Inhibitory effects of Alpinia zerumbet extract against plant virus infection in solanaceous plants

A review of plant antipathogenic constituents: Source, activity and mechanism

Green prevention and control of plant pathogens is a development direction of sustainable and low-carbon agriculture given the limitation of traditional chemicals. Plant-derived antipathogenic constituents (PAPCs) exhibit the advantages of being environmental benign and a broad spectrum of target pathogens over traditional chemicals. Here, we review the research advances on plant sources, chemical compositions, activities of antipathogenic constituents in the past 20 years. Reported PAPCs are classified into categories of phenols, flavonoids, terpenoids, alkaloids and antimicrobial peptides. Angiosperms, gymnosperms and some lower plants are the main plant source of detected PAPCs. The PAPCs act on pathogens through multiple pathways including destroying cell structures, blocking key composition synthesis and inhibiting cell metabolism. The development trends of PAPCs are finally prospected. This review serves as a comprehensive review on the study of plant antipathogenic constituents and a key reference for forecasting the source, characteristic and activity of PAPC.

Inactivation of plant and animal viruses by proanthocyanidins from Alpinia zerumbet extract

Alpinia zerumbet (Pers.) B.L. Burtt and R.M. Smith belongs to the Alpinia genus in the Zingiberaceae family. In East Asia, Alpinia zerumbet has been widely used as food and traditional medicine. Previously, we identified proanthocyanidins (PACs), an anti-plant-virus molecule in A. zerumbet, using Nicotiana benthamiana and tomato mosaic virus (ToMV). Here, we found that PACs from A. zerumbet, apple, and green tea effectively inhibited ToMV infection. Additionally, the PACs from A. zerumbet exhibited greater antiviral activity than those from apple and green tea. The PACs from A. zerumbet also effectively inactivated influenza A virus and porcine epidemic diarrhea virus (PEDV), which acts as a surrogate for human coronaviruses, in a dose-dependent manner. The results from the cytopathic effect assays indicated that 0.1 mg/ml PACs from A. zerumbet decreased the titer of influenza A virus and PEDV by >3 log. These findings suggested that the direct treatment of viruses with PACs from A. zerumbet before inoculation reduced viral activity; thus, PACs might inhibit infections by an influenza virus, coronaviruses, and plant viruses.

Identification of an anti-plant-virus molecule in Alpinia zerumbet

In plants, viral diseases are second only to fungal diseases in terms of occurrence, and cause substantial damage to agricultural crops. The aqueous extracts of shell ginger, Alpinia zerumbet exhibit inhibitory effects against virus infections in belonging to the Solanaceae family. In this study, we isolated an anti-plant-virus molecule from the extracts using a conventional method involving a combination of reversed phase column chromatography, dialysis, and lyophilization. The anti-plant-virus molecule was identified as proanthocyanidin, which mostly consisted of epicatechin and exhibited more than 40 degrees of polymerization.