Evaluation of in vitro and in vivo Biological Activities of Cheilanthes albomarginata Clarke
© Lamichhane et al.; licensee BioMed Central Ltd. 2014
Received: 20 January 2014
Accepted: 16 September 2014
Published: 20 September 2014
The Cheilanthes albomarginata Clarke (CA), a fern belonging to Pteridaceae family, is found mainly in India, Nepal, Pakistan and Bhutan at an altitude of 1300–2700 m. It grows mostly in the rock crevices on slopes. Juice from the rhizome of CA has been used to treat peptic ulcer. In this study, the biological activities (antioxidant, anti-inflammatory, anti-adipogenic and anti-obesity) of the extracts of CA were investigated. The total phenolic content of each extract was quantified. This is the first report regarding the study of biological activities on CA.
In the current study, the crude methanol and fractionated extract of the aerial part of CA were investigated for the antioxidant tests which were namely DPPH assay, hydrogen peroxide scavenging assay and nitrite scavenging assay. Their phenolic contents were measured by the Folin-Ciocalteu’s method.
In vitro anti-inflammatory and anti-adipogenic assays were evaluated against the RAW 264.7 macrophage cells and 3 T3-L1 cells respectively. The crude methanol extract and phenolic fraction (combination of ethyl acetate and butanol fraction) were studied for the in vivo anti-obesity test using male Sprague Dawley rats.
The ethyl acetate fraction showed the strongest DPPH radical scavenging (82.54 ± 0.48%), hydrogen peroxide scavenging (3.41 ± 0.21 mg/ml) and nitrite scavenging activity (61.39%). The highest phenolic content was found in the ethyl acetate fraction followed by the butanol fraction. The ethyl acetate fraction showed the highest in vitro anti-inflammatory and anti-adipogenic activities. From the in vivo study on rats, the crude methanol extract and phenolic fraction showed plasma triglyceride lowering activity as well as reduction of weight of adipose tissue in high fat diet induced obese rats.
The current study suggests that the ethyl acetate and butanol extracts of CA are potential source for antioxidant, anti-inflammatory and anti-adipogenic remedies. In addition to that the results of in vivo studies evidenced the possibility of CA as a source of anti-obesity drug remedies.
KeywordsCheilanthes albomarginata Antioxidant Phenolic content Anti-inflammation Anti-adipogenic
The importance of medicinal plants to the human livelihood is unexplainable. Medicinal plants are the fundamental necessities to human health care needs since the beginning of human civilization. Nepal is blessed with rich and diverse plant biodiversity. It is extremely rich in floral diversity in proportion to its size due to its wide altitude variation (60–8848 m) . A total of 5,856 species of flowering plants, 28 species of gymnosperms, 853 species of bryophytes and 380 species of pteridophytes have been recorded from Nepal [2, 3].
Pteridophytes, which occupy the unique position between non-seed bearing and seed bearing plants make an important contribution to earth’s plant diversity. Pteridophytes are known to man for more than 2000 years for their medicinal values. Pteridophytes are used in Homeopathic, Ayurvedic and Unani medicines and provide insecticides, antibiotics, food and ornamentation . It has been reported that Cheilanthes farinosa (Forsk) Kaulf, a fern which is used to treat skin disorders also possessed strong anti-inflammatory and anti-nociceptive properties . Radhika NK et al. found the plant C. farinosa to produce considerable cytotoxic in hepatoma cell line, Hep 3B without inducing substantial damage to non-cancerous cell line RAW 264.7 . Similarly different biological activities have been reported from the fern.
This study is an investigation of biological activities of the fern Cheilanthes albomarginata Clarke (CA). CA belonging to the family Pteridaceae, grows in rock crevices on slopes at an altitude of 1300 – 2700 m. It is found mainly in India, Nepal, Pakistan and Bhutan . Rhizome of CA bears tufts of hair and pointed scales. Stipes can grow up to 25 cm long. The leaves are glabrous, reddish brown, shiny, and furnished particularly below when young.
It has lanceolate white margined scales. Fronds may be bipinnatisect to bipinnate, deltoid to deltoid lanceolate covered with white waxy powder. CA is a type of farinose fern as it contains white or yellow coating on the lower surface of the leaf . Flavonoids like Apigenin 7-methyl ether (genkwanin), rhamnocitrin and kumatakenin have been isolated from CA .
Traditionally, juice and paste from the CA rhizome are used to treat peptic ulcer, stomach disorders and external cuts and wounds . In a study done by Ghimire et al., the “tharu community” of Nepal was found to use the pounded juice of rhizome and the root from CA as a remedy for peptic ulcers . The aqueous and ethanol extract of CA has antibacterial activity against Agrobacterium tumefaciens, Escherichia coli, Salmonella arizonae and Staphylococcus aureus.
Reactive oxygen species (ROS) such as hydroxyl (OH.) and peroxyl radical (ROO.) and the superoxide anion (O2 .) are constantly produced as a result of metabolic reaction in living systems . At low or moderate concentration, ROS exert beneficial effects on cellular responses and immune function but at high levels, free radicals and oxidants generates oxidative stress, a deleterious process that can damage cell structure, including lipids, proteins, and DNA . Most living organisms possess efficient enzymatic and non-enzymatic defense systems against excess production of ROS. However, different external factors (smoke, diet, alcohol, some drugs), and aging decrease the capability of such protecting systems, resulting in disturbances of the redox equilibrium that is established in healthy conditions. Therefore, antioxidants that scavenge ROS may be of great value in preventing the onset and/or the progression of oxidative diseases .
Inflammation is the reactive state of hyperemia and exudation from blood vessels with consequent redness, heat, swelling and pain in which a tissue manifests a response to physical or chemical injury or bacterial invasion . Several medicinal plant species are commonly used in traditional medicine as anti-inflammatory remedies. A number of anti-inflammatory constituents have been isolated and characterized structurally and pharmacologically from different medicinal plants .
Obesity, which is a strong risk factor for the development of chronic diseases such as type-II diabetes and cardiovascular disease, is characterized by an increase in the number and size of adipocytes differentiated from precursor cells, pre-adipocytes. Recent researches suggest that the accumulated fat in obesity also leads to increased ROS production resulting in systemic oxidative stress, and also contributing to obesity linked chronic diseases . A high fat diet (HFD) increases the release of TNF-α from the gut, alters mucosal immunity, activates mast cells, increases vascular permeability, and disrupts the intestinal basement membranes. HFD promotes inflammation and obesity by interacting with and altering gut microbiota composition . Inhibition of adipocytes differentiation is suggested to be an important strategy for prevention and/or treatment of obesity .
To the best of our knowledge, there has been no works related to antioxidant, anti-inflammatory, anti-adipogenic, and anti-obesity studies of CA. The promising antioxidant activity of the plant guided us to evaluate the anti-inflammatory and anti-adipogenic activity. The supportive in vitro results led us to investigate the in vivo study. So, the main objective of this study is to explore the biological activities of CA.
Aerial parts of CA were collected in Kaski district, Nepal, during June/July 2011 and identified by Dr. Radhe Shyam Kayastha, PhD., Tribhuvan University, Nepal. The voucher specimens (332) were deposited in the Pharmacognosy Laboratory of Pokhara University, Lekhnath Municipality-12, Kaski, Nepal.
Reagents and chemicals
Solvents including methanol, ethyl acetate (EtOAc), n-butanol (BuOH), and chloroform (CHCl3) were purchased from SK chemicals (Seongnam, Korea) and were of analytical grade. 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), Dimethyl sulfoxide (DMSO) were purchased from Junsei chemicals (Tokyo, Japan), Sulfanilic acid, N-(1-napthyl) ethylenediamine dihydrochloride, Folin Ciocalteu reagent, Gallic acid and ascorbic acid from Sigma Chemical Co. (St. Louis, MO), and Hydrogen peroxide from Daejung Chemicals (Daejung, Korea).
Cell culture and bioassay reagents
RAW 264.7 cells and 3 T3-L1 cells were purchased from the American Type Culture Collection (ATCC, Rockville, MD). Dulbecco’s modification of Eagle’s medium (DMEM) was purchased from Gibco® by Life Technologies Co. (Carlsbad, CA) and Fetal bovine serum (FBS) from Hyclone (Logan, UT). Assay kits of total cholesterol, triglyceride, HDL-cholesterol, Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Glutamic pyruvate transaminase (GPT), Gamma-glutamyl transferase (γ-GTP), Blood urea nitrogen (BUN), and Creatinine were purchased from Asan Pharm Co., Ltd (Whasung, Korea). (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Dexamethasone (DEX), insulin, 1-methyl-3-isobutylxanthine (IBMX), Nicotinamide adenine dinucleotide phosphate (NADPH), Oil red O, Xanthine oxidase, and Hydrogen peroxide were purchased from Sigma Chemical Co. (St. Louis, MO).
Extraction and fractionation
The aerial parts of the plant CA were collected and shade dried at room temperature for one week. After cutting them into smaller sizes, hot extraction was carried using methanol at 50°C in Wonkwang University, Korea. The extracts were filtered through Whatman no. 1 filter paper and concentrated using rotatory evaporator. The crude dried methanol extract was suspended in water and subjected to fractionation using chloroform, ethyl acetate and butanol to obtain chloroform, ethyl acetate, butanol, and water fractions.
Total polyphenol content
Total polyphenolic compounds were determined with Folin-Ciocaltue reagent according to the standard method of Singleton and Rossi with some modification . The content of total phenolic compounds in CA extract was determined as milligram of Gallic acid equivalent (GAE).
where, C = Absorbance of the control and T = Absorbance of the test sample
The IC50 value was determined by interpolation form the non-linear regression of plot of percentage of inhibition against the concentration of extracts, which is defined as the amount of extract needed to scavenge 50% of DPPH radicals.
Hydrogen peroxide scavenging assay
The ability of different extracts to scavenge the hydroxyl radicals (OH . ) was measured according to the method of Muller .
Nitrite scavenging assay
The nitrite scavenging activity of the extracts was evaluated by the method of Kato et al. . NaNO2 solution was used for the production of nitrate radical.
Cell culture and viability
The RAW 264.7 murine macrophages were maintained at sub-confluence in a 95% air and 5% CO2 humidified atmosphere at 37°C. DMEM medium supplemented with 10% fetal bovine serum (FBS) was used for routine sub-culturing and in vitro experiments.
3 T3-L1 pre-adipocytes maintained in DMEM with 10% bovine calf serum at 37°C in a humidified atmosphere of 5% CO2. After 2 days of 100% confluence (Day 0), adipocyte differentiation was induced by differentiation/induction medium (DMII) containing 0.5 mM IBMX, 1 μM Dexamethasone, and 10 μg/ml insulin in DMEM containing 10% FBS. Two days after the initiation of differentiation (Day 2), the culture medium was replaced with DMEM supplemented with only 10 μg/ml insulin and 10% FBS. After that the medium was replenished every 2 days (Day 4, Day 6, and Day 8) with 10% FBS in DMEM. To examine the effects of CA extracts on differentiation of pre-adipocytes to adipocytes, cells were differentiated with differentiation media containing various concentrations of the plant extract. Cell viability was determined colorimetrically using an MTT assay.
Oil red O staining
Oil red O staining was used to monitor lipid accumulation in differentiated adipocytes. On day 8, cells were stained with Oil red O. The cells were fixed with 10% formalin for 30 min. After that the formalin was removed and washed with 60% isopropanol. Then the lipid droplets were stained for at least 30 min at room temperature in a freshly diluted Oil Red O solution [0.5% Oil Red O solution in 60:40 (v/v) isopropanol:water]. After Oil Red O stain, cells were photographed using a phase-contrast microscope (Olympus CK, Tokyo, Japan) in combination of digital camera at 100 × magnifications. Finally, the dye retained in the 3 T3-L1 cells was eluted with isopropanol and quantified by measuring the absorbance at 510 nm.
In vitro anti-inflammatory activity
RAW 264.7 cells were plated in a 24 well plate at a density of 106 cells/mL, 500 μL in each well. Then after 24 hr incubation, the medium was changed and the samples (extracts of CA) were added. After 1 hr. of sample treatment LPS (final concentration: 1 μg/ml) was added to both extracts treated as well as untreated wells. Amount of nitrite produced were measured using Griess reagent (1% sulfanilamide and 0.1% napthylethylenediamine dihhydorchloride in 2.5% phosphoric acid). 100 μL of cell culture medium was mixed with 100 μL of Griess reagent. Subsequently, the mixture was incubated at room temperature for 10 min and the absorbance at 540 nm was measured in a microplate reader. Fresh culture media was used as a blank.
In vivo assay
Preparation of samples
Crude methanol extract and phenolic fraction (mixture of butanol and ethyl acetate fraction in equal ratio of weight) were taken to prepare samples for the in vivo assay. The in vitro study evidenced the comparable activity for the butanol and ethyl acetate fraction. In addition, the TLC patterns for both fractions were similar. So we tried to see the in vivo effect of the combination of the two higher phenolic compound containing extracts. Required amount of extracts were weighed and suspended in PBS and homogenized using a homogenizer. The dose fed orally to each rat was 200 mg/kg per day.
Animals and experiment design
Normal diet (ND) or Normal group
High fat diet (HFD) or Control group
HFD-M group- high fat diet supplemented with MeOH extract
HFD-P group- high fat diet supplemented with phenolic fraction.
Body weights were recorded weekly. The amount of food intake was measured in every three days.
Biochemical analysis on blood and evaluation of organ weight
After 8 weeks, all rats were fasted for 12 hr. prior to sacrifice. After the fasting, each rat was deeply anesthetized by an overdose of carbon dioxide and the blood was drawn from the posterior vana cava. The serum was separated by centrifuge and stored at −80°C until analysis. The fat (epididymal and retroperitoneal), liver, spleen and kidney were removed. Their weights were taken immediately and stored at - 70°C.
Total cholesterol (TC) and triglycerides (TG) content were determined with assay kit (AM 202-K, AM 157S-K Asan Pharm Co., Ltd, Whasung, Korea) according to the protocol obtained from manufacturer. High density lipoprotein cholesterol (HDL-C) content was analyzed with assay kit (AM 203-K, Asan Pharm Co., Ltd, Whasung, Korea). Liver function test was determined with commercial assay kits of Catalase (CAT), GPx (glutathione peroxidase) (Asan Pharm Co., Ltd, Whasung, Korea). Superoxide dismutase (SOD) activity was assessed according to the modified method of Oyanagui .
Protein determination and statistical analysis
Protein quantification was measured by Lowry’s method with bovine serum albumin (BSA) as a standard . All data are presented as mean ± SD of triplicate experiments. Statistical analysis was carried out by SPSS statistics 19 software (IBM Co., Armonk, NY) measured by one-way analysis of variance (ANOVA) using Duncan’s multiple range test. P values considered significance at the level of less than 0.05%.
Results and discussion
Total polyphenol content
Total phenolic contents of crude methanol extract and other fractions of CA
Total phenolic content (GAE)
51.2 ± 0.23
37.42 ± 0.25
216.08 ± 1.30
93.15 ± 0.58
24.78 ± 0.10
Determination of DPPH radical scavenging activity
DPPH radical assay of crude methanol extract and other fractions of CA
19.55 ± 2.83bc
38.0 ± 6.03d
16.33 ± 0.48b
24.66 ± 1.35bc
27.80 ± 3.52c
5.36 ± 0.27a
Hydrogen peroxide scavenging activity
Hydrogen peroxide is an intermediate during endogenous oxidative metabolism and mediates radical oxygen formation such as •HO, which may be used to predict the scavenging capability of antioxidants in biological systems .
Hydrogen peroxide scavenging assay of the crude methanol extract and other fractions of CA
21.65 ± 1.73b
46.56 ± 4.81c
3.41 ± 0.21a
6.73 ± 0.20a
28.38 ± 2.20b
1.32 ± 0.07a
Nitric oxide (NO) scavenging assay
Effects of CA on cell viability
Inhibition of NO production in RAW 264.7 cells
Effect of CA extracts on adipocyte differentiation
In vivo assay (Animal experiment)
Body weight, food intake and food efficiency ratio
The effect of extracts on the body weight, weight gain, food intake and feed efficiency body weight gain = final body weight - initial body weight
Food intake (g/day)
Initial body weight (g)
Final body weight (g)
Body weight gain(g)
Feed efficiency ratio (FER)
16.21 ± 3.62a
129.73 ± 3.22a
342.32 ± 8.51a
212.72 ± 6.42b
0.17 ± 3.62
15.53 ± 1.21b
131.31 ± 4.12ab
378.72 ± 10.03b
248.31 ± 12.71b
0.28 ± 1.23
14.95 ± 1.82b
126.15 ± 6.74b
306.37 ± 31.56bc
180.25 ± 24.81bc
0.21 ± 1.84
15.64 ± 1.61b
119.25 ± 2.31c
322.62 ± 38.45c
203.37 ± 36.14c
0.23 ± 1.61
Assessment of potential toxicological effects
To evaluate potential toxic effect of extracts, serum toxicological markers, which indicate liver and kidney injury, were measured at the end of the experimental period. The levels of GPT, AST, ALT, blood nitrogen urea and creatinine were not significantly changed in extract treated rats compared to HFD fed rats. Additionally, the extract treated rats did not induce significant changes in the weight of liver and spleen (data not shown). This indicates that oral administration of 200 mg/kg/day of the extracts for 8 weeks induced no detectable adverse toxic effects in rats.
Weight of adipose tissue and serum lipids
Effect on activity of hepatic enzymes
The plant CA has been traditionally used as remedies for peptic ulcer, cuts, wounds and stomach problems. This present study was designed to examine antioxidant, anti-inflammatory, and in vivo anti-obesity activity.
The polyphenol content assay of CA extracts was followed by the antioxidant activity test. The EtOAc fraction, which was found to contain the highest polyphenol content, also showed the highest antioxidant, anti-inflammatory and anti-adipogenic activity as well. The in vitro activity of BuOH fraction was comparable to EtOAc fraction. The good in vitro antioxidant, anti-inflammatory and anti-adipogenic activity of CA guided us to evaluate the in vivo anti-obesity activity, since oxidative stress and inflammation are the important factors for inducing and promoting obesity [12, 17]. As there was comparable activity for the EtOAc and BuOH fractions, we prepared a phenolic extract sample (mixing EtOAc and BuOH fraction in equal ratio by weight), for the in vivo study.
It has been well known that the size of adipose tissue increases during obesity due to the accumulation of fats in the adipose tissue . Our in vitro experiment showed the decrease in accumulation of fat droplets in 3 T3 L1 adipocytes when the cells were treated with CA extracts. Further the in vivo study revealed reduction in body weight, adipose tissue mass, TG and TC when the extracts of CA were supplemented with HFD. This indicates the anti-obesity activity of CA extract.
The literature survey showed very few number of research works about the anti-obesity activity on fern. So this study has played an important role to get an idea about anti-obesity activity of fern.
From the overall results we can conclude that the plant CA has antioxidant, anti-inflammatory and anti-obesity activity. So, further investigation and research work can play an important role to develop this plant as a remedy for the treatment of diseases associated with oxidative stress, inflammation and obesity.
This research was supported through Basic Science Research Program by the National Research Foundation of Korea (NRF-2010-0024284), under Science and Technology, Ministry of Education.
- Kindlemann P: Himalayan Biodiversity in the Changing World. 1998, New York: SpringerGoogle Scholar
- Iwatsuki K: An Enumeration of the Pteridophyte of Nepal. 1988, Tokyo: University of Tokyo PressGoogle Scholar
- Pradhan N, Joshi SD: A diversity account of BRYACEAE (Bryophyte: MUSCI) of Nepal. J Nat Hist Mus. 2008, 23: 19-26.Google Scholar
- Hynniewta SR, Kumar Y: Herbal remedies among the Khasi traditional healers and village folks in Meghalaya. Indian J Tradit Knowl. 2008, 7: 581-586.Google Scholar
- Yonathan M, Asres K, Assefa A, Bucar F: In vivo anti-inflammatory and anti-nociceptive activities of Cheilanthes farinosa. J Ethnopharmacol. 2006, 108: 462-470. 10.1016/j.jep.2006.06.006.View ArticlePubMedGoogle Scholar
- Radhika NK, Sreejith PS, Asha VV: Cytotoxic and apoptotic activity of Cheilanthes farinosa (Forsk.) Kaulf. against human hepatoma, Hep3B cells. J Ethnopharmacol. 2010, 128: 166-171. 10.1016/j.jep.2010.01.002.View ArticlePubMedGoogle Scholar
- Wu Z, Peter RH, Hong D: Flora of China. 2013, Beijing: Science PressGoogle Scholar
- Wollenweber E, Schneider H: Lipophilic exudates of Pteridaceae - chemistry and chemotaxonomy. Biochem Syst Ecol. 2000, 28: 751-777. 10.1016/S0305-1978(99)00118-0.View ArticlePubMedGoogle Scholar
- Eckhard W: Flavonoid exudations in Farionse Ferns. Phytochemistry. 1976, 15: 2013-10.1016/S0031-9422(00)88885-8.View ArticleGoogle Scholar
- Manandhar NP: Plants and People of Nepal. 2002, USA: Timber PressGoogle Scholar
- Ghimire K, Bastakoti RR: Ethnomedicinal knowledge and healthcare practice of Nawalparasi district in central Nepal. For Ecol Manag. 2009, 257: 2066-2072. 10.1016/j.foreco.2009.01.039.View ArticleGoogle Scholar
- Parihar P, Parihar L, Bohra A: In vitro antibacterial activity of fronds (leaves) of some important pteridophytes. J Microbiol Antimicrob. 2010, 2: 19-22.Google Scholar
- Wang H, Nair MG, Strasburg GM, Chang YC, Booren AM, Gray JI, Deitt DL: Antioxidant and anti-inflammatory activities of anthocyanins and theri aglycon, cyanidin, from tart cherries. J Nat Prod. 1999, 62: 294-296. 10.1021/np980501m.View ArticlePubMedGoogle Scholar
- Lee OH, Kwon YI, Apostolidis E, Shetty K, Kim YC: Rhodiola-induced inhibition of adipogenesis involves antioxidation enzyme response associated with penstose phosphate pathway. Phytother Res. 2010, 25: 106-115.View ArticleGoogle Scholar
- Ebrahimzadeh MA, Nabavi SM, Navavi SF, Bahramian F, Bekhrandia AR: 2010. Antioxidant and free radical scavenging activity of H. officinalis L. Var. Angustifolius, V. odorata, B. Hyracana and C. speciosum. Pak J Pharm Sci. 2010, 23: 29-34.PubMedGoogle Scholar
- Pietta P, Simonetti P, Mauri P: Antioxidant activity of selected medicinal plants. J Agric Food Chem. 1998, 46: 4487-4490. 10.1021/jf980310p.View ArticleGoogle Scholar
- Lee C: The effect of high-fat diet-induced pathophysiological changes in the gut on obesity: what should be the ideal treatment?. Clin Transl Gastroenterol. 2013, 4: 1-8.Google Scholar
- Khan RA, Khan MT, Sahreen S, Ahmed M: Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill. Chem Cen J. 2012, 6: 3-7. 10.1186/1752-153X-6-3.View ArticleGoogle Scholar
- Singleton VL, Rossi JA: Clolrimetry of total phenolics with phosphomolybdic-phosphotungstic and reagents. Am J Enol Vitic. 1965, 16: 144-158.Google Scholar
- Hazra B, Sarkar R, Biswas S, Mandal N: Comparative study of the antioxidant and reactive oxygen species scavenging properties in the extract of the fruits of Terminalia chebula, Terminalia Belerica and Embilica officinalis. BMC Complement Alter Med. 2010, 10: 2-35. 10.1186/1472-6882-10-2.View ArticleGoogle Scholar
- Muller H: Detection of hydrogen peroxide produces by microorganisms on an ABTS peroxidase medium. Zentralbl Bakteriol Mikrobiol Hyg A. 1985, 259: 151-158.PubMedGoogle Scholar
- Kato H, Lee IE, Chuyen NV, Kim SB, Hayase F: Inhibition of nitrosamine formation by nondialzable melanidines. Agric Biol Chem. 1987, 51: 1333-1338. 10.1271/bbb1961.51.1333.Google Scholar
- Oyanagui Y: Reevaluation of assay methods and establishmednt of kit for superoxide dismutase activity. Anal Biochem. 1984, 142: 290-296. 10.1016/0003-2697(84)90467-6.View ArticlePubMedGoogle Scholar
- Lowry O, Rosebrough N, Farr A, Randall R: Protein measurement with folin phenol reagent. J Biol Chem. 1951, 193: 265-275.PubMedGoogle Scholar
- Evans CR, Miller N, Pagana G: Antioxidant properties of Phenolic compounds. Trends Plant Sci. 1997, 2: 152-159. 10.1016/S1360-1385(97)01018-2.View ArticleGoogle Scholar
- Proestos C, Boziaris IS, Nychas GJE, Komaitis M: Analysis of flavonoids and phenolic acids in Greek aromatic plants: Investigation of their antioxidant capacity and antimicrobial activity. Food Chem. 2006, 4: 664-671.View ArticleGoogle Scholar
- Lai HY, Lim YY: Evaluation of antioxidant activities of the methanolic extracts of selected ferns in Malaysia. Int J Environ Sci Dev. 2011, 2: 442-447.View ArticleGoogle Scholar
- Prior RL, Wu X, Schaich K: Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. J Agric Food Chem. 2005, 53: 4290-4302. 10.1021/jf0502698.View ArticlePubMedGoogle Scholar
- Juntachote T, Gerghofer E: Antioxidative properties and stability of ethanolic extracts of Holy basil and Galangal. Food Chem. 2005, 92: 193-202. 10.1016/j.foodchem.2004.04.044.View ArticleGoogle Scholar
- Nabavi SM, Ebrahimzadeh MA, Nabavi SF, Hamidinia A, Bekhradnia AR: Determination of antioxidant activity, phenol and flavonoids content of Parrotia persica Mey. Pharmacologyonline. 2008, 2: 560-567.Google Scholar
- Hagerman AE, Riedl KM, Jones GA, Sovik KN, Ritchard NT, Hartzfeld PW: High molecular weight plant polyphenolics (tannins) as biological antioxidants. J Argic Food Chem. 1998, 46: 1887-1892. 10.1021/jf970975b.View ArticleGoogle Scholar
- Sueishi Y, Hori M, Kita M, Kotake Y: Nitric oxide (NO) scavenging capacity of natural antioxidants. Food Chem. 2011, 129: 866-870. 10.1016/j.foodchem.2011.05.036.View ArticlePubMedGoogle Scholar
- Susan TGL, Jay ZL: Evaluation of the role of xanthine oxidase in myocardial reperfusion injury. J Biol Chem. 1990, 265: 6656-6663.Google Scholar
- Andrew SG, Martin SO: Obesity and the role of adipose tissue in inflammation and metabolism. Am J Clin Nutr. 2006, 83: 461S-465S.Google Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6882/14/342/prepub
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