Interactions between herbal remedies and antirheumatic drugs

Many patients with rheumatological conditions use herbal remedies as an adjunct to their conventional antirheumatic medication, often without seeking advice. Herbal remedies are exempt from the usual drug safety requirements and may be a cause of both adverse effects and drug interactions. Data on interactions between herbal remedies and conventional antirheumatic medication is scarce. Reasons include a perception that herbal remedies are safe, a lack of reporting by patients and healthcare professionals and a lack of knowledge about the pharmacology and composition of herbal remedies, as well as adulteration. Interactions are likely between herbal remedies with antiplatelet or nephrotoxic effects and NSAIDs, hepatotoxic herbal remedies and disease-modifying antirheumatic medication, and between St. John's Wort and cyclosporin.     

Formation of allicin from dried garlic (Allium sativum): a simple HPTLC method for simultaneous determination of allicin and ajoene in dried garlic and garlic preparations.]

In garlic (Allium sativum L.) the enzyme alliin lyase catalyzes the cleavage of alliin into allicin which reacts further to furnish ajoene. A simultaneous determination of allicin and ajoene is introduced which, in contrast to the determination of alliin only, allows for the testing of the activity of alliin lyase. It can be demonstrated that at a pH value of less than 3 the enzyme produces only small amounts of allicin. For this reason preparations from garlic should be administered only as enteric-coated formulations.     

In vitro virucidal effects of Allium sativum (garlic) extract and compounds.

Garlic (Allium sativum) has been shown to have antiviral activity, but the compounds responsible have not been identified. Using direct pre-infection incubation assays, we determined the in vitro virucidal effects of fresh garlic extract, its polar fraction, and the following garlic associated compounds: diallyl thiosulfinate (allicin), allyl methyl thiosulfinate, methyl allyl thiosulfinate, ajoene, alliin, deoxyalliin, diallyl disulfide, and diallyl trisulfide. Activity was determined against selected viruses including, herpes simplex virus type 1, herpes simplex virus type 2, parainfluenza virus type 3, vaccinia virus, vesicular stomatitis virus, and human rhinovirus type 2. The order for virucidal activity generally was: ajoene > allicin > allyl methyl thiosulfinate > methyl allyl thiosulfinate. Ajoene was found in oil-macerates of garlic but not in fresh garlic extracts. No activity was found for the garlic polar fraction, alliin, deoxyalliin, diallyl disulfide, or diallyl trisulfide. Fresh garlic extract, in which thiosulfinates appeared to be the active components, was virucidal to each virus tested. The predominant thiosulfinate in fresh garlic extract was allicin. Lack of reduction in yields of infectious virus indicated undetectable levels of intracellular antiviral activity for either allicin or fresh garlic extract. Furthermore, concentrations that were virucidal were also toxic to HeLa and Vero cells. Virucidal assay results were not influenced by cytotoxicity since the compounds were diluted below toxic levels prior to assaying for infectious virus. These results indicate that virucidal activity and cytotoxicity may have depended upon the viral envelope and cell membrane, respectively. However, activity against non-enveloped virus may have been due to inhibition of viral adsorption or penetration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetic interactions between herbal remedies and medicinal drugs

1. The use of herbal products to treat a wide range of conditions is rising rapidly, leading to increased intake of phytochemicals. Recent studies revealed potentially fatal interactions between herbal remedies and traditional drugs. 2. In transplant patients, self-medication with St John's wort (Hypericum perforatum) has led to a drop in plasma levels of the immunosuppressant drug cyclosporine, causing tissue rejection. 3. Intake of St John's wort increases the expression of intestinal P-glycoprotein and the expression of CYP3A4 in the liver and intestine. The combined up-regulation in intestinal P-glycoprotein and hepatic and intestinal CYP3A4 impairs the absorption and stimulates the metabolism of cyclosporine, leading to subtherapeutic plasma levels. The St John's wort component, hyperforin, contributes to the induction of CYP3A4. 4. St John's wort also enhances the metabolism of other CYP3A4 substrates including the protease inhibitors indinavir and nevirapine, oral contraceptives, and tricyclic antidepressants such as amitriptyline. 5. Other herbal remedies with the potential to modulate cytochrome P450 activity and thus participate in interactions with conventional drugs include Milk thistle, Angelica dahurica, ginseng, garlic preparations, Danshen and liquorice. 6. Herbal products are currently not subject to the rigorous testing indispensable for conventional drugs. However, if potential drug interactions are to be predicted, it is essential that the ability of herbal products to interfere with drug-metabolizing enzyme systems is fully established.     

Pharmacokinetic interactions between herbal remedies and medicinal drugs

1. The use of herbal products to treat a wide range of conditions is rising rapidly, leading to increased intake of phytochemicals. Recent studies revealed potentially fatal interactions between herbal remedies and traditional drugs. 2. In transplant patients, self-medication with St John's wort (Hypericum perforatum) has led to a drop in plasma levels of the immunosuppressant drug cyclosporine, causing tissue rejection. 3. Intake of St John's wort increases the expression of intestinal P-glycoprotein and the expression of CYP3A4 in the liver and intestine. The combined up-regulation in intestinal P-glycoprotein and hepatic and intestinal CYP3A4 impairs the absorption and stimulates the metabolism of cyclosporine, leading to subtherapeutic plasma levels. The St John's wort component, hyperforin, contributes to the induction of CYP3A4. 4. St John's wort also enhances the metabolism of other CYP3A4 substrates including the protease inhibitors indinavir and nevirapine, oral contraceptives, and tricyclic antidepressants such as amitriptyline. 5. Other herbal remedies with the potential to modulate cytochrome P450 activity and thus participate in interactions with conventional drugs include Milk thistle, Angelica dahurica, ginseng, garlic preparations, Danshen and liquorice. 6. Herbal products are currently not subject to the rigorous testing indispensable for conventional drugs. However, if potential drug interactions are to be predicted, it is essential that the ability of herbal products to interfere with drug-metabolizing enzyme systems is fully established.     

大蒜蒜酶提取纯化及临床应用研究

目的:研究从鲜蒜中分离纯化蒜酶的方法和临床常用剂对酶活性的影响,为今后工艺的进一步放大、优化和合理临床应用提供必要理论参数。方法:以天然蒜氨酸作底物,采用丙酮酸法测定酶浓度;以牛血清白蛋白为标准,采用考马斯亮兰G-250法测定蛋白质浓度。结果:从鲜蒜中提取纯化蒜酶,其粗酶浸提液的最佳组成为Na2HPO4-KH2PO4缓冲溶液;硫酸铵沉淀酶蛋白的最适饱和度范围为0%~35%;选用超滤技术脱盐;蒜酶最佳调节等电点为4.9。在临床常用溶剂中,含氯化钠的注射液(不含葡萄糖)对蒜酶活力有显著的激活作用,而含葡萄糖的注射液则较强地抑制了蒜酶活力;75%和95%乙醇具有强烈的杀酶作用。结论:本研究为今后工艺的进一步放大与优化和蒜酶合理临床应用提供了指导。     

Antioxidant role of oils isolated from garlic (Allium sativum Linn) and onion (Allium cepa Linn) on nicotine-induced lipid peroxidation.

Nicotine, a major component of tobacco, is partly responsible for the development of atherosclerosis. It has been suggested that antioxidant nutrients are protective against degenerative diseases. So we have studied the antioxidant effect of oils isolated from onion and garlic on nicotine-induced lipid peroxidation in rat tissues. The lipid peroxidation products and scavenging enzymes were assessed in liver, lungs, heart and kidney. The rats were treated with 0.6 mg nicotine/kg bw and simultaneously given 100 mg garlic or onion oils/kg bw for 21 d. Thiobarbituric acid reactive substances, conjugated dienes and hydroperoxides concentrations were significantly increased in the tissues of nicotine-treated rats. Both the garlic oil and onion oil supplementation to nicotine-treated rats increased resistance to lipid peroxidation. The activities of catalase, superoxide dismutase and glutathione peroxidase decreased in nicotine-treated rats, but there was a trend to increased glutathione content. With garlic oil or onion oil supplementation, nicotine-treated rats had increased activities of antioxidant enzymes and increased concentrations of glutathione. These results indicate that oils of garlic and onion are effective antioxidants against the oxidative damage caused by nicotine.     

An in vitro study of different extracts and fractions of Allium sativum (garlic): vascular reactivity

The aim of this study was to investigate the effect of different novel extracts and fractions obtained from Allium sativum (garlic) on in vitro vessel contraction in order to deepen our knowledge of their mechanism of action on vascular reactivity. The contraction induced by noradrenaline (NE, 10(-6) or 10(-5) M) or KCl (80 mM) was relaxed with all the extracts and fractions studied, but this effect was higher with RG 20-100 (raw garlic fraction) and FG 20-100 (frozen garlic fraction). To increase our understanding of the mechanisms of action of RG 200-100 and FG 200-100, we found their inhibitory actions were retained in the absence of endothelium, whereas inhibition of the entry of extracellular calcium and mobilization of intracellular calcium may play an instrumental role.     

Phytotoxic and genotoxic effects of ZnO nanoparticles on garlic (Allium sativum L.): a morphological study

The effects of zinc oxide nanoparticles (ZnO NPs) on the root growth, root apical meristem mitosis and mitotic aberrations of garlic (Allium sativum L.) were investigated. ZnO NPs caused a concentration-dependent inhibition of root length. When treated with 50 mg/L ZnO NPs for 24 h, the root growth of garlic was completely blocked. The 50% inhibitory concentration (IC(50)) was estimated to be 15 mg/L. The mitosis index was also decreased in a concentration- and time-dependent manner. ZnO NPs also induced several kinds of mitotic aberrations, mainly consisted of chromosome stickiness, bridges, breakages and laggings. The total percentage of abnormal cells increased with the increase of ZnO NPs concentration and the prolongation of treatment time. The investigation provided new information for the possible genotoxic effects of ZnO NPs on plants.     

Hexavalent chromium and its effect on health: possible protective role of garlic (Allium sativum Linn)

Hexavalent chromium or chromium (VI) is a powerful epithelial irritant and a confirmed human carcinogen. This heavy metal is toxic to many plants, aquatic animals, and bacteria. Chromium (VI) which consists of 10%-15% total chromium usage, is principally used for metal plating (H2Cr2O7), as dyes, paint pigments, and leather tanning, etc. Industrial production of chromium (II) and (III) compounds are also available but in small amounts as compared to chromium (VI). Chromium (VI) can act as an oxidant directly on the skin surface or it can be absorbed through the skin, especially if the skin surface is damaged. The prooxidative effects of chromium (VI) inhibit antioxidant enzymes and deplete intracellular glutathione in living systems and act as hematotoxic, immunotoxic, hepatotoxic, pulmonary toxic, and nephrotoxic agents. In this review, we particularly address the hexavalent chromium-induced generation of reactive oxygen species and increased lipid peroxidation in humans and animals, and the possible role of garlic (Allium sativum Linn) as a protective antioxidant.     

Investigation on the antibacterial properties of garlic (Allium sativum) on pneumonia causing bacteria

The antibacterial activity of the crude aqueous extract of garlic was investigated against some pneumonia causing bacteria by an agar dilution technique. The results revealed that Streptococcus pneumoniae standard test organism was completely inhibited by 7.8 mg/ml of media and the clinical isolate of Klebsiella pneumoniae was completely inhibited by 24.38 mg/ml of media, indicating that Streptococcus pneumoniae is the most sensitive and Klebsiella pneumoniae the least. Garlic could be used as an effective antibacterial agent for these pathogenic microorganisms.     

Uptake and accumulation and oxidative stress in garlic (Allium sativum L.) under lead phytotoxicity

The effects of different concentrations of Pb on growth of Allium sativum L, Pb uptake and accumulation, antioxidant enzyme activity and malondialdehyde content were investigated. The results indicated that shoot growth at high concentration of Pb (10⁻³ M) and roots growth at 10⁻³ M and 10⁻⁴ M Pb were significantly inhibited. Lead ions were accumulated mainly in the roots and only small amounts were translocated to bulbs and shoots. SOD activities in shoot and roots exposed to 10⁻³ M Pb were observed to be high. Plants exposed to 10⁻³ M Pb showed a significant increase in POD activity in roots versus the control and other Pb treatments. In roots, CAT activity and MDA concentration at 10⁻³ M Pb is high significantly. The mechanisms of Pb toxicity and tolerance in garlic are briefly discussed.     

An in vitro assessment of the antibacterial effect of garlic (Allium sativum) on bacterial isolates from wound infections

BACKGROUND: Garlic (Allium sativum) has come to be seen as an all rounded treatment for preventing wound infection, common cold, malaria, cough and lung tuberculosis, hypertension, sexually transmitted diseases, mental illness, kidney diseases, liver diseases, asthma, diabetes. OBJECTIVE: The main objective of this study was to assess the antibacterial effect of crude preparation of garlic on bacterial isolates from the wound infections. METHODS: An experimental study was conducted in Gondar University Teaching Hospital School of Medical Laboratory Technology, Microbiology Laboratory from June 2004 to April 2005 by agar dilution technique. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of garlic to control strains of Staphylococcus aureus ATTC 25923 and Escherichia coli ATTCC 25922, as well as to clinical isolates of S. aureus, E. coli, Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa were determined using agar dilution method The data was collected in triplicate. RESULTS: All the tested organisms were inhibited by 33.75 mg/ml of the crude preparation of garlic except control organism and clinical isolates of S. aureus, which were inhibited by 11.25 mg/ml of crude garlic. Garlic did not reveal bactericidal effect up to a concentration of 37.5 mg/ml against all the tested organisms. CONCLUSION: Crude preparation of garlic could be used as an effective antibacterial agent for the tested organisms. Nevertheless, clinical trial on the effect of garlic is essential before advocating large-scale therapy.     

Comparative pharmacological investigations of Allium ursinum and Allium sativum.

Extracts of wild garlic (Allium ursinum) and garlic (A. sativum) with defined chemical compositions were investigated for their in vitro inhibitory potential on 5-lipoxygenase (LO), cyclooxygenase (CO), thrombocyte aggregation (TA), and angiotensin I-converting enzyme (ACE). The inhibition rates as IC50 values of both extracts for 5-LO, CO, and TA showed a good correlation with the %-content of the major S-containing compounds (thiosulfinates and ajoenes) of the various extracts. In the 5-LO and CO test the garlic extracts are slightly superior to the wild garlic extracts whereas, in the TA test, no differences could be found. In the ACE test the water extract of the leaves of wild garlic containing glutamyl-peptides showed the highest inhibitory activity followed by that of the garlic leaf and the bulbs of both drugs. The comparative studies underline the usefulness of wild garlic as a substitute of garlic.     

Effect of garlic (Allium sativum) oil on exercise tolerance in patients with coronary artery disease

The effect of six weeks garlic oil administration was observed on cardiac performance and exercise tolerance in 30 patients of coronary artery disease. After initial treadmill stress test, they were administered garlic oil in the dose of four capsules twice a day for 6 weeks and treadmill stress test was repeated. Garlic significantly (P<0.01) reduced heart rate at peak exercise and also significantly reduced the work load upon the heart resulting in better exercise tolerance (P<0.05) as compared to the initial test. It appears to be a good adaptogen to be utilized in patients with coronary artery disease.     

Extraction of essential oils from garlic (Allium sativum) using ligarine as solvent and its immunity activity in gastric cancer rat

The chemical composition of essential oil from magnolia collected in Suzhou city, China, was studied using gas chromatography-mass spectroscopy. Fifty-four volatile compounds were identified in the essential oil, with eucalyptol (21.55%), β-Pinene(11.07%), D-Limonene (8.93%), 1R-α-Pinene (7.86%), Bicyclo[2.2.1]heptan-2-one, 1,7,7-trimethyl-, (1R)-(6.46%), Cyclohexene, 4-methylene-1-(1-methylethyl)- (5.30%), 1,4-Cyclohexadiene, 1-methyl-4-(1-methylethyl)- (5.10%), camphene (4.72%), being the major chemical constituents. In an in vivo approach, the protective effect of the essential oil against oxidative stress in gastric cancer (GC) mice was also investigated in terms of superoxide dismutase, CAT, and glutathione peroxidase activities. Our results indicate that the essential oil has an effective capability to enhance serum antioxidant enzyme activities and sCD40L, and decrease phosphorylate-activate Akt protein levels in a dose-dependent manner in gastric cencer mice. Overall, essential oil from magnolia appears to be an effective antioxidant and is quite suitable for further biological evaluation.