Natural anti-HIV agents. Part IV. Anti-HIV constituents from Vatica cinerea

In a continuing search for anti-HIV compounds from plants of Vietnam, 19 compounds, including a new triterpene, were isolated from an extract of the leaves and stem of Vatica cinerea. The new triterpene was determined to be a cycloartane triterpenoid with 29 skeletal carbons and was assigned the name vaticinone (1). The known triterpenes included three cycloartanes, a lanostane, two dammaranes, three lupanes, an ursane, and an oleanane. A chlorophyll isolate was identified as pheophorbide a (13). The majority of the triterpenes, the sesquiterpene, 1-hydroxycyclocolorenone, and pheophorbide a showed anti-HIV activity, with the chlorophyll being the most active, demonstrating an IC₅₀ value of 1.5 μg/mL (2.5/μM), while being completely devoid of toxicity up to a concentration of 20 μg/mL (33.8 μM). Vaticinone (1) was found to inhibit the replication of HIV-1, with an IC₅₀ value of 6.5 μg/mL (15.3/μM; selective index = 1.4). The structures of these isolates were determined by spectral data including 1D and 2D NMR spectra.