Psoralen induces hepatic toxicity through PERK and ATF6 related ER stress pathways in HepG2 cells

4-hydroxylonchocarpin and corylifol A: The potential hepatotoxic components of Psoralea corylifolia L

Psoralea corylifolia L. (P. corylifolia) has attracted increasing attention because of its potential hepatotoxicity. In this study, we used network analysis (toxic component and hepatotoxic target prediction, proteinprotein interaction, GO enrichment analysis, KEGG pathway analysis, and molecular docking) to predict the components and mechanism of P. corylifolia-induced hepatotoxicity and then selected 4-hydroxylonchocarpin and corylifol A for experimental verification. HepG2 cells were treated with low, medium, and high concentrations of 4-hydroxylonchocarpin or corylifol A. The activities of ALT, AST, and LDH in cell culture media and the MDA level, SOD activity, and GSH level in cell extracts were measured. Moreover, apoptosis, ROS levels, and mitochondrial membrane potential were evaluated. The results showed that the activities of ALT, AST, and LDH in the culture medium increased, and hepatocyte apoptosis increased. The level of MDA increased, and the activity of SOD and level of GSH decreased, and the ROS level increased with 4-hydroxylonchocarpin and corylifol A intervention. Furthermore, the mitochondrial membrane potential decreased in the 4-hydroxylonchocarpin and corylifol A groups. This study suggests that 4-hydroxylonchocarpin and corylifol A cause hepatocyte injury and apoptosis by inducing oxidative stress and mitochondrial dysfunction, suggesting that these compounds may be the potential hepatotoxic components of P. corylifolia.

Unveiling hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in Fructus Psoraleae by integrating UPLC-Q-TOF-MS and high content analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Psoraleae (FP), the dried and ripe fruit of Cullen corylifolium (L.) Medik., is widely used due to its various clinical pharmacological effects, but its hepatotoxicity restricts its clinical application. So far, its hepatotoxic components and their underlying mechanism have not been systematically elucidated.

AIM OF THE STUDY

This study was undertaken to reveal the hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in FP and elucidate their potential mechanism.

METHODS

Rats were administrated with the aqueous extract of Fructus Psoraleae (AEFP), in which eight coumarin-related compounds were focused. Subsequently, compounds exposed in rats' livers were detected by UPLC-Q-TOF-MS, and the identified hepatotoxic compounds were evaluated to elaborate their possible mechanism by the aid of high content analysis (HCA).

RESULTS

Eight coumarin-related compounds were identified, among which psoralenoside (PO), isopsoralenoside (IPO), psoralen (P), and isopsoralen (IP) were the principally exposed compounds in rats' livers. Furocoumarinic acid glucoside (FAG), (E)-3-(4-(((2S, 3R, 4S, 5S, 6R)-3,4,5-trihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-2-yl) oxy) benzofuran-5-yl) acrylic acid (isofurocoumarinic acid glucoside, IFAG), furocoumarinic acid (FA), and (E)-3-(4-hydroxybenzofuran-5-yl) acrylic acid (isofurocoumarinic acid, IFA) were also detected in low abundance. P, IP, FA, and IFA were identified as the hepatotoxic compounds, while their glycosides were almost non-hepatotoxic. The HCA's results showed that hepatotoxic compounds disrupted the balance in reactive oxygen species (ROS), nuclear area, and mitochondrial membrane potential of HepG2 cells, leading to the occurrence of hepatotoxicity.

CONCLUSIONS

P, IP, FA, and IFA were identified as hepatotoxic compounds, from which P and IP were proposed as the important risk components for hepatotoxicity. The conversion from glycosides to aglycones played an essential role in FP-induced hepatotoxicity.

Psoraleae Fructus Ethanol Extract Induced Hepatotoxicity via Impaired Lipid Metabolism Caused by Disruption of Fatty Acid β-Oxidation

Herb-induced liver injury (HILI) is gradually increasing, and Psoraleae Fructus (PF) has been reported to induce hepatotoxicity. However, its underlying toxicity mechanism has been only poorly revealed. In this paper, we attempted to explore the liver injury and mechanism caused by Psoraleae Fructus ethanol extract (PFE). First, we administered PFE to mice for 4 weeks and evaluated their serum liver function indices. H&E staining was performed to observe the pathological changes of the livers. Oil red O staining was used to visualize hepatic lipids. Serum-untargeted metabolomics and liver proteomics were used to explore the mechanism of PF hepatotoxicity, and transmission electron microscopy was determined to assess mitochondria and western blot to determine potential target proteins expression. The results showed that PFE caused abnormal liver biochemical indicators and liver tissue injury in mice, and there was substantial fat accumulation in liver tissue in this group. Furthermore, metabolomic analysis showed that PFE changed bile acid synthesis, lipid metabolism, etc., and eight metabolites, including linoleic acid, which could be used as potential biomarkers of PFE hepatotoxicity. Proteomic analysis revealed that differential proteins were clustered in the mitochondrial transmembrane transport, the long-chain fatty acid metabolic process and purine ribonucleotide metabolic process. Multiomics analysis showed that eight pathways were enriched in both metabolomics and proteomics, such as bile secretion, unsaturated fatty acid biosynthesis, and linoleic acid metabolism. The downregulation of SLC27A5, CPT1A, NDUFB5, and COX6A1 and upregulation of cytochrome C and ABCC3 expressions also confirmed the impaired fatty acid oxidative catabolism. Altogether, this study revealed that PFE induced hepatotoxicity by damaging mitochondria, reducing fatty acid β-oxidation levels, and inhibiting fatty acids ingested by bile acids.

Discovery of bakuchiol as an AIM2 inflammasome activator and cause of hepatotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Psoralea corylifolia (P. corylifolia Linn.) is a traditional Chinese medicinal plant that exhibits significant aphrodisiac, diuretic, and anti-rheumatic effects. However, it has been reported to cause hepatic injury, but the precise mechanisms remain unclear.

AIM OF THE STUDY

To evaluate the safety and risk of P. corylifolia and to elucidate the underlying mechanisms of drug-induced liver injury.

MATERIALS AND METHODS

Western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, quantitative polymerase chain reaction (Q-PCR), and flow cytometry were used to explore the effect of bakuchiol (Bak), one of the most abundant and biologically active components of P. corylifolia, on the AIM2 inflammasome activation and the underlying mechanism. Furthermore, we used the lipopolysaccharides (LPS)-induced drug-induced liver injury (DILI) susceptible mice model to study the Bak-mediated hepatotoxicity.

RESULTS

Bak induced the maturation of caspase-1 P20, and significantly increased the expression of IL-1β and TNF-α (P < 0.0001) compared with the control group. Moreover, compared to the Bak group, knockdown of AIM2 inhibited Bak-induced caspase-1 maturation and significantly decreased the production of IL-1β and TNF-α, but knockout of NLRP3 had no effect. Mechanistically, Bak-induced AIM2 inflammasome activation is involved in mitochondrial damage, mitochondrial DNA (mtDNA) release, and subsequent recognition of cytosolic mtDNA. Our in vivo data showed that co-exposure to LPS and non-hepatotoxic doses of Bak significantly increased the levels of ALT, AST, IL-1β, TNF-α, and IL-18, indicating that Bak can induce severe liver inflammation (P < 0.005).

CONCLUSIONS

The result shows that Bak activates the AIM2 inflammasome by inducing mitochondrial damage to release mtDNA, and subsequently binds to the AIM2 receptor, indicating that Bak may be a risk factor for P. corylifolia-induced hepatic injury.

Ochratoxin A induces cytotoxicity through ROS-mediated endoplasmic reticulum stress pathway in human gastric epithelium cells

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium species that greatly threatens human health. We previously showed that OTA induced cycle arrest, apoptosis and autophagy in human gastric epithelium cells (GES-1). However, the mechanism underlying these effects is still unclear. Here, we showed that OTA exposure increased the expression of endoplasmic reticulum (ER) stress indicators (GRP78, PERK, ATF6, eIF2α, and CHOP), suggesting the activation of the unfolded protein response pathway. 4-phenylbutyric acid (4-PBA), an ER stress-specific inhibitor, attenuated OTA-induced loss of cell viability and apoptosis in GES-1 cells. It also attenuated the G2 phase arrest and autophagy induced by OTA, as evidenced by upregulated G2 phase-related proteins (Cdc2, Cdc25C, and cyclinB1) and downregulated autophagy markers (LC3B and Beclin-1). Moreover, OTA was found to increase ROS generation, and the inhibition of ROS formation by N-acetylcysteine (NAC), an ROS inhibitor, attenuated OTA-induced ER stress and subsequent apoptosis, cell cycle arrest, and autophagy. Collectively, these results suggest that the ROS-mediated ER stress pathway contributes to the OTA toxin-induced cytotoxicity in GES-1 cells. This study offers new insights into the molecular mechanisms underlying OTA toxicity in gastric cells.

Isobavachalcone disrupts mitochondrial respiration and induces cytotoxicity through ROS accumulation and Akt suppression

Isobavachalcone (IBC) is one of the flavonoid components in Fructus Psoraleae, and has been found multiple pharmacological effects. However, the hepatotoxicity of IBC has been overlooked and not been carefully studied. We aim to find out the cytotoxicity of IBC on HepG2 cells, and explore the underlying mechanisms. HepG2 cells were treated with IBC for 24 h, then MTT assay and LDH assay were used to detect the cell viability. The apoptosis and reactive oxygen species (ROS) production were reflected by the flow cytometry. Using Seahorse Analyzer, we measured the mitochondrial respiratory capacity. The expression of oxidative stress and mitochondrial apoptosis-related proteins were determined by Western blot. The results showed that IBC induced the cell death and apoptosis of HepG2 cells. IBC initiated the accumulation of ROS in cells and impaired the mitochondrial function, triggered apoptosis and suppressed the phosphorylation of Akt. Additionally, scavenging ROS by the antioxidant N-acetyl-l-cysteine (NAC) reduced IBC-induced mitochondria damage and increased Akt phosphorylation. Taken together, IBC caused mitochondrial damage and induced hepatotoxicity by ROS accumulation and Akt suppression. Targeting oxidative stress and depressing mitochondrial damage may provide a theoretical basis for the treatment and prevention of IBC-induced hepatotoxicity in clinic.

A new strategy for the rapid identification and validation of direct toxicity targets of psoralen-induced hepatotoxicity

The interaction between small-molecule compounds of traditional Chinese medicine and their direct targets is the molecular initiation event, which is the key factor for toxicity efficacy. Psoralen, an active component of Fructus Psoraleae, is toxic to the liver and has various pharmacological properties. Although the mechanism of psoralen-induced hepatotoxicity has been studied, the direct target of psoralen remains unclear. Thus, the aim of this study was to discover direct targets of psoralen. To this end, we initially used proteomics based on drug affinity responsive target stability (DARTS) technology to identify the direct targets of psoralen. Next, we used surface plasmon resonance (SPR) analysis and verified the affinity effect of the 'component-target protein'. This method combines molecular docking technology to explore binding sites between small molecules and proteins. SPR and molecular docking confirmed that psoralen and tyrosine-protein kinase ABL1 could be stably combined. Based on the above experimental results, ABL1 is a potential direct target of psoralen-induced hepatotoxicity. Finally, the targets Nrf2 and mTOR, which are closely related to the hepatotoxicity caused by psoralen, were predicted by integrating proteomics and network pharmacology. The direct target ABL1 is located upstream of Nrf2 and mTOR, Nrf2 can influence the expression of mTOR by affecting the level of reactive oxygen species. Immunofluorescence experiments and western blot results showed that psoralen could affect ROS levels and downstream Nrf2 and mTOR protein changes, whereas the ABL1 inhibitor imatinib and ABL1 agonist DPH could enhance or inhibit this effect. In summary, we speculated that when psoralen causes hepatotoxicity, it acts on the direct target ABL1, resulting in a decrease in Nrf2 expression, an increase in ROS levels and a reduction in mTOR expression, which may cause cell death. We developed a new strategy for predicting and validating the direct targets of psoralen. This strategy identified the toxic target, ABL1, and the potential toxic mechanism of psoralen.

Five Constituents Contributed to the Psoraleae Fructus-Induced Hepatotoxicity via Mitochondrial Dysfunction and Apoptosis

Backgrounds: Psoraleae Fructus (PF)-induced hepatotoxicity has been reported in clinical and animal experiments. However, the hepatotoxic constituents and mechanisms underlying PF-induced toxicity have remained unclear. Therefore, this study explored the potentially toxic PF components and revealed their relative mechanisms.

Methods: The hepatotoxicity of PF water (PFW) and ethanol (PFE) extracts was compared using Kunming mice. The different compositions between PFW and PFE, which were considered toxic compositions, were identified using the UHPLC-Q-Exactive MS method. Then, L02 and HepG2 cell lines were used to evaluate the toxicity of these compositions. Cell viability and apoptosis were determined through the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. An automatic biochemical analyzer detected the aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Lastly, we used high-content screening (HCS) to determine the levels of reactive oxygen species (ROS), lipid, and mitochondrial membrane potential (MMP).

Results: The ethanol extraction process aggravated the hepatotoxicity of PF, causing more severe injuries. The content of psoralen, isopsoralen, bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol was higher in the PFE than PFW. Bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol induced cell apoptosis and the AST, ALT, and ALP leakages. Furthermore, these five constituents increased intracellular lipid accumulation and ROS levels but decreased the MMP level.

Conclusion: The ethanol extraction process could induce severe PF hepatotoxicity. Bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol are the main hepatotoxic ingredients. This mechanism could be associated with oxidative stress and mitochondrial damage-mediated apoptosis. Taken together, this study provides a basis for the clinical application of PF that formulates and improves its herbal standards.

Effects of Escitalopram on Endoplasmic Reticulum Stress and Oxidative Stress Induced by Tunicamycin

Background: Major depressive disorder (MDD) was reported to be associated with endoplasmic reticulum stress (ERS) combined with oxidative stress (OS) (ERS/OS). Here, we aimed to investigate the effects of escitalopram (ESC) on blood-brain barrier (BBB) permeability and ERS/OS-related pathways in brain microvascular endothelial cells (bEnd.3 cells) induced by tunicamycin (TM).

Methods: bEnd.3 cells were divided into four groups: control, TM, ESC, and ESC + TM groups. CCK-8 and flow cytometry were used to detect cell survival and apoptosis, respectively. The expression levels of proteins involved in cell permeability and ERS/OS-related pathways were assessed by western blot and immunofluorescence. Malondialdehyde (MDA) concentration and superoxide dismutase (SOD) activity were determined by commercial kits.

Results: We revealed that TM-induced bEnd.3 cells exhibited remarkably decreased viability and increased apoptosis rate, while ESC treatment reversed these changes. Additionally, TM treatment resulted in markedly increased PERK, GRP78, ATF6, XBP1, and CHOP protein expression levels. On the contrary, the expression of PERK, GRP78, XBP1, and CHOP was obviously reduced in TM-induced bEnd.3 cells after ESC treatment. Moreover, TM significantly reduced the expression of p-eNOS and P-gp and increased the expression of CaMKII and MMP9 compared with the control group. However, ESC reversed these changes in TM-induced bEnd.3 cells. Furthermore, the expression of SOD was significantly decreased, while MDA was significantly increased by TM treatment. In contrast, the expression of SOD was dramatically increased, while MDA was remarkably decreased by ESC treatment.

Conclusion: Our results demonstrated that ESC can inhibit ERS/OS and BBB permeability of TM-induced bEnd.3 cells. ESC may alleviate cognitive impairment and prevent comorbidities in MDD patients through ERS/OS.

Molecular Mechanism of the ATF6α/S1P/S2P Signaling Pathway in Hippocampal Neuronal Apoptosis in SPS Rats

Apoptosis of hippocampal neurons is one of the mechanisms of hippocampal atrophy in posttraumatic stress disorder (PTSD), and it is also an important cause of memory impairment in PTSD patients. Endoplasmic reticulum stress (ERS) mediated by activated transcription factor 6α (ATF6α)/site 1 protease (S1P)/S2P is involved in cell apoptosis, but it is not clear whether it is involved in hippocampal neuron apoptosis caused by PTSD. A PTSD rat model was constructed by the single prolonged stress (SPS) method. The study was divided into three parts. Experiment 1 included the control group, SPS 1 d group, SPS 7 d group, and SPS 14 d group. Experiment 2 included the control group, SPS 7 d group, SPS 7 d + AEBSF group, and control + AEBSF group. (4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) is an ATF6α pathway inhibitor). Experiment 3 included the control group, SPS 4 d group, SPS 4 d + AEBSF group, and control + AEBSF group. The protein and mRNA expression levels of ATF6α, glucose-regulated protein (GRP78), S1P, S2P, C/EBP homologous protein (CHOP), and caspase-12 in the hippocampus of PTSD rats were detected by immunohistochemistry, Western blotting and qRT-PCR. Apoptosis of hippocampal neurons was detected by TUNEL staining. In experiment 1, the protein and mRNA expression of ATF6α and GRP78 increased gradually in the SPS 1 d group and the SPS 7 d group but decreased in the SPS 14 d group (P < 0.01). In experiment 2, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly increased in the SPS 7 d group (P < 0.01). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly decreased after AEBSF pretreatment (P < 0.01). In experiment 3, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were increased in the SPS 14 d group (P < 0.05). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were decreased after AEBSF pretreatment (P < 0.05). SPS induced apoptosis of hippocampal neurons by activating ERS mediated by ATF6α, suggesting that ERS-induced apoptosis is involved in the occurrence of PTSD.

Psoralen induces liver injuries through endoplasmic reticulum stress signaling in female mice

Psoralen is the main coumarin component of Fructus psoraleae. Previously, we have found that psoralen induced hepatocytes apoptosis via PERK and ATF6 related ER stress pathways in vitro. In this study, we investigated the toxicity and ER stress induced by psoralen in female C57 mice. Mice were fed with 80 mg/kg of psoralen intra-gastrically for either 3, 7, or 21 days. Liver and kidney were weighed and their coefficients were calculated. The serum was isolated to examine the biochemical parameters including alanine aminotransferase (ALT) activity, aspartate aminotransferase (AST) activity, alkaline phosphatase (ALP) activity, blood urea nitrogen (BUN), total bile acid (TBA), total bilirubin (TBIL), and creatinine (CRE). The transcription and expression of ER stress-related markers were determined by Wes-automated Protein Simple system, Western blot and RT-PCR. Psoralen administration for 3 days significantly increased liver coefficients but decreased kidney coefficients of mice. Histopathological examination showed minimal inflammatory cell foci and vacuolar degeneration in the liver. Besides, serum levels of ALT, TBA, BUN, and CRE were markedly altered by psoralen. Moreover, psoralen significantly increased expression and transcription levels of ER stress related markers, including Grp78, PERK, eIF2α, ATF4, IRE1α, ATF6, and XBP1. These results illustrated that psoralen induced liver injuries through ER stress signaling in female mice.

Effects of psoralen on hepatic bile acid transporters in rats

Fructus Psoraleae (FP), widely used in traditional medicine, is increasingly reported to cause serious hepatotoxicity in recent years. However, the main toxic constituents responsible for hepatotoxicity and the underlying mechanisms are poorly understood. In the present study, psoralen, a main and quality-control constituent of FP, was intragastrically administered to Sprague-Dawley rats at a dose of 60 mg/kg for 1, 3 and 7 days. Blood and selected tissue samples were collected and analyzed for biochemistry and histopathology to evaluate hepatotoxicity. The results showed that psoralen could induce hepatotoxicity by enhanced liver-to-body weight ratio and alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total cholesterol after administration for 3 days. In addition, histopathological examinations also indicated the hepatotoxicity induced by psoralen. Furthermore, the mRNA and protein levels of hepatic bile acid transporters were significantly changed, in which MRP4, ABCG5 and ABCG8 were repressed, while the protein level of NTCP tended to increase in the rat liver. Taken together, psoralen caused liver injury possibly through affecting bile acid transporters, leading to the disorder of bile acid transport and accumulation in hepatocytes.

Mesencephalic Astrocyte-Derived Neurotrophic Factor, a Prognostic Factor of Cholangiocarcinoma, Affects Sorafenib Sensitivity of Cholangiocarcinoma Cells by Deteriorating ER Stress

Purpose

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignant tumor characterized by high malignancy and poor prognosis. Although the efficacy of sorafenib against cholangiocarcinoma cell lines has been demonstrated in vivo and in vitro, limited clinical data are available on the efficacy of sorafenib in patients with cholangiocarcinoma. Sorafenib can enhance endoplasmic reticulum (ER) stress-mediated apoptosis, and ER stress and unfolded protein response are also the mechanisms by which cancer cells resist drug therapy. Mesencephalic astrocyte-derived neurotrophic factor (MANF), initially identified as a neurotrophic factor, can be regulated by ER stress activation. There are no available studies on the diagnostic value and therapeutic significance of MANF in ICC. Hence, the purpose of this study was to evaluate the role of MANF in cholangiocarcinoma, investigating the possibility of whether sorafenib could become a reliable strategy for cholangiocarcinoma therapy.

Methods

In this study, the expression level of MANF in ICC patients was investigated by bioinformatic analysis and the results were verified by tissue microarray assay. Cholangiocarcinoma cell lines were also used to determine how MANF regulates the therapeutic effect of sorafenib and to identify the underlying mechanisms.

Results

The results showed that MANF was correlated with poor prognosis and MANF knockdown could facilitate sorafenib-mediated apoptosis and increase the sensitivity of sorafenib treatment by activating excessive ER stress.

Conclusion

MANF is a prognostic marker of cholangiocarcinoma. MANF knockdown increases sorafenib-mediated ER stress and apoptosis in the cholangiocarcinoma cell lines. This mechanism may lead to a new therapeutic strategy in cholangiocarcinoma.

A Review of the Pharmacological Properties of Psoralen

Psoralen is the principal bioactive component in the dried fruits of Cullen corylifolium (L.) Medik (syn. Psoralea corylifolia L), termed "Buguzhi" in traditional Chinese medicine (TCM). Recent studies have demonstrated that psoralen displays multiple bioactive properties, beneficial for the treatment of osteoporosis, tumors, viruses, bacteria, and inflammation. The present review focuses on the research evidence relating to the properties of psoralen gathered over recent years. Firstly, multiple studies have demonstrated that psoralen exerts strong anti-osteoporotic effects via regulation of osteoblast/osteoclast/chondrocyte differentiation or activation due to the participation in multiple molecular mechanisms of the wnt/β-catenin, bone morphogenetic protein (BMP), inositol-requiring enzyme 1 (IRE1)/apoptosis signaling kinase 1 (ASK1)/c-jun N-terminal kinase (JNK) and the Protein Kinase B(AKT)/activator protein-1 (AP-1) axis, and the expression of miR-488, peroxisome proliferators-activated receptor-gamma (PPARγ), and matrix metalloproteinases (MMPs). In addition, the antitumor properties of psoralen are associated with the induction of ER stress-related cell death via enhancement of PERK: Pancreatic Endoplasmic Reticulum Kinase (PERK)/activating transcription factor (ATF), 78kD glucose-regulated protein (GRP78)/C/EBP homologous protein (CHOP), and 94kD glucose-regulated protein (GRP94)/CHOP signaling, and inhibition of P-glycoprotein (P-gp) or ATPase that overcomes multidrug resistance. Furthermore, multiple articles have shown that the antibacterial, anti-inflammatory and neuroprotective effects of psoralen are a result of its interaction with viral polymerase (Pol), destroying the formation of biofilm, and regulating the activation of tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), interleukin 4/5/6/8/12/13 (IL-4/5/6/8/12/13), GATA-3, acetylcholinesterase (AChE), and the hypothalamic-pituitary-adrenal (HPA) axis. Finally, the toxic effects and mechanisms of action of psoralen have also been reviewed.

The Accumulation of Psoralen Contributes to Its Hepatotoxicity Revealed by Pharmacokinetic and Toxicokinetic Study after Repeated Administration

Psoralen is a furanocoumarin compound found in many herb medicines and is claimed to contribute to the hepatotoxicity caused by lots of traditional Chinese medicine. So far, there has been no research on the differences in pharmacokinetics of single and repeated dosing of psoralen. Moreover, the research on the cumulative toxicity of low concentration and long-term administration on cells has not been reported. Therefore, this study investigated the pharmacokinetic differences and the accumulated cytotoxicity of psoralen from repeated administration. The study found that after single or repeated administration of psoralen for 3 months at various dosages (14, 28, and 56 mg/kg), the pharmacokinetic parameters of female rats between single dose and repeated dose administration are totally different. Compared with a single administration, multiple administrations increased psoralen's in vivo exposure, prolonged the peak time, prolonged the half-life of the drug, reduced the drug clearance rate, and prolonged the drug's stay in the body. HepG2 cells were exposed to low doses (5, 10, 20, or 40 μM) of psoralen for 1, 2, 3, or 4 days. A 20 and 40 μM dose of psoralen did not induced cell death in the 1st day but significantly decreased the cell viability at the 3rd and 4th day of repeated administration, respectively. In addition, multiple administrations of psoralen decreased cell viability due to G2 arrest.