Therapeutic potential of toosendanin: Novel applications of an old ascaris repellent as a drug candidate

Toosendanin: upgrade of an old agent in cancer treatment

Toosendanin (TSN), a tetracyclic triterpenoid derived from Melia toosendan and M. azedarach, demonstrates broad application prospects in cancer treatment. Although previously employed as a pesticide, recent studies have revealed its potential therapeutic value in treating various types of cancer. TSN exerts an anticancer effect via mechanisms including proliferation inhibition, apoptosis induction, migration suppression, and angiogenesis inhibition. However, TSN's toxicity, particularly its hepatotoxicity, significantly limits its therapeutic application. This review explored the dual nature of TSN, evaluating both its anticancer potential and toxicological risks, emphasizing the importance of balancing these aspects in therapeutic applications. Furthermore, we investigated the incorporation of TSN into novel therapeutic strategies, such as Proteolysis-targeting chimeras (PROTAC) technology and nanotechnology-based drug delivery systems (DDS), which enhance treatment efficacy while mitigating toxicity in normal tissues.

Rosmarinic acid alleviates toosendanin-induced liver injury through restoration of autophagic flux and lysosomal function by activating JAK2/STAT3/CTSC pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rosmarinic acid (RA), a natural polyphenol abundant in numerous herbal remedies, has been attracting growing interest owing to its exceptional ability to protect the liver. Toosendanin (TSN), a prominent bioactive compound derived from Melia toosendan Siebold & Zucc., boasts diverse pharmacological properties. Nevertheless, TSN possesses remarkable hepatotoxicity. Intriguingly, the potential of RA to counteract TSN-induced liver damage and its probable mechanisms remain unexplored.

AIM OF THE STUDY

This study is aimed at exploring whether RA can alleviate TSN-induced liver injury and the potential mechanisms involved autophagy.

MATERIALS AND METHODS

CCK-8 and LDH leakage rate assay were used to evaluate cytotoxicity. Balb/c mice were intraperitoneally administered TSN (20 mg/kg) for 24 h after pretreatment with RA (0, 40, 80 mg/kg) by gavage for 5 days. The autophagic proteins P62 and LC3B expressions were detected using western blot and immunohistochemistry. RFP-GFP-LC3B and transmission electron microscopy were applied to observe the accumulation levels of autophagosomes and autolysosomes. LysoTracker Red and DQ-BSA staining were used to evaluate the lysosomal acidity and degradation ability respectively. Western blot, immunohistochemistry and immunofluorescence staining were employed to measure the expressions of JAK2/STAT3/CTSC pathway proteins. Dual-luciferase reporter gene was used to measure the transcriptional activity of CTSC and RT-PCR was used to detect its mRNA level. H&E staining and serum biochemical assay were employed to determine the degree of damage to the liver.

RESULTS

TSN-induced damage to hepatocytes and livers was significantly alleviated by RA. RA markedly diminished the autophagic flux blockade and lysosomal dysfunction caused by TSN. Mechanically, RA alleviated TSN-induced down-regulation of CTSC by activating JAK2/STAT3 signaling pathway.

CONCLUSION

RA could protect against TSN-induced liver injury by activating the JAK2/STAT3/CTSC pathway-mediated autophagy and lysosomal function.

Study on the effects of toosendanin against Eimeria tenella and its impact on the apoptosis of cecal cells in chicks

To investigate the therapeutic effect of toosendanin (TSN) against Eimeria tenella (E. tenella) in chicks. In this experiment, a chick model of artificially induced E. tenella infection was established. The anti-coccidial effect was investigated by treating different doses of TSN. A preliminary mechanism of action was conducted, using cecal cell apoptosis as a starting point. TSN at the concentration of 5 mg/kg BW showed the best effect against E. tenella with the ACI value of 164.35. In addition, TSN reduced pathological damage to cecal tissue, increased the secretion of glycogen and mucus in cecal mucosa, and enhanced the mucosal protective effect. It also elevated the levels of IFN-γ, IL-2, and IgG in serum, and raised the sIgA content in cecal tissue of infected chicks, thereby improving overall immune function. TSN was observed to promote the apoptosis of cecum tissue cells by TUNEL staining analysis. Immunohistochemistry analysis revealed that in TSN-treated groups, the expression of Caspase-3 and Bax was elevated, while the expression of Bcl-2 was reduced. TSN induced apoptosis in host cells by dose-dependently decreasing the Bcl-2/Bax ratio and upregulating Caspase-3 expression. In summary, TSN exhibited significant anticoccidial efficacy by facilitating apoptosis in host cecal cells, with the most pronounced effect observed at a dosage of 5 mg/kg body weight.

Effects of plant extracts and derivatives on cardiac K+, Nav, and Cav channels: a review

Natural products (NPs) are endless sources of compounds for fighting against several pathologies. Many dysfunctions, including cardiovascular disorders, such as cardiac arrhythmias have their modes of action regulation of the concentration of electrolytes inside and outside the cell targeting ion channels. Here, we highlight plant extracts and secondary metabolites' effects on the treatment of related cardiac pathologies on hERG, Nav, and Cav of cardiomyocytes. The natural product's pharmacology of expressed receptors like alpha-adrenergic receptors causes an influx of Ca2+ ions through receptor-operated Ca2+ ion channels. We also examine the NPs associated with cardiac contractions such as myocardial contractility by reducing the L-type calcium current and decreasing the intracellular calcium transient, inhibiting the K+ induced contractions, decreasing amplitude of myocyte shortening and showed negative ionotropic and chronotropic effects due to decreasing cytosolic Ca2+. We examine whether the NPs block potassium channels, particular the hERG channel and regulatory effects on Nav1.7.

Toosendanin induces hepatotoxicity by restraining autophagy and lysosomal function through inhibiting STAT3/CTSC axis

Toosendanin (TSN) is the main active component in the traditional herb Melia toosendan Siebold & Zucc, which exhibits promising potential for development due to its diverse pharmacological properties. However, the hepatotoxicity associated with TSN needs further investigation. Previous research has implicated autophagy dysregulation in TSN-induced hepatotoxicity, yet the underlying mechanisms remain elusive. In this study, the mechanisms of signal transducer and activator of transcription 3 (STAT3) in TSN-induced autophagy inhibition and liver injury were explored using Stat3 knockout C57BL/6 mice and HepG2 cells. TSN decreased cell viability, increased lactate dehydrogenase (LDH) production in vitro, and elevated serum aspartate transaminase (AST) and alanine aminotransferase (ALT) levels as well as liver lesions in vivo, suggesting TSN had significant hepatotoxicity. TSN inhibited Janus kinase 2 (JAK2)/STAT3 pathway and the expression of cathepsin C (CTSC). Inhibition of STAT3 exacerbated TSN-induced autophagy inhibition and hepatic injury, whereas activation of STAT3 attenuated these effects of TSN. Mechanistically, STAT3 transcriptionally regulated the level of CTSC gene, which in turn affected autophagy and the process of liver injury. TSN-administered Stat3 knockout mice showed more severe hepatotoxicity, CTSC downregulation, and autophagy blockade than wildtype mice. In summary, TSN caused hepatotoxicity by inhibiting STAT3/CTSC axis-dependent autophagy and lysosomal function.