Characterization of Essential Oils of the Leaves and Fruits of Adenanthera pavonina L. by GC/MS

The characterization of the hydro distilled essential oils of the leaves and fruits of A. pavonina , growing in Egypt, was analyzed by gas chromatography-mass spectrometry (GC-MS) using Rtx-5MS fused bonded column. The results revealed the identification of 27 compounds in the leaves and fruits oils. The leaves oil consisted mainly of monoterpene hydrocarbons (68.01%). The major compounds from the leaves oil were sabinene, accounting for 27.9% of the oil content followed by D-limonene (14.79%), 3-carene (8.46%), caryophyllene (6.57%), and γ -terpinene (6.16%). The fruits oil consisted mainly of sesquiterpene hydrocarbons (62.8%). The major compounds were β -element (39.6%) followed by sabinene (11.7%) and caryophyllene (11.38%). These findings will assist in the differentiation between the volatile oils from different parts of A. pavonina is a step to establish the first monograph for this plant. This study summarized the chemical profiles of A. pavonina leaves and fruits essential oils growing in Egypt for the first time. The leaves essential oils of A. pavonina demonstrated different composition compared with the oils from


INTRODUCTION
Plants containing essential oils were reported to exert various biological activities including antioxidant, antibacterial, and anti-parasitic effects due to the presence of various volatile ingredients with potent effects on various .Adenanthera pavonina L. belongs to the Fabaceae.A. pavonina L. is commonly known as redwood and a red-bead tree that is described as a deciduous tree with an erect stem, 18-25 m tall, and 60 cm in diameter [5].
Leaves are compound, bipinnate with a large swollen pulvinus.The leaflets are oblong to ovate, dull green and turn yellow with age.Fruits are large pods, flattened, dark brown, filled with a sticky brown sweet pulp, dehiscent from the top to bottom by twisting valves (Fig. 1) [6].Therefore, the study aimed to characterize the chemical constituents of the essential oils obtained from different organs of A. pavonina (leaves and fruits) growing in Egypt for the first time.

Plant material
The leaves and fruits of A. pavonina (Fig. 1) were harvested from El-Orman Botanical Garden, Giza, Egypt.The plant was identified by Mrs. Tereize Labib, the Taxonomy Specialist at El-Orman Botanical Garden.A voucher sample, PHG-P-AP-286 was maintained at the herbarium of the Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University.

Extraction of the essential oil
The volatile components of A. pavonina leaves and fruits were isolated by hydrodistillation for 4 h using a Clevenger-type apparatus at the Pharmacognosy Department, Faculty of Pharmacy, Ain-Shams University to yield 100 μL/100 g of the oil.The yielded oil was stored at -4 °C in sealed vials.

Analysis of essential oil by GC-MS
A. pavonina oil was analyzed on Shimadzu GCMS-QP2010 (Tokyo, Japan) the operating conditions were as follows: (a) Rtx-5MS fused bonded column (30 m × 0.25 mm i.d.× 0.25 μm film thickness) (Restek, USA), (b) the initial temperature of column was adjusted at 45 °C for 2 min (isothermal) and gradually increased to 300 °C at a rate of 5 °C/min and remained at 300 °C for 5 min (isothermal), (c) the temperature of the injector was 250 °C, (d) the flow rate of the helium carrier gas was 1.41 mL/min a split injector, (e) samples (1% v/v) were injected with split ratio 1:15.Certain conditions adjusted to record mass spectra include Filament emission current (equipment current), 60 mA; ionization voltage, 70 eV; ion source, 200 °C.

RESULTS
The volatile constituents are listed in Table 1.The identification of the oil components was dependent on the retention index (RI), molecular ion peaks and fragmentation patterns, then these data were compared with the reported data of the reference compounds analyzed under the same conditions in NIST Mass Spectral Library (December 2005) and other reported data [19,20].
The chromatogram of leaves essential oil revealed the presence of 21 components (Fig. 2) representing 97.9% of the leaves oil content and 14 components representing 98.7% of the fruit's oil.

DISCUSSION
The results of oils characterization demonstrated that there was a significant difference in the chemical profile of the volatile oil obtained from the leaves and fruits of A. pavonina.Monoterpene was the main class of oil from the leaves with sabinene as the major identified compound.On the other hand, the results of the fruit's oil showed that sesquiterpene was the major class of oil with β-elemene as the major identified component.
The results revealed that essential oils obtained from the leaves and fruits of A. pavonina can be used as a potential source for different components with various biological activity such as sabinene which exhibited sedative activity This study focused on the chemical profiles of A. pavonina leaves and fruits essential oils growing in Egypt for the first time.Identification of the nature of oil constituents is the first step in studying the biologic activities of the oil.Based on the composition of the oils, further biological investigations can lead to the discovery of new leads as antimicrobial agents.
biological receptors.Chemical constituents of essential oils were classified into monoterpenes, sesquiterpenes, isothiocyanates, and phenylpropanoids [1, 2].The chemical constituents of the volatile oils in different plant organs depend on various factors including the time of collection and plant habitat [3].Fabaceae (Leguminosae) is considered one of the most important families of flowering plants, comprising 727 genera and 19300

[ 21 ]
, potent anti-fungal, antibacterial [22] and anti-inflammatory activity by the inhibition of NO production [23].D-Limonene is used in dietary supplements as it showed antioxidant activity [24] and antibacterial activity [25].In addition, D-limonene showed antifungal [26] and antibacterial activities [27, 28].Therefore, it was used in the preservation of food.As the essential oil of A. pavonina leaves contains sabinene and D-limonene as the major constituents, it is recommended to study the antimicrobial activity of the oil.Concerning the components of the fruit's oil, β-elemene showed considerable antiproliferative effects on many types of cancer cell lines.It has was reported to inhibit brain cancer cell growth and proliferation [29] and showed significant anti-inflammatory activity and antimicrobial activity[30].Biological investigations on the fruit's oil are recommended to identify the potential applications of the oils.

Table 1 :
GC-MS analysis of the essential oil