Laboratory‐scale preparation of prostaglandins using acetone powder of the red alga Gracilaria vermiculophylla

Summary The red alga Gracilaria vermiculophylla is a prostaglandin (PG)‐producing macroalga. The alga is rich in polyunsaturated fatty acids with 20 carbon atoms, mainly arachidonic acid (AA), which is a precursor of PGs. The purpose of the present study was to analyze the ability of the red alga to produce PGs using acetone powder as the crude enzyme prepared from the alga. The acetone powder (250 mg) was incubated with different amounts of exogenous AA (0.1–4 mg). For the determination of PG contents, 5 μL of a sample solution (5 mL in water) consisting of acetone powder and AA was injected into the HPLC column. For PG analysis, an HPLC system connected with a mass spectrometer was used. Results of the study showed that the released PGs from incubation of acetone powder and AA consisted of PGE2, 15‐keto‐PGE2, 15‐hydroperoxy‐PGE2, PGA2, and PGF2α. The capability of the crude enzyme prepared from the red alga to produce PGs was affected by available oxygen and AA concentrations. The crude enzyme (250 mg) was capable of producing 164 and 141 μg of PGE2 and 15‐keto‐PGE2, respectively, from incubation with 250 μg of AA. This in vitro method could be a simple way to provide PGs in the laboratory.