Extraction, purification and anti-TMV effects of α (β)-2,7,11-cembratriene-4,6-diol from tobacco leaves

Abstract Acetone ethanol extracts from tobacco leaves have antiviral activity against tobacco mosaic virus (TMV), but the antiviral effects of their specialized metabolites have not been systematically studied yet, especially the underlying mechanism is still unexplored. The tobacco cembranoids α(β)-2,7,11-cembratriene-4,6-diol (α(β)-CBD) were extracted and purified with an effective protocol including innovatively added 5% phosphoric acid for elution, one time silica gel chromatographic column separation and impurity removal and further HPLC purification. The in vivo anti-TMV activities showed that α(β)-CBD have higher protective effects of 73.2% and 71.6%, at 75.0 μM, respectively, than control agent Ningnanmycin (53.1%). Notably, The results of ELISA and TMV-GFP fluorescent optical imaging assay indicated a obviously reduced viral protein and weaker GFP fluorescence signal and smaller infection area, which confirmed their antiviral effects at protein level. Furthermore, the enhanced production of SA and JA and the significantly increased transcription of JA (COI1 and PDF1.2) and SA (PR1, NPR1 and EDS1) signaling pathway genes in treated plants further conformed that exogenously applied α(β)-CBD can effectively elicit the tobacco plant immunity against TMV. The α(β)-CBD mainly stimulates disease resistance of tobacco plants to resist TMV and it can be used as bioagents to control TMV in the future.