AbstractBACKGROUND: Brucea javanica (L.) Merr. is widely distributed throughout the southern parts of China and has been used in traditional medicine to treat a variety of diseases. The objective of the present study was to identify the active antiphytoviral compound in the seeds of B. javanica and evaluate the inhibitory activity of the compound against plant virus.RESULTS: Bioassay‐guided fractionation of the most active extract from the seeds led to the isolation of an antiphytoviral compound which was identified as bruceine‐D by conventional spectroscopy methods. The compound exhibited significant inhibitory activity against the infection and replication of tobacco mosaic virus (TMV), with IC50 values of 13.98 and 7.13 mg L−1 respectively. The compound also showed a strong inhibitory effect on the infectivity of potato virus Y (PVY) and cucumber mosaic virus (CMV). Furthermore, the compound could effectively inhibit systemic TMV infection in the host tobacco plant under glasshouse conditions.CONCLUSION: The results suggested that bruceine‐D from Brucea javanica may have the potential to be used as a natural viricide, or a lead compound for new viricides. Copyright © 2007 Society of Chemical Industry