Prostratin is a protein kinase C activator found in the bark of the mamala tree of Samoa, Homalanthus nutans (Euphorbiaceae).

While prostratin was originally isolated and identified as a new phorbol ester from species of the genus Pimelea (Thymelaceae) in Australia, the antiviral activity of prostratin was discovered during research on the traditional knowledge of Samoan healers in Falealupo village by ethnobotanist Paul Alan Cox and a team at the U.S. National Cancer Institute.

[2] Prostratin is of interest because of its unique ability to activate latent viral reservoirs, while preventing healthy cells from infection, as well as its discovery through ethnobotany.

In 2008, a team at Stanford University led by chemist Paul Wender has published an elegant four-step chemical synthesis of prostratin from phorbol.

Phase I human clinical trials of prostratin will be carried out by the AIDS ReSearch Alliance in Los Angeles, California.