Convallatoxin induces HaCaT cell necroptosis and ameliorates skin lesions in psoriasis-like mouse models.

Psoriasis is considered an immune-mediated inflammatory skin disorder that affects the quality of life of nearly four percent of the world population. Considering the side effects of existing therapeutic drugs and the urgent need for new drug development, we screened more than 250 traditional Chinese medicine compounds to identify drugs that significantly reduced the viability of human HaCaT keratinocytes, a psoriasis-related model cell line. Convallatoxin (CNT) was found to be a highly effective inhibitor of HaCaT cell viability. Subsequent mechanistic studies revealed that CNT induced HaCaT cell death by necroptosis rather than by apoptosis. CNT destroyed the membrane integrity of HaCaT cells, as detected by nuclear propidium iodide (PI) staining and lactate dehydrogenase (LDH) release. Additionally, the intercellular levels of adenosine triphosphate (ATP) were lower in HaCaT cells treated with CNT than in control HaCaT cells, and typical necroptosis-associated characteristics were observed by electron microscopy in cells treated with CNT. Furthermore, compared with control HaCaT cells, CNT-treated HaCaT cells produced more reactive oxygen species (ROS), but this effect was inhibited by the antioxidants N-acetyl-cysteine (NAC), diphenyleneiodonium chloride (DPI), and apocynin and the necroptosis inhibitor Nec-1. In addition, antioxidant treatment attenuated necroptotic cell death, suggesting that CNT-induced HaCaT necroptosis is mediated by oxidative stress. More importantly, CNT ameliorated skin lesions and inflammation in imiquimod (IMQ)- and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced psoriasis-like mouse models. In conclusion, our results demonstrate that CNT is cytotoxic against HaCaT cells in vitro and exerts antipsoriatic activities in two mouse models of psoriasis in vivo, making CNT a potential promising candidate drug for future research.

HPLC-QTOF-MS/MS profiling, antioxidant, and α-glucosidase inhibitory activities of Pyracantha fortuneana fruit extracts.

This study was carried out to optimize the solvent for extracting the antioxidants and α-glucosidase inhibitors (AGIs) from Pyracantha fortuneana fruit (PFF) and the major chemical components were characterized by HPLC-QTOF-MS/MS. The results showed that 50% and 70% acetone (v/v, ml/ml) gave the best extraction efficiency on phenolics and total flavonoids, while 70% acetone and 50% methanol possess better recovery on protein and polysaccharides, respectively. In addition, the 50% and 70% acetone extracts gave the strongest radical scavenging ability and α-glucosidase inhibitory activity (p > 0.05), but the Fe3+ reducing power of the 50% acetone extract was higher than that of 70% acetone. Correlation analysis indicated that phenolic acids and flavonoids were connected to the antioxidant activity and α-glucosidase inhibitory activity closely. Moreover, 25 compounds including 7 flavonoids, 6 phenolic acids, 7 organic acids, 3 tannins, 1 terpene, and 1 alkaloid were identified or tentatively identified in the 50% acetone extract. Overall, 50% acetone can be a proper solvent for extracting antioxidants and AGIs from PFF. PRACTICAL APPLICATIONS: Imbalance between production and clearance of reactive oxygen species (ROS) in the body could induce various chronic diseases. PFF is an edible fruit beneficial to human health; it is reported to be capable of optimizing blood glucose levels and may prevent premature aging. In the present study, PFF was found to be excellent in antioxidant activities and α-glucosidase inhibitory ability; 50% acetone was found to be the best extraction solvent. In addition, the predominant phytochemical components of the 50% acetone extract were characterized. This study can promote further research of Pyracantha fortuneana in natural functional products, especially in the prevention of type II diabetes and its complication.