Logeracemin A, an Anti-HIV Daphniphyllum Alkaloid Dimer with a New Carbon Skeleton from Daphniphyllum longeracemosum

Logeracemin A (1), the first Daphniphyllum alkaloid dimer featuring an unprecedented carbon skeleton with a unique conjugated trispiro­[4,5] decane backbone, was isolated from Daphniphyllum longeracemosum. Its structure and absolute configuration were established on the basis of spectroscopic data and X-ray crystallography. Logeracemin A showed significant anti-HIV activity with an EC50 of 4.5 ± 0.1 μM and a selectivity index of 6.2. The structure–activity relationship of the tested compounds was briefly discussed.