Content uploaded by Jinous Asgarpanah
Author content
All content in this area was uploaded by Jinous Asgarpanah
Content may be subject to copyright.
Journal of Medicinal Plants Research Vol. 6(46), pp. 5714-5719, 3 December, 2012
Available online at http://www.academicjournals.org/JMPR
DOI: 10.5897/JMPR12.540
ISSN 1996-0875 ©2012 Academic Journals
Review
Phytochemistry and pharmacologic properties of Urtica
dioica L.
Jinous Asgarpanah* and Razieh Mohajerani
Department of Pharmacognosy, Pharmaceutical Sciences Branch, Islamic Azad University (IAU), Tehran, Iran.
Accepted 10 July, 2012
Urtica dioica is known as Stinging Nettle. U. dioica extracts are important areas in drug development
with numerous pharmacological activities in many countries. For a long time U. dioica has been used in
alternative medicine, food, paint, fiber, manure and cosmetics. U. dioica has recently been shown to
have antibacterial, antioxidant, analgesic, anti-inflammatory, antiviral, anti-colitis, anticancer and anti-
Alzheimer activities. Flavonoids, tanins, scopoletin, sterols, fatty acids, polysaccharides, isolectins and
sterols are phytochemicals which are reported from this plant. Due to the easy collection of the plant
and being widespread and also remarkable biological activities, this plant has become both medicine
and food in many countries especially in Mediterranean region. This paper presents comprehensive
analyzed information on the botanical, chemical and pharmacological aspects of U. dioica.
Key words: Urtica dioica, Urticaceae, pharmacology, phytochemistry.
INTRODUCTION
Urtica dioica L. commonly known as Stinging Nettle is an
herbaceous perennial plant that grows in temperate and
tropical wasteland areas around the world (Krystofova et
al., 2010). Stinging Nettle has been among the key plants
of the European pharmacopoeia since ancient times. It
belongs to Urticaceae family in the order of Rosales that
contains about 60 genera and more than 700 species. U.
dioica has been known as “Gazaneh” in Iran and
distributed in North, North-West and central parts of Iran.
U. dioica is a dioecious herbaceous perennial, reaches to
1-2 m high (Figure 1). It has widely spreading rhizomes
and stolons, which are bright yellow as are the perennial
roots (Figure 2). The soft green leaves are 3-15 cm long
and are borne oppositely on an erect wiry green stem.
The leaves have a strongly serrated margin, a cordate
base and an acuminate tip with a terminal leaf tooth
longer than adjacent laterals (Figure 3). It bears small
greenish or brownish numerous flowers in dense axillary
inflorescences (Figure 4). The male flowers have stamens
only, and the female ones have only pistil or seed-
producing organs. Usually a plant will bear either male or
female flowers throughout (Zargari, 1998). The leaves and
*Corresponding author. E-mail: asgarpanah@iaups.ac.ir. Tel:
22640051. Fax: 22602059.
stems are very hairy with non-stinging hairs and also
bear many stinging hairs or trichomes (Figure 5), whose
tips come off when touched, transforming the hair into a
needle that will inject several chemicals including
acetylcholine, histamine, 5-HT (serotonin), moroidin,
leukotrienes and possibly formic acid (Casarett et al.,
2008; Greenberg, 2003). After contacting human skin, the
irritant is released and produces pain, wheals or a
stinging sensation which may last for even more than 12
h (Oliver et al., 1991). The burning property of the juice is
dissipated by heat, enabling the young shoots of the
Nettle, when boiled, to be eaten as a pot-herb.
For a long time, in folklore medicine, U. dioica has been
used as a diuretic agent and to treat arthritis and
rheumatism. Nowadays it is an important medical herb
and consumed as a component of the human diet due to
its content of minerals, chlorophyll, amino acids, lecithin,
carotenoids and vitamins. A number of chemical
constituents such as flavonoids, tanins and sterols have
been isolated from different parts of the plant (Krystofova
et al., 2010).
From current pharmaceutical studies, additional
pharmaceutical applications of U. dioica have revealed
antioxidant (Mavi et al., 2004), anti-inflammatory, anti-
ulcer (Gulcin et al., 2004), antiviral (Krystofova et al.,
2010), anticancer (Koch, 2001), antibacterial, antifungal
(Meepagala et al., 2005), antiandrogenic (Khouri and El-
Figure 1. Urtica dioica L. (Stinging nettle).
Figure 2. Urtica dioica roots.
Akawi, 2005), insecticide (Barbosa et al., 2011), effects
among others.
Since review and systemic analysis of chemistry,
pharmacology and clinical properties of U. dioica have
not been reported, we prompted to provide the currently
available information on traditional and local knowledge,
ethno biological and ethno medicinal issues, identification
of pharmacologically important molecules and pharma-
cological studies on this useful plant. The aim of this
Asgarpanah and Mohajerani. 5715
Figure 3. U. dioica leaf.
Figure 4. U. dioica flowers.
paper is to introduce U. dioica as a potent medicinal plant
by highlighting its traditional applications as well as the
recent findings for novel pharmacological and clinical
applications.
CHEMICAL COMPOSITION
The commonly known phytochemical compounds from U.
dioica are flavonoids, tanins, volatile compounds and
sterols (Krystofova et al., 2010; Gul et al., 2005).
Three smooth-muscle stimulating substances including
acetylcholine, histamine, and 5-hydroxytryptamine (5-HT)
have been identified in U. dioica (Collier and Chesher,
1956). Formic acid, histamine and serotonin are also
identified as the pain-inducing agents in the stinging hairs
of U. dioica (Fu et al., 2006). Carvacrol (38.2%), carvone
(9.0%), naphthalene (8.9%), (E)-anethol (4.7%), hexa-
hydrofarnesyl acetone (3.0%), (E)-geranyl acetone
(2.9%), (E)-β-ionone (2.8%) and phytol (2.7%) are
characterized as the main components of U. dioica
essential oil (Gul et al., 2005).
5716 J. Med. Plants Res.
Figure 5. U. dioica trichomes.
Rhizomes of U. dioica contain other biological active
compounds such as scopoletin, sterols, fatty acids,
polysaccharides and isolectins (Krystofova et al., 2010).
These rhizomes contain a complex mixture of agglutinin
isolectins which are differ definitely with respect to their
amino acid composition. It is likely that at least some of
them are different polypeptides coded for by different
genes (Van Damme et al., 1988).
ANTI-INFLAMMATORY AND ANALGESIC PROPERTIES
Although a number of steroidal or non-steroidal anti-
inflammatory drugs have been developed, researchers
are changing their focus to natural products to develop
new anti-inflammatory agents due to the side-effects of
chemical drugs (Hyun and Kim, 2009; Shokrzadeh and
Saeedi Sarvari, 2009). As a result, the search for other
alternatives seems necessary and beneficial. U. dioica is
an open door for new and effective compounds. Many
cells and mediators are involved in proceeding inflame-
mation. For example, macrophages are representative
inflammatory cells involved in acute or chronic
inflammatory responses by over-production of pro-
inflammatory cytokines [for example, tumor necrosis
factor (TNF)-a, interleukin (IL)-1b and granulocyte/
macrophage colony stimulating factor (GMCSF)] and
inflammatory mediators (Rhee et al., 2009; Lundberg,
2003; Walsh, 2003). U. dioica sting seems a safe
treatment for musculoskeletal pain. It contains serotonin
and histamine that are involved in the cascade of
stimulation affecting levels of nerve growth factor which in
turn increases activation of nociceptive pain neurons
(McMahon, 1996). The mechanism of this plant analgesia
could be hyper stimulation of the sensory nociceptors
causing a TENS-like effect (Melzack and Wall, 1965), a
substance P depletion effect similar to that of capsaicin
(Frucht-Pery et al., 1997), an acupuncture-like effect
(Lewith and Kenyon, 1984), or a counter irritant effect
(Turner, 1984). A stinging rash might also have a power-
ful effect on patients cognitive perception of pain
(Weisenberg, 1998).
Leaf extracts from U. dioica acts by switching Th1
derived responses to Th2; therefore it may inhibit
inflammatory events of rheumatoid arthritis (Riehemann
et al., 1999). The combination of 50 mg U. dioica with 50
mg diclofenac showed similar effectiveness to 200 mg
diclofenac and this is important for patients suffering from
non steroidal anti-inflammatory drugs (Chrubasik et al.,
1997).
Type 2 diabetes is a metabolic disorder that is strongly
associated with cardiovascular risk. Inflammation is a
potential risk factor for cardiovascular disease. Hydro
alcoholic extract of U. dioica has also shown effective-
ness on some inflammatory indicators in type 2 diabetic
patients. Patients were adjusted by age, sex and duration
of diabetes, then randomly divided into two groups, an
intervention and control group. They received, 100 mg kg
-
1
nettle extract or placebo in three portions a day for 8
weeks. Interleukin 6 (IL-6) and High Sensitive C-Reactive
protein (hs-CRP) showed a significant decrease in
patients with type 2 diabetes after eight weeks inter-
vention (Namazi et al., 2007).
Phytalgic®
Phytalgic® consists of capsules containing fish oils, U.
dioica, zinc, and vitamin E. The medicinal treatment of
osteoarthritis (OA) is mostly symptomatic to relieve pain
and incapacity with analgesics and non-steroidal anti-
inflammatory drugs (NSAIDs), drugs with well-known
risks. Complementary medicines might reduce the
symptoms of OA and decrease the need for NSAIDs. A
randomized double-blind parallel-groups clinical trial
compared Phytalgic® to a placebo for three months, in 81
patients with OA of the knee or hip using NSAIDs and/or
analgesics regularly. The food supplement tested appeared
to decrease the need for analgesics and NSAIDs and
improve the symptoms of osteoarthritis. The effect size
(ES) of this supplement for pain reduction was -1.27,
which corresponds to a very large ES and indicated that
Phytalgic® is 76% more efficacious than intra-articular
corticosteroid therapy for knee OA (Zhang et al., 2007).
Osteoarthritis experts who endorse nutraceuticals would
probably agree that a nutraceutical with an ES above 0.5
is rarely seen and it has never been seen anything as
efficacious as Phytalgic® (Bliddal and Christensen, 2009).
HEPATOPROTECTIVE PROPERTIES
U. dioica has a protective effect on hepatic damage created
with ischemia-reperfusion. Since U. dioica is known to be
a strong antioxidant, breaking up free radicals, it is
expected to be protective in hepatic ischemia-reperfusion
injury of rats. U. dioica exhibited liver protection effect by
increasing the activity of paraoxonase, arylesterase, and
liver tissue catalase activity. Treatment with U. dioica
reduced oxidative stress resulting in a decrease in
ceruloplasmin levels. Also, it was found that treatment
with U. dioica decreased the lipid hydroperoxide activity,
indicating that the antioxidant effect of U. dioica had
prevented the emergence of an oxidant agent such as
LOOH with creation of hepatic ischemia-reperfusion
(Kandis et al., 2010).
A histopathological examination detected no
pathological changes. Also, evaluation of liver enzymes
and histopathological findings of liver tissue indicated that
UD had beneficial effects on the liver, so UD can be
considered a preventive treatment agent in hepatic
ischemia-reperfusion injury (Kandis et al., 2010).
U. dioica extract has shown hypocholesterolemic
effects in animal models at doses of 100 and 300 mg/kg
and significantly reduced the levels of total cholesterol
and LDL and also markedly decreased liver enzymes and
weight in animals with a high cholesterol diet (Nassiri-Asl
et al., 2009).
U. dioica treatment for 60 days has exhibited significant
reduction in liver enzyme levels and also has increased
the reduced antioxidant enzyme levels in CCl4-treated
rats (Kanter et al., 2005). U. dioica has also shown a
protective effect against oxidative damage in isolated rat
hepatocytes (Daba and Abdel-Rahman, 1998). It was
found that the fixed oil of this plant has both antioxidant
and anti-eicosanoid effects greater than thymoquinone
which is its active constituent (Houghton et al., 1995).
Furthermore, U. dioica has antioxidant activity by
suppressing the chemiluminescence in phagocytes (Haq
et al., 1995). Recently, it is observed that U. dioica has a
significant hepatoprotective effect in CCl4-administrated
rabbits, and that hepatocellular degenerative and necrotic
changes are slight without advanced fibrosis and cirrhotic
process (Turkdogan et al., 2003). However, it is found
that U. dioica can prevent liver fibrosis and cirrhosis,
suggesting that this plant protects liver against fibrosis
possibly through immunomodulator and antioxidant
activities (Turkdogan et al., 2001). U. dioica extract pre-
vented CCl4-induced hepatotoxicity in rats by decreasing
the lipid peroxidation and increasing the antioxidant
defense system activity (Kanter et al., 2005).
U. dioica leaves extract (100 mg/kg/day for 5 days)
before inducing diabetes in rats could prevent reduction
of hepatocyte area in the periportal zone and increase in
the nucleus area in the perivenous zone in the protective
group.
Since the U. dioica extract has antioxidant properties, it
can possibly affect the mechanisms of STZ and modulate
or limit the effects of diabetes on the liver tissue
(Golalipour et al., 2010).
Asgarpanah and Mohajerani. 5717
ANTIVIRAL ACTIVITY
Mannose-binding proteins derived from several plants
inhibit human immunodeficiency virus (HIV) replication
and select for drug-resistant viruses that show profound
deletion of N-glycosylation sites in the GP120 envelope.
The N-acetylglucosamine-binding protein from U. dioica
(UDA) prevented HIV entry and eventually selected for
viruses in which conserved N-glycosylation sites in
GP120 were deleted. In contrast to the mannose-binding
proteins, which have a 50 to 100-fold decreased antiviral
activity against the UDA-exposed mutant viruses, UDA
has decreased anti-HIV activity to a very limited extent,
even against those mutant virus strains that lack at least
9 of 22 glycosylation sites in their GP120 envelope. UDA
represents the prototype of a new conceptual class of
carbohydrate-binding agents with an unusually specific
and targeted drug resistance profile. It forces HIV to
escape drug pressure by deleting the indispensable
glycans on its GP120 (Balzarini et al., 2005).
U. dioica EFFECTS ON BPH
Effects of U. dioica on benign prostatic hyperplasia (BPH)
induced by testosterone have been exhibited. In vitro
studies were conducted to assess the 5α-reductase
inhibitory potential of this plant. Hyperplasia was induced
in rats by subcutaneous administration of testosterone (3
mg/kg sc.) for 28 days. Simultaneous administration of
petroleum ether and ethanolic extracts (10, 20 and 50
mg/kg po.) and isolated β-sitosterol (10 and 20 mg/kg
po.) was undertaken. Measurement of prostate/body
weight ratio, weekly urine output and serum testosterone
levels, prostate-specific antigen levels (on day 28) and
histological examinations carried out led to conclude that
U. dioica can be used as an effective drug for the
management of BPH. These effects are related to two
biochemical markers, β-sitosterol and scopoletin (Nahata
and Dixit, 2002).
U. dioica EFFECTS ON PROSTATIC CANCER
Various extracts of U. dioica were commonly used in the
treatment of prostatic disease. Some extracts from U.
dioica roots were demonstrated to exert proliferation-
reducing effects in an in vivo animal model. It has been
observed that some sterols and hydroxyl fatty acids, even
they exist at low concentrations in this plant can inhibit
aromatase, which is a key enzyme in steroid hormone-
metabolism mediation the conversion of androgens into
estrogens. The aqueous extract of U. dioica roots
demonstrated a dose dependent inhibition of the binding
globulin to its receptor and directly inhibits cell
proliferation of HeLa cells and block binding of epidermal
growth factor to its receptor. The aqueous extract of U.
5718 J. Med. Plants Res.
dioica leaves also caused significant inhibition on ADA
activities in prostate tissues from prostate cancer patients
(Durak et al., 2004).
Cisplatin (CP) is a widely used cytotoxic agent against
cancer, and high doses of CP have been known to cause
nephrotoxicity and hepatotoxicity. The hepatoprotective,
nephroprotective, and antioxidant activities of U. dioica
methanolic extract against CP toxicity in Erhlich ascites
tumor-bearing mice have been demonstrated. After a
single dose of CP administration on day 1, the extract
was given at the doses of 50, 100, 200, and 400 mg/kg
body weight daily during 6 days. Almost all doses of the
extract performed a significant preventive role against CP
toxicity by decreasing aspartate aminotransferase,
alanine aminotransferase, lactate dehydrogenase, blood
urea nitrogen, creatinine, lipid peroxidation, protein
oxidation levels, and myeloperoxidase activity, as well as
increasing reduced glutathione content, superoxide
dismutase, catalase, glutathione S-transferase, and
glutathione peroxidase activities. This suggests that
methanolic extract of this plant has a protective capacity
and antioxidant activity against CP toxicity in EAT-
bearing mice, probably by promoting antioxidative
defense systems (Ozkol et al., 2000).
CONCLUSION
The objective of this paper has been to show the recent
advances in the exploration of U. dioica as phytotherapy
and to illustrate its potential as a therapeutic agent. With
the current information, it is evident that U. dioica has
pharmacological functions including anti-inflammatory,
analgesic, antiandrogenic, antihyperglycemia, anti-
hyperlipidemia, antiviral and anticancer activities, among
others. As the current information shows, it is also
possible that Scopoletin, polysaccharides, isolectins and
sterols might be useful in the development of new drugs
to treat various diseases. However, the present results
suggest a possibility that scopoletin, polysaccharides and
isolectins can be further developed as potential disease-
curing remedy. It must be kept in mind that clinicians
should remain cautious until more definitive studies
demonstrate the safety, quality and efficacy of U. dioica.
For these reasons, extensive pharmacological and
chemical experiments, together with human metabolism
will be a focus for future studies. Last but not the least,
this article emphasizes the potential of U. dioica to be
employed in new therapeutic drugs and provide the basis
for future research on the application of transitional
medicinal plants.
REFERENCES
Balzarini J, Van Laethem K, Hatse S, Froeyen M, Peumans W, Van
Damme E, Schols D (2005). Carbohydrate-binding agents cause
deletions of highly conserved glycosylation sites in HIV GP120. J.
Biol. Chem. 280(49):41005-41014.
Bliddal H, Christensen R (2009). The treatment and prevention of knee
osteoarthritis: a tool for clinical decision-making. Exp. Opin
Pharmacother. 10:1793-1804.
Casarett LJ, Klaassen CD, Doull J (2008). Casarett and Doull's
toxicology: the basic science of poisons. McGraw-Hill Professional:
p.1104.
Chrubasik S, Enderlein W, Bauer R, Grabner W (1997). Evidence for
anti-rheumatic effectiveness of herba Urtica dioica in acute arthritis: a
pilot study. Phytomed., 4:105-108.
Collier HOJ, Chesher GB (1956). Identification of 5-hydroxytryptamine
in the stinging nettle (Urtica dioica). Brit. J. Pharmacol. 11:186.
Daba MH, Abdel-Rahman MS (1998). Hepatoprotective activity of
thymoquinone in isolated rat hepatocytes. Toxicol. Lett. 95:23-29.
Durak I, Biri H, Devrim E, Sozen S, Avci A (2004). Aqueous extract of
Urtica dioica makes significan inhibition adenosine deaminase activity
in prostate tissue from patients with prostate cancer. Cancer Biol.
Ther. 3(9):855-857.
Frucht-Pery J, Feldman ST, Brown SI (1997). The use of capsaicin in
herpes zoster ophtalmicus neuralgia. Acta. Ophthalmol. Scand.
5:311-313.
Fu HY, Chen SJ, Chen RF, Ding WH, Kuo-Huang LL, Huang RN
(2006). Identification of oxalic acid and tartaric acid as major
persistent pain-inducing toxins in the stinging hairs of the nettle,
Urtica thunbergiana. Ann. Bot. 98:57-65.
Golalipour MJ, Ghafari S, Afshar M (2010). Protective role of Urtica
dioica L. (Urticaceae) extract on hepatocytes morphometric changes
in STZ diabetic Wistar rats. Turk. J. Gastroenterol. 21(3):262-269.
Greenberg MI (2003). Occupational, industrial, and environmental
toxicology. Elsevier Health Sci. p.180.
Gul S, Demirci B, Başer KH, Akpulat HA, Aksu P (2005). Chemical
composition and in vitro cytotoxic, genotoxic effects of essential oil
from Urtica dioica L. Biol. Pharm. Bull. 18(5):523-527.
Gulcin I, Küfrevioglu OI, Oktay M, Büyükokuroglu ME (2004).
Antioxidant, antimicrobial, antiulcer and analgesic activities of nettle
(Urtica dioica L.). J. Ethnopharmacol. 90:205-215.
Haq A, Abdullatif M, Lobo PI, Khabar KS, Sheth KV, Al-Sedairy ST
(1995). Nigella sativa: effect on human lymphocytes and
polymorphonuclear leukocyte phagocytic activity. Immunopharmacol.
30:147-155.
Houghton PJ, Zarka R, de las Heras B, Hoult JR (1995). Fixed oil of
Nigella sativa and derived thymoquinone inhibit eicosanoid
generation in leukocytes and membrane lipid peroxidation. Planta
Med. 61:33-36.
Hyun TK, Kim JS (2009). The pharmacology and clinical properties of
Kalopanax pictus. J. Med. Plants. Res. 3(9):613-620.
Kandis H, Karapolat S, Yildirim U, Saritas A, Gezer S, Memisogullari R
(2010). Effects of Urtica dioica on hepatic ischemia-reperfusion injury
in rats. Clinics 65(12):1357-1361.
Kanter M, Coskun O, Budancamanak M (2005). Hepatoprotective
effects of Nigella sativa L and Urtica dioica L on lipid peroxidation,
antioxidant enzyme systems and liver enzymes in carbon
tetrachloride-treated rats. World J. Gastroenterol. 11(42):6684-6688.
Koch E (2001). Extracts from fruits of saw palmetto (Sabal serrulata)
and roots of stinging nettle (Urtica dioica): Viable alternatives in the
medical treatment of benign prostatic hyperplasia and associated
lower urinary tracts symptoms. Planta Med. 67:489-500.
Krystofova O, Adam V, Babula P, Zehnalek J, Beklova M, Havel L,
Kizek R (2010). Effects of various doses of selenite on stinging nettle
(Urtica dioica L.). Int. J. Environ. Res. Public Health 7:3804-3815.
Lewith GT, Kenyon JN (1984). Physiological and psychological
explanations for the mechanism of acupuncture as a treatment for
chronic pain. Soc. Sci. Med. 19:1367-1378.
Lundberg IE (2003). Clinical symptoms in patients with myositis- an
acquired metabolic myopathy idiopathy inflammation myopathies:
Why do the muscles become weak? Curr. Opin. Rheumatol. 15:675-
678.
Mavi A, Terzi Z, Ozgen U, Yildirim A, Coskun M (2004). Antioxidant
properties of some medicinal plants: Prangos ferulacea (Apiaceae),
Sedum sempervivoides (Crassulaceae), Malva neglecta (Malvaceae),
Cruciata taurica (Rubiaceae), Rosa pimpinellifolia (Rosaceae),
Galium verum subsp. verum (Rubiaceae), Urtica dioica (Urticaceae).
Biol. Pharm. Bull. 27(5):702-705.
McMahon SB (1996). NGF as a mediator of inflammatory pain. Phil.
Trans R. Soc. B. 351:431-440.
Melzack R, Wall PD (1965). Pain mechanisms: a new theory. Sci.
150:971.
Nahata A, Dixit VK (2002). Ameliorative effects of stinging nettle (Urtica
dioica) on testosterone-induced prostatic hyperplasia in rats. Biol.
Pharm. Bull. 11(6):30-35.
Namazi N, Esfanjani AT, Heshmati J, Bahrami A (2007). The effect of
hydro alcoholic Nettle (Urtica dioica) extracts on insulin sensitivity
and some inflammatory indicators in patients with type 2 diabetes: a
randomized double-blind control trial. Biol. Pharm. Bull. 14(3):70-75.
Nassiri-Asl M, Zamansoltani F, Abbasi E, Daneshi MM, Zangivand AA
(2009). Effects of Urtica dioica extract on lipid profile in
hypercholesterolemic rats. J. Chinese Integ. Med. 7(5):428-433.
Oliver F, Amon EU, Breathnach A, Francis DM, Sarathchandra P,
Kobza Black A, Greaves MW (1991). Contact urticaria due to the
common stinging nettle (Urtica dioica)-histological, ultrastructural and
pharmacological studies. Clin. Exp. Dermatol. 16:1-7.
Ozkol H, Musa D, Tuluce Y, Koyuncu I (2000). Ameliorative influence of
Urtica dioica L against cisplatin-induced toxicity in mice bearing
Ehrlich ascites carcinoma. Cancer Biol. Ther. 7(3):65-69.
Rhee MH, Park HJ, Cho JY (2009). Salicornia herbaceae: Botanical,
Chemical and pharmacological review of halophyte marsh plant. J.
Med. Plants Res. 3(8):548-555.
Riehemann K, Behnke B, Schulze-Osthoff K (1999). Plant extracts from
stinging nettle (Urtica dioica L.), an anti-rheumatic remedy, inhibit the
pro-inflammatory transcription factor NF-Kappa B. Febs. Lett. 442:89-
94.
Shokrzadeh M, Saeedi SSS (2009). Chemistry, Pharmacoligy and
clinical properties of Sambucus ebulus: A review. J. Med. Plants.
Res. 4(2):95-103.
Turkdogan MK, Agaoglu Z, Yener Z, Sekeroglu R, Akkan HA, Avci ME
(2001). The role of antioxidant vitamins (C and E), selenium and
Nigella sativa in the prevention of liver fibrosis and cirrhosis in
rabbits: new hopes. Dtsch. Tierarztl Wochenschr 108:71-73.
Asgarpanah and Mohajerani. 5719
Turkdogan MK, Ozbek H, Yener Z, Tuncer I, Uygan I, Ceylan E (2003).
The role of Urtica dioica and Nigella sativa in the prevention of
carbon tetrachloride-induced hepatotoxicity in rats. Phytother. Res.
17:942-946.
Turner NJ (1984). Counter-irritant and other medicinal uses of plants in
Ranunculaceae by native people in British Columbia and neighboring
areas. J. Ethnopharmacol. 11:181-201.
Van Damme EJM, Broekaert WF, Peumans WYJ (1988). The Urtica
dioica Agglutinin Is a Complex Mixture of Isolectins. Plant Physiol. 86:
598-601.
Walsh LJ (2003). Mast cells and oral inflammation. Crit. Rev. Oral Biol.
Med. 14:188-198.
Weisenberg M (1998). Cognitive aspects of pain and pain control. Int. J.
Clin. Exp. Hypnosis 46:44-61.
Zargari A (1988). Medicinal plants. Vol 2. Tehran University Press, Iran:
42.
Zhang W, Moskowitz RW, Nuki G, Abramson S, Altman RD, Arden N,
Bierma-Zeinstra S, Brandt KD, Croft P, Doherty M, Dougados M,
Hochberg M, Hunter DJ, Kwoh K, Lohmander LS, Tugwell P (2007).
OARSI recommendations for the management of hip and knee
osteoarthritis, Part I: Critical appraisal of existing treatment guidelines
and systematic review of current research evidence. Osteoarthritis
Cartilage 15:981-1000.
