二枚貝類のΔ^<5,7>-ステロール成分

The composition of Δ^<5,7>-sterols and other sterols of six bivalves collected in Okinawa, Japan, was investigated. Sterols were identified by gas-liquid chromatography (GLC) on 1.5% OV—17 and GLC-mass spectrometry. The bivalves examined contained seven Δ^<5,7>-sterols and a few Δ^<7>-sterols besides Δ^<5>-sterols commonly occurring in marine molluscs. Saxostrea mordax and Tridacna crocea contained cholesta-5,7-dienol as the major sterols (about 50% of total Δ^<5,7>-sterols), whereas Protostrea hyotis and Pinctada margaritifera possessed 24-methylcholesta -5,7,22-trienol at the levels of 65% and 53%, respectively. Atrina vexillum contained cholesta-5,7-dienol (40%), 24-methylcholesta-5,7,22-trienol (32%), and cholesta-5,7,22-trienol as the prominent sterols. Hippopus hippopus involved cholesta-5,7-dienol (14%), 24-methylcholesta-5,7-dienol (12%), 24-methylcholesta-5,7,22-trienol (37%), and 24-ethylcholesta-5,7-dienol (37%). A possitive correlation was observed between the compositions of some Δ^<5>-sterol (% of total Δ^<5>-sterols) and corresponding Δ^<5,7>-sterol (% of total Δ^<5,7>-sterols)