Plant Part Used
Flowering buds
Active Constituents
Napthodianthrones (hypericin, pseudohypericin protohypericin, protopseudohypericin), flavonoids (including rutin, quercitrin(37), isoferulic acid, hyperoside, quercitin, isoquercitrin, hyperoside, astilbin, miquelianin, I3,II8-biapigenin (38)), phloroglucinols (hyperforin and adhyperforin (38)), melatonin(1),(2) and phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid).(38) [span class=alert]
This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]
Introduction
St. John’s wort has gained a great deal of attention for its use in minor depression. Its popularity has stemmed from its extensive use by physicians in Europe as an agent of choice in the treatment of mild to moderate depression. There are a variety of studies which are claimed to support the use of St. John’s wort in treating mild to moderate depression. (3) , (4) , (5) Also, sales of this herb in Europe, based on physician recommendation, outperform the popular pharmaceutical fluoxetine (Prozac). It is reported that during the floral bud stage of St. John’s wort, the concentration of napthodianthrone compounds is at the highest. (39)
Results from two independent randomized controlled trials have indicated that St. John’s wort is no more beneficial than placebo in individuals with major depression. However, one of these trials used sertraline (50 to 100 mg/day) as an active control and found no significant superiority of sertraline over placebo in this patient population as well. Though these two trials may indicate that St. John’s wort is not effective for major depression, they neither confirm nor deny the use of St. John’s wort in mild to moderate depression.(6) , (7) More recent meta-analysis support the use of St. John’s wort for use in mild to moderate depression.(40) , (41)
Interactions and Depletions
Interactions
- Antidepressants
- reserpine
- digoxin
- theophylline
- Immunosuppressive medications
- Oral contraceptives
- Barbiturates
- Anesthesic agents
- Protease inhibitors
- Drugs metabolized by the cytochrome P-450 pathway
- Hormone replacement therapy (HRT)
- warfarin
- 5-hydroxytryptophan (5-HTP)
Dosage Info
Dosage Range
900mg (standardized extract) daily, in divided doses. (Some individuals may experience benefit with as little as 300-600mg daily.) Higher doses are used in viral infections, and should only be performed under the supervision of a doctor.
Topically: Apply oil extract as needed to affected area(s).
Liquid Extract: 1:1 in 25% ethanol – 2-4 milliliters, 3 times a day. (8)
Tincture: (1:10) in 45% ethanol – 2-4 milliliters, 3 times a day. (9)
Most Common Dosage
300mg (standardized extract), 3 times a day.
Topically: Apply oil extract as needed to affected area(s).
Liquid Extract: 1:1 in 25% ethanol – 2 milliliters, 3 times a day.
Tincture: (1:10) in 45% ethanol – 2 milliliters, 3 times a day.
Standardization
[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]
The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 0.3-0.5% hypericin and/or 3-5% hyperforin per dose.
Uses
Frequently Reported Uses
- Antiviral.
- Depression
- SAD (Seasonal Affective Disorder)
Other Reported Uses
- Myalgia
- Neuralgia
- Fear
- Genitourinary
- Externally For Bruises, Sprains (Leaf)
- HIV And Retroviruses
- Nervous Symptoms Associated With Menopause And PMS
- Wound Healing
- Diuretic
- Antibiotic
- Nootropic
Toxicities & Precautions
General
Although no real evidence has been presented to support it, there is theoretically a potential for an interaction with tyramine-containing foods, so these foods should be avoided. (10)
Based on evidence that St. John’s wort may cause changes in the need for certain medications, do not use St. John’s wort supplements if you are taking prescription and/or OTC medications without the advice of your doctor or pharmacist.
Allergy
Allergic reactions have occurred in a small percentage of individuals who use St. John’s wort.
Health Conditions
Should not be taken in suicidal depression, psychosis or severe depression.
St. John’s wort has affected the metabolism of certain medications via alteration of P-glycoprotein and cytochrome P-450 3A4 expression. Changes in cyclosporine levels have been confirmed. Based on human data, do not use St. John’s wort in transplant patients. Complications as well as transplant rejection have occurred with the use of this herb. (11) , (12)
Photosensitivity
Based on pharmacology, animal data and human data, may cause photosensitivity. (13)
May cause photosensitivity in high doses such as those used by the AIDS population. (14)
Side Effects
Fatigue and GI distress may occur in about 0.5 percent of the individuals who take St. John’s wort.
Based on animal studies, it may induce liver enzymes in large doses, but these return to normal with discontinuation. (15)
217 out of 440 patients treated with St. John’ s wort for one year were reported to have adverse events, including gastrointestinal (abdominal pain or gastritis) and skin (rash or pruritus) being the most common. (42)
A study conducted on rats and human using electric field stimulation test reported that St, John’s wort inhibits the contraction of vas deferens that indirectly delays ejaculation function, potentially due to the hyperforin constituent content. (43)
Pregnancy/ Breast Feeding
Based on animal studies, do not use in pregnancy. (16) , (17)
Age Limitations
Do not use in children under 2 years of age unless recommended by a physician.
Pharmacology
St. John’s wort is a perennial flowering plant, which grows in many areas of the world, including Europe and the United States. The parts of the plant used are the portions above the ground. Studies with St. John’s wort have centered around the use of a 0.3 percent hypericin content standardized extract at a dose of 300mg, three times a day. It is viewed as safe and effective in Europe and its monograph is part of the Commission E Monographs for herbal medicines in Europe.
St. John’s wort is believed to have several possible effects on body chemistry. These include:
- The inhibition of cortisol secretion and the blocking of catabolic hormones, such as interleukin 6 (IL-6). (18)
The inhibition of the breakdown of several central nervous system neurotransmitters, including serotonin. It may have mild MAO-inhibiting activity. This has not been clearly defined and cannot explain all the activity of St. John’s wort. Researchers do not consider this to be its major mechanism of action. (19) , (20) , (21) A laboratory study in mice reported that St.John’s wort increased sleeping duration and increased open arm entries indicating sedating and anxiolytic effect. (44) In addition, St. John’s wort has inhibitory ability of acetylcholinesterase although not as potent as Hypericum androsaemum. (45)
St. John’s wort may amplify and improve the signal produced by serotonin once it binds to its receptor sites in the brain. (22) , (23) A study reported that when the efficacy of St.John’s wort was compared with selective serotonin reuptake inhibitor (SSRI) for the treatment of major depressive disorder, both showed similar and positive results with St. John’s wort having a lower withdrawal adverse events. (46)
St. John’s wort contains the chemical melatonin (approximately 4.39 mcg/gm), which may also contribute to the antidepressant effects of the plant. (24) Pseudo-hypericin and hyperforin may enhance serotonin, catecholamines, and glutamine levels in the brain.
A study on the relationship between nicotine withdrawal from smoking cessation with the antidepressant effect from St. John wort’s reported significant results in the increase of serotonin content in St. John’s wort treated mice having nicotine withdrawal. (47) However, large doses of St. John wort’s should be used with caution since studies have reported that when rats are treated with 200mg/kg for 3 days, prepulse inhibition occurs causing problems in managing memory process disturbances.(48)
A human trial reported improvement in symptoms of attention-deficit hyperactive disorder (ADHD) when using St. John’s wort, as found when testing with Conners’ hyperactivity.(49)
Additionally, Hypericum has been used as an antiviral agent, including HIV. (26) It has been reported that, in sufficient blood levels, it may decrease HIV titer and it may increase T-killer cell activity. (27) Hypericum and the xanthrones are thought to be responsible for the antiviral activity. (28) Although its antiviral action has been questioned, several studies report this potential action. (29) , (30) The drawback is that large doses must be taken and this is where side effects related to St. John’s wort (such as phototoxicity) can occur. However, if compared with pure hypericin, administrating St. John’s wort which contained the same compound will cause lesser skin photosensitization reactions. (50) A recent study has reported no positive effect when using St. John’s wort as an antiretroviral agent. (31) If an individual is taking protease inhibitor medications do not use St. Johns wort as a therapy for HIV due to changes in liver metabolism of these agents.(32) Also, since anti-retroviral agents are hepatically metabolized, use extreme caution when taking these medications and St. John’s wort. Use only under the direction of a physician. A study reported that when tested on pigs infected with porcine respiratory and reproductive syndrome virus, the St. John’s wort is effective in reducing the virus in the blood stream but not significant in playing a role in reducing the virus in the lungs.(51) In addition, St. John’s wort plays a role as an anti-hepatitis B agent as studies report that it is able inhibit viral antigens by affecting the transcription of hepatitis-B virus.(52)
Although St John’s wort is reported to have antimicrobial activity as well, it is the least potent among other plant extracts when tested on antimicrobial assay.(53)
Recent literature has reported cytochrome P-450 enzyme-inducing activity of St. John’s wort in human studies. Interactions between St. John’s wort and anticoagulants, indinavir, cyclosporin, digoxin, ethinyloestradiol/desogestrel and theophylline have occurred.(33) The mechanism of action was believed to be liver enzyme induction and subsequent alterations of drug levels by the herb. Also, several reports have suggested that concurrent use of St. John’s wort and SSRIs may result in “serotonin syndrome,” including sweating, tremor, confusion, flushing and agitation.(34),(35) Use St. John’s wort with caution if individuals are on these medications. However, interaction between bromocriptine and St. John’s wort reported to have synergistic effect in treating MPTP- induced Parkinson’s disease by improving movement performance, reducing dopamine level and decreasing corpus striatum antioxidant level.(54)
St. John’s wort has also been used topically to increase wound and burn healing, as well as for myalgia and neuralgia.(36) It is reported that the healing effect is due to the ability of the herb to activate and also produce fibroblast cells and collagen which has the same potency as Centella asiatica plant. (55) Another study further supports the wound-healing ability by showing tissue regenerating, improved tensile strength and epithelization due to the anti-inflammatory hyperforin component. (56) A laboratory study reported that this anti-inflammatory effect was due to two pathway mechanism identified as JAK-STAT pathway and eicosanoid pathway, which reduced prostaglandin-E2 production. (57) The use of St. John’s wort in pain management is reported to be effective in the treatment of dental pain when homeopathic Hypericum perforatum was the preferred remedy for pain, including post extraction pain and swelling. (58)
When acute inflammation is induced with carrageenan in the lungs of mice, St. John’s wort was found to reduce the tissue injury by playing a role in the neutrophils and proinflammatory cytokines as well as up-regulation of poly(ADP) ribose and activation of redox-sensitive transcription factor and other transcription factors like STAT-3. (59) This is further supported by another animal study whereby multiple organ dysfunction induced by oxidative stress in mice was reduced by St John’s wort due to its ability to reduce inducible nitric oxide synthase which subsequently prevent formation of nitric oxide. (60) In addition, the ability of St. John wort’s to reduce oxidative stress is reported in a study whereby the flavanoid constituent of the herb is able to inhibit peroxyl radicals induced by AAPH (inductor of lipid peroxidation). (61) An animal study reported that St John’s wort have the potential to protect liver injury (ischemia reperfusion) in rats treated with the herb for a week due to its antioxidant effect. (62)
St. John’s wort extract is reported to be effective in causing apoptosis towards bladder cancer cells when used in photodynamic therapy due to its ability as a photosensitizer. (63)
A laboratory animal study found that ingestion of St. John’s wort by 20 rabbits as diet regime for 45 days followed by regular diet and St. John’s wort for 30 reduced cholesterol levels, leading to a decrease in the progression of atherosclerosis. (64)
The therapeutic ability of St. John’s wort to reduce sensitivity to pain stimuli was reported when administered to rats with thermal-induced and chemical-induced pain. (65) Hypericin and hyperforin are the main constituents responsible for increasing the pain threshold. St. John’s wort has been used in dressing wounds, along with soluble collagen and gotu kola.
References
- Derbentseva NA, et al. Action of Tannins from Hypericum perforatum L. on the Influenza Virus. Mikrobiol Zh. 1972;34(6):768-72.
- View Abstract: Wagner H, et al. Pharmaceutical Quality of Hypericum Extracts. J Geriatric Psychiatry and Neurology. Oct1994;7(Supp 1):S65-68.
- View Abstract: Volz HP. Controlled Clinical Trials of Hypericum Extracts in Depressed Patients–An Overview. Pharmacopsychiatry. 1997;30(Suppl 2):72-76.
- View Abstract: Muller WE, et al. Effects of Hypericum Extract (LI 160) in Biochemical Models of Antidepressant Activity. Pharmacopsychiatry. 1997;30(Supp 2):102-07.
- View Abstract: Linde K, et al. St. John’s Wort for Depression–An Overview and Meta-analysis of Randomised Clinical Trials. BMJ. 1996;313m:253-58.
- View Abstract: Hypericum Depression Trial Study Group. Effect of Hypericum perforatum (St John’s Wort) in Major Depressive Disorder: A Randomized Controlled Trial. JAMA. Apr2002;287(14):1807-1814.
- View Abstract: Shelton RC, Keller MB, Gelenberg A, Dunner DL, Hirschfeld R, Thase ME, et al. Effectiveness of St John’s wort in major depression: a randomized controlled trial. JAMA. Apr2001;285(15):1978-86.
- PDR for Herbal Medicines, 2nd edition. Montvale, NJ: Medical Economics Company; 2000:722.
- PDR for Herbal Medicines, 2nd edition. Montvale, NJ: Medical Economics Company; 2000:722.
- View Abstract: Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med. Nov1998;158(20):2200-11.
- View Abstract: Ruschitzka F, et al. Acute Heart Transplant Rejection Due to St. John’s Wort. Lancet. Feb2000;355(9203): 548-49.
- View Abstract: Ernst E. St John’s Wort Supplements Endanger the Success of Organ Transplantation. Archives of Surgery. Mar2002;137:316-319.
- View Abstract: Brockmoller J, et al. Hypericin and Pseudohypericin: Pharmacokinetics and Effects of Photosensitivity in Humans. Pharmacopsychiatry. 1990;30(Supp 2):94-101.
- View Abstract: Gulick RM, et al. Phase I Studies of Hypericin, The Active Compound in St. John’s Wort, As An Antiretroviral Agent in HIV-infected Adults. AIDS Clinical Trials Group Protocols 150 and 258. Ann Intern Med. Mar1999;130(6):510-14.
- View Abstract: Brockmoller J, et al. Hypericin and Pseudohypericin: Pharmacokinetics and Effects of Photosensitivity in Humans. Pharmacopsychiatry. 1990;30(Supp 2):94-101.
- Grush LR, et al. St John’s Wort During Pregnancy. JAMA. 1998;280(18):1566.
- View Abstract: Ondrizek RR, et al. An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid. Fertil Steril. Mar1999;71(3):517-22.
- View Abstract: Nordfors M, Hartvig P. St John’s wort against depression in favour again. Lakrtidningen. 1997;94:2365-67.
- Bloomfield H, et al. Can Depression Be Successfully Treated with a Safe, Inexpensive, Medically Proven Herb Available Without a Prescription? Hypericum and Depression. California: Prelude Press; 1996:110-12.
- Suzuki O, et al. Inhibition of Monoamine Oxidase by Hypericin. Planta Medica. 1984;50:272-74.
- View Abstract: Bladt S, et al. Inhibition of MAO by Fractions and Constituents of Hypericum Extract. J Geriatric Psychiatry and Neurology. 1994;7:S57-S59.
- Murray M. Natural Alternatives to Prozac. New York: William Morrow and Company, Inc; 1996:137.
- View Abstract: Muller WEG, et al. Effects of Hypericum Extract on the Expression of Serotonin Receptors. J Geriatric Psychiatry and Neurology. 1994;7:S63-S64.
- Murch SJ, et al. Melatonin in Feverfew and Other Medicinal Plants. Lancet. Nov1997;350(9091):1598-99.
- View Abstract: Kaehler ST, et al. Hyperforin Enhances the Extracellular Concentrations of Catecholamines, Serotonin and Glutamate in the Rat Locus Coeruleus. Neurosci Lett. Mar1999;262(3):199-202.
- View Abstract: Degar S, et al. Inactivation of the Human Immunodeficiency Virus Uncoating. AIDS Res Hum Retroviruses. 1992;8(11):1929-36.
- View Abstract: Dwyer JT, et al. The Use of Unconventional Remedies Among HIV-positive Men Living in California. J Assoc Nurses AIDS Care. 1995;6(1):17-28.
- View Abstract: Lavie G, et al. Studies of the Mechanisms of Action of the Antiretroviral Agents Hypericin and Pseudohypericin. Proc Natl Acad Sci, USA. 1989;86:5963-67.
- View Abstract: Meruelo D, et al. Therapeutic Agents with Dramatic Antiretroviral Activity and Little Toxicity at Effective Doses: Aromatic Polycyclic Diones Hypericin and Pseudohypericin. Proc Natl Acad Sci. 1988;85:5230.
- View Abstract: Hudson JB, et al. Antiviral Activities of Hypericin. Antiviral Research. 1991;15:110-12.
- View Abstract: Gulick RM, et al. Phase I Studies of Hypericin, The Active Compound in St. John’s Wort, As An Antiretroviral Agent in HIV-infected Adults. AIDS Clinical Trials Group Protocols 150 and 258. Ann Intern Med. Mar1999;130(6):510-14.
- View Abstract: Piscitelli SC, et al. Indinavir Concentrations and St. John’s Wort. Lancet. Feb2000;355(9203):547-48.
- Ernst E. Second Thoughts About Safety of St John’s Wort. Lancet. Dec1999;354(9195):2014-16.
- Gordon JB. SSRIs and St.John’s Wort: Possible Toxicity? Am Fam Physician. Mar1998;57(5):950,953.
- View Abstract: Lantz MS, et al. St. John’s Wort and Antidepressant Drug Interactions in the Elderly. J Geriatr Psychiatr Neurol. 1999;12:7-10.
- View Abstract: Shipochliev T, et al. Anti-inflammatory Action of a Group of Plant Extracts. Vet Med Nauki. 1981;18(6):87-94.
- Vijeshwar V, Andrija S, Sebastian Z, Mir A H, Syed M A, Thorsten Z, Ghulam N Q, Michael S. Phenolic constituents and genetic profile of Hypericum perforatum L. from India. Biochemical Systematics and Ecology. Mar2008;36(3):201-206
- Evangelos C. Tatsis, B. Sjef, E. Vassiliki, N.T. Anastassios, V. Jacques, P.G. Ioannis. Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS. Phytochemistry. Feb2007; 68(3):383-393.
- Gioti E.M, Fiamegos Y.C, Skalkos D.C, Stalikas C.D. Antioxidant activity and bioactive components of the aerial parts of Hypericum perforatum L. from Epirus, Greece. Food Chemistry. Dec2009;117(3):398-404.
- Rahimi R, Nikfar S, Abdollahi M. Efficacy and tolerability of Hypericum perforatum in major depressive disorder in comparison with selective serotonin reuptake inhibitors: a meta-analysis. Prog Neuropsychopharmacol Biol Psychiatry. Feb2009;33(1):118-127.
- Kasper S, Gastpar M, Müller WE, Volz HP, Dienel A, Kieser M, Möller HJ. Efficacy of St. John’s wort extract WS 5570 in acute treatment of mild depression: a reanalysis of data from controlled clinical trials. Eur Arch Psychiatry Clin Neurosci. Feb2008;258(1):59-63.
- Brattström A. Long-term effects of St. John’s wort (Hypericum perforatum) treatment: A 1-year safety study in mild to moderate depression. Phytomedicine. Apr2009;16(4):277-283.
- Altieri V, Montanaro V, Capasso R, Aviello G, Capasso F, Napodano G,Izzo A. The Antidepressant St. John’s Wort (Hypericum perforatum) inhibits rat and human vas deferens contractility. European Urology Supplements. Apr2006;5(2):215.
- Rezaie A, Rezaee Dorostkar K, Pashazadeh M, Mohammad Nejad S. Study of Sedative and Anxiolytic Effects of Herbal Extract Hypericum perforatum in Comparison with Diazepam in Rats. International Journal of Infectious Diseases. Dec2008; 12( Suppl1):e171.
- Maria F H, Pedro LV F, Maria E M A, Maria L M S. Acetylcholinesterase inhibition and antioxidant activity of the water extracts of several Hypericum species. Food Chemistry. Jun2010; 120(4)15:1076-1082.
- Rahimi R, Nikfar S, Abdollahi M. Efficacy and tolerability of Hypericum perforatum in major depressive disorder in comparison with selective serotonin reuptake inhibitors: a meta-analysis. Prog Neuropsychopharmacol Biol Psychiatry. 1Feb2009;33(1):118-127.
- Mannucci C, Pieratti A, Firenzuoli F, Caputi AP, Calapai G. Serotonin mediates beneficial effects of Hypericum perforatum on nicotine withdrawal signs. Phytomedicine. Oct2007;14(10):645-651.
- Tadros MG, Mohamed MR, Youssef AM, Sabry GM, Sabry NA, Khalifa AE. Proapoptotic and prepulse inhibition (PPI) disrupting effects of Hypericum perforatum in rats. J Ethnopharmacol. Apr2009;122(3):561-566.
- Niederhofer H. St. John’s wort may improve some symptoms of attention-deficit hyperactivity disorder. Nat Prod Res.Feb2010;24(3):203-205.
- Schmitt LA, Liu Y, Murphy PA, Petrich JW, Dixon PM, Birt DF. Reduction in hypericin-induced phototoxicity by Hypericum perforatum extracts and pure compounds. J Photochem Photobiol B. 1Nov2006;85(2):118-130.
- Xiu-Ying P,Jian-Ping L,Ruo-Fen ,Xue-Hong W,Zuo-Xin W, Lan-Ying H,Yu L. Influence of Hypericum perforatum Extract on Piglet Infected with Porcine Respiratory and Reproductive Syndrome Virus. Agricultural Sciences in China. Jun2009; 8(6):730-739.
- Pang R, Tao J, Zhang S, Zhu J, Yue X, Zhao L, Ye P, Zhu Y. In vitro anti-hepatitis B virus effect of Hypericum perforatum L. J Huazhong Univ Sci Technolog Med Sci. Feb2010;30(1):98-102.
- Radulovic N, Stankov-Jovanovic V, Stojanovic G, Smelcerovic A, Spiteller M, Asakawa Y. Screening of in vitro antimicrobial and antioxidant activity of nine Hypericum species from the Balkans. Food Chemistry. 2007;103(1):15-21.
- Mohanasundari M, Srinivasan MS, Sethupathy S, Sabesan M. Enhanced neuroprotective effect by combination of bromocriptine and Hypericum perforatum extract against MPTP-induced neurotoxicity in mice. J Neurol Sci.15Nov2006;249(2):140-144.
- Oztürk N, Korkmaz S, Oztürk Y. Wound-healing activity of St. John’s Wort (Hypericum perforatum L.) on chicken embryonic fibroblasts. J Ethnopharmacol. 20Apr2007;111(1):33-39.
- Süntar IP, Akkol EK, Yilmazer D, Baykal T, Kirmizibekmez H, Alper M, Yeşilada E. Investigations on the in vivo wound healing potential of Hypericum perforatum L. J Ethnopharmacol. 3Feb2010;127(2):468-477.
- Hammer KD, Yum MY, Dixon PM, Birt DF. Identification of JAK-STAT pathways as important for the anti-inflammatory activity of a Hypericum perforatum fraction and bioactive constituents in RAW 264.7 mouse macrophages. Phytochemistry. May2010;71(7):716-725.
- Raak CK, Büssing A, Ostermann T. A systematic review of remedies and indications of the use of homeopathic Hypericum perforatum (St. John’s Wort) in dental practice. European Journal of Integrative Medicine. Dec2009; 1(4):252.
- Menegazzi M, Di Paola R, Mazzon E, Muià C, Genovese T, Crisafulli C, Suzuki H, Cuzzocrea S. Hypericum perforatum attenuates the development of carrageenan-induced lung injury in mice. Free Radic Biol Med.1Mar2006;40(5):740-753.
- Mazzon E, Muià C, Crisafulli C, Genovese T, Di Bella P, Esposito E, Menegazzi M, Meli R, Suzuki H, Cuzzocrea S. Protective effect of Hypericum perforatum in zymosan-induced multiple organ dysfunction syndrome: relationship to its inhibitory effect on nitric oxide production and its peroxynitrite scavenging activity. Nitric Oxide.Feb2007;16(1):118-130.
- Silva B.A, Malva J.O, Dias A.C.P. Alberto. St. John’s Wort (Hypericum perforatum) extracts and isolated phenolic compounds are effective antioxidants in several in vitro models of oxidative stress. Food Chemistry.Oct2008;110(3):611-619.
- Sakrak O, Aydin A, Kerem M, Pasaoglu H, Alper M, Akkol E, Bedirli A. The Effect of Hypericum perforatum extract on hepatic ischemia reperfusion injury in rats. Clinical Nutrition Supplements. 2009; 4(2):171.
- Stavropoulos NE, Kim A, Nseyo UU, Tsimaris I, Chung TD, Miller TA, Redlak M, Nseyo UO, Skalkos D. Hypericum perforatum L. extract – novel photosensitizer against human bladder cancer cells. J Photochem Photobiol B. 3Jul2006;84(1):64-69.
- Asgary S, Kabiri N, Madani H, Mahzoni P, Rahim P. Regression of Hypercholesterolemic Atherosclerosis in rabbits by hydroalcoholic extracts of Hypericum perforatum. Atherosclerosis Supplements. Jun2009; 10(2):e819.
- Galeotti N, Vivoli E, Bilia AR, Bergonzi MC, Bartolini A, Ghelardini C. A prolonged protein kinase C-mediated, opioid-related antinociceptive effect of St John’s Wort in mice. J Pain. Feb2010;11(2):149-159.