Pharmacological hypothesis: TPC2 antagonist tetrandrine as a potential therapeutic agent for COVID-19.

More than ten million patients worldwide have been diagnosed with coronavirus disease 19 (COVID-19) to date (WHO situation report, 1st July 2020). There is no vaccine to prevent infection with the causative organism, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), nor a cure. In the struggle to devise potentially useful therapeutics in record time, the repurposing of existing compounds is a key route of action. In this hypothesis paper, we argue that the bisbenzylisoquinoline and calcium channel blocker tetrandrine, originally extracted from the plant Stephania tetrandra and utilized in traditional Chinese medicine, may have potential in the treatment of COVID-19 and should be further investigated. We collate and review evidence for tetrandrine's putative mechanism of action in viral infection, specifically its recently discovered antagonism of the two-pore channel 2 (TPC2). While tetrandrine's particular history of use provides a very limited pharmacological dataset, there is a suggestion from the available evidence that it could be effective at doses used in clinical practice. We suggest that further research to investigate this possibility should be conducted.

Molecular mechanisms involved in drug-induced liver injury caused by urate-lowering Chinese herbs: A network pharmacology study and biology experiments.

As an important part of the comprehensive treatment methods, the urate-lowering Chinese herbs could provide favorable clinical effects on hyperuricemia in its ability to invigorate spleen and remove dampness. Owing to the long-term duration, it brought up the potential adverse reactions (ADRs) and concerns about the drug-induced liver injury from these herbs. To address this problem, the bioinformatics approaches which combined the network pharmacology, computer simulation and molecular biology experiments were undertaken to elucidate the underlying drug-induced liver injury molecular mechanisms of urate-lowering Chinese herbs. Several electronic databases were searched to identify the potential liver injury compounds in published research. Then, the putative target profile of liver injury was predicted, and the interaction network was constructed based on the links between the compounds, corresponding targets and core pathways. Accordingly, the molecular docking simulation was performed to recognize the representative compounds with hepatotoxicity. Finally, the cell experiments were conducted to investigate the biochemical indicators and expression of the crucial protein that were closely associated with liver injury. In conclusion, the current research revealed that the compounds with potential liver injury including diosgenin, baicalin, saikosaponin D, tetrandrine, rutaecarpine and evodiamine from urate-lowering Chinese herbs, could lead to decline the survival rate of L-02 cell, increase the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in cell-culture medium, enhance the expression of p-p38/p38, while the p38 inhibitor could achieve the trend of regulating and controlling liver injury. These research findings bring further support to the growing evidence that the mechanism of the liver injury induced by the compounds from urate-lowering Chinese herbs may be associated with the activation of p38α.

c-MYC and reactive oxygen species play roles in tetrandrine-induced leukemia differentiation.

Tetrandrine is a broadly used bisbenzylisoquinoline alkaloid component of traditional Chinese medicine that has antitumor effects in some cancer types. In this study, we investigated the effects of tetrandrine on leukemia in vitro and in vivo. The results showed that tetrandrine effectively induced differentiation and autophagy in leukemia cells. In addition, tetrandrine treatment activated the accumulation of reactive oxygen species (ROS) and inhibited c-MYC protein expression. Further, we found that treatment with the ROS scavengers N-acetyl-L-cysteine (NAC) and Tiron as well as overexpression of c-MYC reduced tetrandrine-induced autophagy and differentiation. Moreover, a small molecular c-MYC inhibitor, 10058-F4, enhanced the tetrandrine-induced differentiation of leukemia cells. These results suggest that ROS generation and c-MYC suppression play important roles in tetrandrine-induced autophagy and differentiation, and the results from in vivo experiments were consistent with those from in vitro studies. Therefore, our data suggest that tetrandrine may be a promising agent for the treatment of leukemia.

Liensinine- and Neferine-Induced Cardiotoxicity in Primary Neonatal Rat Cardiomyocytes and Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Due to drug-induced potential congestive heart failure and irreversible dilated cardiomyopathies, preclinical evaluation of cardiac dysfunction is important to assess the safety of traditional or novel treatments. The embryos of Nelumbo nucifera Gaertner seeds are a homology of traditional Chinese medicine and food. In this study, we applied the real time cellular analysis (RTCA) Cardio system, which can real-time monitor the contractility of cardiomyocytes (CMs), to evaluate drug safety in rat neonatal CMs and human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs). This study showed detailed biomechanical CM contractility in vitro, and provided insights into the cardiac dysfunctions associated with liensinine and neferine treatment. These effects exhibited dose and time-dependent recovery. Neferine showed stronger blocking effect in rat neonatal CMs than liensinine. In addition, the effects of liensinine and neferine were further evaluated on hiPS-CMs. Our study also indicated that both liensinine and neferine can cause disruption of calcium homeostasis. For the first time, we demonstrated the potential cardiac side effects of liensinine or neferine. While the same inhibition was observed on hiPS-CMs, more importantly, this study introduced an efficient and effective approach to evaluate the cardiotoxicity of the existing and novel drug candidates.

Anti-nociceptive, anti-inflammatory and toxicological evaluation of Fang-Ji-Huang-Qi-Tang in rodents.

BACKGROUND: Fang-Ji-Huang-Qi-Tang (abbreviated as FJHQT), composed by six medicinal herbs including Radix Stephania Tetrandra, Radix Astragali, Rhizoma Atractylodis Macrocephalae, Radix Glycyrrhizae, Rhizoma Zingiberis and Fructus Ziziphi Jujubae, is a frequently Chinese prescription for treating painful and inflammatory disorders such as rheumatoid arthritis. When Radix Stephania Tetrandra was misused with Aristolochia species, acute or chronic nephropathy caused by aristolochic acid was happened. Thus, the present study was aimed to identify Radix Stephania Tetrandra and performed the pharmacological and toxicological evaluation of FJHQT extract in rodents. METHODS: Radix Stephania Tetrandra was identified by macroscopic and microscopic observation, and the content of tetrandrine in FJHQT extract was measured by high performance liquid chromatography. Then, the pharmacological activities of FJHQT extract with respect to clinical use was investigated with acetic acid-induced writhing response, formalin-induced licking response and carrageenan-induced paw edema. Finally, we evaluated the subacute toxicology of FJHQT extract after 28-day repeated oral administration in rats. RESULTS: Radix Stephania Tetrandra was correctly used in FJHQT extract, and the content of tetrandrine in FJHQT extract was 2.5 mg/g. FJHQT extract produced a pronounced and dose-dependent antinociceptive and anti-inflammatory effects in three above models. FJHQT extract after 28-day repeated administration did not caused any hematological, biochemical and histological change in rats. CONCLUSIONS: We suggest that FJHQT extract is a high safety index Chinese medicine for antinociceptive and anti-inflammatory application when Radix Stephania Tetrandra was correctly used in FJHQT. Its antinociceptive and anti-inflammatory mechanism might be related to peripheral nociceptive pathway such as prostaglandins.

Synergistic effects of tetrandrine on the antifungal activity of topical ketoconazole cream in the treatment of dermatophytoses: a clinical trial.

OBJECTIVE: To evaluate the synergistic effects of tetrandrine (TET) on the antifungal activity of topical ketoconazole (KCZ) in the treatment of dermatophytoses. METHODS: The minimum inhibitory concentrations (MICs) for KCZ and combined KCZ and TET were compared in vitro. A randomized, double-blind trial was conducted among 97 patients with dermatophytoses who were assigned to 3 groups and received: treatment with combination of 2% KZC and 2% TET cream (KCZ + TET group), or only 2% KZC cream (KCZ group), or 2% TET cream (TET group). Patients with tinea corporis and/or tinea cruris were treated for 2 weeks, separately. The patients with tinea pedis and/or tinea manuum were treated for 4 weeks. RESULTS: Compared with KZC alone, combined use of KZC and TET showed lower MICs against clinical isolates of dermatophytes (P<0.05 for all). In the patients with tinea corporis and/or tinea cruris, the rates of overall cure (clinical cure plus mycologic clearance) were 81.25% vs. 33.33% for combined treatment and KZC monotherapy, respectively, after 4 weeks. All clinical indices were significantly different between the combination therapy and only KCZ therapy groups (P<0.05). Among the patients with tinea pedis and/or tinea manuum after 4 weeks treatment, the overall cure rates in the KCZ + TET group and KCZ group were 75.00% vs. 40.00%, respectively. In the KCZ + TET group, all the clinical indices were significantly better than those in the KCZ group and TET group (P<0.05). The rates of overall efficacy in the TET group were all zero. No local skin redness or itching was observed during TET treatment. No clinically significant changes were found in post-treatment routine blood, urine, or stool tests, ECG, or tests for liver and kidney function; no serious adverse events occurred. CONCLUSION: TET synergistically enhanced the clinical efficacy of topical KZC cream in the treatment of dermatophytoses.

Therapeutic potential of the biscoclaurine alkaloid, cepharanthine, for a range of clinical conditions.

Cepharanthine (CEP) is a naturally occurring alkaloid extracted from the plant Stephania cepharantha Hayata. It has been widely used in Japan for more than 40 years to treat a wide variety of acute and chronic diseases. CEP inhibits tumor necrosis factor (TNF)-α-mediated NFκB stimulation, plasma membrane lipid peroxidation and platelet aggregation and suppresses cytokine production. It has also been shown to scavenge free radicals and to have a protective effect against some of the responses mediated by pro-inflammatory cytokines such as TNF-α, interleukin (IL)-1ß and IL6. CEP has successfully been used to treat a diverse range of medical conditions, including radiation-induced leukopenia, idiopathic thrombocytopenic purpura, alopecia areata, alopecia pityrodes, venomous snakebites, xerostomia, sarcoidosis, refractory anemia and various cancer-related conditions. No safety issues have been observed with CEP, and side effects are very rarely reported.

Tetrandrine-induced apoptosis in rat primary hepatocytes is initiated from mitochondria: caspases and endonuclease G (Endo G) pathway.

Tetrandrine, a bisbenylisoquinoline alkaloid isolated from the dried root of Stephenia tetrandra (S Moore), possesses a remarkable pharmacological profile. However, the mechanisms of tetrandrine hepatotoxicity remain to be elucidated. In this study, we first proved apoptosis and mitochondrial dysfunction induced by tetrandrine in Sprague-Dawley rat liver in vivo. By further assuming apoptosis as an important mechanism in tetrandrine-induced hepatotoxicity, we focused on mitochondria-initiated apoptosis in primary hepatocytes isolated from Sprague-Dawley male rats. Tetrandrine treatment led to significant release of cytochrome c and downregulation of Bcl-X(L) accompanied by caspase 3 activation, and ultimately, DNA fragmentation. Caspase 3 activation was markedly inhibited by cyclosporin A (CsA) and Ac-DEVD-CHO. Furthermore, Endo G, a caspase-independent apoptotic protein, was detected for its expression and DNase activity. CsA blocked the release both of Endo G and cytochrome c significantly. Additionally, the generation of reactive oxygen species (ROS) increased in a time-dependent manner corresponding with a fall in intracellular GSH content after 10 microM tetrandrine treatment in 4h. Tetrandrine also induced mitochondrial dysfunction indicated by transition of mitochondrial transmembrane potential and decrease of intracellular ATP level. The findings indicated that the caspase-dependent mitochondrial apoptosis pathway was primarily involved in tetrandrine-induced apoptosis in rat primary hepatocytes. In addition, a caspase-independent pathway indicated by Endo G also contributed to apoptosis caused by tetrandrine. Meanwhile, ROS was proved an important inducer in this apoptosis process.