A research group led by Professor Wei Li of the Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Toho University, in collaboration with Shenyang Pharmaceutical University in China and Duke University Medical Center in the United States, has discovered that Daphne pedunculata (Thymelaeaceae), contains rare daphnane diterpenoids with odd-numbered aliphatic side chains. Furthermore, these researchers revealed that these compounds inhibit the replication of the human immunodeficiency virus (HIV).