Bryostatin

Overview
Bryostatins are a group of macrocyclic lactones first discovered in the late 1960s in a species of bryozoan, Bugula neritina. Believed to be produced by symbiont bacteria to protect the bryozoan larva from predation, they have cytotoxic properties and are under investigation as anti-cancer agents and as a memory enhancement agent.

In vitro trials have shown bryostatins to act synergistically with other anti-cancer drugs and to modulate protein kinase C (PKC) activity, with a potent antileukemic effect and action against lung, prostate and non-Hodgkin's lymphoma tumor cells.

Human clinical trials have been less promising, but suggest bryostatins to have a potentially useful synergistic action with other chemotherapeutic agents.

The low concentration in bryozoans (to extract one gram of bryostatin, roughly one tonne of the raw bryozoans is needed) makes extraction unviable for large scale production. Due to the structural complexity, synthesis has proved difficult, with only a few total syntheses reported so far. However, structurally simpler synthetic analogs have been prepared which exhibit similar biological profile and in some cases greater potency, which may provide a practical supply for clinical use.