The Scientific World Journal

The Scientific World Journal / 2012 / Article

Research Article | Open Access

Volume 2012 |Article ID 564367 | 12 pages | https://doi.org/10.1100/2012/564367

Phenolic Compounds Analysis of Root, Stalk, and Leaves of Nettle

Academic Editor: Yiannis Fiamegos
Received17 Oct 2011
Accepted19 Dec 2011
Published19 Apr 2012

Abstract

Types of nettles (Urtica dioica) were collected from different regions to analyze phenolic compounds in this research. Nettles are specially grown in the coastal part. According to this kind of properties, nettle samples were collected from coastal part of (Mediterranean, Aegean, Black sea, and Marmara) Turkey. Phenolic profile, total phenol compounds, and antioxidant activities of nettle samples were analyzed. Nettles were separated to the part of root, stalk, and leaves. Then, these parts of nettle were analyzed to understand the difference of phenolic compounds and amount of them. Nettle (root, stalk and leaves) samples were analyzed by using High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD) to qualitative and quantitative determination of the phenolic compounds. Total phenolic components were measured by using Folin-Ciocalteu method. The antioxidant activity was measured by using DPPH (2,2-diphenyl-1-picrylhydrazyl) which is generally used for herbal samples and based on single electron transfer (SET).

1. Introduction

Nettle (Urtica dioica L.), naturally found in pathway, field, and wildwood. Nettles are grown in mild climate areas, bottom of barriers, ruins and grassy places, between cultivated plants, street, and water runnels. This plant prefers nutrient riches and lighted places, hot and mild climate. It has broad distribution of the world. It is also grown in the different region, of Turkey. Some local names of nettle are “dalagan, dizlagan, agdalak, and isirgi”. Nettle is annual or perennial, herbaceous plant. This plant which is specially grown in Black Sea region has reach chemical composition. It is used as drug, food, fibrous, dye, and cosmetic from centuries. Numbers of medical and pharmacologic researches about nettle are increased day by day. On the other hand, nettle has valuable fibrous content which is light, elegant, long, and resistant. In Turkey, nettle could be an alternative product in Black Sea region in which it could be grown easily [1].

Nettle has dark green leaves, root, stem, serration, and stinging nettle. The nettle flowers are small and green. It could give flowers from May to September. The fruits of nettle are arid and single germ. It has two species. Both of them have 2–4 cm long, oval, and core shape leaves. Fresh nettle could cause blushing and burning of skin when it is touched [2].

Plants could be used as a cure for different types of diseases for centuries. In recent years, usage of plant is increased. In Turkey, plants could be used as household and herbal remedy. Phenolic compounds could be defined as biologically active and herbal and have positive effects on health. The scientific researches are increased about the positive effect of phenolic compounds into coronary heart disease and high blood pressure, diabetes, cancer, inflammative, viral and parasitic disease, psychotic disorders [3].

Systematic properties of nettle could be classified as [4];
Scientific name: Urtica dioica. Traditional name: Nettle.Genus: Urticaceae.Used parts: root, stalk, and leaves.Usage as a food: tea (root, stalk, and leaves), vegetable dish (stalk and leaves), salad (stalk and leaves), and so forth.

A research about nettle indicates that it has wide field of usage as household remedy in Italy from gastrointestinal diseases to rheumatism pains [5]. Another research indicates household remedy usage in Moorish, stalk, and leaves of nettle used in treatment of diabetes, hypertension, astringent, antirheumatic, diuretic, antidiuretic, and cholagogue [6].

Nettle has agglutinin, acetophenone, alkaloids, acetylcholine, chlorogenic acid, butyric acid, chlorophylll, caffeic acid, carbonic acid, choline, histamine, coumaric acid, formic acid, pantothenic acid, kaempferol, coproporphyrin, lectin, lecithin, lignan, linoleic and linolenic acids, palmitic acid, xanthophyll, quercetin, quinic acid, serotonin, stigmasterol, terpenes, violaxanthin, and succinic acid in its chemical content. Nettle also contains 2,5% fatty substance, 14–17% albumins, and 18% protein in dry matter. Seeds of nettle contain 8–10% fixed oil. 1 kg fresh plant contains 130 mg vitamin C, 730 mg carotene, and oxalate. Stinging hair of nettle contains formic acid, histamine, and acetylcholine. Leaves of nettle contain provitamin A, vitamin B1, K, xanthophylls, and sistosterin and ashes of nettle contain 6,3% ferric oxide, potassium, calcium, and silicium [1].

Analysis of methanolic extracts of nettle was made by using Gas Chromatography-Mass Spectrometry (GC-MS) method; vanillic acid, homovanillic acid, 2-hydroxycinnamic acid, 4-hydroxycinnamic acid, and ferulic acid were found [7]. Methanolic extract of nettle leaves analysis was made by using Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method, UV detector; syringic acid, gallic acid, and ferulic acid were found [8].

In a research about nettle root, analysis was done by using extract which were prepared in different pH of organic solvent and by using GC-MS method. The results indicate that roots have 18 different phenolic components and 8 different lignan components. But the chemical composition of these components was not identified in this study [9]. In another research, some kind of components (ferulic acid 20 μg/g, homovanillly alcohol 8 μg/g, and p-coumaric acid 5 μg/g) were identified by using isocratically fractionate, commercial Urtica dioica root extracts without hydrolisation [10]. In another research, 7 flavonoid glycosides (kaempferol-3-O-glycoside, quercetin-3-O-glycoside, isorhamnetin-3-O glycoside, quercetin-3-O-rutinoside, isorhamnetin-3-O-rutinoside, kaempferol-3-O-rutinoside and isorhamnetin-3-O-neohesperidoside) were isolated from Urtica dioica flowers. Structure of these components was identified by using chromatographic and spectroscopic method [11].

Methanolic extracts of nettle leaves and stalks were studied about anthocyanin glycosides, and 3 different components (pelargonidin xylobioside, pelargonidin monoxyloside, and another component which give pelargonidin, D-glucose, and L-rhamnose after acid hydrolysis) were isolated [12]. In addition to the 7 different components, quercetin and rutin flavonoids were also found in leaves and stalks of nettle by using modern spectroscopic (Nuclear magnetic resonance-NMR-, Mass Spectrometry-MS-, etc.) methods [13].

By using Supercritical Fluids Extraction (SFE) method in which liquid CO2, different pressure, and temperature profiles were used, chlorophylll a, chlorophylll b, β-carotene, and lutein components were found in nettle leaves [14]. In another research chlorophylll a and chlorophyll b were isolated from nettles, which could be used as a coloring agents (E140) in the field of drug and food. The most efficient process was identified as 4-step extraction and nettle was firstly dried at 40°C, stored at dark place in plastic bags at 4°C [15].

Linoleic acid, palmitic acid, oleic acid, palmitoleic acid, stearic acid, gadoleic acid, and erucic acid were found in nettle roots analysis by using GC about fatty acids composition [16]. In a research (−)-epi catechin and (+)-catechin were found in nettle leaves by using RP-HPLC method and UV detector. Nettle has some antimicrobial effects as its phenolic contents. Nettle could inhibit Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes [8].

A plant mix “Antidiabetis” is used which could decrease blood glucose level and contains root and other parts of nettle in Croatia [17]. Nettle is also used as an antioxidant which could decrease muscular contraction as analgesic. It also shows antimicrobial effect and it has some benefit on gastric mucosal damage [18]. In household remedy nettle is used against muscle paralysis. According to this point, nettles effect on proteolytic activity of Botulinum neurotoxins was studied. Nettle leaves extract could inhibit Botulinum neurotoxin serotype A light chain protease activity without competition, but it has no effect on serotype B [19].

The aim of this study was to analyze phenolic component and antioxidant activity of nettle, which is grown in coastal part of Turkey (Mediterranean, Aegean, Black sea, and Marmara). In this paper the nettle was taken apart (root, stalk, and leaves), and these parts were analyzed separately. These analyses were done to indicate differences of nettles between regions and parts. The samples were coded as Mediterranean (01-Adana, 07-Antalya, 07F-Fethiye, 32-Isparta), Aegean (09Y-wild sample from Aydın, 09-Aydın, 20-Denizli, 35-Izmir, 45A-Alasehir, 45S-Salihli, 45T-Turgutlu, 48-Mugla), Black Sea (52-Ordu, 53-Rize, 55-Samsun, 61-Trabzon, 74-Bartın) and Marmara (16-Bursa, 41-Kocaeli) which are name of cities. On the other hand, the moisture content of nettles was also analyzed. Firstly nettles were extracted. Then, analysis was done by using extract of nettles. Phenolic profiles of nettle were determined by using HPLC (High-Performance Liquid Chromatography) method.

2. Materials and Methods

2.1. Materials
2.1.1. Nettle Samples

Samples were collected from Aegean, Black Sea, Marmara, and Mediterranean region. These samples were rapidly washed and dried. Then, they were separated into root, stalk and leaves. After this process, part of samples was kept in a zip lock bag at −20°C for inhibition of air contact before analysis.

2.1.2. Sample Preparation and Extraction

Required amount of the samples were taken and then whittle into small particles to increase extraction yield.

After trials of different types of extraction method [20, 21], 80% methanol-water mixture was used as an extraction liquid. 1 g samples were taken from each of samples. 10 mL extraction liquid was added into the samples and extracted during 1 h at 50°C. The extraction was done in closed vessels to inhibit loss of the extraction liquid. After extraction process, the eluate was filtered.

2.1.3. Chemical Materials

Standards-Gallic acid (Sigma, G7384), ferulic acid (Fluka, 42280), rutin (Sigma, R5143), myricetin (Sigma, M6760), syringic acid (Sigma, S6881), caffeic acid (Sigma, C0625), chlorogenic acid (Sigma, C3878), quercetin hydrate (Sigma, 337951), p-coumaric acid (Sigma, C9008), kaempferol (Sigma, K0133), catechin hydrate (Fluka, 22110), fumaric acid (Fluka, 47910), vanillic acid (Fluka, 94770), naringin (Sigma, N1376), ellagic acid (Sigma, E2250), and isorhamnetin (Fluka, 17794) were used.

Chemicals-Folin-ciocalteau phenol reactive (Sigma-Aldrich, E9252), acetic acid (Panreac, 361008), sodium carbonate (J.T. Baker, 2024), DPPH (2,2 diphenil, 1, picrylhydrazyl) (Sigma, D9132), and Chromatographically pure gradient solvent-Methanol (Labscan, A17C11) were used.

2.2. Method
2.2.1. Moisture Analysis

Moisture analysis of samples was done by using “Fruit and Vegetables Moisture Analysis” method [22].

According to method we have the following:(i)3 gr of nettle from each part (root, stalk, and leaves) was weighed (0,001 of accuracy).(ii)Firstly weighing bottles were kept in drying oven for 1 h at 103 ± 2°C and then samples were put in weighing bottles and kept in drying oven for 4 h at 103 ± 2°C.(iii)Then samples were taken out from drying oven and then kept in desiccators for 30 min to reach the room temperature.(iv)After being weighed, samples were put again in drying oven for 1 h to dry.(v)These drying periods (1 h) were done until reaching the constant weighing (7 h).(vi)The moisture contents of samples were measured by using the following formula: 𝑚Moisture%=1𝑚2𝑚1100,(1) where 𝑚1 is initial weigh of sample, 𝑚2 is final weigh of sample.

2.2.2. Total Phenolic Content Analysis

Total phenolic content analysis of nettle extracts was done by using Folin-Ciocalteau (FC) method [23, 24]. The results were expressed as gallic acid equivalents in milligrams per gram of dry matter. The solutions was as follows:(i)FC Reactive,(ii)7% Na2CO3 solution,(iii)gallic acid standard solution (50–100–150–200–300 ppm) preparing by using 80% methanol.

According to the method, we have the following.(i)250 μL FC reactive was added into 50 μL nettle extract or standard solution.(ii)This mixture was stayed at room temperature in dark place for 5 min.(iii)At the end of this period, 750 μL 7% Na2CO3 solution was added. By this way, phenolics hydroxyl groups could give H to water.(iv)This mixture was completed to 5 mL with pure water.(v)Then, mixture was stayed at room temperature in dark place for 120 min for reaction.(vi)Samples and standards absorbance was measured at 760 nm.(vii)For blank solution instead of 50 μL extract, 80% methanol solution was added.(viii)Total phenolic content was measured with calibration curve by using gallic acid equivalent standards.

2.2.3. DPPH Antioxidant Capacity Analysis Method

Nettle extracts antioxidant capacity analysis was done by using DPPH radical degradation activity method [25].

According to the method, we have the following.(i)6 × 10-5 M (molar) DPPH radical was prepared daily by using pure methanol.(ii)2 μL methanolic DPPH solution was added into 100 μL sample extract or standard solution.(iii)This mixture was stayed in dark place for 20 min.(iv)At the end of this time, absorbance was measured at 515 nm.(v)Pure methanol was used as blank solution.(vi)For control solution, instead of 100 μL extract 100 μL pure water was used.(vii)Sample extract antioxidant capacities were measured by using calibration curve which was prepared by using different concentrations (10–100 ppm) of gallic acid solution.

2.2.4. HPLC Analysis of Phenolic Component

Qualitative and quantitative analyses of caffeic acid, vanillic acid, naringin, syringic acid, and ferulic acid, ellagic acid, myricetin, kaempferol, isorhamnetin, catechin, chlorogenic acid, p-coumaric acid, rutin, fumaric and gallic acid component in nettle samples were done by HPLC. HPLC analysis was done by using graded elution program. The elution program could be summarized as follows, 0–11 min, 100% A, 30–40 min, 35% A, and 65% B, and 42 min 100% A. A and B solvents were used as elution solvent. Solvent A consists of 2% acetic acid, 10% methanol, and 88% pure water, and B consists of 2% acetic acid, 90% methanol, and 8% pure water. The flow rate was 1 mL/min, temperature was 40°C, and the injection volume was 20 μL. On the other hand, according to maximum absorbance of standards, analysis was done at 254, 270, 280, and 370 nm wavelength. Some chromatogram samples are given at Figure 1. The standards chromatogram is given at Figure 2.

In HPLC analysis of nettle samples, the methanolic extracts were used. Samples and standards were filtered from 0,45 μm Agilent micro filter, then were put into vials, and finally they were given to HPLC.

3. Results and Discussion

3.1. Moisture Contents

Moisture content analysis of root, stalk, leaves, and total of nettle was done. This moisture analysis was given in the table (Tables 1 and 2) as region. Analysis was duplicated. The results were given with standard deviations. The differences between samples were determined by using SPSS (v.17)/one-way-aNOVA/Duncan test (𝑃<0.001).


Moisture %FC (mg GAE/g DM)DPPH (mg GAE/g DM)

Sample
M0184,61 ± 0,05b157,27 ± 5,33b147,20 ± 2,09a
M0774,93 ± 0,04c307,10 ± 1,12a241,63 ± 2,72a
M07F74,03 ± 0,02c344,12 ± 9,19a247,16 ± 1,14a
M3289,74 ± 0,02a123,62 ± 1,68b98,70 ± 1,35b
A09Y89,80 ± 0,11a243,68 ± 3,35c51,44 ± 2,74b
A0988,84 ± 0,18a113,69 ± 2,87d145,83 ± 0,39a
A2088,88 ± 0,21a730,65 ± 5,85d52,78 ± 0,48b
A3584,09 ± 0,06b126,95 ± 1,07a141,54 ± 1,14a
A45A80,74 ± 0,00c277,25 ± 3,65c114,04 ± 1,30a
A45S86,96 ± 0,21a,b123,88 ± 0,98d53,27 ± 0,31b
A45T85,56 ± 0,15b383,93 ± 3,96b72,73 ± 0,35b
A4889,08 ± 0,15a66,97 ± 0,89d114,11 ± 0,47a
B5276,29 ± 0,11b440,49 ± 16,06b106,69 ± 0,91a
B5378,45 ± 0,04a233,93 ± 5,16b235,38 ± 2,19a
B5569,66 ± 0,05c723,93 ± 37,56a152,26 ± 1,05a
B6178,64 ± 0,03a353,92 ± 11,34b224,87 ± 1,92a
B7478,10 ± 0,02a,b297,15 ± 2,90b234,18 ± 1,16a
MS1662,55 ± 0,05b410,53 ± 3,21b260,92 ± 1,01a
MS4176,43 ± 0,03a443,96 ± 6,33a249,96 ± 1,91a
Root Sample
M0187,89 ± 0,02b70,47 ± 1,14c150,85 ± 0,42a
M0774,96 ± 0,08a370,12 ± 0,93a300,60 ± 1,83a
M07F77,92 ± 0,01a170,99 ± 4,39b250,81 ± 0,95a
M3289,79 ± 0,04b20,44 ± 0,24c130,01 ± 2,35a
A09Y93,45 ± 0,05a60,03 ± 0,34a30,60 ± 1,16b
A0991,31 ± 0,19a20,12 ± 0,31b50,60 ± 0,12b
A2089,96 ± 0,10a,b100,89 ± 0,18b40,22 ± 0,20b
A3586,36 ± 0,07b,c90,86 ± 1,56b170,42 ± 1,96a
A45A84,35 ± 0,00c40,49 ± 0,45b90,74 ± 0,01a
A45S89,46 ± 0,53a,b90,94 ± 2,24b40,31 ± 0,19b
A45T86,39 ± 0,08b,c90,35 ± 2,53b60,97 ± 0,55b
A4870,45 ± 0,26a390,33 ± 9,60b120,24 ± 0,51a
B5271,38 ± 0,08a790,21 ± 43,65a140,58 ± 2,46a
B5370,44 ± 0,01a40,52 ± 0,13a340,31 ± 1,31a
B5573,56 ± 0,11a1020,16 ± 69,40a190,91 ± 2,35a
B6178,09 ± 0,00a270,62 ± 8,87a350,72 ± 1,69a
B7492,32 ± 0,01a190,67 ± 0,36a270,62 ± 0,67a
MS1671,42 ± 0,03b430,34 ± 6,20b370,27 ± 0,11a
MS4176,12 ± 0,00a470,78 ± 0,46a300,15 ± 2,13a

∗ M is representing Mediterranean, A is Aegean, B is Black Sea, and MS is Marmara region. The statistical analysis was done within Region.

Moisture %FC (mg GAE/g DM)DPPH (mg GAE/g DM)

Stalk Sample
M0185,29 ± 0,02b20,24 ± 0,68b,c90,06 ± 0,52b
M0784,11 ± 0,01b,c80,46 ± 2,46b300,61 ± 2,40a
M07F81,32 ± 0,04c150,35 ± 2,16a180,39 ± 1,72a
M3292,81 ± 0,02a370,58 ± 8,51c230,39 ± 5,16a
A09Y93,40 ± 0,20a10,08 ± 0,06e30,31 ± 0,19b
A0991,17 ± 0,30b,c60,71 ± 1,34c50,77 ± 0,15b
A2091,62 ± 0,03a,b150,07 ± 2,31b40,85 ± 0,48b
A3587,85 ± 0,02d100,42 ± 0,64a140,15 ± 0,91a
A45A84,66 ± 0,05e70,49 ± 1,60b,c130,82 ± 0,42a
A45S90,71 ± 0,01b,c40,66 ± 2,03c,d40,29 ± 0,17b
A45T89,15 ± 0,09c,d60,25 ± 0,59c,d70,19 ± 0,07b
A4877,84 ± 0,12c,d30,28 ± 0,96d,e30,71 ± 0,68b
B5279,41 ± 0,08a160,72 ± 3,47a90,41 ± 0,15a
B5379,86 ± 0,13a320,85 ± 4,53a290,63 ± 3,65a
B5580,36 ± 0,01a270,62 ± 28,61a90,35 ± 0,10a
B6177,48 ± 0,05a260,61 ± 6,84a240,45 ± 3,04a
B7489,41 ± 0,03a480,30 ± 3,33a300,93 ± 2,01a
MS1643,78 ± 0,04b120,71 ± 3,38a240,86 ± 1,48a
MS4178,91 ± 0,05a100,90 ± 4,79b320,99 ± 3,44a
Leaves Sample
M0186,63 ± 0,02b320,88 ± 12,39a110,39 ± 4,14a
M0780,65 ± 0,11c400,83 ± 0,26a190,04 ± 1,15a
M07F65,72 ± 0,02c490,80 ± 14,67a170,79 ± 0,07a
M3262,84 ± 0,01a330,20 ± 4,12a70,54 ± 1,20b
A09Y82,57 ± 0,10a330,61 ± 0,38d80,53 ± 6,89a
A0984,04 ± 0,04a190,01 ± 4,74d,e320,38 ± 0,89a
A2085,07 ± 0,48a220,40 ± 2,22d,e60,77 ± 0,75a
A3578,07 ± 0,09a,b1941,00 ± 15,06a100,90 ± 0,53a
A45A80,59 ± 0,12b150,52 ± 1,41c80,17 ± 0,49a
A45S80,72 ± 0,01a1000,61 ± 9,06d,e100,56 ± 0,34a
A45T81,13 ± 0,25a670,40 ± 7,78b170,28 ± 3,81a
A4873,22 ± 0,00a290,50 ± 0,45e70,96 ± 0,06a
B5284,56 ± 0,14a370,54 ± 1,06b80,02 ± 0,11a
B5358,68 ± 0,11a340,43 ± 10,82b60,62 ± 1,60a
B5581,99 ± 0,00b881,00 ± 14,67a160,43 ± 0,71a
B6178,74 ± 0,06a530,52 ± 18,32b70,29 ± 1,02a
B7485,51 ± 0,04a220,49 ± 5,01b110,71 ± 0,79a
MS1672,44 ± 0,09b680,55 ± 0,04b160,14 ± 1,44a
MS4174,25 ± 0,04a760,20 ± 13,75a110,85 ± 0,15a

∗ M is representing Mediterranean, A is Aegean, B is Black Sea, and MS is Marmara region. The statistical analysis was done within region.

According to scientific studies, moisture analysis was done to a nettle tea bag which includes all parts of nettle and as a result its moisture content was 6,3% [26]. In another study about nettle leaves which was collected from Macedonian, moisture content was 8,3% [1]. In another research about nettles (root, stalk and leaves), moisture contents of nettles root, stalk and leaves were 80,01%, 88,88%, and 78,67%, respectively [27].

In our study, average moisture content of nettles in total samples was 80,94%, root samples 81.87%, stalk samples 83,11%, and leaves samples 77,75%. The highest moisture content was 09 and the lowest one was 16 in total. In root the highest moisture content was 09Y and the lowest one was 53. In stalk the highest moisture content was 09Y and the lowest one was 16. In leaves the highest moisture content was 32 and the lowest one was 07F. On the other hand, the moisture content was different among the regions. As a general comment moisture content could be ranged like stalk > root > leaves.

Nettle samples, which were used in this study, are fresh samples that could be a reason of the high moisture content results.

3.2. Total Phenolic Content Analysis of Nettle

According to the analysis result (Tables 1 and 2), total phenolic content of nettle was indicated with FC method, which is a wide used method. Nettles (total, root, stalk, and leaves) were analyzed and this analysis result was given at 760 nm wavelengths. SPSS (v.17) statistical program, one-way-aNOVA/Duncan test (𝑃<0,001) was used to indicate the difference among samples. As a general comparison among samples, total phenolic content of nettle could be ranged as leaves > root > stalk.

According to a scientific research, total phenolic content analyses of nettle parts (root, stalk, and leaves) were done by using FC method. The results were given as mg Gallic Acid Equivalent (GAE)/g Dry Matter (DM). In this paper, the results were given as root 7,82, stalk 9,91, and leaves 7,62 mg GAE/g DM [27]. In comparison, our nettle samples total phenolic content is higher than this research results. In a research about phenolic analysis of nettle as cultivated and wild, total phenolic contents of nettles were given for stalk of nettle 28,6% in cultivated and 24,4% in wild samples, while 71,5% and 76,5% for leaves of nettle, respectively [28].

In another research, total phenolic content of nettle tea bag which includes all parts of nettle (root, stalk, and leaves) was 2,5 mg GAE/g DM [26].

3.3. Total Antioxidant Activity Analysis

Antioxidant activity analysis of nettle parts (root, stalk, and leaves) was done by using DPPH antioxidant activity method. The analysis result was given at 515 nm wavelengths. The results are given in Tables 1 and 2. SPSS (v.17) statistical program, one-way-aNOVA/Duncan test (𝑃<0,001) was used to indicate the difference among samples.

In a research related to nettle parts (root, stalk, and leaves), antioxidant activities were given as root 9,86, stalk 37,56, and leaves 76,06 mg GAE/g DM [27]. On the other hand, in another study about herbal tea, a nettle tea bag (include root, stalk, and leaves of nettle) total antioxidant activity was 2,5 mg GAE/g DM [26]. The process of nettle to prepare tea could be the reason of the lower antioxidant activity instead of fresh nettle parts. In a general perspective, antioxidant activity could be ranged as root > stalk > leaves. The 41 sample has the highest total antioxidant activity, and the 20 sample has the lowest one. In root sample, the highest one was 16 and the lowest one was 20. In stalk sample, the highest one was 41 and the lowest one was 09Y. In leaves sample, the highest one was 09 and the lowest one was 53.

The total antioxidant activity of nettle parts (root, stalk and leaves) was analyzed by using DPPH method. While the results were compared with literatures total antioxidant activity of fresh nettle was higher than the others (nettle tea, dry nettle leaves). According to the DPPH analysis results statistical discrepancy were observed between Mediterranean, Aegean, Black Sea, Marmara Region, root, stalk and leaves. On the other hand, there was no statistical discrepancy between Mediterranean leaves sample, Black Sea root, and stalk sample.

3.4. HPLC Analyses of Phenolic Component of Nettle

The total phenolic content and antioxidant activity of nettle samples which were collected from different regions and cities of Turkey were diverse between regions, cities, root, stalk and leaves. Nettles (total, root, stalk, and leaves) were analyzed and the results are given in Tables 3, 4, and 5. 16 antioxidant standards were used for identification of phenolic component of nettle sample in this research. Samples methanolic extracts were analyzed with these standards by HPLC-DAD. SPSS (v.17) statistical program, one-way-aNOVA/Duncan test (𝑃<0,001) was used to indicate the difference among samples.

(a)

SampleGallicSyringicMyricetinQuercetinKaempferolFumaricVanillic

M011,45 ± 0,13a,b0,74 ± 0,02a0,49 ± 0,11a
M070,64 ± 0,014b0,84 ± 0,10a0,47 ± 0,19a
M07F2,18 ± 0,079a,b0,73 ± 0,01a0,52 ± 0,52a
M324,90 ± 1,83a0,75 ± 0,01a0,46 ± 0,01a
A09Y0,00 ± 0,00b0,70 ± 0,08b0,38 ± 0,54b0,44 ± 0,01a
A090,00 ± 0,00b1,13 ± 0,34b0,78 ± 0,08a,b0,25 ± 0,35a
A204,31 ± 2,74a21,93 ± 3,69a0,77 ± 0,07a,b0,46 ± 0,01a
A350,31 ± 0,43b0,89 ± 0,08b0,76 ± 0,02a,b0,24 ± 0,34a
A45A0,00 ± 0,00b0,64 ± 0,01b0,78 ± 0,09a,b0,45 ± 0,03a
A45S0,00 ± 0,00b0,75 ± 0,02b0,73 ± 0,01a,b0,22 ± 0,32a
A45T0,00 ± 0,00b4,36 ± 2,76b1,15 ± 0,33a0,51 ± 0,09a
A480,00 ± 0,00b0,34 ± 0,48b0,71 ± 0,01a,b0,22 ± 0,31a
B520,64 ± 0,02a0,73 ± 0,00a0,23 ± 0,32a
B530,49 ± 0,69a0,76 ± 0,01a0,24 ± 0,33a
B550,71 ± 0,06a0,84 ± 0,14a0,66 ± 0,09a
B610,69 ± 0,01a0,76 ± 0,05a0,51 ± 0,08a
B740,69 ± 0,02a0,74 ± 0,01a0,46 ± 0,02a
MS162,99 ± 0,83a0,00 ± 0,00b0,38 ± 0,55a0,24 ± 0,33a6,28 ± 8,88a
MS410,00 ± 0,00a0,66 ± 0,01a0,75 ± 0,01a0,54 ± 0,09a0,00 ± 0,00a

M is representing Mediterranean, A is Aegean, B is Black Sea, and MS is Marmara Region. The statistical analyses were done within region.
(b)

SampleRutinEllagicIsorhamnetinCatechinCaffeic + chlorogenicp-coumaricFerulicNaringin

M016,38 ± 4,10b6,50 ± 1,62b1,86 ± 0,32a1,15 ± 1,14b2,66 ± 0,23b
M073,93 ± 0,80b1,86 ± 1,86b3,37 ± 2,01a10,18 ± 1,01a37,97 ± 5,67a
M07F59,60 ± 20,79a2,03 ± 2,03b5,29 ± 2,38a27,43 ± 10,52a5,61 ± 1,61b
M320,00 ± 0,00b26,81 ± 0,18a0,00 ± 0,00a0,39 ± 0,39b0,00 ± 0,00b
A09Y0,00 ± 0,00b0,00 ± 0,00b0,00 ± 0,00b1,94 ± 0,33b2,57 ± 0,41b0,00 ± 0,00d
A090,92 ± 0,31a,b3,51 ± 0,50a,b3,42 ± 4,83b3,16 ± 1,19a,b0,00 ± 0,00b0,49 ± 0,69c,d
A200,90 ± 0,27a,b3,95 ± 5,59a,b0,00 ± 0,00b8,42 ± 5,60a29,34 ± 3,06a0,46 ± 0,06a
A350,73 ± 1,03a,b0,00 ± 0,00b84,85 ± 4,04a3,83 ± 0,33a,b0,00 ± 0,00b2,52 ± 1,45b,c,d
A45A0,49 ± 0,69a,b0,00 ± 0,00b0,00 ± 0,00b5,06 ± 0,75a,b0,00 ± 0,00b3,10 ± 0,21b,c
A45S0,00 ± 0,00b0,00 ± 0,00b27,63 ± 13,48b2,53 ± 0,25a,b0,00 ± 0,00b0,00 ± 0,00d
A45T0,98 ± 0,58a,b12,92 ± 13,09a0,00 ± 0,00b3,00 ± 4,24a,b0,99 ± 1,41b0,87 ± 1,23c,d
A481,53 ± 0,52a0,00 ± 0,00b23,70 ± 33,52b2,49 ± 0,69a,b1,21 ± 1,71b5,04 ± 2,45a,b
B521,71 ± 0,35a10,74 ± 1,81a17,49 ± 17,24a3,71 ± 1,64a4,26 ± 2,87a9,84 ± 12,01a
B531,39 ± 0,64a3,94 ± 0,05a,b5,65 ± 8,00a5,02 ± 0,83a3,74 ± 4,80a19,72 ± 11,27a
B554,20 ± 1,25a3,59 ± 5,09a,b15,29 ± 11,32a8,34 ± 0,15a11,27 ± 0,52a20,49 ± 0,93a
B616,43 ± 5,60a1,39 ± 1,97b1,37 ± 1,93a4,16 ± 1,77a3,83 ± 1,05a14,50 ± 4,68a
B744,53 ± 4,48a5,39 ± 1,92a,b0,37 ± 0,52a6,99 ± 6,09a7,06 ± 5,01a10,15 ± 6,11a
MS162,43 ± 2,37a2,01 ± 2,83a5,47 ± 7,74a3,23 ± 0,52a4,23 ± 1,25a13,56 ± 5,64a
MS412,55 ± 3,07a2,03 ± 2,87a10,91 ± 15,43a4,76 ± 1,77a6,05 ± 2,46a17,31 ± 1,79a

M is representing Mediterranean, A is Aegean, B is Black Sea, and MS is Marmara Region. The statistical analyses were done within region.
(a)

SampleGallicSyringicMyricetinQuercetinKaempferolFumaricVanillic

M010,00 ± 0,00a1,15 ± 0,18a,b0,72 ± 0,01a0,24 ± 0,24a6,18 ± 6,18a
M070,00 ± 0,00a0,75 ± 0,08b0,37 ± 0,37a0,38 ± 0,38a11,66 ± 0,99a
M07F2,63 ± 1,94a1,57 ± 0,21a1,02 ± 0,05a0,24 ± 0,24a9,17 ± 1,32a
M320,00 ± 0,00a0,66 ± 0,01b0,76 ± 0,05a0,26 ± 0,26a2,09 ± 2,96a
A09Y0,00 ± 0,00a0,50 ± 0,72b0,36 ± 0,51a0,48 ± 0,05a0,00 ± 0,00b
A090,00 ± 0,00a0,76 ± 0,16b0,75 ± 0,01a0,44 ± 0,01a0,00 ± 0,00b
A201,20 ± 1,69a8,96 ± 11,65a0,77 ± 0,05a0,51 ± 0,05a0,00 ± 0,00b
A352,49 ± 1,22a1,26 ± 0,01b0,78 ± 0,07a0,45 ± 0,01a39,46 ± 18,00a
A45A0,00 ± 0,00a4,61 ± 5,61b0,77 ± 0,05a0,45 ± 0,01a0,00 ± 0,00b
A45S49,28 ± 69,69a1,85 ± 1,10b4,54 ± 5,33a0,31 ± 0,44a0,00 ± 0,00b
A45T0,00 ± 0,00a3,70 ± 2,59b0,79 ± 0,03a0,25 ± 0,35a0,00 ± 0,00b
A480,00 ± 0,00a3,02 ± 2,14b0,73 ± 0,01a0,49 ± 0,04a0,00 ± 0,00b
B520,78 ± 0,14a0,74 ± 0,03a0,63 ± 0,26b
B530,85 ± 0,22a0,77 ± 0,02a0,22 ± 0,32b
B550,76 ± 0,10a0,73 ± 0,01a0,52 ± 0,12b
B610,93 ± 0,40a0,73 ± 0,03a1,21 ± 0,20a
B740,67 ± 0,03a0,74 ± 0,01a0,47 ± 0,39b
MS161,12 ± 1,32a0,32 ± 0,46a0,73 ± 0,01a8,18 ± 0,85a
MS410,00 ± 0,00a0,71 ± 0,07a0,32 ± 0,01b0,00 ± 0,00b

M is representing Mediterranean, A is Aegean, B is Black Sea, and MS is Marmara Region. The statistical analyses were done within region.
(b)

SampleRutinEllagicIsorhamnetinCatechinCaffeic + chlorogenicp-coumaricFerulicNaringin

M0129,62 ± 26,66a2,93 ± 2,92a0,94 ± 0,94a,b25,91 ± 23,73a3,87 ± 2,55a20,82 ± 1,37a,b3,79 ± 0,77b
M077,72 ± 3,17a1,96 ± 1,96a0,00 ± 0,00b0,00 ± 0,00a0,00 ± 0,00a0,00 ± 0,00b8,81 ± 0,25a
M07F6,41 ± 1,66a3,82 ± 0,19a3,14 ± 0,78a17,18 ± 1,75a8,07 ± 1,59a44,50 ± 22,24a6,05 ± 2,29a,b
M3233,65 ± 33,65a0,00 ± 0,00a0,00 ± 0,00b0,00 ± 0,00a0,00 ± 0,00a0,00 ± 0,00b0,00 ± 0,00c
A09Y0,00 ± 0,00b0,00 ± 0,00b0,00 ± 0,00a1,64 ± 0,57b4,44 ± 0,58b0,00 ± 0,00c
A091,20 ± 0,24b1,54 ± 2,17b0,00 ± 0,00a2,41 ± 0,21b0,03 ± 0,05b0,21 ± 0,30c
A201,61 ± 0,15b1,90 ± 2,69b5,81 ± 8,22a0,00 ± 0,00b0,12 ± 0,16b0,00 ± 0,00c
A350,00 ± 0,00b3,62 ± 0,04b46,49 ± 0,10a22,04 ± 6,32a0,00 ± 0,00b12,08 ± 0,24a
A45A0,35 ± 0,50b0,00 ± 0,00b0,00 ± 0,00a2,70 ± 1,65b0,00 ± 0,00b1,27 ± 0,77b,c
A45S3,34 ± 4,72b4,96 ± 7,01b19,39 ± 21,21a7,18 ± 10,16b11,20 ± 15,84a,b3,95 ± 3,38b
A45T19,31 ± 0,14a29,39 ± 1,82a0,00 ± 0,00a1,50 ± 2,13b24,16 ± 11,28b1,62 ± 2,29b,c
A481,76 ± 2,48b2,35 ± 3,33b34,96 ± 49,45a2,79 ± 0,52a,b8,77 ± 0,78a,b1,08 ± 0,63b,c
B523,07 ± 1,85a6,07 ± 3,80a0,51 ± 0,71b6,45 ± 1,79a5,53 ± 0,00a13,04 ± 15,16b
B531,32 ± 0,39a4,06 ± 2,08a11,03 ± 2,51a,b8,88 ± 1,47a2,04 ± 2,88a12,91 ± 0,01b
B550,79 ± 1,12a5,38 ± 2,16a16,91 ± 15,55a,b3,29 ± 0,34a1,66 ± 1,95a16,42 ± 5,41b
B619,32 ± 8,65a7,85 ± 2,38a30,02 ± 7,46a9,69 ± 3,75a5,68 ± 1,37a63,19 ± 8,68a
B749,76 ± 2,49a5,68 ± 2,76a0,00 ± 0,00b3,08 ± 0,77a5,84 ± 1,46a32,00 ± 10,27b
MS162,03 ± 0,75a1,48 ± 0,11a0,86 ± 1,21a7,19 ± 0,22a
MS414,38 ± 3,72a3,78 ± 1,19a0,00 ± 0,00a22,48 ± 12,20a

M is representing Mediterranean, A is Aegean, B is Black Sea and MS is Marmara Region. The statistical analyses were done within Region.
(a)

SampleGallicSyringicMyricetinQuercetinKaempferolFumaricVanillic

M010,00 ± 0,00a1,15 ± 0,33b0,96 ± 0,13b0,61 ± 0,15a26,15 ± 36,98a
M0723,10 ± 32,67a0,75 ± 1,48a,b1,37 ± 0,03a,b0,60 ± 0,01a0,00 ± 0,00a
M07F2,78 ± 3,93a1,57 ± 0,55a1,78 ± 0,17a0,61 ± 0,17a0,42 ± 0,59a
M320,00 ± 0,00a0,65 ± 0,01b1,23 ± 0,50a,b0,49 ± 0,06a0,00 ± 0,00a
A09Y16,20 ± 2,07b0,79 ± 0,22b0,91 ± 0,11a5,96 ± 2,05a0,00 ± 0,00b
A09341,68 ± 21,04a2,08 ± 1,45b1,19 ± 0,42a1,68 ± 0,03b40,68 ± 10,78b
A200,00 ± 0,00b1,91 ± 0,73b3,48 ± 2,30a0,75 ± 0,13b0,00 ± 0,00b
A350,00 ± 0,00b1,67 ± 0,35b1,16 ± 0,16a0,68 ± 0,32b295,21 ± 82,59a
A45A0,00 ± 0,00b1,20 ± 0,33b1,38 ± 0,82a0,93 ± 0,39b0,00 ± 0,00b
A45S0,00 ± 0,00b1,03 ± 0,28b1,38 ± 0,24a2,15 ± 2,16b20,85 ± 4,61b
A45T0,00 ± 0,00b6,39 ± 0,56a2,95 ± 2,23a0,59 ± 0,16b0,00 ± 0,00b
A484,05 ± 5,73b1,12 ± 0,63b1,77 ± 0,12a1,34 ± 1,30b0,00 ± 0,00b
B527,80 ± 2,20a0,82 ± 0,16a1,30 ± 0,27a,b0,97 ± 0,76a
B535,04 ± 7,13a0,91 ± 0,36a1,28 ± 0,15a,b0,74 ± 0,18a
B550,00 ± 0,00a1,26 ± 0,76a1,37 ± 0,43a1,07 ± 0,03a
B615,24 ± 7,42a0,75 ± 0,13a0,85 ± 0,06a,b0,76 ± 0,47a
B747,49 ± 5,46a1,26 ± 0,25a0,79 ± 0,02b1,33 ± 0,27a
MS1648,99 ± 12,66a0,88 ± 0,29a0,96 ± 0,20a0,85 ± 0,32a10,93 ± 10,86a
MS4146,92 ± 5,20a2,18 ± 0,83a0,84 ± 0,15b1,69 ± 1,10a0,00 ± 0,00a

M is representing Mediterranean, A is Aegean, B is Black Sea and MS is Marmara Region. The statistical analyses were done within Region.
(b)

SampleRutinEllagicIsorhamnetinCatechinCaffeic + chlorogenicp-coumaricFerulicNaringin

M0121,85 ± 23,91c4,65 ± 6,57a,b7,00 ± 9,90a60,89 ± 1,87a3,34 ± 0,01b1,66 ± 1,02a7,35 ± 2,78a
M0796,67 ± 10,09b9,62 ± 1,87a,b12,42 ± 17,16a0,00 ± 0,00b1,87 ± 0,44b11,61 ± 16,42a9,41 ± 0,46a
M07F191,07 ± 35,23a15,76 ± 4,11a8,34 ± 11,53a80,38 ± 21,43a9,25 ± 3,72a7,14 ± 2,86a12,79 ± 5,21a
M320,80 ± 0,26c0,00 ± 0,00b0,00 ± 0,00a4,77 ± 6,75b0,00 ± 0,00b0,00 ± 0,00a11,62 ± 0,31a
A09Y2,74 ± 1,14b8,18 ± 11,56b11,37 ± 16,09a,b0,00 ± 0,00b3,42 ± 1,12a8,69 ± 7,73b8,73 ± 4,59b
A0960,74 ± 26,33a29,91 ± 25,44a,b0,00 ± 0,00b61,63 ± 18,81a2,94 ± 0,19a20,36 ± 1,76a34,04 ± 13,58a
A200,97 ± 0,25b5,73 ± 0,47b7,71 ± 0,36a,b26,13 ± 36,96b1,31 ± 1,85a0,23 ± 0,33c0,00 ± 0,00b
A355,78 ± 1,33b17,44 ± 1,97a,b32,81 ± 14,81a0,00 ± 0,00b12,80 ± 18,11a1,06 ± 1,49c24,08 ± 2,37a
A45A0,71 ± 0,49b5,53 ± 1,84b12,45 ± 5,09a,b0,00 ± 0,00b2,25 ± 0,22a0,00 ± 0,00c2,92 ± 0,61b
A45S2,39 ± 1,06b6,06 ± 1,48b24,55 ± 21,45a,b0,00 ± 0,00b0,00 ± 0,00a0,00 ± 0,00c2,68 ± 0,16b
A45T6,64 ± 3,18b42,35 ± 5,88a0,70 ± 0,99b0,00 ± 0,00b4,28 ± 1,42a3,36 ± 1,59b,c6,26 ± 5,57b
A480,84 ± 1,19b11,39 ± 16,11b0,00 ± 0,00b0,00 ± 0,00b4,87 ± 0,14a0,52 ± 0,22c4,77 ± 0,13b
B527,29 ± 4,32a10,73 ± 10,47a46,91 ± 58,43a4,70 ± 1,68a2,54 ± 0,05a4,05 ± 1,03a
B534,01 ± 0,39a,b4,63 ± 1,91a12,56 ± 10,05a4,71 ± 1,51a2,72 ± 3,06a2,85 ± 1,12a
B553,85 ± 0,71a,b9,14 ± 3,29a11,52 ± 11,00a4,12 ± 2,82a3,35 ± 3,77a5,29 ± 2,63a
B610,62 ± 0,88b7,68 ± 3,80a0,00 ± 0,00a4,68 ± 4,75a5,64 ± 5,55a17,15 ± 18,45a
B748,27 ± 1,75a10,21 ± 6,05a10,04 ± 14,20a5,12 ± 0,55a0,28 ± 0,39a9,48 ± 4,41a
MS1620,43 ± 4,91a5,14 ± 1,28a1,54 ± 0,37a2,43 ± 3,43a10,24 ± 0,57a
MS4116,97 ± 2,85a17,78 ± 1,71a1,80 ± 2,54a4,71 ± 2,42a17,65 ± 1,75a

M is representing Mediterranean, A is Aegean, B is Black Sea and MS is Marmara Region. The statistical analyses were done within Region.

According to the result, total phenolic components of nettle samples were considerably high by comparison of other researches. The analysis results have statistical discrepancy between regions, cities, and parts of nettles (root, stalk, and leaves). Nettle parts (root, stalk, and leaves) phenolic content analysis was done qualitative and quantitative by using HPLC-DAD.

According to the results, there were not any gallic acid, syringic, fumaric, vanillic, isorhamnetin, catechin, caffeic, and chlorogenic acid in the root samples from Mediterranean region, but there were myricetin, rutin, ellagic acid, ferulic, and naringin. These standards have statistical discrepancy. There were not any gallic acid, vanillic, and catechin in stalk samples, but there were myricetin, isorhamnetin, ferulic and naringin. These standards have statistical discrepancy. There were not gallic acid, fumaric, and catechin in leaves samples, but there were myricetin, quercetin, rutin, ellagic, caffeic, and chlorogenic acid. These standards have statistical discrepancy.

There were not gallic acid, fumaric, vanillic, catechin, caffeic, and chlorogenic acid in root samples from Aegean region; other standards were found in these samples. There were not gallic acid, fumaric, catechin, caffeic, and chlorogenic acid, but there were syringic, quercetin, kaempferol, and isorhamnetin in stalk samples. There were not gallic acid, fumaric, and catechin, but there were quercetin and p-coumaric acid in leaves samples.

There were not gallic acid, syringic, fumaric, vanillic, catechin, caffeic, and chlorogenic acid, but other standards were found in root samples from Black Sea region. There were not gallic acid, syringic, fumaric, vanillic, catechin, caffeic, and chlorogenic acid in stalk samples, but there were kaempferol, isorhamnetin, and naringin. There were not gallic acid, fumaric, vanillic, catechin, caffeic, and chlorogenic acid in leaves samples, but there was statistical discrepancy in quercetin and fumaric acid.

There were not gallic acid, vanillic, catechin, caffeic, and chlorogenic acid in Marmara region root samples, but other standards were found. There were not gallic acid, kaempferol, vanillic, catechin, ellagic, isorhamnetin, caffeic, and chlorogenic acid in stalk samples, but other standards were found. There were not gallic acid, vanillic, isorhamnetin, catechin, caffeic, and chlorogenic acid in leaves samples, but other standards were found.

By comparison of root samples, p-coumaric, kaempferol, and quercetin have not statistical discrepancy. On the other hand, there were no gallic acid, fumaric, vanillic, catechin, caffeic, and chlorogenic acid. By comparison of stalk samples, syringic, myricetin, quercetin, kaempferol, and rutin have not statistical discrepancy. On the other hand, there were not gallic acid, vanillic acid, catechin, caffeic, and chlorogenic acid. By comparison of leaves samples, p-coumaric, isorhamnetin, and quercetin have not statistical discrepancy. On the other hand, there were not gallic acid, fumaric acid, and catechin.

In a research about cultivated and wild nettle samples phenolic profile and HPLC analysis, caffeic acid derivative, chlorogenic acid, 2-O-caffeoylmalic acid, rutin, quercetin 3-O-glucoside, kaempferol 3-O-rutinoside, and isorhamnetin 3-O-rutinoside were found in cultivated leaves samples. Caffeic acid derivative, p-coumaric acid, caffeoylquinic acid, chlorogenic acid, rutin, quercetin 3-O-glucoside, kaempferol 3-O-rutinoside, and isorhamnetin 3-O-rutinoside, peonidin 3-O-rutinoside, peonidin 3-O-(6′′-O-p-coumaroylglucoside), and rosinidin 3-O-rutinoside were found in cultivated stalk samples. Caffeic acid derivative, p-coumaric acid, chlorogenic acid, 2-O-caffeoylmalic acid, rutin, quercetin 3-O-glucoside, kaempferol 3-O-rutinoside, isorhamnetin 3-O-rutinoside were found in wild leaves samples. Finally, caffeic acid derivative, p-coumaric acid, caffeoylquinic acid, chlorogenic acid, rutin, quercetin 3-O-glucoside, kaempferol 3-O-rutinoside, isorhamnetin 3-O-rutinoside, peonidin 3-O-rutinoside, rosinidin 3-O-rutinoside were found in wild stalk samples [28]. According to our results, there were not any gallic acid, vanillic, and catechin in stalk samples, but there were myricetin, isorhamnetin, ferulic, and naringin in the stalk samples from Mediterranean region. There were not gallic acid, fumaric, catechin, caffeic, and chlorogenic acid, but there were syringic, quercetin, kaempferol, and isorhamnetin in stalk samples from Agean region. There were not gallic acid, syringic, fumaric, vanillic, catechin, caffeic, and chlorogenic acid in stalk samples from Black Sea region, but there were kaempferol, isorhamnetin, and naringin. There were not gallic acid, kaempferol, vanillic, catechin, ellagic, isorhamnetin, caffeic, and chlorogenic acid in stalk samples from Marmara region, but other standards were found. There were not gallic acid, fumaric, and catechin, but there were myricetin, quercetin, rutin, ellagic, caffeic, and chlorogenic acid in leaves samples from Mediterranean region. There were not gallic acid, fumaric, and catechin, but there were quercetin, and p-coumaric acid in leaves samples from Agean region. There were not gallic acid, fumaric, vanillic, catechin, caffeic, and chlorogenic acid in leaves samples from Black Sea region, but there was statistical discrepancy in quercetin, and fumaric acid. There were not gallic acid, vanillic, isorhamnetin, catechin, caffeic, and chlorogenic acid in leaves samples from Marmara region, but other standards were found.

In another research, some kinds of plants HPLC-MS analysis were done. One of these plants was nettle, and according to the results nettles included 18 ppm quercetin, 13 ppm myricetin, and 7,7 ppm kaempferol [29]. In comparison to our study, root, stalk, and leaves parts of nettle have lower phenolics components than those in this study, as seen in Tables 1 and 2.

4. Conclusions

Nettle is a plant easy to grow. Nettle is rich of chemical component and composition. It is as widely used from cosmetics to food. It is widely used plant in complementary and alternative treatment method (CTM and ATM) as cancer, and so forth. It is thought that nettle has these positive properties as its phenolic contents. Also, these plant parts (root, stalk, and leaves) have different phenolic composition and contents. The nettle part content differences indicate that different parts could be used for different cancers in ATM. Because of that reason, the phenolic compounds and contents of nettle parts were tried to identify. By this way, different kinds of phenolic components of nettles part (root, stalk, and leaves) indicate different usage area to the plant parts. Phenolic content analyses were done by using nettle parts (root, stalk and leaves) and the nettles were collected from different regions of Turkey (Aegean, Black Sea, Mediterranean, Marmara), according to these properties of nettle.

Nettle prefers nutrient riches and lighted places, hot and mild climate. Therefore, the higher total phenolic contents and antioxidant activities of nettles and roots of nettles were found in Marmara and Black Sea region in this research, while the higher moisture contents of nettles, roots, and stalks of nettles were found in Aegean and Mediterranean region. The higher moisture contents of leaves were found in Aegean and Black Sea region. The higher total phenolic contents of stalk samples was found in Black Sea and Mediterranean region, while the higher total antioxidant activities of stalk samples were found in Marmara and Black Sea region. The higher total phenolic contents of leaves samples were found in Marmara and Aegean region, while the higher total antioxidant activity of leaves samples were found in Marmara and Mediterranean region. According to analysis results, nettles phenolic compounds and contents were different between regions and parts of nettles. The difference between parts of nettle shows that all the parts of nettle could have different usages. In comparison of nettle tea and dried nettle from other researches, fresh samples phenolic contents were higher than others. For that reason, fresh nettle consumption could be healthier.

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Copyright © 2012 Semih Otles and Buket Yalcin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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