in P. scabiosifolia flowers, which comprised 96.21% of the total volatiles. Esters (87.40%) were dominant in the flowers. The most abundant compound is cis-3-hexenyl isovalerate (28.91%), followed by pentanoic acid phenylmethyl ester (20.79%), hexyl n-valerate (10.44%), 3-methyl-2-phenylethyl butanoic acid ester (9.80%), 3-methylbutanoic acid 3-methylbutyl ester (8.75%), and trans-2-hexenyl valerate (5.79%). cis-3-Hexenyl isovalerate, which has a flowery fragrance and new fresh fruit fragrant and the ripe apple fragrance, is often used in tobacco and flavoring. 3-Methylbutanoic acid 3-methylbutyl ester is used widely as a food odorant in imitation apple, banana, and fruit odor type essences. It can also be used in synthesizing some medicine. trans-2-Hexenyl valerate has a fruity fragrance, while 3-methyl-2-phenylethyl butanoic acid ester has a strong fruit and rose fragrance and is commonly used in flavoring and cosmetics 12. Eugenol which has an intense clove smell, is used to make the essences, isoeugenol and vanillin. It may also be used as a pesticide and antiseptic. So it is considered that these ingredients are the main source of fragrance of P. scabiosifolia flowers. Plant Material. The air-dried P. scabiosifolia flowers were collected in Henan, China, in July 2009. They were identified by Prof. Changqin Li, and voucher specimens were deposited in the Institute of Natural Products, Henan University. Extraction of Volatile Constituents. Volatile organic compounds were extracted by a manual SPME holder together with 5 mL vials and PDMS-DVB fibers purchased from Supelco Inc. (Bellefonte, USA). Prior to extraction, the fiber was activated for 10 min in the GC 6890 system (Agilent, USA). The powder of P. scabiosifolia flowers, about 0.7 g, was placed in vials (5 mL), then the SPME fiber was exposed in the upper space of the sealed vial for 30 min at 80C to adsorb the analytes. After that, the fiber was withdrawn and directly inserted into the GC-MS inlet for desorption of the volatiles for 1 min. HS-SPME-GC-MS Analyses. The volatile constituents were analyzed by HS-SPME-GC-MS. Analysis was carried out using an Agilent 6890 N gas chromatograph equipped with a DB-5 MS capillary column (5% phenylmethylsiloxane, 30 m 0.25 mm, film thickness 0.25 m, Agilent Technologies, USA) coupled with a 5975B mass selective detector spectrometer from the same company. The front inlet was kept at 250C in splitless mode. The temperature program was as follows: initial column temperature 50C, held for 1 min, then programmed to 120C at a rate of 3 min –1 and held for 2 min; finally programming to 210C at a rate of 4 min –1 , then held at 210C for 10 min. As a carrier gas, helium at 1.0 mL min –1 was used.