This study aimed at evaluating the antibiofilm activity of the Red Sea metabolites from
green alga Avrainvillea amadelpha, sea cucumber Holothuria atra and costal plant Sarcocornia fruticosa
against three biofilm bacterial strains isolated from Jeddah coast. Free fatty acids (FFAs) and other
lipoidal matters were extracted from these organisms and analyzed by GC-MS. The composition of
lipoidal fractions showed that A. amadelpha is rich by 74% saturated FAs, while sea cucumber H. atra
revealed high content (60%) of unsaturated FAs. Palmitic acid is the major FA component in all species
ranging from 14.5 to 26.7%. Phytol, sterols and hydrocarbons (C8-C29) were represented in the
alga A. amadelpha as high contents with values 25.8, 21.9 and 18.5%, respectively. The extracts and
lipoidal contents showed biofilm inhibitory activity against the isolated bacterial strains, where the unsaponified
lipoidal fraction of S. fruticosa exhibited highest inhibitory activity against Planomicrobium
sp. at concentration of 200 µg/mL.