Physodes and the Phenolic Compounds of Brown Algae, Composition and Significance of Physodes in vivo

The composition and significance of physodes, brown algal subcellulai bodies characterized by reactivity with vanillin-hydrochloric acid, have been the subject of debate for the past Century. This research is critically reviewed, and it is demonstrated that aJthough physodes aie primarily composed of phloroglucinol derivatives, they may also contain other tannins and terpenes. The recent discoveries of homologous series of phloroglucinol polymers in brown algal extracts provide an attractive chemical rationalization for the observed heterogeneity of physodes.