LAUSR

Calliandra haematocephala Hassk., belonging to the Leguminosae family, is distributed in tropical and subtropical areas and is also widely cultivated in Taiwan, Hainan, and Guangdong in China [1]. Research has revealed that 20 galloylated flavonol glycosides have been isolated from the leaves and stems of C. haematocephala, which exhibits moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical, superoxide anion generation, and DPPH radical [2]. At present phytochemical and biological research on C. haematocephala is scanty. There is no research on the volatile components of C. haematocephala. In this paper we study the volatiles of the flowers, stems, and leaves of C. haematocephala using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC/MS) techniques for the first time. The flowers, stems, and leaves of C. haematocephala were collected from Wanning, Hainan Province, China in July 2013 and identified by Prof. Changqin Li. A voucher specimen (No. 20130926) was deposited in the Institute of Natural Medicine of Huanghe Science and Technology College. Volatile organic compounds in flowers, stems, and leaves of C. haematocephala were extracted by a manual SPME holder together with 5 mL vials and PDMS-DVB fibers (65 m) purchased from Supelco Inc. (Bellefonte, USA) for 30 min at 80 C 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 After that, the fiber was withdrawn and directly inserted into the GC-MS inlet for desorption of the volatiles for 1 min.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 analysis was carried out using an Agilent 6890 N gas chromatograph equipped with an HP-5 MS capillary column (5% phenylmethylsiloxane, 30 m 0.25 mm, film thickness 0.25 m, Agilent Technologies, USA) and coupled with a 5975 B mass selective detector spectrometer from the same company. The front inlet was kept at 250 C in splitless mode. The temperature program was as follows: initial column temperature 50 C, held for 2 min and then programmed to 120 C at a rate of 8 C per minute and held for 2 min; finally programmed to 220 C at a rate of 4 C per minute and held at 220 C for 5 min. As a carrier gas, helium at 1.0 mL per minute was used. The MS detector was used in the EI mode with an ionization voltage of 80 eV. The ion source temperature was at 230 C. The transfer line was at 280 C. The spectra were collected over the mass range (m/z) 30–400. Retention indices were calculated by using the retention times of C6–C26 n-alkanes that were injected under the same chromatographic conditions [3, 4]. The volatile constituents were identified by comparison of their relative retention indices and their mass spectra with the MS Library (NIST 08L). The volatiles in the flowers, stems, and leaves of C. haematocephala are presented in Table 1. Six, eight, and nine species of volatile constituents were identified from flowers, stems, and leaves of C. haematocephala, and the identified compounds accounted for 69.3%, 57.0%, and 59.5% of the total volatiles, respectively. The major volatile constituents in the flowers, stems, and leaves were alkanes (39.2%, 47.1%, and 23.9%, respectively). The major volatile constituents in the flowers were n-hexadecanoic acid (27.2%), octacosane (16.5%), heptadecane (9.9%), and hexadecane (9.0%). The volatile constituents in the stems were pentacosane (20.4%), heptadecane (7.0%), nonadecane (6.2%), and n-hexadecanoic acid (6.2%). The volatile constituents in leaves were 6,10,14-trimethyl-2-pentadecanone (17.6%), heptadecane (9.2%), and hexadecane (8.8%). Four compounds were found in the flowers, stems, and leaves: hexadecane, heptadecane, octadecane, and n-hexadecanoic acid. Therefore, there are some differences regarding types and total amount of volatile substances in the flowers, stems, and leaves, and their relative contents obviously differed.