Acute and subchronic oral toxicities of Pu-erh black tea extract in Sprague-Dawley rats

Combining bioinformatics and multiomics strategies to investigate the key microbiota and active components of Liupao tea ameliorating hyperlipidemia

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperlipidemia as a major health issue has attracted much public attention. As a geographical indication product of China, Liupao tea (LPT) is a typical representative of traditional Chinese dark tea that has shown good potential in regulating glucose and lipid metabolism. LPT has important medicinal value in hyperlipidemia prevention. However, the active ingredients and metabolic mechanisms by which LPT alleviates hyperlipidemia remain unclear.

AIM OF THE STUDY

This study aimed to systematically investigate the metabolic mechanisms and active ingredients of LPT extract in alleviating hyperlipidemia.

MATERIALS AND METHODS

Firstly, we developed a mouse model of hyperlipidemia to study the pharmacodynamics of LPT. Subsequently, network pharmacology and molecular docking were performed to predict the potential key active ingredients and core targets of LPT against hyperlipidemia. LC-MS/MS was used to validate the identity of key active ingredients in LPT with chemical standards. Finally, the effect and metabolic mechanisms of LPT extract in alleviating hyperlipidemia were investigated by integrating metabolomic, lipidomic, and gut microbiome analyses.

RESULTS

Results showed that LPT extract effectively improved hyperlipidemia by suppressing weight gain, remedying dysregulation of glucose and lipid metabolism, and reducing hepatic damage. Network pharmacology analysis and molecular docking suggested that four potential active ingredients and seven potential core targets were closely associated with roles for hyperlipidemia treatment. Ellagic acid, catechin, and naringenin were considered to be the key active ingredients of LPT alleviating hyperlipidemia. Additionally, LPT extract modulated the mRNA expression levels of Fxr, Cyp7a1, Cyp8b1, and Cyp27a1 associated with bile acid (BA) metabolism, mitigated the disturbances of BA and glycerophospholipid (GP) metabolism in hyperlipidemia mice. Combining fecal microbiota transplantation and correlation analysis, LPT extract effectively improved species diversity and abundance of gut microbiota, particularly the BA and GP metabolism-related gut microbiota, in the hyperlipidemia mice.

CONCLUSIONS

LPT extract ameliorated hyperlipidemia by modulating GP and BA metabolism by regulating Lactobacillus and Dubosiella, thereby alleviating hyperlipidemia. Three active ingredients of LPT served as the key factors in exerting an improvement on hyperlipidemia. These findings provide new insights into the active ingredients and metabolic mechanisms of LPT in improving hyperlipidemia, suggesting that LPT can be used to prevent and therapeutic hyperlipidemia.

Acute and Subacute Safety Evaluation of Black Tea Extract (Herbt Tea Essences) in Mice

Theabrownin (TB) is a heterogeneous biomacromolecule, extracted from tea, with many functional groups. Importantly, TB possesses diverse health benefits, such as antitumor activity and blood lipid-lowering effects. Presently, the content of TB in tea extract is relatively low. Here, we obtained a deep-processed black tea extract with a high content of TB (close to 80%), which was named Herbt Tea Essences (HTE). Currently, this study was designed to evaluate the biosafety of high-content TB products on mice. We implemented acute and subacute toxic experiments to assess its safety on organs, the serum biochemical and molecular levels. In the acute exposure study, we found that the median lethal dose (LD50) value of HTE was 21.68 g/kg (21.06–24.70 g/kg, greater than 5 g/kg), suggesting that HTE had a low acute toxicity. In the 28-day subacute exposure study, our results showed that no abnormal effects were observed in the 40 and 400 mg/kg/day HTE-treated groups. However, we observed slight nephrotoxicity in the 4000 mg/kg/day HTE-treated group. The HTE-induced nephrotoxic effect might involve the inflammatory response activation mediated by the nuclear transcription factor kappa-B (NF-κB) signaling pathway. This study would provide valuable data for the TB safety assessment and promote this natural biomacromolecule application in daily drinking.

3-Methylxanthine production through biodegradation of theobromine by Aspergillus sydowii PT-2

Background

Methylxanthines, including caffeine, theobromine and theophylline, are natural and synthetic compounds in tea, which could be metabolized by certain kinds of bacteria and fungi. Previous studies confirmed that several microbial isolates from Pu-erh tea could degrade and convert caffeine and theophylline. We speculated that these candidate isolates also could degrade and convert theobromine through N-demethylation and oxidation. In this study, seven tea-derived fungal strains were inoculated into various theobromine agar medias and theobromine liquid mediums to assess their capacity in theobromine utilization. Related metabolites with theobromine degradation were detected by using HPLC in the liquid culture to investigate their potential application in the production of 3-methylxanthine.

Results

Based on theobromine utilization capacity, Aspergillus niger PT-1, Aspergillus sydowii PT-2, Aspergillus ustus PT-6 and Aspergillus tamarii PT-7 have demonstrated the potential for theobromine biodegradation. Particularly, A. sydowii PT-2 and A. tamarii PT-7 could degrade theobromine significantly (p < 0.05) in all given liquid mediums. 3,7-Dimethyluric acid, 3-methylxanthine, 7-methylxanthine, 3-methyluric acid, xanthine, and uric acid were detected in A. sydowii PT-2 and A. tamarii PT-7 culture, respectively, which confirmed the existence of N-demethylation and oxidation in theobromine catabolism. 3-Methylxanthine was common and main demethylated metabolite of theobromine in the liquid culture. 3-Methylxanthine in A. sydowii PT-2 culture showed a linear relation with initial theobromine concentrations that 177.12 ± 14.06 mg/L 3-methylxanthine was accumulated in TLM-S with 300 mg/L theobromine. Additionally, pH at 5 and metal ion of Fe²⁺ promoted 3-methylxanthine production significantly (p < 0.05).

Conclusions

This study is the first to confirm that A. sydowii PT-2 and A. tamarii PT-7 degrade theobromine through N-demethylation and oxidation, respectively. A. sydowii PT-2 showed the potential application in 3-methylxanthine production with theobromine as feedstock through the N-demethylation at N-7 position.

Acute, Subacute, and Genotoxicity Assessments of a Proprietary Blend of Garcinia mangostana Fruit Rind and Cinnamomum tamala Leaf Extracts (CinDura®)

The present communication describes a battery of toxicity studies that include an acute oral toxicity, a subacute twenty-eight-day repeated oral dose toxicity, and genotoxicity studies on a herbal formulation CinDura® (GMCT). This proprietary herbal composition contains the extracts of the Garcinia mangostana fruit rind (GM) and the Cinnamomum tamala leaf (CT). The toxicological evaluations were performed following the Organization for Economic Cooperation and Development (OECD) guidelines. The acute oral toxicity study in Wistar rats suggests that the median lethal dose of CinDura® is at least 2000 mg/kg body weight. Acute dermal and eye irritation tests in New Zealand white rabbits indicate that the test item is nonirritant to the skin and eyes. A twenty-eight-day repeated dose oral toxicity study was conducted in male and female Wistar rats using daily doses of 250, 500, and 1000 mg/kg body weight, followed by a fourteen-day reversal period for two satellite groups. The CinDura®-supplemented animals did not show any sign of toxicity on their body weights, organ weights, and on the hematobiochemical parameters. The gross pathology and histopathological examinations indicated no treatment-related changes in the experimental animals. Overall, the no-observed-adverse-effect level (NOAEL) of the herbal blend is 1000 mg/kg body weight, the highest tested dose. Also, the results of the bacterial reverse mutation test and the erythrocyte micronucleus assay in mouse bone marrow suggest that CinDura® (GMCT) is neither mutagenic nor clastogenic.

Antibacterial activity and subchronic toxicity of Cassia fistula L. barks in rats

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Extract and ethyl acetate fraction of Cassia fistula L. have potent antibacterial activity against resistant bacteria such as Salmonella typhosa.

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Extract and Ethyl acetate fraction of Cassia fistula L. barks revealed the most active in vivo antibacterial activity.

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At 1000 mg/kg dose of extract exposured for 90 days, histological damages were found either in liver or kidney, but after 30 days the abnormality fully were recovered.

Increasing incidence of antibiotic resistance necessitates the development of more potent antibiotics. The aim of this work was to evaluate the antibacterial activity of Cassia fistula L. barks as an alternative agent for resistant pathogenic bacteria. The C. fistula barks were extracted with ethanol, followed by partition of the extract to give n-hexane, ethyl acetate and water fractions. An in vitro antibacterial assay was conducted to evaluate inhibitory activity of the extract and fractions against Salmonella typhosa and Shigella dysenteriae. An in vivo antibacterial activity was examined using S. typhosa-infected mouse models, in which the colony number of S. typhosa were counted from the infected rats’ feces. Assesment on safety of the extract was conducted by a subchronic toxicity test which mainly examined alteration occured in biochemical parameters and hystopatological conditions of livers and kidneys. The results showed that the ethanol extract inhibited the growth of both S. typhosa and S. dysenteriae with the MIC of 0.3125% w/v, and the ethyl acetate fraction with the MIC of 0.625% b/v. In the in vivo antibacterial assay, the extract at three doses decreased the colony number of S. typhosa significantly, and after the fourth to sixth days, the precentage of decrease reached more than 90% by 1000 mg/kg dose. The subchronic toxicity test revealed that after the extract exposured for 90 days, a dose of 1000 mg/kg induced liver and kidney damages histologically, however, it returned to normal condition after 30 days of recovery. The results of this study indicated that the extract of C. fistula L. barks had potent in vivo antibacterial activity against S. typhosa as sample of resistant bacteria, and is safe to be used as a herbal medicine, preferably at a dose lower than 1000 mg/kg.

Isolation, characterization and application of theophylline-degrading Aspergillus fungi

Background

Caffeine, theobromine and theophylline are main purine alkaloid in tea. Theophylline is the downstream metabolite and it remains at a very low level in Camellia sinensis. In our previous study, Aspergillus sydowii could convert caffeine into theophylline in solid-state fermentation of pu-erh tea through N-demethylation. In this study, tea-derived fungi caused theophylline degradation in the solid-state fermentation. The purpose of this study is identify and isolate theophylline-degrading fungi and investigate their application in production of methylxanthines with theophylline as feedstock through microbial conversion.

Results

Seven tea-derived fungi were collected and identified by ITS, β-tubulin and calmodulin gene sequences, Aspergillus ustus, Aspergillus tamarii, Aspergillus niger and A. sydowii associated with solid-state fermentation of pu-erh tea have shown ability to degrade theophylline in liquid culture. Particularly, A. ustus and A. tamarii could degrade theophylline highly significantly (p < 0.01). 1,3-dimethyluric acid, 3-methylxanthine, 3-methyluric acid, xanthine and uric acid were detected consecutively by HPLC in A. ustus and A. tamarii, respectively. The data from absolute quantification analysis suggested that 3-methylxanthine and xanthine were the main degraded metabolites in A. ustus and A. tamarii, respectively. 129.48 ± 5.81 mg/L of 3-methylxanthine and 159.11 ± 10.8 mg/L of xanthine were produced by A. ustus and A. tamarii in 300 mg/L of theophylline liquid medium, respectively.

Conclusions

For the first time, we confirmed that isolated A. ustus, A. tamarii degrade theophylline through N-demethylation and oxidation. We were able to biologically produce 3-methylxanthine and xanthine efficiently from theophylline through a new microbial synthesis platform with A. ustus and A. tamarii as appropriate starter strains.

Production of theophylline via aerobic fermentation of pu-erh tea using tea-derived fungi

Background

Caffeine is one of the most abundant methylxanthines in tea, and it remains stable in processing of general teas. In the secondary metabolism of microorganism, theophylline is the main conversion product in caffeine catabolism through demethylation. Microorganisms, involved in the solid-state fermentation of pu-erh tea, have a certain impact on caffeine level. Inoculating an appropriate starter strain that is able to convert caffeine to theophylline would be an alternative way to obtain theophylline in tea. The purpose of this study was to isolate and identify the effective strain converting caffeine to theophylline in pu-erh tea, and discuss the optimal conditions for theophylline production.

Results

Caffeine content was decreased significantly (p < 0.05) and theophylline content was increased significantly (p < 0.05) during the aerobic fermentation of pu-erh tea. Five dominant fungi were isolated from the aerobic fermentation and identified as Aspergillus niger, Aspergillus sydowii, Aspergillus pallidofulvus, Aspergillus sesamicola and Penicillium mangini, respectively. Especially, A. pallidofulvus, A. sesamicola and P. mangini were detected in pu-erh tea for the first time. All isolates except A. sydowii TET-2, enhanced caffeine content and had no significant influence on theophylline content. In the aerobic fermentation of A. sydowii TET-2, 28.8 mg/g of caffeine was degraded, 93.18% of degraded caffeine was converted to theophylline, and 24.60 mg/g of theophylline was produced. A. sydowii PET-2 could convert caffeine to theophylline significantly, and had application potential in the production of theophylline. The optimum conditions of theophylline production in the aerobic fermentation were 1) initial moisture content of 35% (w/w), 2) inoculation quantity of 8%, and 3) incubation temperature at 35 °C.

Conclusions

For the first time, we find that A. sydowii PET-2 could convert caffeine to theophylline, and has the potential value in theophylline production through aerobic fermentation.

Inhibitory effect of black tea (Camellia sinensis) theaflavins and thearubigins against HCT 116 colon cancer cells and HT 460 lung cancer cells

Recently, phytochemical-based dietary intervention has gained attention as a preventive and curative strategy against cancers owing to their safety, better tolerance, and economics. Against this background, black tea extract which contains the flavanol-3-ol, theaflavins (TF), and thearubigins (TR) with promising anti-oncogenic activity were assessed to determine its in vitro inhibitory impact on colon cancer (HCT 116) and lung cancer cell lines (HT 460). In a dose-dependent manner, results revealed that TF, TR, and their combinations cause inhibition in cell viability. However, TF imparted a maximum reduction in cell viability of HCT 116 and HT 460. Flow cytometry data revealed that TF, TR, and their combinations exhibited substantial cell arrest at the G2/M phase. The influence was more prominent in lung cancer cells (HT 460) when compared with colon cells (HCT 116). All treatments resulted in apoptosis, however, the combination of TF and TR exhibited the highest apoptotic ability in comparison to individual treatments. TF and TR exhibited a synergistic impact and significantly inhibited cell proliferation of HCT 116 and HT 460 in dose- and time-dependent manners by inducing apoptosis and cell cycle arrest, wherein TF showed a more pronounced impact. PRACTICAL APPLICATIONS: Results from the present study revealed that black tea-isolated polyphenols (TF and TR) exhibited a significant inhibition of lung and colon cancer cell growth. A promising synergistic effect of TF and TR as inhibitors of cancer cells was observed. More clinical work, perhaps on a human subject, is needed before these two isolated compounds can be prescribed as anticancer drugs.

Pu-erh Tea Ameliorates Atherosclerosis Associated with Promoting Macrophage Apoptosis by Reducing NF-κB Activation in ApoE Knockout Mice

We explored whether pu-erh tea consumption ameliorates atherosclerosis and the possible mechanism for its effects in apolipoprotein E-deficient (ApoE^−/−) mice. Our data showed that pu-erh tea consumption markedly reduced early fatty streak formation and the advanced fibrofatty plaque sizes. Additionally, the mean proportion of inflammatory macrophages in the plaque decreased, and the number of apoptotic macrophages increased significantly. NF-κB activity in peritoneal macrophages decreased by 75.6% compared to the controls, similar with the levels of IL-6, IL-12, and TNF-α expression. The tea extract increased the apoptosis of RAW264.7 cells by decreasing NF-κB activation and reducing the inflammatory cytokine expression. In conclusion, pu-erh tea ameliorates atherosclerosis progress by alleviating the chronic inflammatory state by reducing NF-κB activation and promoting macrophage apoptosis in atherosclerotic plaques.

Biodegradation of caffeine by whole cells of tea-derived fungi Aspergillus sydowii, Aspergillus niger and optimization for caffeine degradation

BACKGROUND

Pu-erh tea is a traditional Chinese tea and produced by natural solid-state fermentation. Several studies show that the natural microbiota influence caffeine level in pu-erh tea. Our previous research also found that the caffeine declined significantly (p < 0.05) in the fermentation, which suggested that the caffeine level could be influenced by specific strains. The purpose of this study was to isolate and identify microorganisms for caffeine degradation, and this research explored the degradation products from caffeine and optimal condition for caffeine degradation.

RESULTS

11 Fungi were isolated from pu-erh tea fermentation and 7 strains could survive in caffeine solid medium. Two superior strains were identified as Aspergillus niger NCBT110A and Aspergillus sydowii NRRL250 by molecular identification. In the substrate tests with caffeine, A. niger NCBT110A could use caffeine as a potential carbon source while glucose is absent, A. sydowii NRRL250 could degrade 600 mg/L caffeine completely in a liquid medium. During the degradation product analysis of A. sydowii NRRL250, theophylline and 3-methlxanthine were detected, and the level of theophylline and 3-methlxanthine increased significantly (p < 0.05) with the degradation of caffeine. The single factor analysis showed that the optimum conditions of caffeine degradation were 1) substrate concentration of 1200 mg/L, 2) reaction temperature at 30 °C, and 3) pH of 6. In the submerged fermentation of tea infusion by A. sydowii NRRL250, 985.1 mg/L of caffeine was degraded, and 501.2 mg/L of theophylline was produced.

CONCLUSIONS

Results from this research indicate that Aspergillus sydowii NRRL250 was an effective strain to degrade caffeine. And theophylline and 3-methlxanthine were the main caffeine degradation products.

Subacute Oral Toxicity Assesment of Ethanol Extract of Mariposa christia vespertilionis Leaves in Male Sprague Dawley Rats

The term Butterfly tea refers to decoction of Mariposa christia vespertilionis leaves which is widely consumed by cancer patients throughout Malaysia and has gained a huge popularity among Malaysians, not only cancer patients but also researchers to discover the real potential of this plant. Herein, the study is aimed at evaluating the possible toxicity in 28-day subacute oral toxicity of ethanolic extract M. christia vespertilionis in male Sprague Dawley rats. The 28-day subacute toxicity study was conducted to detect the no-observed adverse effect level (NOAEL). In this study, a total of 30 rats were divided into the control, 5% DMSO (vehicle), low dose (75 mg/kg), medium dose (125 mg/kg) and high dose (250 mg/kg) groups. The extract was administered daily from day 1 until day 28. At the end of the study, the animals were humanely sacrificed and assessed for the effect extract of Mariposa christia vespertilionis leaves on body weight and relative organ weights and haematological, biochemical and histopathological parameters. The haematological and serum biochemical parameters for the assessment of kidney and liver injuries were carried out. Results of haematological and serum biochemistry results showed no changes in the control and treated groups. In the histopathology, evaluation of kidney tissues in all treated groups showed no significant (p > 0.05) lesions. In contrast to kidney, liver tissues showed significant differences (p < 0.05) in lesions observed in low dose (430 mg), medium dose (700 mg) and high dose (1480 mg) groups with very mild, mild and mild to moderate lesion of hepatic necrosis, in the respective groups, and very mild hepatic degeneration and hepatitis were scored in all three groups.

In vivo toxicity evaluation of aqueous acetone extract of Terminalia bellirica (Gaertn.) Roxb. fruit

Terminalia bellirica (Gaertn.) Roxb. (Family: Combretaceae), known as Bhibhitaki in Sanskrit and locally known as Behera in India is one of the oldest medicinal plants which has widely been used in the traditional system of medicine, especially in Ayurveda for centuries. The dried fruit of Terminalia bellirica is used for treating various ailments. Aqueous acetone extract of Terminalia bellirica (Gaertn.) Roxb fruits (AATB), showed antioxidant potential in our screening study is selected for the present in vivo toxicity evaluation. Acute administration of AATB was done in female Wistar Albino rats as a single dose up to 2000 mg/kg body weight. At the end of the study, Blood was collected for biochemical and hematological analyses, while histological examinations were performed on liver and kidney. There was no alteration in the behavioral pattern, food and water intake in the treated animals. The relative organ weight, biochemical parameters, hematological parameters and histopathological analysis were also found normal. All the parameters of the toxicity evaluation were found to be normal and the data suggests aqueous acetone extract of Terminalia bellirica fruit is safe, to be used as a traditional herbal formulation for its antioxidant potential and other health benefits.

Pu-erh Tea Protects the Nervous System by Inhibiting the Expression of Metabotropic Glutamate Receptor 5

Glutamate is one of the major excitatory neurotransmitters of the CNS and is essential for numerous key neuronal functions. However, excess glutamate causes massive neuronal death and brain damage owing to excitotoxicity via the glutamate receptors. Metabotropic glutamate receptor 5 (mGluR5) is one of the glutamate receptors and represents a promising target for studying neuroprotective agents of potential application in neurodegenerative diseases. Pu-erh tea, a fermented tea, mainly produced in Yunnan province, China, has beneficial effects, including the accommodation of the CNS. In this study, pu-erh tea markedly decreased the transcription and translation of mGluR5 compared to those by black and green teas. Pu-erh tea also inhibited the expression of Homer, one of the synaptic scaffolding proteins binding to mGluR5. Pu-erh tea protected neural cells from necrosis via blocked Ca²⁺ influx and inhibited protein kinase C (PKC) activation induced by excess glutamate. Pu-erh tea relieved rat epilepsy induced by LiCl-pilocarpine in behavioural and physiological assays. Pu-erh tea also decreased the expression of mGluR5 in the hippocampus. These results show that the inhibition of mGluR5 plays a role in protecting neural cells from glutamate. The results also indicate that pu-erh tea contains biological compounds binding transcription factors and inhibiting the expression of mGluR5 and identify pu-erh tea as a novel natural neuroprotective agent.

Long-term intake of white tea prevents oxidative damage caused by adriamycin in kidney of rats

BACKGROUND

White tea infusion (Camelia sinensis) has antioxidants properties. The infusion contains polyphenols that have been proposed to induce antioxidant response element (ARE) response via nuclear factor E2-related factor 2 (NRF2). Adriamycin (ADR) has antitumour properties and oxidative effects. Oxidative stress is related to a variety of kidney diseases. Prevention of the oxidative stress through long-term intake of white tea and the study of the molecular mechanisms involved in protection could be of great interest. Rats were given distilled water, 0.015 or 0.045 g of solid white tea extract kg(-1) body weight for 12 months. Animals received an injection of ADR. In kidney, oxidative stress parameters were measured, the expressions of nuclear factor E2-related factor 2 gene (Nrf2), and detoxifying and antioxidants genes were analysed, and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) were measured.

RESULTS

ADR administration increased oxidative parameters and decreased the antioxidant activity; significantly increased the expression of analysed genes and the activity of CAT and SOD and decreased GR activity. The highest white tea dose protected redox status and inhibited ARE response.

CONCLUSION

Long-term intake of white tea protected kidney against the oxidative stress. ADR activated the ARE response but in animals treated with the highest dose of white tea, this response was inhibited, probably for antioxidant protection. © 2015 Society of Chemical Industry.

Safety evaluation and antihyperlipidemia effect of aqueous extracts from fermented puerh tea

Fermented puerh tea, having undergone a long period of secondary oxidization and fermentation, has become more and more popular in recent years. In the present paper, a safety evaluation of aqueous extracts from fermented puerh tea (EFPT) was performed, including an oral acute toxicity study in rats and mice, mutation tests, a mouse micronucleus test, mouse sperm abnormality test and a 30 day feeding study in rats. Meanwhile, the antihyperlipidemia effect of EFPT was investigated as well. It was found that the oral maximum tolerated dose of EFPT was more than 10.0 g per kg body weight both in rats and mice. And it had no mutagenicity as judged by negative experimental results of the mutation test. No abnormal symptoms, clinical signs or deaths have been found in rats in each group throughout the experiments. In addition, EFPT in this study showed certain effects on hyperlipidemia.

Repeated dose studies with pure Epigallocatechin-3-gallate demonstrated dose and route dependant hepatotoxicity with associated dyslipidemia

EGCG (Epigallocatechin-3-gallate) is the major active principle catechin found in green tea. Skepticism regarding the safety of consuming EGCG is gaining attention, despite the fact that it is widely being touted for its potential health benefits, including anti-cancer properties. The lack of scientific data on safe dose levels of pure EGCG is of concern, while EGCG has been commonly studied as a component of GTE (Green tea extract) and not as a single active constituent. This study has been carried out to estimate the maximum tolerated non-toxic dose of pure EGCG and to identify the treatment related risk factors. In a fourteen day consecutive treatment, two different administration modalities were compared, offering an improved [i.p (intraperitoneal)] and limited [p.o (oral)] bioavailability. A trend of dose and route dependant hepatotoxicity was observed particularly with i.p treatment and EGCG increased serum lipid profile in parallel to hepatotoxicity. Fourteen day tolerable dose of EGCG was established as 21.1 mg/kg for i.p and 67.8 mg/kg for p.o. We also observed that, EGCG induced effects by both treatment routes are reversible, subsequent to an observation period for further fourteen days after cessation of treatment. It was demonstrated that the severity of EGCG induced toxicity appears to be a function of dose, route of administration and period of treatment.

Acute and subchronic (13-week) toxicity of fermented Acanthopanax koreanum extracts in Sprague Dawley rats

The biological fermentation of plants is usually used to improve their product properties, including their biological activity. Acanthopanax koreanum is a plant indigenous to Jeju, Korea; however, fermented A. koreanum (FAK) has not been guaranteed to be safe. Therefore, in this study, a safety evaluation of aqueous extracts of FAK was performed using Sprague Dawley rats. The acute toxicity of FAK did not influence animal mortality, body weight changes or the animals' clinical appearance at a concentration of 5000 mg/kg body weight. Using doses of 500, 1000 and 2000 mg/kg/day in a subchronic (13-week) toxicity study, the administration of FAK in male rats increased their body weight, food consumption, absolute liver weight, liver-associated enzymes and total cholesterol content. However, these effects of FAK were not considered toxic because the changes were not accompanied by any evidence of clinical signs or any change in the histopathological examination. On the other hand, the FAK-treated female rats did not exhibit significant changes in their body weight, food consumption, absolute and relative organ weights or liver enzymes. These results suggest that the acute oral administration of FAK is non-toxic to rats, and 13 weeks of repeated dosing demonstrated no FAK-related toxicity at a concentration of 2000 mg/kg. Therefore, the no-observed-adverse-effect level (NOAEL) of FAK was determined to be 2000 mg/kg/day for both male and female rats.

General and Genetic Toxicology of Guayusa Concentrate (Ilex guayusa)

Tea from the leaves of guayusa (Ilex guayusa) has a long history of consumption by Ecuadorian natives in regions where the plant is indigenous. The tea contains the methylxanthines caffeine and theobromine as well as chlorogenic acids, flavonoids, and sugars. Various studies were performed to evaluate the general and genetic toxicology of a standardized liquid concentrate of guayusa (GC). Guayusa concentrate was found to be negative in in vitro genotoxicity tests including the Ames test and a chromosome aberration study in human lymphocytes. The oral median lethal dose (LD50) of GC was >5,000 mg/kg for female rats. Guayusa concentrate was administered to male and female rats in a 90-day subchronic study at 1,200, 2,500, and 5,000 mg/kg/d of GC and a caffeine-positive control at 150 mg/kg/d corresponding to the amount of caffeine in the high-dose GC group. Effects observed in the GC-treated groups were comparable to those in the caffeine control group and included reductions in body weights, food efficiency, triglycerides values, and fat pad weights and increases in blood chemistry values for serum aspartate aminotransferase, serum alanine aminotransferase, and cholesterol and adaptive salivary gland hypertrophy. No signs of incremental toxicity due to any other components of guayusa were observed. The studies indicate no harmful effects of GC in these test systems.

Indicience of bacteria nad antibacterial activity of selected types of tea

The purpose of this study was to determine in vitro antibacterial activity of selected teas (Assam: Indian black tea from Camellia sinensis, Pu-erh: darkpu-erh (shu) from Camellia sinensis, Sencha: Japanese green tea from Camellia sinensis) against five species of pathogenic microorganisms. In our study, we determined the total viable count (TVC), yeasts (Y) andEnterobacteriaceae counts (E). MALDI-TOF MS Biotyper was used for identification of colonies after cultivation. Evaluation of the antimicrobial activity was performed by disc diffusion method, well diffusion method and detection of minimum inhibitory concentration (MIC). For antibacterial activity against Escherichia coli CCM 2024, Yersinia enterocolitica CCM 5671, Klebsiella pneumonie CCM 2318, Staphylococus aureus CCM 2461 and Bacillus thurigiensis CCM19 were detected. The inhibition zones were measured in mm in disc diffusion method and well diffusion method. The MIC of the individual extracts was measured spectrophotometrically. The high number of total viable count was found in Pu-erh tea (2.1 log CFU.g-1) and lowest number was found in Assam tea (0.7 log CFU.g-1). The high number of Enterobacteriacea was found in Pu-erh tea (2.03 log CFU.g-1) and lowest in Assam tea (0 log CFU.g-1). The higher number of yeasts was found in Pu-erh tea (1.83 log CFU.g-1) and lowest in Assam tea (0.3 log CFU.g-1). Mass spectrometry revealed the presence of seven Gram positive bacteria Bacillus cereus, B. mycoides, B. pumilus, Enterococcus durans, Staphylococcus epidermis, S. hominis, S. warneri, four Gram negative bacteriaAcinetobacter junii, Hafnia alvei, Klebsiella pneumoniae, Sphingomonas spp. and two yeast - Candida glabrata, Cryptococcus albidus. The results show that certain tea extracts are particularly active against various pathogenic bacteria. Tea extracts (Sencha, Rooibos, Mate, Assam) were found to have the strongest antibacterial activity against Staphylococcus aureus CCM 2461.

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.

Effects of Pu-erh tea aqueous extract (PTAE) on blood lipid metabolism enzymes

Effects of Pu-erh tea aqueous extract (PTAE) on blood lipid metabolism enzymes (e.g.HMGR) are assayedin vitro.

Molecular mechanisms by which white tea prevents oxidative stress

The flavonoid content of tea (Camellia sinensis) has beneficial properties in the prevention of diseases. However, the mechanisms by which white tea can protect against oxidative stress remain unclear. To shed light on this issue, rats were given distilled water (controls), 0.15 mg/day (dose 1) or 0.45 mg/day (dose 2) of solid tea extract/kg body weight for 12 months. All the animals received an injection of adriamycin (ADR; 10 mg/kg body weight), except half of the control group, which were given an injection of saline solution. The expression of the nuclear factor, E2-related factor 2 (Nrf2), NAD(P)H:quinone oxidoreductase 1 (Nqo1), glutathione S-transferase (Gst), haem oxygenase-1 (Ho1), catalase (Cat), superoxide dismutase (Sod) and glutathione reductase (Gr) in liver was analysed by real-time PCR, and the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) was measured spectrophotometrically. ADR significantly increased the expression of Nrf2, Gst, Nqo1, Ho1, Cat, Sod and Gr with respect to the control levels and also increased the activity of CAT, SOD and GR. The intake of white tea increased in a higher degree the expression of Nrf2, Gst, Nqo1 and Ho1 in the tea + ADR group compared with the control group and C + ADR group. In addition, tea + ADR groups decreased the expression and activity of CAT, SOD and GR in a dose-dependent manner.

In vivo toxicity evaluation of a standardized extract of Syzygium aqueum leaf

In this study, the acute and subchronic toxicity effect of the Syzygium aqueum leaf extract (SA) was evaluated. For the acute toxicity study, a single dose of 2000 mg/kg of the SA was given by oral-gavage to male Sprague-Dawley (SD) rats. The rats were observed for mortality and toxicity signs for 14 days. In the subchronic toxicity study the SA was administered orally at doses of 50, 100, and 200 mg/kg per day for 28 days to male SD rats. The animals were sacrificed at the end of the experiment. The parameters measured including food and water intake, body weight, absolute and relative organ weight, blood biochemical tests and histopathology observation. In both the acute and subchronic toxicity studies, SA did not show any visible signs of toxicity. There were also no significant differences between the control and SA treated rats in terms of their food and water intake, body weight, absolute and relative organ weight, biochemical parameters or gross and microscopic appearance of the organs. There were no acute or subchronic toxicity observed and our results indicate that this extract could be devoid of any toxic risk. This is the first in vivo study reported the safety and toxicity of SA.

Metabolic changes during the pu-erh tea pile-fermentation revealed by a liquid chromatography tandem mass-spectrometry-based metabolomics approach

In the current study, liquid chromatography-mass spectrometry combined with multivariate statistical analyses was employed to investigate the time-varying biochemical changes during the pile-fermentation process with the emphasis on the active ingredients to clarify the manufacturing process of ripened pu-erh tea as a whole. The metabolite profiles of different manufacturing processes were unique and could be distinguished with the aid of principal component analysis. Furthermore, partial least-squares discriminant analysis revealed a pairwise discrimination between the raw material group and pile-fermentation process groups or the final product group, and 48 differential metabolites with variable importance in the projection value greater than 1 were identified, which was confirmed by the subsequent hierarchical cluster analysis. These results highlight our current understanding of the exact changing process of the bioactive compounds during the pile fermentation, and the global change of these bioactive compounds provides the special flavor, taste, and health promoting effects of ripened pu-erh tea.

Mineral constituents and toxicological profile of Jateorhiza macrantha (Menispermaceae) aqueous extract

ETHNOPHARMACOLOGICAL RELEVANCE

Jateorhiza macrantha is a medicinal plant used in popular medicine to treat several diseases, including cardiovascular disorders. To date, there is no documented report available on the toxicological profile of this medicinal plant.

THE AIM OF THE STUDY

The present study was carried out to investigate the mineral content and the safety of the oral administration of the leaf aqueous extract of Jateorhiza macrantha in mice.

MATERIALS AND METHODS

The presence of Ca, Mg, K, Na, Cu, Mn, Fe and Zn in the extract was analyzed using Atomic Absorption Spectrophotometer. In the acute toxicity study, Male and female Balb-C mice were administered single doses of 2.5 and 5 g/kg of body weight by gavage, and were monitored for 7 days. In the subacute toxicity study, the extract was administered by gavage at doses of 150, 300 and 600 mg/kg body weight daily for 6 weeks to mice (8 mice/dose/sex). After this period of treatment, 5 mice per sex and per group were sacrificed. The rest of animals per group were observed without any treatment for 2 weeks. After the treatments, some biochemical and hematological parameters were analyzed.

RESULTS

Our findings indicate the presence of all mineral elements tested. Acute study indicates no signs of toxicity at the doses used. The LD50 value is >5.00 g/kg body weight, since there was no death registered at that dose. In subacute study, hematological and biochemical parameters showed a significant decrease in platelet and significant increases in ALT and AST in both sexes and creatinin levels only in male suggesting that some compounds of the plant extract were responsible of disturbances of hematopoiesis, liver and kidney functions.

CONCLUSIONS

Our results show that Jateorhiza macrantha acute toxicity towards animals is very low. However, in subacute administration, this extract induces slight injuries on hematopoiesis, liver and kidney functions, suggesting its use with caution.

Evaluation of reproductive and developmental toxicities of Pu-erh black tea (Camellia sinensis var. assamica) extract in Sprague Dawley rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pu-erh black tea, which is obtained by first parching crude green tea leaves and followed by secondary fermentation with microorganisms, has been believed to be beneficial beverages for health in PR China. But its potential toxicity when administered at a high dose as concentrated extract has not been completely investigated.

AIM OF THE STUDY

The present study was aimed at evaluating potential reproductive and developmental toxicities of Pu-erh black tea extract (BTE) in Sprague Dawley rats.

MATERIALS AND METHODS

Growing rats were given BTE by gavage at levels of 0, 200, 700 and 2500mg/kg/day as the F0 generation in reproductive toxicity study. Additionally, BTE was administered to mate female rats from gestation day 0.5 through 19.5 at the doses of 0, 200, 700 and 2500mg/kg/day to evaluate the developmental toxicity.

RESULTS

In the reproductive toxicity study, only 2500mg/kg/day BTE reduced the body weight gain and altered the relative organ weights including testes, prostata and ovary both for F0 parents and F1 offspring compared to the controls. High dose of BTE (2500mg/kg/day) administration caused developmental disturbances in embryo-to-foetus period including resorbed embryos, decreased embryo size and skeletal anomalies.

CONCLUSION

In conclusion, the no-observed-adverse-effect level of BTE is 700mg/kg/day both for reproductive toxicity and developmental toxicities.

Antioxidant phenolic compounds from Pu-erh tea

Eight compounds were isolated from the water extract of Pu-erh tea and their structures were elucidated by NMR and MS as gallic acid (1), (+)-catechin (2), (−)-epicatechin (3), (−)-epicatechin-3-O-gallate (4), (−)-epigallocatechin-3-O-gallate (5), (−)-epiafzelechin-3-O-gallate (6), kaempferol (7), and quercetin (8). Their in vitro antioxidant activities were assessed by the DPPH and ABTS scavenging methods with microplate assays. The relative order of DPPH scavenging capacity for these compounds was compound 8 > compound 7 > compound 1 > compound 6 > compound 4 ≈ compound 5 > compound 2 > VC (reference) > compound 3, and that of ABTS scavenging capacity was compound 1 > compound 2 > compound 7 ≈ compound 8 > compound 6 > compound 5 > compound 4 > VC (reference) > compound 3. The results showed that these phenolic compounds contributed to the antioxidant activity of Pu-erh tea.

Evaluation of oral subchronic toxicity of Pu-erh green tea (camellia sinensis var. assamica) extract in Sprague Dawley rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pu-erh green tea, originally produced in the Yunnan province of P.R. China for about 1700 years, is believed to be beneficial to health in Asian countries. The potential toxicity of Pu-erh green tea when administered at high doses via concentrated extract, however, has not been completely investigated.

THE AIM OF THE STUDY

The present study was aimed to evaluate the potential toxicity of Pu-erh green tea extract (PGTE) of sub-chronic administration to Sprague Dawley (SD) rats.

MATERIALS AND METHODS

Growing SD rats were administrated orally by gavage with PGTE at doses of 0, 1250, 2500, and 5000 mg/kg/day for 91 consecutive days. Clinical observations, including survival, hematology, serum biochemistry, urinalysis and histopathological examination were measured to monitor treatment-related adverse effects in rats.

RESULTS

The results showed that oral administration of high dose of PGTE led to body weight gain suppression, liver and calcium deposition dysfunctions.

CONCLUSIONS

In conclusion, the no-observed-adverse-effect level for Pu-erh green tea extract derived from the results of the present study was 2500 mg/kg/day for both genders.

Inhibition of advanced glycation end product formation by Pu-erh tea ameliorates progression of experimental diabetic nephropathy

Accumulation of advanced glycation end products (AGEs) has been implicated in the development of diabetic nephropathy. We investigated the effects of Pu-erh tea on AGE accumulation associated with diabetic nephropathy. Although it did not affect blood glucose levels and insulin sensitivy, Pu-erh tea treatment for 8 weeks attenuated the increases in urinary albumin, serum creatinine, and mesangial matrix in db/db mice. We found that Pu-erh tea prevented diabetes-induced accumulation of AGEs and led to a decreased level of receptor for AGE expression in glomeruli. Both production and clearance of carbonyl compounds, the main precursor of AGE formation, were probably attenuated by Pu-erh tea in vivo independent of glyoxalase I expression. In vitro, HPLC assay demonstrated Pu-erh tea could trap methylglyoxal in a dose-dependent manner. Our study raises the possibility that inhibition of AGE formation by carbonyl trapping is a promising approach to prevent or arrest the progression of diabetic complications.

Protective effect of white tea extract against acute oxidative injury caused by adriamycin in different tissues

Adriamycin (ADR) is an anticancer agent that increases oxidative stress in cells. We evaluated the protective effect of the long term consumption of white tea at two different doses against this drug. For this purpose rats were given distilled water (controls), 0.15 mg (Dose 1) or 0.45 mg (Dose 2) of solid tea extract/kg body weight for 12 months. All the animals received an injection of ADR, except half of the control group, which were given an injection of saline solution. This gave four experimental groups: Control (C), C+ADR, Dose 1+ADR, and Dose 2+ADR. The antioxidant activity (in liver, heart and brain microsomes) was analysed. White tea consumption for 12 months, at a non-pharmacological dose, reversed the oxidative damage caused by ADR, on both protein and lipid levels in all three organs. The heart recovered its antioxidant activity only at the highest dose of tea.

Pu-erh tea inhibits tumor cell growth by down-regulating mutant p53

Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms' metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects.