LAUSR

The production of bioactive agents from lignocelluloses has received limited attention due to the fact that plant cell walls are essentially non-bioactive. In this study, we first report a chemical reaction that produces a lignin-derived antiviral substance from sugarcane bagasse by a microwave heating at 200 °C in aqueous glycerol containing 0.5% H 2 SO 4 . The purified fraction, designated as FR 200 , strongly inhibited replication of encephalomyocarditis virus (EMCV) in L929 cells without cytotoxicity. HSQC NMR spectra demonstrated that the principal interunit linkages in the native lignin were cleaved by the reaction. GPC and pyrolysis-GCMS revealed that FR 200 is composed of oligomeric lignin with a weight average molecular weight of approximately 2,000. When the bagasse was reacted at lower temperatures, 140 °C and 160 °C, the native lignin substructures were partially retained and the antiviral activity significantly decreased. Our results thus indicate that the antiviral activity emerged through severe alteration of the native lignin structure. Furthermore, it was revealed that the antiviral lignin inactivated the EMCV virions through direct contact, as the innate immune system of L929 was not activated by FR 200 treatment, and no antiviral activity was found when L929 was pre-treated with the lignin before viral infection.