Abstract: Fatty acids play very important and diverse roles in living organisms, from signal transduction, energy management, maintaining of structural integrity to the normal metabolic processes. Due to its diverse presence and roles, Fatty Acid Synthase (FAS) is an attractive drug target under different pathologic contexts such as cancer, TB, obesity, microbial infection, etc. There are a number of molecules targeting Fatty Acid Synthase (FAS) in the prior art like Cerulenin, Orlistat, Pyrimidine, Triclosan, C75 etc. The present invention relates to a compound of formula I having fatty acid synthase inhibitory properties which was confirmed by an FAS inhibition assay. The present invention also relates to a process for collection, extraction, isolation, purification and characterization of the claimed compound from marine cyanobacterium, Phormidium ambiguum.