Hoang VD, Tan GT, Zhang HJ, Tamez PA, Hung NV, Cuong NM, Soejarto DD, Fong HH, Pezzuto JM. Natural anti-HIV agents-part I: (+)-demethoxyepiexcelsin and verticillatol from Litsea verticillata. Phytochemistry. 2002 Feb; 59(3):325-9.