western blot, immunofluorescence, quantitative PCR were used to evaluate the expression of fibrotic markers, autophagy levels and Nrf2 (nuclear factor E2-related factor 2) signaling.
RESULTS: Herein, we demonstrated that tricetin strongly attenuated the proliferation, migration, lipid droplets (LDs) loss and fibrotic markers Col 1a1 (type I α 1 collagen) and α-SMA (α-smooth muscle actin) expression in LX-2 cells. Moreover, tricetin time- and dose-dependently provoked autophagic formation in LX-2 cells. Autophagy inhibition by pharmacological intervention or genetic ATG5 (autophagy related 5) silencing facilitated tricetin-induced downregulation of profibrotic markers in LX-2 cells. Additionally, tricetin treatment reduced reactive oxygen species (ROS) accumulation, promoted Nrf2 signaling in LX-2 cells and pretreatment with ROS scavenger NAC partially reversed tricetin-induced autophagy and enhanced tricetin-mediated HSCs inactivation. Nrf2 silencing partially reversed tricetin-mediated inhibition of α-SMA expression. Finally, utilizing primary mouse hepatic stellate cells (mHSCs), we demonstrated that tricetin also induced autophagy activation, repressed TGF-β1-induced LDs loss and fibrotic marker expression and pretreatment with CQ further sensitized these effects.
CONCLUSIONS: Our study indicates that tricetin\'s actions may represent an effective strategy to treat liver fibrosis and help identify novel therapeutic targets, especially in combination with autophagy inhibitors.

Proliferative vitreoretinopathy (PVR) is a visual-threatening disease, which cause from the migration of retinal pigment epithelium (RPE). Tricetin, a family of flavonoids, can inhibit the metastasis of several cancers. Herein, we aim to evaluate the possible effect of tricetin on inhibiting ARPE-19 cells migration. The Boyden chamber assay, wound healing assay, RNA sequencing, and Western blot analysis were applied in our experiment. The results revealed that tricetin inhibited the cell migration abilities of ARPE-19 cells. Moreover, using RNA sequencing technology, we revealed that tricetin repressed bone morphogenetic protein-6 (BMP-6) gene expressions in ARPE-19 cells. Overexpression of BMP-6 resulted in significant restoration of cell migration capabilities of tricetin-treated ARPE-19 cells. Furthermore, tricetin suppressed the phosphorylation of the p38 signaling pathway. Moreover, blocking the p38 pathway also inhibits BMP-6 expression and migration in the ARPE-19 cells. In conclusion, this study revealed that tricetin inhibits the ARPE-19 cell migration mainly via the suppression of BMP-6 expression and p38 signaling pathway.

Acute pancreatitis (AP) poses a worldwide challenge due to the growing incidence and its potentially life-threatening course and complications. Specific targeted therapies are not available, prompting the identification of new pathways and novel therapeutic approaches. Flavonoids comprise several groups of biologically active compounds with wide-ranging effects. The flavone compound, tricetin (TCT), has not yet been investigated in detail but sporadic reports indicate diverse biological activities. In the current study, we evaluated the potential protective effects of TCT in AP. TCT (30 μM) protected isolated primary murine acinar cells from the cytotoxic effects of cerulein, a cholecystokinin analog peptide. The protective effects of TCT were observed in a general viability assay (calcein ester hydrolysis), in an apoptosis assay (caspase activity), and in necrosis assays (propidium iodide uptake and lactate dehydrogenase release). The effects of TCT were not related to its potential antioxidant effects, as TCT did not protect against H2O2-induced acinar cell death despite possessing radical scavenging activity. Cerulein-induced expression of IL1β, IL6, and matrix metalloproteinase 2 and activation of nuclear factor-κB (NFκB) were reduced by 30 μM TCT. In vivo experiments confirmed the protective effect of TCT in a mouse model of cerulein-induced AP. TCT suppressed edema formation and apoptosis in the pancreas and reduced lipase and amylase levels in the serum. Moreover, TCT inhibited interleukin-1β (IL1β), interleukin-6 (IL6), and tumor necrosis factor-α (TNFα) expression in the pancreas and reduced the activation of the oxidative DNA damage sensor enzyme poly(ADP-ribose) polymerase-1 (PARP-1). Our data indicate that TCT can be a potential treatment option for AP.

Tricetin (5,7,3\',4\',5\'-pentahydroxyflavone) is a dietary flavone from flowers of Myrtales plants with demonstrated functions in promoting human health. By contrast, the bioactivity of its glucosylated derivative tricetin 4\'-O-glucoside has not been extensively explored. We conducted metabolite profiling analysis of pomegranate (a Myrtales plant) floral tissues and revealed that tricetin and tricetin 4\'-O-glucoside accumulate in anthers, but not petals. In addition, the comparative analysis of anther and petal transcriptomes identified 10 UGTs that are more highly expressed in anthers than petals. Of the 10 UGTs, PgUGT76Z1 and PgUGT73AL1 glucosylated specifically at the 4\'-O position of tricetin to form tricetin 4\'-O-glucoside. The phylogenetic analysis indicated that PgUGT76Z1 and PgUGT73AL1 belong to different plant UGT groups, suggesting a convergent evolution of these tricetin UGTs. Overall, identification and characterization of PgUGT76Z1 and PgUGT73AL1 not only provides evolutionary insights into tricetin glucosylation, but also offers an opportunity to produce tricetin 4\'-O-glucoside in large quantities through microbial biotransformation or plant metabolic engineering, thus facilitating the investigation of tricetin 4\'-O-glucoside bioactivities.

Lymph node migration results in poor prognoses for nasopharyngeal carcinoma (NPC) patients. Tricetin, a flavonoid derivative, regulates tumorigenesis activity through its antiproliferative and antimetastatic properties. However, the molecular mechanism of tricetin affecting the migration and invasion of NPC cells remains poorly understood. In this paper, we examined the antimetastatic properties of tricetin in human NPC cells. Our results demonstrated that tricetin at noncytotoxic concentrations (0-80 3M) noticeably reduced the migration and invasion of NPC cells (HONE-1, NPC-39, and NPC-BM). Moreover, tricetin suppressed the indicative protease, presenilin-1 (PS-1), as indicated by protease array. PS-1 was transcriptionally inhibited via the Akt signaling pathway but not mitogen-activated protein kinase pathways, such as the JNK, p38, and ERK1/2 pathways. In addition to upregulating GSK-3[Formula: see text] phosphorylation through Akt suppression, tricetin may downregulate the activity of PS-1. Overall, our study provides new insight into the role of tricetin-induced molecular regulation in the suppression of NPC metastasis and suggests that tricetin has prospective therapeutic applications for patients with NPC.

Atherosclerosis is the primary cause of many cardiovascular diseases. Endothelial dysfunction is recognized as a crucial early event in atherosclerotic lesion formation. Tricetin is a natural flavonoid derivative that has demonstrated a wide range of therapeutic properties. This study investigates the protective effect of tricetin in cultured endothelial cells. The results of our study show that tricetin suppressed oxidized low-density lipoprotein (ox-LDL)-induced expression of pro-inflammatory monocyte chemotactic protein-1 (MCP-1) and interleukin-1β (IL-1β), as well as the generation of reactive oxygen species (ROS). Furthermore, our findings indicate that tricetin suppressed ox-LDL-induced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). At the cellular level, the presence of tricetin inhibited ox-LDL-induced monocyte adhesion to endothelial cells. Mechanistically, we showed that tricetin suppressed the induction of the endothelial receptor for ox-LDL, lectin-like ox-LDL receptor-1 (LOX-1), and the transcriptional factor early growth response 1 (Egr-1) as well as extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) activation. These data demonstrate that tricetin is a natural protective agent in vascular endothelial cells, indicating that tricetin could have a potentially beneficial effect in the modulation of atherosclerosis.

In this study, flavonoid tricetin was used as a reducing and capping agent for the synthesis of gold nanoparticles (AuNPs). Further, the antibacterial efficacy of the synthesised AuNPs was evaluated against the opportunistic bacterial pathogens that cause respiratory infections. The optimum levels for the synthesis of AuNPs were found to be pH 8, temperature 30 °C, tricetin 125 μM and chloroauric acid 250 μM. The tricetin synthesised AuNPs exhibited in spherical shape with an average size of 12 nm. FT-IR results confirmed that the hydroxyl (OH) and carbonyl (CO) groups of tricetin were mainly participated in the synthesis of AuNPs. The opportunistic bacterial pathogens isolated from immunocompromised patients suffering with different respiratory infections were identified as Staphylococcus aureus, Enterobacter xiangfangensis, Bacillus licheniformis, Escherichia fergusonii, Acinetobacter pittii, Pseudomonas aeruginosa, Aeromonas enteropelogenes and Proteus mirabilis. The antibacterial studies confirmed the broad-spectrum antibacterial activity of AuNPs against the tested Gram-positive and Gram-negative bacteria. The synthesised AuNPs showed high biocompatibility on primary normal human dermal fibroblast (NHDF-c) cells up to 50 μM mL-1. Best of our knowledge, this is the first report on the synthesis of AuNPs using tricetin, which may be a potential antibacterial nanomedicine to treat bacterial infections.

Apoptosis of DA neurons is a contributing cause of disability and death for Parkinson\'s disease (PD). In this experiment, the neuroprotective effect of Tricetin was examined in PD models both in vitro and in vivo. The results suggested that 6-OHDA-induced cytotoxicity was accompanied by an increase in ROS generation, an increase in caspase-3 protein activity, an increase in Lactate dehydrogenase (LDH) release and an increase in the ratio of Bax/Bcl-2, but the pretreatment with Tricetin significantly improved cell viability and suppressed mitochondria-mediated apoptosis. Moreover, Tricetin also induced the protein expression of Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and its transcriptional activation, resulting in the up-regulated expression of heme oxygenase-1 (HO-1), which conferred neuroprotection against 6-OHDA-induced oxidative damage. Results from molecular docking indicated that Tricetin could be a potent competitive inhibitor of the Keap1-Nrf2 Protein Protein Interaction (PPI). Finally, in vivo findings were confirmed in the 6-OHDA-PD C. elegans model. Thus, Tricetin may be an attractive therapeutic candidate for the neuroprotection.

Tricetin is a dietary flavonoid with cytostatic properties and antimetastatic activities in various solid tumors. The anticancer effect of tricetin in nonsolid tumors remains unclear. Herein, the molecular mechanisms by which tricetin exerts its anticancer effects on acute myeloid leukemia (AML) cells were investigated. Results showed that tricetin inhibited cell viability in various types of AML cell lines. Tricetin induced morphological features of apoptosis such as chromatin condensation and phosphatidylserine (PS) externalization, and significantly activated proapoptotic signaling including caspase-8, -9, and -3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in HL-60 AML cells. Of note, tricetin-induced cell growth inhibition was dramatically reversed by a pan caspase and caspase-8- and -9-specific inhibitors, suggesting that this compound mainly acts through a caspase-dependent pathway. Moreover, treatment of HL-60 cells with tricetin induced sustained activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), and inhibition of ERK and JNK by their specific inhibitors respectively promoted and abolished tricetin-induced cell apoptosis. Dichlorofluorescein (DCF) staining showed that intracellular reactive oxygen species (ROS) levels were higher in tricetin-treated HL-60 cells compared to the control group. Moreover, an ROS scavenger, N-acetylcysteine (NAC), reversed tricetin-induced JNK activation and subsequent cell apoptosis. In conclusion, our results indicated that tricetin induced cell death of leukemic HL-60 cells through induction of intracellular oxidative stress following activation of a JNK-mediated apoptosis pathway. A combination of tricetin and an ERK inhibitor may be a better strategy to enhance the anticancer activities of tricetin in AML.

Tricetin is a flavonoid derivative and a potent anti-inflammatory and anticancer agent. However, the molecular mechanism underlying the effects of tricetin on human oral cancer cell migration remains unclear. The cell migration and invasion abilities of three oral cancer cell lines (SCC-9, HSC-3, and OECM-1) were analyzed using Boyden chamber migration assays. Our results demonstrated that tricetin attenuates 12-O-tetradecanoylphorbol-13-acetate-induced SCC-9, HSC-3, and OECM-1 cell invasiveness and migration by reducing matrix metalloproteinase (MMP)-9 enzyme activity. The reverse transcription polymerase chain reaction and luciferase reporter assay revealed that tricetin downregulates the mRNA expression and promoter activity of MMP-9. In addition, Western blot analysis revealed that tricetin significantly reduced the levels of phosphorylated c-Jun N-terminal kinase (JNK) 1/2 and p38 levels but not those of extracellular signal-regulated kinase 1/2. In conclusion, this study demonstrated that tricetin suppresses MMP-9 enzymatic activity by downregulating the p38/JNK1/2 pathway and might be a beneficial chemopreventive agent.