Antioxidant, Anti-Lung Cancer, and Anti-Bacterial Activities of Toxicodendron vernicifluum

Abstract

This work tested antioxidant, anti-lung cancer, and antibacterial activities by in vitro, in vivo, and computational experiments for the metabolites extracted from the bark, seed, and stem of Toxicodendron vernicifluum. The results showed that all the extracts significantly scavenged 1,2-diphenyl-1-picrylhydrazyl (DPPH) in a dose-dependent manner. But, the total phenol content (TPC) ranged from 2.12 to 89.25% and total flavonoids content (TFC) ranged from 1.02 to 15.62% in the extracts. The methanolic bark extract (MBE) exhibited higher DPPH scavenging activity than the other extracts, probably due to the higher content of the TPC and TFC present in it. Among the extracts, only the MBE showed anti-lung cancer activity at an acceptable level with a therapeutic index value (22.26) against human lung carcinoma. This was due to the cancer cell death in A549 induced by MBE through reactive oxygen species (ROS) generation, apoptosis, and cell arrest in G1 phase and inhibition of anti-pro-apoptotic protein survivin. Among the extracts, MBE showed significantly higher antibacterial activity as evident through the higher zone of inhibition 13 ± 0.5 mm against methycilin resistant strain of Staphylococcus aureus (MRSA), Salmonila enteria subp. enterica, and P. aeruginosa, 11 ± 0.3 mm against E. coli and 10 ± 0.2 mm against B. cereus. The MBE also showed an excellent antibacterial activity with lower minimal inhibitory concentration (MIC). Particularly, the MBE showed more significant antibacterial activity in MRSA. The in vivo antibacterial activity of the MBE was further tested in C. elegans model. The treatment of the MRSA induced cell disruption, damage and increased mortality of C. elegans as compared to the untreated and MBE treated C. elegans with normal OP50 diet. Moreover, the MBE treatment enhanced the survival of the MRSA infected C. elegans. The compounds, such as 2,3,3-trimethyl-Octane and benzoic from the MBE, metabolized the novel bacterial topoisomerases inhibitor (NBTI) and MRSA related protein (PBP2a). Overall the T. vernicifluum is potentially bioactive as evident by antioxidant, anti-lung cancer, and antibacterial assays. Further studies were targeted on the purification of the novel compounds for the clinical evaluation.