Advances on toxicity and metabolism of alkaloids from the "toxic" traditional Chinese medicines / 药学学报

The "toxicity" and safety of traditional Chinese medicines have been seriously concerned. Alkaloids are the main pharmacodynamic components of many kinds of traditional Chinese medicines, which show strong biological activity at low concentration. It will also cause toxic side effects but if used improperly. Some alkaloids are both active and toxic, and the safety of related traditional Chinese medicines is particularly noteworthy. The efficacy or toxicity of alkaloids may be the result of the combined action of parent compounds and metabolites, which is not only related to the structural types of compounds, but also has obvious species differences between humans and animals. This review focused on the alkaloids contained in the "toxic" traditional Chinese medicines that are officially recorded in Chinese Pharmacopoeia and the metabolism patterns of alkaloids with different structures as well as the enzymes involved were summarized and discussed by referencing the publications in recent two decades. The present study will be beneficial to the rational use of these traditional Chinese medicines in clinic.

Bear bile powder attenuates senecionine-induced hepatic sinusoidal obstruction syndrome in mice / 中国天然药物

Hepatic sinusoidal obstruction syndrome (HSOS) via exposure to pyrrolizidine alkaloids (PAs) is with high mortality and there is no effective treatment in clinics. Bear bile powder (BBP) is a famous traditional animal drug for curing a variety of hepatobiliary diseases such as cholestasis, inflammation, and fibrosis. Here, we aim to evaluate the protective effect of BBP against HSOS induced by senecionine, a highly hepatotoxic PA compound. Our results showed that BBP treatment protected mice from senecionine-induced HSOS dose-dependently, which was evident by improved liver histology including reduced infiltration of inflammatory cells and collagen positive cells, alleviated intrahepatic hemorrhage and hepatic sinusoidal endothelial cells, as well as decreased conventional serum liver function indicators. In addition, BBP treatment lowered matrix metalloproteinase 9 and pyrrole-protein adducts, two well-known markers positively associated with the severity of PA-induced HSOS. Further investigation showed that BBP treatment prevents the development of liver fibrosis by decreasing transforming growth factor beta and downstream fibrotic molecules. BBP treatment also alleviated senecionine-induced liver inflammation and lowered the pro-inflammatory cytokines, in which tauroursodeoxycholic acid played an important role. What's more, BBP treatment also decreased the accumulation of hydrophobic bile acids, such as cholic acid, taurocholic acid, glycocholic acid, as well. We concluded that BBP attenuates senecionine-induced HSOS in mice by repairing the bile acids homeostasis, preventing liver fibrosis, and alleviating liver inflammation. Our present study helps to pave the way to therapeutic approaches of the treatment of PA-induced liver injury in clinics.

The protective effect of ritonavir against Gynura japonica-induced liver injury in rats / 药学学报

Numerous in vitro studies have shown that most pyrrolizidine alkaloids (PAs) are hepatotoxic after being metabolically activated by cytochrome P450 (CYP) 3A4. However, the key role of CYP3A4 has not been confirmed in vivo. Therefore, the CYP3A4 chemical inhibitor ritonavir was employed in this work and the effect of ritonavir on Gynura japonica-induced liver injury in rats was investigated. All experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine. Animal welfare and the animal experimental protocols were strictly consistent with related ethics regulations of Shanghai University of Traditional Chinese Medicine. Acute liver injury was induced by a single gavage of Gynura japonica extracts (GJE, 8 g·kg-1); rats in the protection group were gavaged with ritonavir (RIT, 30 mg·kg-1) 1 h before GJE treatment. The results show that RIT could significantly attenuate GJE-induced liver injury in rats. Rats in the protection group showed decreased serum activities for alanine aminotransferase and aspartate aminotransferase, as well as lower total bile acids. In addition, the infiltration of inflammatory cells, sinusoidal hemorrhage, and hepatic necrosis in GJE-treated rats were markedly attenuated in the protection group. The content of pyrrole-protein adducts (PPAs), a recommended biomarker for PA-induced hepatotoxicity in clinics, was determined at 10 min to 24 h after GJE treatment. The content of 13 bile acids was also quantified. RIT treatment reduced the content of PPAs in serum dramatically and restored the impaired bile acid homeostasis caused by GJE. These studies indicate that RIT attenuated Gynura japonica-induced liver injury in rats, which was closely related to the inhibition of the metabolic activation of PAs and the regulation of bile acid metabolism. These results provide a better understanding of the relationship between CYP3A4 and PA-induced toxicity. This work will also be helpful in developing effective treatments for PA-induced liver injury and making a reasonable evaluation of the safety of drugs containing PAs in clinic.

The protective effect of schisandrol A against senecionine-induced hepatotoxicity in mice / 药学学报

Hepatotoxicity induced by herbal medicines such as Gynura japonica, which contains large amount of pyrrolizidine alkaloids (PAs) such as senecionine (SEN), is among the most serious problems of herbal drug-induced liver injury, yet there is no effective treatment in clinic. We have previously reported that ritonavir (the well-known CYP3A4 inhibitor) protected rats against Gynura japonica-induced liver injury in rats, which was closely related to the inhibition of the metabolic activation of PAs. A large number of lignans have been identified in Schisandrae Chinensis Fructis and are reported to attenuate drug-induced liver injuries by modulating the drug metabolism enzymes. Therefore, the present study investigated the protective effect and potential mechanism of schisandrol A (SoA, a representative lignan identified in Schisandrae Chinensis Fructis) against SEN-induced hepatotoxicity in mice. All experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine (PZSHUTCM210604002). Animal welfare and the animal experimental protocols were strictly consistent with related ethics regulations of Shanghai University of Traditional Chinese Medicine. Liver injury was induced by a single gavage of SEN (150 μmol·kg-1); mice in the protection group were gavaged with SoA (116 μmol·kg-1) 7 days before SEN treatment. The results show that SoA dramatically alleviated SEN-induced liver injury in mice. Mice in the protection group showed decreased serum activities for alanine aminotransferase and aspartate aminotransferase; in addition, the hepatic necrosis and sinusoidal hemorrhage in SEN-treated mice were markedly attenuated in the protection group. The serum contents of SEN metabolites in mice were decreased. In vitro studies were performed by using human liver microsomes and proved that SoA inhibits CYP3A4 to decrease the metabolism of SEN. These studies indicate that SoA attenuated SEN-induced liver injury in mice, which was closely related to the inhibition of the metabolic activation of SEN. These results provide a better understanding of the relationship between CYP3A4 and PA-induced toxicity. This work also will be helpful in developing effective treatments for SEN-induced liver injury based on inhibition of its metabolic activation, and in making reasonable evaluations of the safety of herbal medicines containing PAs such as G. japonica.

The protective effect of salvianolic acid B against senecionine-induced hepatotoxicity in mice / 药学学报

In recent years, there has been an increase in the incidence of herbal-induced liver injury due to the accidental ingestion of herbal medicines containing pyrrolizidine alkaloids (PAs) in domestic. Salvianolic acid B (Sal B), a hydrophilic component in Salvia miltiorrhiza Bge., shows activities of anticoagulation, antioxidation, and other pharmacological activities. This research aims to investigate the protective effect of Sal B on hepatotoxicity induced by senecionine (SEN) and its potential mechanism. The animal experiment was approved by the Experimental Animal Ethical Committee of Shanghai University of Traditional Chinese Medicine, and all mice have received humane care in compliance with the institutional animal care guidelines. Mice were treated with Sal B (10 mg·kg-1) 3 days before and 1 day after SEN (50 mg·kg-1) treatment. The animals were sacrificed 48 h after SEN administration. As a result, Sal B effectively ameliorated SEN-induced liver injury. The mice in the group treated with Sal B showed lower serum activities of alanine aminotransferase and aspartate aminotransferase, less hepatic sinusoidal hemorrhage, and reduced hepatocyte necrosis. Besides, contents of pyrrole-protein adducts, the marker for PA-induced toxicity, were also decreased in serum. The key factors related to coagulation, oxidative stress, and liver fibrosis were further analyzed. It was found that Sal B inhibited the coagulant system by reducing the expression of plasminogen activator inhibitor-1. Sal B also modulated glutathione and superoxide dismutase levels and improved the anti-oxidative defense system. In addition, Sal B decreased the excessive deposition of extracellular matrix and inhibited the progression of liver fibrosis via down-regulating several key factors related to liver fibrosis, including matrix metalloproteinase 9, transforming growth factor-β1, signal transducer and activator of transcription 3, and chemokine 1. In conclusion, Sal B ameliorated SEN-induced liver injury in mice by regulating the blood coagulation system, improving oxidative stress, and modulating liver fibrosis-related factors. Our present study pointed to the possibility of utilizing salvianolic acid B for protection against PA-induced liver injury clinically.

The protective effects and mechanism of Alismatis Rhizoma extracts against senecionine-induced acute liver injury in mice / 药学学报

Drug-induced liver injury and herbal preparations containing pyrrolizidine alkaloid (PA) have gained global attention. The purpose of this research was to investigate the effects and mechanisms of Alismatis Rhizoma, a traditional Chinese medicine, to protect against acute liver injury in mice induced by senecionine (SEN), a representative toxic PA compound. All experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine. Animal welfare and the animal experimental protocols were strictly consistent with related ethics regulations of Shanghai University of Traditional Chinese Medicine. Acute liver injury was induced by a single intragastric administration of SEN (50 mg·kg-1). Mice in the protection groups received intragastric administration of Alismatis Rhizoma water extract (WE, 18 g·kg-1 per day) or ethanol extract (EE, 18 g·kg-1 per day) 5 days before SEN treatment. The results show that Alismatis Rhizoma extracts can significantly attenuate acute liver injury in mice. Mice in the protection groups showed decreased serum activities of alanine aminotransferase and aspartate aminotransferase, as well as decreased total bile acids. In addition, the infiltration of inflammatory cells, sinusoidal hemorrhage, and hepatic necrosis in SEN-treatment mice was clearly attenuated in the protection groups. Interestingly, EE showed a better effect than WE. The content of principal bile acids in serum and the mRNA and protein expression of key factors related to bile acid metabolism were also measured. Alismatis Rhizoma up-regulated the bile acid transporters and drug metabolism enzymes, consistent with the observed bile acid homeostasis and alleviation of SEN-induced injury to hepatocytes. The present study points to the possibility of utilizing Alismatis Rhizoma for protection against liver injury caused by drugs and preparations containing PA.

Kinetic study of pyrrolizidine alkaloid-derived pyrrole-protein adducts in rats after intragastric administration of Gynura japonica / 药学学报

Recently, hepatic sinusoidal obstruction syndrome (HSOS) induced by misuse of Gynura japonica has increased and gained global attention. Large amounts of pyrrolizidine alkaloids (PAs) are present in G. japonica; these PAs are metabolically activated to generate pyrrole-protein adducts (PPAs). In this study, male SD rats were treated orally with a single dose of G. japonica extract (GJE) at 0.062 5, 0.25, 0.5, 1, and 2 g·kg-1. Blood was collected from the orbital venous plexus at 2, 12, 24 and 48 h, and at 48 h after treatment the rats were anesthetized with isoflurane and livers were collected for hematoxylin & eosin staining. The kinetics of PPAs at different doses were studied at 10, 20, 30 min, 1, 2, 4, 6, 12, 24 h, and 48 h, after a single gavage of GJE. The experimental scheme was approved by the ethics committee of animal experiments of Shanghai University of Traditional Chinese Medicine (PZSHUTCM190912019). The concentration of PPAs in serum was determined by liquid chromatography-mass spectrometry (LC-MS). Kinetic data were processed by using the non-compartmental pharmacokinetics data analysis software program PK solutions 2™. The results demonstrate that the concentration of PPAs increased with the dose of GJE and positively correlated with the severity of liver injury. The elimination rate of PPAs in rats was significantly prolonged at higher doses. The level of PPAs and their clearance rate may serve as useful references for the detoxification of PAs-induced injuries.

Systematical analysis of multiple components in drainage bear bile powder from different sources / 中国中药杂志

Bear Bile Powder contains bile acids, protein, amino acids, bilirubin and microelements and other compounds. Among them, the bile acids are the most active components. Currently, there are many studies on bile acids, but few reports on other components. Therefore, the purpose of this study is to carry out a systematical analysis of multiple components in drainage Bear Bile Powder from different sources. Bilirubin and protein were quantified by microplate spectrophotometer. The contents of bile acids and amino acids were determined by liquid chromatography coupled with mass spectrometry (LC-MS). The contents of microelements were determined by inductively coupled plasma mass spectrometry (ICP-MS) The result indicated that among 20 batches of bear bile powder from different sources there is high similarity (0.922-0.977). Tauroursodeoxycholic acid (TUDCA) and taurochenodeoxycholic acid (TCDCA) were the two most abundant components. The total contents of them were 41%-59% and met the current standard for quality control of bear bile powder. However, significant differences were found in their contents among samples from different sources. Besides, bilirubin, protein, amino acids and microelements also contributed to the differentiation of samples from different sources. The main components of bear bile powder from the different sources were with satisfactory similarity. But bile acids, bilirubin, protein, amino acids and microelements all contributed to the different among samples. Our present study provided a systematical approach for the better quality control and evaluation of bear bile powder.

Identification of metabolites of senecionine, a hepatotoxic pyrrolizidine alkaloid, by liquid chromatography/tandem mass spectrometry / 中国药学杂志

OBJECTIVE: To investigate the metabolic profile of senecionine in rats. METHODS: Liquid chromatography-tandem mass spectrometry (LC-MSn) mass spectrometry was used for the analysis of senecionine and its metabolites in rats bile, urine, and feces after a single oral dose of senecionine. RESULTS: In total 38 metabolites were identified, including oxidation products, hydroxylation products, hydrolysis products, sulfation products, glucuronidation products, and GSH-conjugations. And metabolites were found to be more abundant in bile and urine than those in feces. CONCLUSION: Senecionine undergoes extensive metabolism in rats.