Novel Compounds from Marine Microorganisms that Inhibit Mammalian DNA Polymerase

We screened for selective inhibitors of mammalian DNA polymerase (Pol) species from natural products. We then identified compounds that are potential anticancer agents based on Pol inhibition. In this review, the focus is on symbiotic microorganisms that grow on wild marine plants and which could be used as a new screening source for anticancer compounds. The fungal strains were isolated from wild marine plants such as seaweeds and sea mosses collected in Japan. Nine novel compounds were isolated from the cultured broth extracts of isolated fungal strains. These compounds showed bioactivities such as selective inhibition of mammalian Pol activity among 10 mammalian Pol species and suppression of proliferation of human cancer cells while having no effect on the growth of normal human cells. The probability of discovering novel compounds from such sources is high. Therefore, microorganisms derived from wild marine plants appear to be a good screening source for bioactive compounds compared with other naturally occurring materials.