Background: Porcine circovirus type 2 (PCV2) is an immunosuppressive pathogen with high prevalence rate in pig farms. It has caused serious economic losses to the global pig industry. Due to the rapid mutation of PCV2 strain and co-infection of different genotypes, vaccination could not eradicate the infection of PCV2. It is necessary to screen and develop effective new compounds and explore their anti-apoptotic mechanism. The 13 natural compounds were purchased, with a clear plant origin, chemical structure and content and specific biological activities. Results: The maximum no-cytotoxic concentration (MNTC) and 50% cytotoxic concentration (CC₅₀) of 13 tested compounds were obtained by the cytopathologic effect (CPE) assay and (3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method in PK-15 cells. The results of qPCR and Western blot showed that, compared with the PCV2 infected group, the expression of Cap in Paeonol (0.4 mg/mL and 0.2 mg/mL), Cepharanthine (0.003 mg/mL, 0.0015 mg/mL and 0.00075 mg/mL) and Curcumin (0.02 mg/mL, 0.001 mg/mL and 0.005 mg/mL) treated groups were significantly lowered in a dose-dependent manner. The results of Annexin V-FITC/PI, JC-1, Western blot and ROS analysis showed that the expression of cleaved caspase-3 and Bax were up-regulated Bcl-2 was down-regulated in Cepharanthine or Curcumin treated groups, while ROS and MMP value were decreased at different degrees and the apoptosis rate was reduced. In this study, Ribavirin was used as a positive control. Conclusions: Paeonol, Cepharanthine and Curcumin have significant antiviral effect. And the PCV2-induced Mitochondrial apoptosis was mainly remitted by Cepharanthine and Curcumin.

Background: Encephalomyocarditis virus (EMCV) infection can cause reproductive failure in sows and acute myocarditis and sudden death in piglets. It has caused huge economic losses to the global pig industry and that is why it is necessary to develop effective new treatment compounds. Zedoary turmeric oil has been used for treating myocarditis. Curcumol extracted from the roots of curcuma is one of the main active ingredient of zedoary turmeric oil. The anti-EMCV activity of curcumol along with the molecular mechanisms involved with a focus on IFN-β signaling pathway was investigated in this study. Method: 3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the maximum non-toxic concentration (MNTC), 50% cytotoxic concentration (CC₅₀), maximum inhibition rate (MIR) and 50% effective concentration (EC₅₀) against EMCV. Through EMCV load, the anti-viral effect of curcumol was quantitatively determined using real-time quantitative PCR (qPCR). The effect of curcumol on the expression of IFN-β was investigated using real-time quantitative PCR and ELISA. Western blot was used to determine the amounts of MDA5, MAVS, TANK, IRF3 and P-IRF3 proteins in human embryonic kidney 293 T (HEK-293 T) cells infected with EMCV. Results: The results of MTT showed that compared with the ribavirin positive control group, the maximum inhibition ratio (MIR) of curcumol was greater but the selection index (SI) value was much smaller than that of ribavirin. The results of qPCR showed that curcumol and ribavirin significantly reduced the replication of EMCV in HEK-293 T cells. The curcumol (0.025 mg/mL) treatment has significantly increased IFN-β mRNA expression in the EMCV-infected HEK-293 T cells while ribavirin treatment did not. The results of ELISA showed that curcumol (0.025 mg/mL and 0.0125 mg/mL) has significantly increased the expression of IFN-β protein in EMCV-infected HEK-293 T cells. The results of Western blot showed that curcumol can inhibit the degradation of TANK protein mediated by EMCV and promote the expression of MDA5 and P-IRF3, while the protein expression level of MAVS and IRF3 remain unchanged. Conclusion: Curcumol has biological activity against EMCV which we suggest that IFN-β signaling pathway is one of its mechanisms.

Background: Porcine circovirus type 2 (PCV2) is an important and common DNA virus that infect pig and can cause immunosuppression and induce apoptosis in the infected cells. To escape the host immune system, PCV2 constantly builds up complex mechanisms or mutates genes, and that is why it is difficult to eradicate complex PCV2 infection by relying on vaccines and single compound. At present, there is few literature reports on the effective prevention and treatment of PCV2 infection by a combination of two or more compounds. Previously, we have demonstrated the anti-PCV2 effect of Matrine in vitro, but its mechanism has not been further evaluated. Literatures have proven that Osthole has a variety of pharmacological activities, and we tested the ability of Osthole to inhibit PCV2 replication in cell culture. Therefore, this study explored the synergistic antiviral effect of Matrine combined with Osthole and their synergistic anti-apoptotic mechanism. Results: Osthole alone had an anti-PCV2 effect, and then its synergistic anti-PCV2 effect of Osthole and Matrine was better than that of Matrine or Osthole alone as demonstrated by qRT-PCR, IFA and Western blotting results. The anti-apoptotic mechanism of these two compounds by inducing the PERK pathway by PCV2 was elucidated through Annexin V-FITC/PI, JC-1 and Western blotting. Matrine and Osthole combination could inhibit the expression of Cap in Cap-transfected PK-15 cells, thus inhibiting Cap-induced PERK apoptosis. Ribavirin was used as a positive control. Conclusions: The combination of Osthole and Matrine had the synergistic effect of anti-PCV2 infection by directly inhibiting the expression of PCV2 Cap protein. The combination of these two compounds also inhibited PERK apoptosis induced by PCV2 Cap protein, possibly by regulating the level of GRP78. The results formed a base for further studies on the mechanism of anti-PCV2 in vivo using Matrine and Osthole combination and developing new anti-PCV2 compounds with Cap and GRP78 as therapeutic targets.

Some natural compounds derived from medicinal plants show anti-tumor activity with high efficacy and safety, low toxicity and residual levels etc. The aim of this study was to select natural compounds and biomarkers having high inhibitory effects against A549 adenocarcinoma cells. A total of eight natural compounds having pure plant origin were initially screened, purchased, and their potential anti-cancer activities were comprehensively and systematically evaluated against A549 lung adenocarcinoma cells. The maximum non-cytotoxic concentration (MNTC) and 50% cytotoxic concentration (CC₅₀) of the eight compounds against A549 cells were obtained by cytopathological and MTT assays, respectively. Using Cisplatin as a positive control, the effect of selected compounds were elucidated on the proliferation, migration and invasion of A549 cells by MTT, wound healing and invasion assays, respectively. AnnexinV-FITC/PI, JC-1, ROS and Cell Cycle Kits were used to detect the pro-apoptotic mechanism of A549 cells induced by the tested compounds. qRT-PCR and RNA-seq were used to investigate the effective biomarkers involved in the inhibition process. The results showed that Curcumin, Osthole, Paeonol, Cepharanthine and Cisplatin significantly reduced the proliferation, migration and invasion abilities of A549 cells in a dose-dependent manner. Post 48 h of treatment, Osthole inhibited the metastatic ability of A549 cells by regulating mitochondrial apoptosis, arresting A549 cell in G1-phase and inhibiting release of ROS, while Curcumin, Paeonol and Cepharanthine did not showed the same response. It was therefore elucidated that Osthole was the optimal natural compound showing powerful anti-inhibitory properties against A549 cells. Moreover, the expressions of EGF, IL-2 and IL-10 genes were significantly decreased in Osthole treated group, while IL-6 gene was significantly increased. This study suggested that EGF gene has the potential to be used as a biomarker for Osthole treatment against A549 cells, involved in mitochondrial apoptosis and ROS down-regulation, inhibiting proliferation and epithelial mesenchymal transition (EMT), inflammation and immune processes in A549 cells providing a foundation to develop Osthole as a potential target drug to prevent the occurrence and development of lung adenocarcinoma.

Non-small cell lung cancer (NSCLC) is the major type of malignant tumor in the lungs. Emerging epidemiological evidence implicates environmental copper exposure as a potential risk modulator for NSCLC progression. This study investigated the effects of low-dose Copper (Cu) exposure on A549 cells and evaluated the therapeutic potential of two natural compounds, osthole and matrine. The results demonstrated that Cu exposure (5 μg/mL, 12 h) significantly promoted the migration, invasion and colony formation of A549 cells (P < 0.05), accompanied by a reduction in cell apoptosis, a decrease in ROS levels and an increase in mitochondrial membrane potential. Meanwhile, osthole and matrine treatment could reverse these phenotypes and arrest the cell cycle of A549 in the G1 phase. Transmission electron microscopy results revealed that Cu exposure induced slightly swollen mitochondria and as well as the increase in the number of mitochondria, while osthole and matrine treatments resulted in severe degenerative changes in mitochondria. Both qPCR and Western blot examinations indicated that Cu exposure promoted the expression of PGC-1α but inhibited the expressions of STAT1, TNF-α and IL-2. Osthole treatment could down-regulate the expression of PGC-1α and up-regulate the expressions of STAT1, TNF-α and IL-2, while matrine treatments could up-regulate the expressions of STAT1 and TNF-α and down-regulate the expressions of PGC-1α and IL-2. Taken together, these findings indicate that low-dose Cu exposure can promote the proliferation, migration, invasion and mitochondrial damage of A549 cells, while osthole and matrine treatments inhibit Cu effects by regulating the STAT1, BGC-1 α, TNF-α and IL-2.