Modification of metal-induced micronuclei formation in mouse bone marrow erythrocytes by Phyllanthus fruit extract and ascorbic acid

Critical review of the publications on the genotoxicology of aluminium salts: 1990-2018

Since the mid-1970s, there have been many reports that purport to implicate aluminium in the aetiology of neurodegenerative disease. After several decades of research, the role of aluminium in such disease remains controversial and is not the subject of this review. However, if aluminium is implicated in such disease then it follows that there must be a toxicological mechanism or mode of action, and many researchers have investigated various potential mechanisms including the involvement of oxidative damage, cytotoxicity and genotoxicity. This paper reviews many of the publications of studies using various salts of aluminium and various genotoxicity end points, both in vitro and in vivo, with a focus on oxidative damage. The conclusion of this review is that the majority, if not all, of the publications that report positive results have serious technical flaws and/or implausible findings and consequently should contribute little or no weight to a weight of evidence (WoE) argument. There are many high-quality, Good Laboratory Practice (GLP)-compliant genotoxicity studies, that follow relevant OECD test guidelines and the European Chemicals Agency (ECHA) integrated mutagenicity testing strategy, on several salts of aluminium; all demonstrate clear negative results for both in vitro and in vivo genotoxicity. In addition, the claim for an oxidative mode of action for aluminium can be shown to be spurious. This review concludes that there are no reliable studies that demonstrate a potential for genotoxicity, or oxidative mode of action, for aluminium.

(Ascorb)ing Pb Neurotoxicity in the Developing Brain

Lead (Pb) neurotoxicity is a major concern, particularly in children. Developmental exposure to Pb can alter neurodevelopmental trajectory and has permanent neuropathological consequences, including an increased vulnerability to further stressors. Ascorbic acid is among most researched antioxidant nutrients and has a special role in maintaining redox homeostasis in physiological and physio-pathological brain states. Furthermore, because of its capacity to chelate metal ions, ascorbic acid may particularly serve as a potent therapeutic agent in Pb poisoning. The present review first discusses the major consequences of Pb exposure in children and then proceeds to present evidence from human and animal studies for ascorbic acid as an efficient ameliorative supplemental nutrient in Pb poisoning, with a particular focus on developmental Pb neurotoxicity. In doing so, it is hoped that there is a revitalization for further research on understanding the brain functions of this essential, safe, and readily available vitamin in physiological states, as well to justify and establish it as an effective neuroprotective and modulatory factor in the pathologies of the nervous system, including developmental neuropathologies.

Protective role of ascorbic acid on lead-induced damage to the thyroid gland in the rat

Lead exposure is known to affect the pituitary-thyroid axis. Likewise, ascorbic acid (AA) has a protective action against lead poisoning. We examine the protective role of AA in lead-induced damage to the thyroid gland. The Wistar rats were divided into three groups: control that received 0.2% AA in drinking water throughout the experiment (15 days), intoxicated with lead acetate (20 mg/kg) intraperitoneally every 48 h for 15 days, and the experimental group treated with lead acetate and 0.2% AA in drinking water throughout the experiment. Plasma thyroid-stimulating hormone, triiodothyronine, thyroxine, and lead were determined. The thyroid gland was weighed, then epithelial cell height and nuclear volume were measured on histological slides. The results show that AA reduced the thyroid atrophy caused by lead acetate, as well as the loss of weight of the gland. In addition, it prevented the decrease of the hormone triiodothyronine, although the thyroxine hormone remained lower than the control values ​​and the thyroid-stimulating hormone remains high. Our results indicated that AA could play a protective role in lead poisoning in the thyroid gland.

Composition and biological activities of hydrolyzable tannins of fruits of Phyllanthus emblica

Fruits of emblic leafflower have been used as food and traditional medicine in Asia. A wide range of biological activities have been shown in modern research suggesting potential of the fruits as healthy food and raw material for bioactive ingredients of food. Hydrolyzable tannins are among the major bioactive components of the fruits. Mucic acid gallate, mucic acid lactone gallate, monogalloylglucose, gallic acid, digalloylglucose, putranjivain A, galloyl-HHDP-glucose, elaeocarpusin, and chebulagic acid are the most abundant hydrolyzable tannins. The compositional profiles of tannins in the fruits vary depending on the cultivars as well as ripening stages. Fruits and tannin-rich extracts of fruits have shown antidiabetic, antimicrobial, anti-inflammatory, and immune-regulating activities in vitro and in animal studies. The fruits and fruit extracts have manifested protective effects on organs/tissues from damages induced by chemicals, stresses, and aging in animal models. The fruits and fruit extracts have potential in inhibiting the growth of cancer cells and reducing DNA damage induced by chemicals and radiation. Antioxidative activities are likely among the mechanisms of the biological activities and physiological effects. Human intervention/clinical studies are needed to investigate the bioavailability and metabolism of the tannins and to substantiate the health benefits in humans. Emblic leafflower may be a potential raw material for natural food preservatives.

Immunomodulatory role of Emblica officinalis in arsenic induced oxidative damage and apoptosis in thymocytes of mice

BACKGROUND

Arsenic is widely distributed in the environment and has been found to be associated with the various health related problems including skin lesions, cancer, cardiovascular and immunological disorders. The fruit extract of Emblica officinalis (amla) has been shown to have anti-oxidative and immunomodulatory properties. In view of increasing health risk of arsenic, the present study has been carried out to investigate the protective effect of amla against arsenic induced oxidative stress and apoptosis in thymocytes of mice.

METHODS

Mice were exposed to arsenic (sodium arsenite 3 mg/kg body weight p.o.) or amla (500 mg/kg body weight p.o.) or simultaneously with arsenic and amla for 28 days. The antioxidant enzyme assays were carried out using spectrophotometer and generation of ROS, apoptotic parameters, change in cell cycle were carried out using flow cytometer following the standard protocols.

RESULTS

Arsenic exposure to mice caused a significant increase in the lipid peroxidation, ROS production and decreased cell viability, levels of reduced glutathione, the activity of superoxide dismutase, catalase, cytochrome c oxidase and mitochondrial membrane potential in the thymus as compared to controls. Increased activity of caspase-3 linked with apoptosis assessed by the cell cycle analysis and annexin V/PI binding was also observed in mice exposed to arsenic as compared to controls. Co-treatment with arsenic and amla decreased the levels of lipid peroxidation, ROS production, activity of caspase-3, apoptosis and increased cell viability, levels of antioxidant enzymes, cytochrome c oxidase and mitochondrial membrane potential as compared to mice treated with arsenic alone.

CONCLUSIONS

The results of the present study exhibits that arsenic induced oxidative stress and apoptosis significantly protected by co-treatment with amla that could be due to its strong antioxidant potential.

Therapeutic potential of Phyllanthus emblica (amla): the ayurvedic wonder

Medicinal plants are nature's gift to human beings to promote a disease free healthy life. Many medicinal plants are present in a group of herbal preparations of the Indian traditional health care system (Ayurveda) named Rasayana proposed for their interesting antioxidant activities. Phyllanthus emblica Linn. (syn. Emblica officinalis), commonly known as Indian gooseberry or amla, family Euphorbiaceae, is an important herbal drug used in unani (Graceo - arab) and ayurvedic systems of medicine. The plant is used both as a medicine and as a tonic to build up lost vitality and vigor. Phyllanthus emblica is highly nutritious and could be an important dietary source of vitamin C, amino acids, and minerals. The plant also contains phenolic compounds, tannins, phyllembelic acid, phyllembelin, rutin, curcum-inoids, and emblicol. All parts of the plant are used for medicinal purposes, especially the fruit, which has been used in Ayurveda as a potent rasayana and in traditional medicine for the treatment of diarrhea, jaundice, and inflammation. Various plant parts show antidiabetic, hypolipidemic, antibacterial, antioxidant, antiulcerogenic, hepatoprotective, gastroprotective, and chemopreventive properties. Here we discuss its historical, etymological, morphological and pharmacological aspects.

Protective effect of Kalpaamruthaa in combating the oxidative stress posed by aflatoxin B1-induced hepatocellular carcinoma with special reference to flavonoid structure-activity relationship

AIMS/BACKGROUND

Aflatoxin B1 (AFB1) is a potent hepatotoxic and hepatocarcinogenic mycotoxin. It has been postulated to play a major role in the aetiology of primary human liver cancer. Lipid peroxidation (LPO) is one of the main manifestations of oxidative damage and has been found to play an important role in the toxicity and carcinogenesis of many carcinogens. The present investigation aimed at assessing the effect of Kalpaamruthaa (KA), a modified Siddha preparation, on AFB1-mediated hepatocellular carcinoma (HCC).

METHODS

The drug was administered orally (300 mg/kg body weight/day) for 28 days to HCC-bearing rats. The level of lipid peroxides, antioxidant enzymes, glutathione and glutathione-metabolizing enzyme activity were determined in the plasma, haemolysate and liver homogenate of control and experimental rats.

RESULTS

Rats subjected to AFB1showed a decline in the thiol capacity of the cell, accompanied by high malondialdehyde levels along with lowered activities of enzymic and non-enzymic antioxidant and glutathione-metabolizing enzyme levels. KA treatment restored the deranged LPO and enzyme activities almost to control levels, thereby suggesting hepatoprotection.

CONCLUSION

This study highlighted the beneficial effect of KA in reversing the damage posed by AFB1 and thereby bringing about an improvement in the antioxidant status to combat the oxidative stress.

Anticlastogenic effects of Hibiscus sabdariffa fruits against sodium arsenite-induced micronuclei formation in erythrocytes in mouse bone marrow

An in vivo micronucleus assay using albino mice was used to examine the anticlastogenic effects of a crude aqueous extract of Hibiscus sabdariffa fruits in bone marrow cells of mice. Various doses of freshly prepared crude extract of Hibiscus sabdariffa (50, 100 and 150 mg/kg b.w.) were given by gavaging to male laboratory bred Swiss albino mice for 7 days as a dietary supplement followed by a single dose of sodium arsenite (2.5 mg/kg b.w.) After 24 h, the animals were killed and bone marrow smears were prepared and stained in Giemsa. The results show that sodium arsenite effectively induced micronuclei in polychromatic erythrocytes (PCEs). Administration of a crude extract of Hibiscus sabdariffa led to a significant reduction of micronuclei in PCEs. The results also show that a combination of Hibiscus sabdariffa and sodium arsenite reduced significantly the frequencies of micronucleated PCEs induced by sodium arsenite.

Role of vitamin C on lead acetate induced spermatogenesis in swiss mice

In the present study significantly increased lipid peroxidation value (LPP) after a single intraperitioneal injection of lead acetate (LA) (100 mg/kg b.w.) indicated enormous generation of Reactive Oxygen Species (ROS). Lead-induced ROS has a direct inhibitory effect on the growth and differentiation of the spermatogonial cells showing a significant decline in sperm count. Chromosomal analysis of the primary spermatocytes at week 4 post-treatment in lead-treated mice revealed significantly higher no of aberrant cells including chromosomal deficiency, autosomal and XY-asynapsis plates compared to untreated control mice, Sperm morphology studies at week 1-4 and at week 8 post-treatment, indicated higher percentage of deformed sperm population compared to vehicle injected groups of mice. Supplementation of vitamin C (Vit C) at a dose of 10 mg/kg body weight to lead-treated mice groups, however, significantly reduced the LPP with a concomitant increase in sperm count, marked decrease in the no of aberrant cells and significant decline in the percentage of morphologically abnormal sperm population. Protective role of Vit C in combating lead-induced oxidative stress in mice testicular cells, has been discussed.

Cyto-protective and immunomodulating properties of Amla (Emblica officinalis) on lymphocytes: an in-vitro study

The fruits extracts of Emblica officinalis (Amla) has been reported to have strong anti-oxidant properties. There is a paucity of studies on the immunomodulatory properties of fruit extracts of Amla in immuno-compromised states, with the emphasis on lymphocytes. Therefore, the aim of the study was to determine the anti-oxidant and immunomodulatory properties of Amla using chromium (VI) as an immunosuppressive agent. Chromium (Cr) treatment results in enhanced cytotoxicity, free radical production, lipid peroxidation and decreased glutathione peroxidase (GPx) activity and diminished glutathione (GSH) levels. There was a significant inhibition of both lipopolysaccharide and concanavalin-A-stimulated lymphocyte proliferation. Chromium also inhibited Con A stimulated interleukin-2 and gamma-interferon production significantly. Further, there was enhanced apoptosis and DNA fragmentation in the presence of Cr. Amla significantly inhibited Cr-induced free radical production and restored the anti-oxidant status back to control level. Amla also inhibited apoptosis and DNA fragmentation induced by Cr. Interestingly, Amla relieved the immunosuppressive effects of Cr on lymphocyte proliferation and even restored the IL-2 and gamma-IFN production considerably.

Studies on the antimutagenesis of Phyllanthus orbicularis: mechanisms involved against aromatic amines

Phyllanthus orbicularis is a medicinal plant, endemic to Cuba, whose aqueous extract has proven antiviral properties. This plant extract is being studied for treatment of viral diseases in animals and humans. Antimutagenic activities of this plant aqueous extract have been investigated as an additional and possible valuable property. Antimutagenesis was assayed against the mutagenic activity of m-phenylenediamine (m-PDA), 2-aminofluorene (2-AF), 1-aminopyrene (1-AP), 2-aminoanthracene (2-AA) and 9-aminophenantrene (9-AP) in Salmonella typhimurium (S. typhimurium) YG1024, in different co-treatment approaches. This plant extract produced a significant decrease of the mutagenesis mediated by these aromatic amines (AA) in the following order: m-PDA>2-AA>2-AF>9-AP>1-AP. Interactions with S9 enzymes and transformation of promutagenic amines and their mutagenic metabolites by chemical reactions to non-mutagenic compounds are proposed as possible mechanisms of antimutagenesis. Mutagenesis mediated by m-PDA was almost completely abolished when S9 mixture was co-incubated with the plant extract during 40 min, previous to the addition of the m-PDA and bacterial cells to the assay. Similar results were found with 2-AA and 1-AP, but the reduction of the mutation rate was not so dramatic. In contrast, the most significant antimutagenic effect against 2-AF and 9-AP was seen when these chemicals were co-incubated with the plant extract, before addition of the S9 mixture and bacterial cells to the assay. Therefore, inhibition or competition for S9 enzymes seems to be the main antimutagenic mechanism of this plant extract against m-PDA, 2-AA and 1-AP, whilst a chemical modification of 2-AF and 9-AP into non-promutagenic derivatives is likely to be the main mechanism of antimutagenesis against both compounds.

Review on some plants of Indian traditional medicine with antioxidant activity

A lot of medicinal plants, traditionally used for thousands of years, are present in a group of herbal preparations of the Indian traditional health care system (Ayurveda) named Rasayana proposed for their interesting antioxidant activities. Among the medicinal plants used in ayurvedic Rasayana for their therapeutic action, some of these have been throughly investigated. In the present paper seven plants (Emblica officinalis L., Curcuma longa L., Mangifera indica L., Momordica charantia L., Santalum album L., Swertia chirata Buch-Ham, Withania somnifera (L.) Dunal) are viewed for their historical, etymological, morphological, phytochemical and pharmacological aspects. The plants described contain antioxidant principles, that can explain and justify their use in traditional medicine in the past as well as the present. In order to identify the plants with antioxidant activity in Ayurveda, a formulation of some rasayanas with well defined antioxidant properties has been examinated. For this purpose, we have considered Sharma's work on the preparation MAK4, MAK5, MA631, MA 471, MA Raja's Cup, MA Student Rasayana, MA Ladies Rasayana.

Inhibitory effect of Emblica officinalis on the in vivo clastogenicity of benzo[a]pyrene and cyclophosphamide in mice

Benzo[a]pyrene (B[a]P) and cyclophosphamide (CP) are potent carcinogens/mutagens. Effect of Emblica officinalis extract administration on the in vivo genotoxicity of B[a]P and CP was studied using bone marrow chromosomal aberration and micronucleus induction tests in mice. Three doses (50, 250 and 500 mg/kg body weight) of the plant extract were administered orally for 7 consecutive days prior to the administration of single dose of mutagens (B[a]P 125 mg/kg oral; CP 40 mg/kg i.p.). It was found that administration of 250 and 500 mg/kg of E. officinalis extract significantly inhibited the genotoxicity of B[a]P as well as CP in both the assay systems. Administration of 50 mg/kg of the plant extract had no inhibitory effect. Vitamin C, a major constituent of E. officinalis when administered at dose level of 9 mg/kg b.w. (the approximate estimated amount present in the highest dose of plant extract, i.e. 500 mg) for 7 days did inhibit chromosomal aberrations and micronuclei induction, but not in a significant manner. Effect of administration of the abovementioned effective doses (250 and 500 mg/kg oral for 7 days) of plant extract and vitamin C (9 mg/kg oral for 7 days) on the hepatic activation and detoxification enzymes was also studied. Significant induction in the levels of glutathione content (GSH) and of antioxidant and detoxification enzymes viz., glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S transferase (GST) resulted from plant extract treatment to animals. On the other hand, cytochrome P 450 level was significantly decreased in the plant-extract-treated animals. There was no significant change in cytochrome P 450, GSH contents and activities of enzymes on treatment with vitamin C. The data indicate that the possible mechanism of inhibition by plant extract is mediated by its modulatory effect on hepatic activation and disposition processes.

Protection against cytotoxic effects of arsenic by dietary supplementation with crude extract of Emblica officinalis fruit

Dietary administration of a crude aqueous extract of Emblica officinalis Gaertn. fruit reduced significantly the cytotoxic effects of sodium arsenite administered orally. The crude extract (685 mg/kg bw) was given daily by gavaging to age and sex matched laboratory bread Swiss albino mice for 7 and 14 days, followed by a single dose of sodium arsenite (2.5 mg/kg bw = 1/10 of LD(50)). The animals were killed after 24 h and chromosome preparations made following a schedule of colchicine-fixative-air drying-Giemsa. The endpoints screened were chromosomal aberrations and damaged cells. The crude extract reduced arsenic damage bringing the cells almost to the normal level.

Dietary chemoprevention of clastogenic effects of 3,4-benzo(a)pyrene by Emblica officinalis Gaertn. fruit extract

Dietary supplementation with extract of fruit of Emblica officinalis Gaertn. (a rich source of vitamin C) to mice in vivo significantly reduced the cytotoxic effects of a known carcinogen, 3,4-benzo(a)pyrene. Age-matched Swiss albino mice were fed by gavaging the fruit extract daily for 28 days. From day 9, one dose of the carcinogen was given on alternate days up to a total of eight doses. On day 29, all mice were transferred to normal diet. Control sets received the extract alone, the carcinogen alone and olive oil alone. All mice were sacrificed at 12 weeks and 14 weeks after the end of the experiment. Chromosome preparations were made from bone marrow after the usual colchicine-hypotonic-fixative-air drying-Giemsa staining schedule. Cytogenetic end points screened were the frequencies of chromosomal aberrations and of damaged cells induced. The cytotoxic effects were significantly lower in the mice given the fruit extract with the carcinogen than in those given the carcinogen alone.

Chlorophyll and chromosome breakage

Increased consumption of green vegetables in the diet has been associated with protection against carcinogenic effects and related mutagenic and clastogenic (chromosome breaking) activity of genotoxic agents. Chlorophyll, present in all green plant parts, has been suggested to be a major protective factor in the process. We have, however, observed that while a crude aqueous extract of Indian spinach leaf significantly reduced genotoxic effects, chlorophyll alone was ineffective. On the other hand, chlorophyll, both as an aqueous extract from the leaf and in a purified commercial form, induced a significantly high frequency of chromosome breaks in bone marrow cells of mice on oral administration. The crude aqueous extract of the leaf was non-toxic. The protective activity of the crude leaf extract may be attributed to the total effect of the interaction between different components, in which the clastogenicity of chlorophyll has been neutralized.

Bone marrow micronucleus assay: a review of the mouse stocks used and their published mean spontaneous micronucleus frequencies

We have examined published negative control data from 581 papers on micronucleated bone marrow polychromatic erythrocytes (mnPCE) for differences in mean frequency and the frequency distribution profile among the mouse stocks used with the bone marrow micronucleus assay. For the 55 mouse stocks with published micronucleus assay data, the overall mean frequency is 1.95 mnPCE/1,000 PCE (1.95 mnPCE/1,000); for the 13 stocks most commonly used in the assay, it is 1.88 mnPCE/1,000. During the last 5 years, the mnPCE rate for these 13 major stocks has been 1.74 mnPCE/1,000. This current mean frequency is a substantial decrease from the mean of 3.07 mnPCE/1,000 observed for these 13 stocks for data published prior to 1981. Of the major stocks, the highest mean mnPCE negative control frequencies were observed for MS/Ae > BALB/c > C57Bl/6, and the lowest for CD-1 < Swiss Webster. We note that hybrid mouse stocks appear to have lower and less variable negative control frequencies than either of their parent strains and that the negative control frequency for some progeny stocks have diverged significantly from that of the parent stocks. Overall mean negative control frequencies appear to be correlated with breadth of the frequency distribution profile of published mean negative control values. Furthermore, a possible correlation between negative control frequency in the micronucleus assay and sensitivity to clastogens of different mouse strains may be indicated. The databases generated here allow us to define a range of norms for both the historical mean frequency and individual experimental mean frequencies for most stocks, but in particular, for the more commonly used mouse stocks. Our analysis, for the most part, bears out the recommendation of the first Gene-Tox Report on the micronucleus assay that the historical negative control frequency for a mouse stock should fall between 1 and 3 mnPCE/1,000. Eighty-six percent of the most commonly used mouse stocks have historical mean frequencies within this range. Though individual experimental mean values would not necessarily be expected to fall within the 1-3.00 mnPCE/1,000 range, 65.3% of the 2,327 published negative control values do, and 83.5% are < 3 mnPCE/1,000. The frequency with which an individual experimental mean value lies outside the 1.00 to 3.00 mnPCE/1,000 range differs among stocks and appears related to the mouse mean frequency. We suggest that the recommended range for historical mean frequency be extended slightly, to approximately 3.4 mnPCE/1,000, to accommodate some commonly used strains with overall mean negative control frequencies just above 3.00 mnPCE/1,000.(ABSTRACT TRUNCATED AT 400 WORDS)