Toxicological effects of Camellia sinensis (green tea): A review.

Many scientific articles proved that green tea (GT), Camellia sinensis, has a great potential to manage central nervous system, cardiovascular, and metabolic diseases and treat cancer and inflammatory disorders. However, it is important to consider that "natural" is not always "safe." Some relevant articles reported side effects of GT, detrimental effects on health. The aim of this study is to provide a classified report about the toxicity of GT and its main constituents in acute, subacute, subchronic, and chronic states. Furthermore, it discusses on the cytotoxicity, genotoxicity, mutagenicity, carcinogenicity, and developmental toxicity of GT and its main constituents. The most important side effects have been reported hepatotoxicity and gastrointestinal disorders specially while consumed on an empty stomach. GT and its main components are not major teratogen, mutagen, or carcinogen substances. However, there is limited data in using them during pregnancy, and they should be used with caution in pregnancy, breast-feeding, and susceptible people. Because GT and its main components have a wide variety of drug interactions, consideration should be taken in coadministration of them with narrow therapeutic indexed drugs. Furthermore, they evoke selective cytotoxicity on cancerous cells that could engage them as an adjuvant substance in cancer therapy.

Preservative effect of Camellia sinensis (L.) Kuntze seed extract in soy sauce and its mutagenicity.

The purpose of this study was to investigate the applicability of green tea seed (GTS) extract as a natural preservative in food. Food preservative ability and mutagenicity studies of GTS extract and identification of antimicrobial compounds from GTS extract were carried out. The GTS extract showed only anti-yeast activity against Candida albicans with MIC value of 938µg/mL and Zygosaccharomyces rouxii with a MIC of 469µg/mL. The active compounds were identified as theasaponin E1 (1), assamsaponin A (2), and assamsaponin B (3). And GTS extracts didn't show mutagenicity because there were no dose-dependent changes in colonies of Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA regardless of the metabolic activation system. And GTS extract also showed a potent food preservation affect which eliminated all yeast below the MIC value in application test at soy sauce. Overall, these results indicate that GTS extract could be a safe and effective food preservative with anti-yeast activity.

Hepatotoxicity of green tea: an update.

Green tea (GT), obtained from the leaves of Camellia sinensis (L.) Kuntze (Fam. Theaceae), is largely used for its potential health benefits such as reduction in risk of cardiovascular diseases and weight loss. Nevertheless, it is suspected to induce liver damage. Present work reviews the hepatic adverse reactions associated with GT-based herbal supplements, published by the end of 2008 to March 2015. A systematic research was carried out on PubMed, MedlinePlus, Scopus and Google Scholar databases, without any language restriction. Moreover, some accessible databases on pharmacovigilance or phytovigilance were consulted. The causality assessment was performed using the CIOMS/RUCAM score. Nineteen cases of hepatotoxicity related to the consumption of herbal products containing GT were identified. The hepatic reactions involved mostly women (16/19); the kind of liver damage was generally classified as hepatocellular (16/19). The causality assessment between consumption of herbal preparation and hepatic reaction resulted as probable in eight cases and as possible in eleven cases. In seven cases, patients used preparations containing only GT, while twelve reactions involved patients who took multicomponent preparations (MC). The reactions induced by GT had a generally long latency (179.1 ± 58.95 days), and the outcome was always resolution, with recovery time of 64.6 ± 17.78 days. On the contrary, liver injury associated with MC had a shorter latency (44.7 ± 13.85 days) and was more serious in four cases that required liver transplantation and, when resolution occurred, the recovery time was longer (118.9 ± 38.79). MC preparations contained numerous other components, many of which are suspected to induce liver damage, so it is difficult to ascribe the toxicity to one specific component, e.g., GT. Present data confirm a certain safety concern with GT, even if the number of hepatic reactions reported is low considering the great extent of use of this supplement. The mechanism of GT hepatotoxicity remains unclear, but factors related to the patient are becoming predominant. A major safety concern exists when GT is associated with other ingredients that can interact between them and with GT, enhancing the risk of liver damage. Patients should be discouraged from using herbal or dietary supplements containing complex mixtures and should be encouraged to use herbal and dietary supplement possibly under supervision of healthcare professionals.

Acute and sub-chronic oral toxicity study of black tea in rodents.

OBJECTIVES: Systematic oral toxicity study for black tea (Camellia sinensis), the most commonly consumed variety of tea, is lacking. The present study was undertaken to assess the iron load on black tea (Camellia sinensis) and its safety aspects in animals. MATERIALS AND METHODS: The analysis of iron was done in six tea samples as per American Public Health Association method using flame atomic absorption spectrophotometer. Maximum physical iron-loaded tea sample was identified on black tea sample 2 (BTS-2), and this was further studied for acute and 90-day sub-chronic toxicity following Organisation for Economic Co-operation and Development guidelines. RESULTS: Black tea sample 2 did not show any signs of toxicity or mortality at up to 2 g/kg per oral dose in Swiss albino mice. 90-day toxicity studies in Wistar rats did not reveal any evidence of toxicity at up to 250 mg/kg/day (2.5% infusion of BTS-2) oral dose as exhibited by regular observations, body weight, food consumption, hematology, serum chemistry, organ weights, and histopathology. Further, serum iron, total iron binding capacity, unsaturated iron binding capacity, and ferritin were not altered after 90 days of treatment. Masson trichrome staining and Perls' staining did not reveal any abnormalities in hepatic tissue following 90-day treatment of high iron-loaded BTS-2. CONCLUSIONS: This safety study provides evidence that BTSs, in spite of relatively high iron content, show no significant iron-related toxicity on acute or sub-chronic oral administration in animals.

Tres casos de hepatotoxicidad por un suplemento dietético destinado a frenar la caída del cabello / Three cases of liver toxicity with a dietary supplement intended to stop hair loss

La toxicidad hepática asociada al uso de productos de herboristería y suplementos nutricionales es un fenómeno creciente. En la literatura se han comunicado varios casos de hepatitis tóxica en relación con productos utilizados para la pérdida de peso que incluyen extractos de té verde en su composición. A continuación se describen tres casos de hepatotoxicidad relacionados con la toma de Inneov masa capilar®, un suplemento nutricional destinado a detener la caída del cabello cuyo componente principal son las catequinas de té verde. En todos ellos se descartaron otras posibles causas de hepatitis aguda. Recalcamos la importancia de incluir la ingesta de este tipo de sustancias a la hora de realizar la anamnesis para poder detectar y notificar las reacciones hepáticas adversas secundarias a productos herbales de apariencia inocua, como el descrito en el manuscrito (AU)

Liver toxicity associated with herbal remedies and dietary supplements is an increasing concern. Several toxic hepatitis cases have been reported in the literature in association with products intended for weight loss where green tea extracts are an ingredient. Three hepatotoxicity cases are reported below in association with the use of Inneov masa capilar®, a dietary supplement intended to stop hair loss whose primary component is green tea catechins. In all of them, other potential causes of acute hepatitis were ruled out. We highlight the importance of awareness regarding these substances at history taking in order to identify and report hepatic adverse reactions secondary to apparently safe herbs as described in the present manuscript (AU)

Safety evaluation of tea (Camellia sinensis (L.) O. Kuntze) flower extract: assessment of mutagenicity, and acute and subchronic toxicity in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Tea (Camellia sinensis (L.) O. Kuntze, Theaceae) flowers possess many physiological functions and have been used in traditional medicines for deodorization, skin care, cough suppressant and expectorant in China. However, there is a little information about its possible toxicity. AIM OF THE STUDY: The present investigation was carried out to evaluate the safety of tea flower extract by mutagenicity and acute and subchronic toxicity studies. MATERIALS AND METHODS: Mutagenicity of tea flower extract was evaluated by the Ames test in Salmonella typhimurium strains TA97, TA98, TA100 and TA102 at concentrations of 0.008, 0.04, 0.2, 1.0, 5.0 mg/plate. In the acute toxicity study, Sprague-Dawley rats were administered a single dose of 12.0 g/kg of body weight by gavage, and were monitored for 14 days. In the subchronic toxicity study, tea flower extract was administered by gavage at doses of 1.0, 2.0 and 4.0 g/kg body weight daily for 13 weeks to Sprague-Dawley rats. RESULTS: In the Ames test, there was no mutagenic effect of tea flower extract (up to 5.0 mg/plate) towards four tested strains (TA97, TA98, TA100, TA102), with or without metabolic activation (S9). In the acute toxicity study, all animals gained weight and appeared active and normal, so the LD(50) value must be >12.0 g/kg body weight. In the subchronic toxicity study, no dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed. CONCLUSION: These results indicate that tea flower extract does not possess mutagenic potential, and that both acute and subchronic toxicity towards animals is very low. A no-observed adverse-effect level (NOAEL) for tea flower extract is 4.0 g/kg bw/day for rats under the conditions of this study.

Hepatitis tóxica por Camellia sinensis / Toxic hepatitis due to Camellia sinensis

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Hepatitis aguda inducida por Camellis sinensis (té verde) / Acute hepatitis induced by Camellia sinensis (green tea)

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