Abstract: To study the chemical constituents from 95% ethanol extract of  Periplaneta americana.The chemical constituents were isolated and purified by silica gel column chromatography,Sephadex LH-20 column chromatography,ODS column chromatography and semi-preparative HPLC.Fourteen compounds were obtained from the ethyl acetate fraction of  P.americana  based on NMR and MS spectroscopic methods.Their structures were identified as cyclo (L-Val-L-Pro) (1),3,4-dihydroxyphenylethanol (2),protocatechuic acid (3),cyclo(L-Ile-L-Pro) (4),cyclo (L-Phe-L-Val) (5),nicotinic acid (6),hippuric acid (7),aspongpyrazine A (8),aspongopusin (9),(2R,3S)-2-(3′,4′-dihydroxyphenyl)-3-acetylamino-7-hydroxyethyl-1,4-benzodioxane (10),(2R,3S)- 2-(3′,4′-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2′′-aminoethylene)-1,4-benzodioxane (11),cyclo (Leu-Pro)(12),1,2-dehydro-N-acetyldopamine (13) and 3,4-dihydro-8-hydroxy-2(1H)-quinolinone(14).Among them,compounds 1,4-9 and 10-13 were isolated from the genus for the first time.The spectral data of compound 10 were reported for the first time.All compounds were evaluated for antioxidant activity.Compounds 2,3 and 13 showed potential antioxidant activity by DPPH and ABTS⁺ radical scavenging methods.

Key words: Periplaneta americana, chemical constituents, structural elucidation, antioxidant activity