Structure-dependent antiviral activity of catechol derivatives in pyroligneous acid against the encephalomycarditis virus.

The pyrolysis product, wood vinegar (WV), from Japanese larch exhibited strong antiviral activity against the encephalomycarditis virus (EMCV). Catechol, 3-methyl-, 4-methyl-, 4-ethyl-, and 3-methoxycatechol, and 2-methyl-1,4-benzenediol were identified as the major antiviral compounds. The viral inhibition ability of these compounds was affected by the structure and position of the substituent group attached to the aromatic skeleton. The IC50 of catechol was 0.67 mg mL-1 and those of its derivatives were <0.40 mg mL-1. Methyl and ethyl substitution in the para position relative to a hydroxyl group obviously increased the antiviral activities. The mode of antiviral action was investigated by adding catechol derivatives at different times of the viral life cycle. It was found that direct inactivations of EMCV by these compounds were the major pathway for the antiviral activity. The effect of catechol derivatives on the host immune system was studied by quantification of Il6 and Ifnb1 expression levels. Increased Il6 expression levels indicate NF-κB activation by reactive oxygen species from auto-oxidations of catechol derivatives, which is also a possible antiviral route. The present research provides indices for production of potent antiviral agents form lignocellulose biomass.

Identification of a germicidal compound against picornavirus in bamboo pyroligneous acid.

The germicidal activity of pyroligneous acid (PA) against a picornavirus, encephalomyocarditis virus (EMCV), was analyzed, and the component responsible for its disinfectant activity was identified. Bamboo PA (BPA) inactivated EMCV, but neutralization of BPA abolished this activity. Using liquid-liquid phase extraction and silica gel column chromatography, the hydrophobic active fraction of BPA was separated and its 12 major components were identified. The active fraction was reconstructed by mixing synthetic chemicals at the determined concentrations, and a subtraction series of one chemical from the complete mixture was prepared. An in vitro virus assay demonstrated that phenol was the sole germicidal component, and acetic acid augmented the phenol's inactivating activity resulting in >5-log decrease in EMCV infectivity. Considering the low environmental risk of PA, these findings suggest that BPA is a potentially useful agent for preventing viral epidemics in agricultural and human environments.

A sesquiterpene hydrocarbon from the bogwoods of Cryptomeria japonica D. Don, presumably formed by diagenetic hydrogenation.

Structure of an hitherto unknown component of the essential oils from two bogwoods of Cryptomeria japonica D. Don was determined by mass spectrometry and NMR analyses. It was identified as cadina-1(10)-ene, a new cadinane-type sesquiterpene hydrocarbon with a single double bond.