~ 22 ~ American Journal of Essential Oils and Natural Products 2017; 5(1): 22-26 ISSN: 2321-9114 AJEONP 2017; 5(1): 22-26 © 2017 AkiNik Publications Received: 17-11-2016 Accepted: 18-12-2016 Prabodh Satyal Department of Chemistry, University of Alabama in Huntsville, Huntsville, USA William N Setzer Department of Chemistry, University of Alabama in Huntsville, Huntsville, USA Correspondence: William N Setzer Department of Chemistry, University of Alabama in Huntsville, Huntsville, USA Chemical composition and enantiomeric distribution of monoterpenoids of the essential oil of Abies spectabilis from Nepal Prabodh Satyal and William N Setzer Abstract Two subspecies of Abies spectabilis, A. spectabilis subsp. densa and A. spectabilis subsp. langtangensis, were collected from Dhankuta (eastern Himalaya) and Jumla (western Himalaya) of Nepal, respectively. The leaf (needle) essential oils were obtained by hydrodistillation and analyzed by gas chromatography – mass spectrometry as well as chiral gas chromatography. The major components in the essential oil of A. s. densa were limonene (26.9%, 99% (–)-enantiomer), α-pinene (22.2%, 90% (–)-enantiomer), bornyl acetate (10.3%, 100% (–)-enantiomer, β-phellandrene (9.7%, 99% (–)-enantiomer), camphene (7.1%, 100% (+)-enantiomer), and β-pinene (6.5%, 96% (–)-enantiomer). A. s. langtangensis was composed largely of α-pinene (33.4%, 75% (+)-enantiomer), bornyl acetate (10.9%, 100% (–)-enantiomer), selin- 11-en-4β-ol (9.4%), and α-bisabolol (4.0%). Keywords: essential oil, chemical composition, enantiomeric distribution, chiral gas chromatography, Abies spectabilis. 1. Introduction The genus Abies (Pinaceae) is comprised of about 46 northern temperate species [1] . Abies spectabilis (D. Don) Spach is a high altitude conifer of the Himalayas from Afghanistan to Nepal [2] , including Kashmir [3] and Tibet [4] . In Nepal, the tree ranges in elevation from about 2500 m to 4000 m [5–7] . The leaves (needles) are used to treat bronchitis and whooping cough [8, 9] . Previous phytochemical investigations of A. spectabilis have focused on solvent extracts of the aerial parts [10] and the bark [11] . From the aerial parts, three triterpenoids, 23 diterpenoids, a sesquiterpenoid, 13 flavonoids, 12 lignans, and 20 miscellaneous compounds were identified [10] , while the bark extract showed several condensed tannins [11] . The essential oil compositions of several species of Abies have been investigated, including A. alba [12, 13] , A. balsamea [14] , A. cilicica [15] , A. koreana [16, 17] , A. nephrolepis [18] , A. pindrow [19] , and A. sachalinensis [20] . In this work, we present the chemical compositions of two subspecies of A. spectabilis, A. spectabilis subsp. densa (Griff.) Silba, from eastern Nepal, and A. spectabilis subsp. langtangensis (Silba) Silba, from western Nepal. To our knowledge, this work represents the first report of the chemical compositions of A. spectabilis essential oils, including enantiomeric distribution of monoterpenoid constituents. 2. Materials and Methods 2.1 Plant Material A. spectabilis subsp. langtangensis from Jumla, Nepal (29° 16′ 28.99ʺ N, 82° 11′ 1.79ʺ E, elevation 2500 m asl), was identified by Nawal Shrestha, and collected on July 2, 2016. The fresh needles (100 g) were hydrodistilled for 4 h using a Clevenger-type apparatus and collected to give 200 mg colorless essential oil after drying with Na 2 SO 4 . A. spectabilis subsp. densa from Dhankuta Nepal (26° 59′ 0.44″ N, 87° 19′ 17.37″ E, elevation 2700 m asl) was identified by Saugat Shrestha, and collected on September 1, 2016. The fresh needles (100 g) were hydrodistilled for 4 h using a Clevenger-type apparatus and collected to yield 280 mg pale yellow essential oil after drying with Na 2 SO 4 . 2.2 Gas Chromatography – Mass Spectrometry The essential oils of A. spectabilis chemotypes were analyzed by GC-MS using a Shimadzu GCMS-QP2010 Ultra operated in the electron impact (EI) mode (electron energy = 70 eV), scan range = 40–400 amu, scan rate = 3.0 scans/sec, and GC-MS solution software.