Five new prenylated dihydrostilbenes, alpha,alpha'-dihydro-3,5,4'-trihydroxy-4,5'-diisopentenylstilbene (1), alpha,alpha'-dihydro-3,5,3',4'-tetrahydroxy-4,5'-diisopentenylstilbene (2), alpha,alpha'-dihydro-3,5,4'-trihydroxy-5'-isopentenylstilbene (3),