Communesin B is a cytotoxic chemical compound isolated from Penicillium strains found on the marine alga Ulva intestinalis.[1] [2] It exhibits cytotoxicity in vitro against human lung carcinoma, prostate carcinoma, colorectal carcinoma, cervical adenocarcinoma, and breast adenocarcinoma cell lines.[3]
Communesin B is a dimeric indole alkaloid with a hexadienoyl moiety originating from polyketide synthesis. Biosynthesis starts with two L-tryptophan molecules processed by different pathways. The first pathway involves a decarboxylation step catalyzed by CnsB to produce tryptamine. The second pathway starts the synthesis of 4-L-dimethylallyl tryptophan by CnsF followed by further processing of CnsA and CnsD to form aurantioclavine. These two indole-containing fragments are combined through a radical oxidative coupling by CnsC, a cytochrome P450 enzyme, to form the core scaffold of communesin alkaloids.[4] CnsE transfers a methyl group to the indole nitrogen, and CnsJ creates an epoxide ring on the dimethylallyl substituent off the ring structure to form communesin I.[5] Separately, CnsI synthesizes a hexadienoyl group using acetyl-CoA as a starting material and extending it with two malonyl-CoA units. Then, CnsK performs N-acylation with the CnsI-synthesized hexadienoyl chain to form communesin B.