Gandhrayan (Angelica glauca Edgew.; Family Apiaceae), a high value medicinal and aromatic plant is native to the Himalaya and distributed at the altitudes of 2,000–3,800 m in North-Western Himalaya [1]. Due to the high demand of raw material, unsustainable harvesting, over exploitation and grazing problems, naturally growing populations of the species have become very rare and restricted to a very few habitats [2], hence the species is now reported to be endangered for the Himalayan region, adopting IUCN criteria [3]. The whole herb is reported to be useful as stimulant, cordial, appetizer, dyspepsia, cardioactive, carminative, expectorant, diaphoretic and also in stomach troubles and urinary disorders, constipation and gastric problems, bilious complaints, rheumatism, bronchitis, menorrhiza, for treating rinderpest etc. [1, 4–12]. Roots of this plant yield essential oils which bring high prices due to multiple utility in modern medicine including aromatherapy [13]. The species is reported to have a great pharmaceutical importance and shown to have therapeutical and anti-inflammatory effects due to their active components like butylidene phthalide and ligustilide [14–18]. Previous work has done on essential oil of A. glauca from Himalayan regions (Kashmir, Himachal Pradesh and Kumaun Himalaya), which has shown great qualitative and quantitative variations in their oil compositions [19–23]. It is well established that primary and secondary metabolites such as alkaloids, terpenoids, essential oil content and composition are generally influenced by various environmental factors like habitats, altitudes, season, drying method and harvesting times [24–26].

In view of the importance of the species, a detailed and systematic study has been carried out on essential oil composition of the species, naturally growing in two locations of Garhwal Himalaya (Uttarakhand).

Fresh root of A. glauca was collected during the month of October, 2012 from two naturally growing areas of Uttarakhand Himalaya (India); Kedarnath (Rudraprayag); altitude 3,400 m and Ghesh, Ghodapani (Chamoli); 3,100 m. The specimens were identified by Prof. R.D. Gaur, Department of Botany, H.N.B. Garhwal University, Srinagar Garhwal and deposited at herbarium of HAPPRC (Acc. No.: HAPPRC- AG/G SBB-1, 2).

The shade dried roots (100 g), collected from two high alpine locations were subjected to hydro-distillation for 5 h using Clevenger apparatus. The isolated essential oils were dried over anhydrous sodium sulphate and stored carefully in dark vial at low temperature before analysis.

GC analyses of the oil samples was carried out using Agilent (HP7890 GC) gas chromatograph equipped with a Flame Ionization detector (FID) and a HP-5 fused silica column (30 m × 0.32 mm, 0.25 μm film thickness). The sample was injected directly into the column. Nitrogen was used as a carrier gas during analysis. The injector and detector temperature were maintained at 210 and 230 °C, respectively. The column oven temperature was programmed from 60° to 220° with an increase in rate of 3°/min. The injection volume was 0.2 μl.

GC-MS analyses of the oils were performed on Agilent mass spectrometer (Model 5975C) coupled to an Agilent gas chromatograph with a 60 m × 0.32 mm, 0.25 μm film thickness column (DB5). The sample was injected directly in split less mode. Helium was used as the carrier gas (flow rate 1 ml/min). The oven temperature was programmed from 60° to 220° at 3 °C/min. Other conditions were the same as described under GC. The mass spectrum was taken with a mass range of 40–600 Daltons.

The identification of constituents was performed on the basis of retention index (RI), determined with reference to the homologous series of n-alkanes, C8–C24 with co-injection of standards (Sigma Aldrich USA) under same analytical conditions and by matching their recorded mass spectra with the MS library (NIST/Pfleger/Wiley) and available literature [27].

Angelica glauca roots yielded 0.3 and 1.8 % (v/w) volatile oils in Ghesh and Kedarnath, respectively. The content in Kedarnath sample was found to be maximum as compared to previous reports from Uttarakhand [21] and other Himalayan locations [19–23]. The percentage composition of the oils is presented in Table 1. GC and GC–MS analyses revealed an identification of 26 components, accounting 98.2 and 97.7 % in the oils from Kedarnath and Ghesh populations, respectively. The major portions in both the oils were constituted by lactone containing compounds (phthalides and ligustilides) which comprised 69.3 and 90.6 % in Ghesh and Kedarnath samples, respectively. The major constituents in the oils of A. glauca were characterised as (Z)-ligustilide (53.0 and 40.6 % in Kedarnath and Ghesh, respectively), (Z)-butylidene phthalide (32.8 % in Kedarnath and 20.7 % in Ghesh), (E)-butylidene phthalide (2.5 % in Kedarnath and 5.9 % in Ghesh) and (E)-ligustilide (2.3 % in Kedarnath and 2.1 % in Ghesh) and showed high degree of variation. Present study closely resembled with a report from Kumaun region of the Uttarakhand in terms of major components [21] and identified (Z)-ligustilide and (Z)-butylidene phthalide as the main compounds, constituted 54.1 and 29.8 %, respectively. Monoterpene hydrocarbons were also found in appreciable amounts in Ghesh population (19.5 %), having major compounds such as myrcene (8.3 %), α-phellandrene (6.9 %), sabinene (2.3 %) and p-cymene (0.7 %), whereas in the essential oil from Kedarnath population, monoterpene hydrocarbons constituted only 3.8 % of the oil having comparatively lesser portions of myrcene, α-phellandrene, sabinene, p-cymene and α-pinene. β-Phellandrene which afforded 1.3 % in Kedarnath population, constituted only 0.2 % in Ghesh population. From Table 1, it is evident that the volatile oils of both the populations are different mostly quantitatively than qualitatively.

Table 1 Constituents of Angelica glauca roots essential oil from two locations of Uttarakhand Himalaya (India)
Full size table

Chemical profiling studies on this species showed its great pharmaceutical importance as well as flavour and fragrance value. Previous studies revealed that butylidene phthalide, an important component of Chinese drug plants Ligusticum wallichiana and Angelica sinensis has been found to possess antispasmodic activity and improve blood flow [16, 18]. Ligustilide alleviates brain damage and improves cognitive function [15]. (Z)-ligustilide and phthalide lactones showed therapeutical effects in several diseases and possessed anti-proliferative [17] and anti-inflammatory effects [14].

Further researches still need to be done for pharmacological properties of Uttarakhand specific Angelica root oil. There is a need to identify the active compounds in the extracted oil, responsible for various pharmacological activities. Due to the higher relative area quantum of monomeric lactones (phthalides and ligustilides) in A. glauca populations growing in Uttarakhand, there is a need to develop propagation protocol for mass multiplication and in situ and ex situ conservation.