Phytochemicals are defined as bioactive non-nutrient plant compounds in fruits, vegetables, grains, and other plant foods that have been linked to reducing the risk of major chronic diseases (Hai, 2004; Magee and Rowland, 2004; Altameme et al., 2015; Hameed et al., 2015a). General description of Urtica dioica erect perennial, 50 to 300 cm tall with 4-sided stems, armed with stinging hairs, opposite leaves, 7 to 15 cm long, the stalks from about 1/10 as long to nearly 1/2 as long as the blades, depending on variety. The stipules prominent, mostly 10  to 15 mm long. Fruits are achenes, lens-shaped, flattened, about 1.5 mm long, enclosed by the 2 inner sepals. U. dioica has many hollow stinging hairs called trichomes on its leaves and stems, which act like hypodermic needles that inject histamine and other chemicals that produce the stinging sensation when contacted by humans and other animals (Kavalali, 2003; Petlevski et al., 2003; Gulcin, 2004).

The other compounds isolated are derivatives of the terpenoids previously isolated from the roots and flowers of U. dioica (Gozum et al., 2003; Luo, 2009), and they include stigmasterol derivative, sitosterol derivative and ethyl cholestanol (Belyakova et al., 2002; Benkeblia, 2004; Golalipour et al., 2009).

This study aims to analyze the chemical compounds of U. dioica leaves by fourier-transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS).

Collection and preparation of plant material

The leaves were dried at room temperature for seven days and when properly dried then powdered using clean pestle and mortar, and the powdered plant was size reduced with a sieve (Hameed et al., 2015). The fine powder was then packed in airtight container to avoid the effect of humidity and then stored at room temperature (Hussein et al., 2015). 

 

Preparation of sample

About 9 g of the plant sample powdered were soaked in 100 ml methanol individually. It was left for 72 h so that alkaloids, flavonoids and other constituents if present will get dissolved. The methanol extract was filtered using Whatman’s No.1 filter paper and the residue was removed (Jasim et al., 2015).

 

Gas chromatography-mass spectrum analysis

The GC-MS analysis of the plant extract was made in a (Agilent 7890 A) instrument under computer control at 70 eV. About 1 μL of the methanol extract was injected into the GC-MS using a micro syringe and the scanning was done for 45 min. As the compounds were separated, they eluted from the column and entered a detector which was capable of creating an electronic signal whenever a compound was detected (Mohammed and Imad, 2013; Kareem et al., 2015; Imad et al., 2014). The greater the concentration in the sample, bigger was the signal obtained which was then processed by a computer. The time from when the injection was made (Initial time) to when elution occurred is referred to as the retention time (RT). While the instrument was run, the computer generated a graph from the signal called chromatogram. Each of the peaks in the chromatogram represented the signal created when a compound eluted from the gas chromatography column into the detector. The X-axis showed the RT and the Y-axis measured the intensity of the signal to quantify the component in the sample injected. As individual compounds eluted from the gas chromatographic column, they entered the electron ionization (mass spectroscopy) detector, where they were bombarded with a stream of electrons causing them to break apart into fragments. The fragments obtained were actually charged ions with a certain mass .The mass/charge (M/Z) ratio obtained was calibrated from the graph obtained, which was called the Mass spectrum graph which is the fingerprint of a molecule (Imad et al., 2014).

Before analyzing the extract using GC-MS, the temperature of the oven, the flow rate of the gas used and the electron gun were programmed initially. The temperature of the oven was maintained at 100°C. Helium gas was used as a carrier as well as an eluent. The flow rate of helium was set to 1 ml per min. The electron gun of mass detector liberated electrons having energy of about 70eV. The column employed here for the separation of components was Elite 1 (100% dimethyl poly siloxane) (Imad et al., 2014). The identity of the components in the extracts was assigned by the comparison of their retention indices and mass spectra fragmentation patterns with those stored on the computer library and also with published literatures.

GC-MS analysis of compounds was carried out in methanolic leaves extract of U. dioica, as shown in Table 1. The GC-MS chromatogram of the 15 peaks of the compounds detected was shown in Figure 1. Chromatogram GC-MS analysis of the methanol extract of U. dioica showed the presence of fifteen major peaks and the components corresponding to the peaks were determined as follows. The first set up peak was determined to be Oxime- methoxy-phenyl (Figure 2). The second peak indicated to be 2, 6,-Nonadienal, 3, 7-dimethyl (Figure 3). The next peaks considered to be 1, 2, 3-Butanetriol, Silane, triethyl(2-phenylethoxy), Benzofuran, 2,3,-dihydro, 2,5,5,8a-Tetramethyl-1,2,3,5,6,7,8, 8a-octahydronaphthalen-1-ol, 2H-Indeno[1,2-b]furan-2-one, 3,3a, 4,5,6,7,8, 8b-octahydro-8,8-dimet, 1-Dodecanamine, N, N-dimethyl, 2(3H)-Naphthalenone, 4, 4a,5,6,7,8-hexahydro-1-methoxy, D-Fructose, diethyl mercaptal, pentaacetate, [1,1-Bicyclopropyl-2-octanoic acid 2hexyl-methyl ester, Estra-1,3,5(10)-trien-17B-ol, Cyclopropaneoctanoic acid, 2-[2-pentylcycloproyl)methyl]-methyl, 1-Hydroxy-2-(2,3,4,6-tetra-O-acetyl-beta-d-glucopyranosyl)-9H-xanthe and Ethyl iso- allochlate. (Figure 4-16).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The FTIR analysis of U. dioica leaves proved the presence of aromatic rings, alkenes, aliphatic fluoro, alcohols, ethers, carboxlic acids, esters, nitro compounds, hydrogen bonded alcohols and phenols which shows major peaks at 891.11, 958.69, 1010.70, 1091.71, 1242.16, 1319.31, 2686.84 and 3363.86 (Table 2; Figure 17). Polar extract of the U. dioica contains lignans +)-neoolivil, (-)-secoisolariciresinol, Dehydrodiconiferyl alcohol, isolariciresinol, pinoresinol, and 3,4divanillyltetrahydrofuran, and has antiinflammatory effects and stimulates the proliferation of human lymphocytes (Obertreis et al.,1996; Harput et al.,2005; Kanter et al., 2005; Hameed et al., 2015c). Traditionally, it has been used for uterine hemorrhage, cutaneous eruption, infantile and psychogenic eczema, epistaxis, and melena and specifically for nervous eczema (Bandow  et  al.,  2003;  Burt,  2004;  Banso  and Adeyemo, 2006). Among those identified, phytocompounds have the property of antioxidant and antimicrobial activities (Silva et al., 2004; Sein et al., 2008). Plant based antimicrobials have enormous therapeutic potential as they can serve the purpose with lesser side effects. Continued further exploration of plant derived antimicrobials is needed today. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

U. dioica is native plant of Iraq. It contains chemical constitutions which may be useful for various herbal formulation as  anti-inflammatory,  analgesic,  antipyretic, cardiac tonic and antiasthamatic properties. 

The authors wish to express their deepest gratitude to Prof. Dr. Adul-Kareem for his valuable contributions and support throughout this study. They would also like to ex-press their gratitude to Dr. Ali for his valuable suggestions and comments. 

The authors have none to declare.