Discovery of anthraquinone derivative from Ophiorrhiza alatiflora with dual-functions of direct virucidal activity and induce host immunity against TMV
Ma, Jiachen) ; Zhao, Long ; Liu, Binbin ; Zhang, Haiyan ; Khan, Asif Zaman ; Li, Xue ; Tian, Xiangrong
DOI 10.1016/j.pestbp.2026.107145
Abstract
Tobacco mosaic virus (TMV) poses persistent threats to agriculture. Given the overuse of chemical agent, developing antiviral agents from natural products is a promising sustainable strategy. Plants of the genus Ophiorrhiza, which belongs to the Rubiaceae family, contain chemical constituents such as alkaloids and anthraquinones. However, the potential anti-TMV effects of phytochemical constituents from Ophiorrhiza plants have not been reported. Herein, the first systematic phytochemical study of Ophiorrhiza alatiflora led to the isolation of ten known compounds (1-10). Among all isolated compounds, the anthraquinone compound 8 was identified as the key active constituent. It demonstrated superior, multi-modal anti-TMV efficacy, outperforming the commercial agent Ningnanmycin in inactivation (66.76% to 53.50%), protection (52.07% to 51.01%), curation (62.54% to 47.46%), and induced resistance (57.33% to 49.23%) at 500 mu g/mL. Its mechanism involves a dual-mode action: directly disrupting TMV particle integrity and downregulating the TMV-CP gene, which was also proved by molecular docking results with binding energy of-6.2 kcal/mol, and activating the salicylic acid (SA) pathway to induce systemic plant resistance, evidenced by upregulated defense enzymes and PR genes, as well as accumulated SA and H2O2 content. This work clarifies the anti-TMV material basis of O. alatiflora, providing evidence for developing plant-based antiviral agents that combine direct virucidal activity with host immunity induction.