Abstract: Paeonia ostii was produced in Phoenix mountain of Tongling in Anhui.In this study,the oil from P.ostii seed was extracted by Soxhlet extraction and some of the physicochemical properties of P.ostii seed oil were determined.After being methyl-esterified,the fatty acid composition of P.ostii seed oil was analyzed by gas chromatography/mass spectrometry (GC/MS) and the relative contents of fatty acids were determined by peak area normalization method.The results showed that P.ostii seed contained about 34.86% oil;the physicochemical properties of the oil were as follows:relative density (d²⁰₄) was 0.91,acidity value was 3.85 mg KOH/g,iodine value was 175.63 gl/100 g,saponification value was 113.66 mg KOH/g,peroxide value was 2.91 meq/kg;21 components were identified from P.ostii seed oil,which included 89.00% of unsaturated fatty acids,10.77% of saturated fatty acids and a small amount of phenols and alkanes.The major fatty acids were 9,12,15-octadecatrienoic acid,9,12-octadecadienoic acid(Z,Z),hexadecanoic acid and octadecanoic acid. P.ostii seed oil had abundant unsaturated fatty acids and can be used as a new resource of oil industry for future development.

Key words: Paeonia ostii seed oil, gas chromatography/mass spectrometry, fatty acid, physicochemical properties