Ahmad, FarediahSalleh, Wan MohdSirat, Hasnah MohdYen, Khong Heng2012-11-152012-11-152012-11-151611-2156http://hdl.handle.net/2003/2975810.17877/DE290R-4900The essential oils obtained by hydrodistillation from the fresh leaf and stem of Piper porphyrophyllum N.E. Br. were analyzed by GC and GC/MS. Thirty four constituents were identi-fied in the leaf oil, while thirty eight constituents were identified in the stems oil. The most abundant components in the leaf oil included bicyclogermacrene (14.7 %), α-copaene (13.2 %) and β-phellandrene (9.5 %) while sabinene (15.5 %), bicyclogermacrene (12.3 %) and α-copaene (8.1 %) were the main constituents in the stem oil. The evaluation of antibacterial activity by using microdilution method revealed that both oils were moderately active against all the Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas putida and Escherichia coli) with minimum inhibitory concentration (MIC) values in the range 125-1000 μg/ml.enEXCLI Journal ; Vol. 11, 2012antimicrobial activitychemical compositionsessential oilsPiper porphyrophyllum610article (journal)