A new alkaloid compound I was obtained from Solanum cathayanum, a folk medicine of Hubei Province, together with a knownalkaloid, orotic acid ethyl ester. On the basis of spectroscopic data and chemical methods, I was identified as 8-hydroxy-3-methoxy-5H-pyrido[2,1-c]pyrazin-5-one. Compound 1 can inhibit the production of NO in peritoneal macrophage of mice induced with LPS.The content of NO was determined by enzyme methods.