Evaluation of the genotoxic potential of Mangifera indica L. extract (Vimang), a new natural product with antioxidant activity

"Mango in all her majesty"-the potential of mangiferin and its analogues in the inhibition of Eimeria tenella hexokinase-a computational approach

The potential of natural products in mitigating infections and diseases are being considered lately. Herein, via in silico methods, we report the possible molecular mechanism of mangiferin (isolated from the fruit, peel, bark and leaves of mango tree) and its derivatives in inhibiting Eimeria tenella hexokinase. We evaluated the binding affinity of these inhibitors to the glucose binding site of EtHK and thereafter proceeded to molecular dynamics simulation. The Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) reveals that three of the derivatives (CPAMM, MxPAMM and NAMM) had better total binding free energy than mangiferin. The ADMET and physicochemical properties assessed shows that inhibitors also hold a potential to be drug-likely. Finally, in mediating their inhibitory potentials, the ligands stabilize both the global and local structures of the protein. This study provides a theoretical premise on which the anti-coccidial propensities of mangiferin most especially its derivatives can be investigate in vitro and in vivo.Communicated by Ramaswamy H. Sarma.

Bioactive extracts from brewer's spent grain

In this study, antioxidant-rich extracts from brewer's spent grain (BSG) extracted by solid-to-liquid extraction using different solvents water and ethanol and their mixtures at two ratios (80% ethanol : water (v/v) and 60% ethanol : water (v/v)) were characterized. Nutritional composition was evaluated for the extracts and for the solid residues obtained after extraction. Additionally, the extracts were analyzed for the total phenolic content and individual phenolic compounds and related biological properties including antioxidant capacity (ABTS; ORAC and DNA protection), antihypertensive capacity, antibacterial activity and antibiofilm capacity. Safety was also demonstrated through genotoxicity and cytotoxicity tests. The results obtained showed that while all the extracts exhibited high antioxidant capacity (except ethanolic extract), the highest values were obtained for the 60% ethanol : water extract. The identification of phenolic compounds using HPLC showed that catechin and vanillin were the main compounds identified with the highest concentration being obtained for 60% ethanol : water extraction. In the biological activity assays, water and hydroethanolic extracts were multifunctional (antioxidant and antihypertensive capacity, antibacterial and antibiofilm activity), and the 80% ethanol : water presented better results in some assays. All were non-genotoxic, but the cytotoxicity was dependent on the extract concentration, with complete safe application for all up to 1 mg mL-1. Therefore, this study shows the potential of a viable green solvent based and low cost extraction recovery method of bioactive compounds from brewer's spent grain.

Evaluation of cytogenotoxic potential of Morinda lucida leaf extract on Swiss albino male mice using two bioassays

BACKGROUND

Utilization of Morinda lucida for the treatment of ailments such as malaria, diarrhea, infertility in women, and dysentery in many countries including Nigeria is on increase due to its efficiency, availability, and affordability. However, its cytogenotoxicity has not been elucidated. This study investigated the phytochemical constituents and possible genotoxic and cytotoxic effects of M. lucida leaf extract in Swiss albino male mice using bone marrow micronucleus and sperm morphology assays.

METHODS

Plant materials was collected, thoroughly washed, and air-dried at room temperature prior to maceration. The extract was assessed for the presence of the phytochemical compounds. Swiss albino male mice (Mus musculus) (n=4) were treated with different concentrations of this extract (400 mg/kg, 800 mg/kg, and 1200 mg/kg) while distilled water was used as negative control.

RESULTS

Phytochemical analysis revealed that the extract contains saponins, terpenoids, flavonoids, glycosides, and tannins. We observed micronucleated polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE) of 3.20%, 1.10%, and 1.95% at different concentrations of 400 mg/kg, 800 mg/kg, and 1200 mg/kg respectively in the treated animals. The result showed no significant increase in the frequency of abnormalities (p < 0.05) when compared to the negative control; however, in separate analysis of mono-micronucleated PCE and mono-micronucleated NCE per group, a significant increase at 400 mg/kg and 1200 mg/kg concentrations was observed. The sperm anomalies decreased with increase in concentration.

CONCLUSIONS

This study recommends 800 mg/kg concentration of the plant extract; however, it should be further and properly investigated as it contains some pharmaceutical components that can be used for pharmacological purposes.

A Toxicological Evaluation of Mango Leaf Extract (Mangifera indica) Containing 60% Mangiferin

A battery of OECD- and GLP-compliant toxicological studies was performed on mango leaf extract (Mangifera indica) containing 60% mangiferin (MLE). No evidence of genotoxicity was found in a bacterial reverse mutation test (Ames). While evidence of clastogenic activity was noted in an in vitro chromosomal aberration test, an in vivo mammalian micronucleus test showed no findings up to the limit dose (2000 mg/kg bw). A 90-day repeated dose oral toxicity study was conducted in rats using doses of 0 (vehicle control), 500, 1000, and 2000 mg/kg bw/day. Based on the lack of mortality or toxic effects in the 90-day study, the NOAEL for MLE in Han:Wist male and female rats was determined to be 2000 mg/kg bw/day, the highest dose tested.

Mangiferin: A multipotent natural product preventing neurodegeneration in Alzheimer's and Parkinson's disease models

Alzheimer's disease (AD) and Parkinson's disease (PD) are recognized as the universal neurodegenerative diseases, with the involvement of misfolded proteins pathology, leading to oxidative stress, glial cells activation, neuroinflammation, mitochondrial dysfunction, and cellular apoptosis. Several discoveries indicate that accumulation of pathogenic proteins, i.e. amyloid β (Aβ), the microtubule-binding protein tau, and α-synuclein, are parallel with oxidative stress, neuroinflammation, and mitochondrial dysfunction. Whether the causative factors are misfolded proteins or these pathophysiological changes, leading to neurodegeneration still remain ambiguous. Importantly, directing pharmacological researches towards the prevention of AD and PD seem a promising approach to detect these complicating mechanisms, and provide new insight into therapy for AD and PD patients. Mangiferin (MGF, 2-C-β-D-glucopyranosyl-1, 3, 6, 7-tetrahydroxyxanthone), well-known as a natural product, is detached from multiple plants, including Mangifera indica L. With the structure of C-glycosyl and phenolic moiety, MGF possesses multipotent properties starting from anti-oxidant effects, to the alleviation of mitochondrial dysfunction, neuroinflammation, and cellular apoptosis. In particular, MGF can cross the blood-brain barrier to exert neuronal protection. Different researches implicate that MGF is able to protect the central nervous system from oxidative stress, mitochondrial dysfunction, neuroinflammation, and apoptosis under in vitro and in vivo models. Additional facts support that MGF plays a role in improving the declined memory and cognition of rat models. Taken together, the neuroprotective capacity of MGF may stand out as an agent candidate for AD and PD therapy.

Toxicological studies on the botanical supplement LI12542F6 containing extracts of Sphaeranthus indicus flower heads and Mangifera indica (mango tree) bark

LI12542F6, a botanical extract composed of Sphaeranthus indicus and Mangifera indica, was evaluated for mutagenicity in bacteria, clastogenicity in mouse bone marrow, acute oral and dermal toxicity in the rat, irritation (dermal, eye) in rabbit, and subacute and subchronic toxicity (28 and 90 days) in the rat. All studies followed standard OECD test protocols, in accordance with the principles of Good Laboratory Practice (GLP). LI12542F6 did not induce mutations in the bacterial assay using Salmonella and Escherichia coli strains, nor did it induce genotoxic effects in erythrocytes from mouse bone marrow. LI12542F6 was found to have oral and dermal LD 50 values greater than the limit dose of 2,000 mg/kg body weight in the rat. In an eye irritation/corrosion test, LI12542F6 caused conjunctival redness, corneal opacity, and chemosis and is classified as Category 2A ("irritating to eyes - reversible eye effect"). Doses in the 28-day and 90-day rat oral toxicity studies were 0, 500, 1,000, and 1,500 and 0, 1,000, 1,500, and 2,000 mg/kg body weight/day, respectively, administered by gavage. Both studies featured a recovery period. Minor effects were random and not treatment related except for local irritation of the forestomach in the 28-day study, evidenced by histopathologic examination, in mid- and high-dose animals. The frequency and severity of these effects were reduced in the recovery group; irritation was not found in the forestomach of rats in the 90-day study. The no observed adverse effect level (NOAEL) was greater than the highest dose tested, that is, >2,000 mg/kg in the 90-day study. This botanical composition will be marketed commercially for muscle health as Myotor™.

Assessment of genetic integrity, splenic phagocytosis and cell death potential of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid and its effect when combined with commercial chemotherapeutics

The increased incidence of cancer and its high treatment costs have encouraged the search for new compounds to be used in adjuvant therapies for this disease. This study discloses the synthesis of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid (IR-01) and evaluates not only the action of this compound on genetic integrity, increase in splenic phagocytosis and induction of cell death but also its effects in combination with the commercial chemotherapeutic agents doxorubicin, cisplatin and cyclophosphamide. IR-01 was designed and synthesized based on two multifunctionalyzed structural fragments: 4-aminoantipyrine, an active dipyrone metabolite, described as an antioxidant and anti-inflammatory agent; and the pharmacophore fragment 1,4-dioxo-2-butenyl, a cytotoxic agent. The results indicated that IR-01 is an effective chemoprotector because it can prevent clastogenic and/or aneugenic damage, has good potential to prevent genomic damage, can increase splenic phagocytosis and lymphocyte frequency and induces cell death. However, its use as an adjuvant in combination with chemotherapy is discouraged since IR-01 interferes in the effectiveness of the tested chemotherapeutic agents. This is a pioneer study as it demonstrates the chemopreventive effects of IR-01, which may be associated with the higher antioxidant activity of the precursor structure of 4-aminoantipyrine over the effects of the 1,4-dioxo-2-butenyl fragment.

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS.

Antimicrobial and Antiproliferative Potential of Anadenanthera colubrina (Vell.) Brenan

The aim of the present study was to perform an in vitro analysis of the antimicrobial and antiproliferative potential of an extract from Anadenanthera colubrina (Vell.) Brenan (angico) and chemically characterize the crude extract. Antimicrobial action was evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration, and the inhibition of formation to oral biofilm. Cell morphology was determined through scanning electron microscopy (SEM). Six strains of tumor cells were used for the determination of antiproliferative potential. The extract demonstrated strong antifungal activity against Candida albicans ATCC 18804 (MIC = 0.031 mg/mL), with similar activity found regarding the ethyl acetate fraction. The extract and active fraction also demonstrated the capacity to inhibit the formation of Candida albicans to oral biofilm after 48 hours, with median values equal to or greater than the control group, but the difference did not achieve statistical significance (P > 0.05). SEM revealed alterations in the cell morphology of the yeast. Regarding antiproliferative activity, the extract demonstrated cytostatic potential in all strains tested. The present findings suggest strong antifungal potential for Anadenanthera colubrina (Vell.) Brenan as well as a tendency toward diminishing the growth of human tumor cells.

Effects of a Mangifera indica L. stem bark extract and mangiferin on radiation-induced DNA damage in human lymphocytes and lymphoblastoid cells

OBJECTIVES

Mangifera indica L. (mango) stem bark aqueous extract (MSBE) that has antioxidant, anti-inflammatory and immunomodulatory properties, can be obtained in Cuba. It is rich in polyphenols, where mangiferin is the main component. In this study, we have tested DNA damage and protection effects of MSBE and mangiferin on primary human lymphocytes and lymphoblastoid cells.

MATERIAL AND METHODS

Cell suspensions were incubated with the products (50-1000 μg/ml) for experiments on damage induction, and evaluation of any potential protective effects (5-100 μg/ml) for 60 min at 37 °C. Irradiation was performed using a γ-ray source, absorbed dose 5 Gy. At the end of exposure, DNA damage, protection and repair processes were evaluated using the comet assay.

RESULTS

MSBE (100-1000 μg/ml) induced DNA damage in a concentration dependent manner in both cell types tested, primary cells being more sensitive. Mangiferin (200 μg/ml) only induced light DNA damage at higher concentrations. DNA repair capacity was not affected after MSBE or mangiferin exposure. On the other hand, MSBE (25 and 50 μg/ml) and mangiferin (5-25 ug/ml) protected against gamma radiation-induced DNA damage.

CONCLUSIONS

These results show MSBE has protector or harmful effects on DNA in vitro depending on the experimental conditions, which suggest that the extract could be acting as an antioxidant or pro-oxidant product. Mangiferin was involved in protective effects of the extract.

Combination of Mangifera indica L. extract supplementation plus methotrexate in rheumatoid arthritis patients: a pilot study

The purpose of the present study was to evaluate the possible therapeutic effects and the safety of Mangifera indica extract (Vimang tablets, 300 mg) combined with methotrexate (MTX) on reducing disease activity in rheumatoid arthritis (RA). Twenty patients with active RA underwent a year of treatment with MTX (12.5 mg/week) associated to non-steroidal anti-inflammatory drugs (NSAIDs) and/or prednisone (5-10 mg/day) were randomly allocated to the experimental group (n=10), that received the extract supplementation (900 mg/day) or preceding usual treatment (n=10) during 180 days. RA activity was evaluated using the tender and swollen joint counts, erythrocyte sedimentation rate, disease activity score-28 (DAS 28), visual analogue scale (VAS) and health assessment questionnaire (HAQ). Treatment's efficacy was demonstrated with ACR criteria. Only the patients of MTX-Vimang group revealed statistically significant improvement in DAS 28 parameters with respect baseline data but no differences were observed between groups. ACR improvements amounted 80% only in MTX-Vimang group at the 90 days (p<0.001). In MTX-Vimang group, 100% of patients decreased NSAIDs administration (p<0.01) and 70% of those eradicated gastrointestinal side effects (p<0.01) ensuing of the preceding treatment. Other adverse effects were not reported.

Multiparametric evaluation of the cytoprotective effect of the Mangifera indica L. stem bark extract and mangiferin in HepG2 cells

OBJECTIVE

Mango (Mangifera indica L.) stem bark extract (MSBE) is a natural product with biological properties and mangiferin is the major component. This paper reported the evaluation of the protective effects of MSBE and mangiferin against the toxicity induced in HepG2 cells by tert-butyl hydroperoxide or amiodarone.

METHOD

Nuclear morphology, cell viability, intracellular calcium concentration and reactive oxygen species (ROS) production were measured by using a high-content screening multiparametric assay.

KEY FINDINGS

MSBE and mangiferin produced no toxicity below 500 mg/ml doses. A marked recovery in cell viability, which was reduced by the toxicants, was observed in cells pre-exposed to MSBE or mangiferin at 5-100 mg/ml doses. We also explored the possible interaction of both products over P-glycoprotein (P-gp). MSBE and mangiferin above 100 mg/ml inhibited the activity of P-gp in HepG2 cells.

CONCLUSIONS

MSBE and mangiferin showed cytoprotective effects of against oxidative damage and mitochondrial toxicity induced by xenobiotics to human hepatic cells but it seemed that other constituents of the extract could contribute to MSBE protective properties. In addition, the drug efflux should be taken into account because of the inhibition of the P-gp function observed in those cells exposed to both natural products.

Evaluation of a Propolis Water Extract Using a Reliable RP-HPLC Methodology and In Vitro and In Vivo Efficacy and Safety Characterisation

Since the beginning of propolis research, several groups have studied its antibacterial, antifungal, and antiviral properties. However, most of these studies have only employed propolis ethanolic extract (PEE) leading to little knowledge about the biological activities of propolis water extract (PWE). Based on this, in a previous study, we demonstrated the anti-inflammatory and immunomodulatory activities of PWE. In order to better understand the equilibrium between effectiveness and toxicity, which is essential for a new medicine, the characteristics of PWE were analyzed. We developed and validated an RP-HPLC method to chemically characterize PWE and PEE and evaluated the in vitro antioxidant/antimicrobial activity for both extracts and the safety of PWE via determining genotoxic potential using in vitro and in vivo mammalian micronucleus assays. We have concluded that the proposed analytical methodology was reliable, and both extracts showed similar chemical composition. The extracts presented antioxidant and antimicrobial effects, while PWE demonstrated higher antioxidant activity and more efficacious for the most of the microorganisms tested than PEE. Finally, PWE was shown to be safe using micronucleus assays.

In vitro assessment of the cytotoxic, apoptotic, and mutagenic potentials of isatin

Isatin (1H-indole-2,3-dione) is a chemical found in various medicinal plant species and responsible for a broad spectrum of pharmacological and biological properties that may be beneficial to human health, as an anticonvulsant, antibacterial, antifungal, antiviral, and anticancer agent. The aim of the present study was to determine in vitro the cytotoxic, mutagenic, and apoptotic effects of isatin on CHO-K1 and HeLa cells using the MTT viability assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide), micronucleus (MN) test, apoptosis index, and nuclear division index (NDI). The 5 isatin concentrations evaluated in the mutagenicity and apoptosis tests were 0.5, 1, 5, 10, and 50 μM, selected through a preliminary MTT assay. Positive (doxorubicin, DXR) and negative (phosphate buffered saline, PBS) control groups were also included in the analysis. Isatin did not exert a mutagenic effect on CHO-K1 after 3 and 24 h of treatment or on HeLa cells after 24 h. However, 10 and 50 μM concentrations inhibited cell proliferation and promoted apoptosis in both CHO-K1 and HeLa cells. Data indicate that the cytotoxic, apoptotic, and antiproliferative effects of isatin were concentration independent and cell line independent.

Genotoxic and mutagenic properties of Bauhinia platypetala extract, a traditional Brazilian medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE

Bauhinia platypetala Burch. is a traditionally used Brazilian medicinal plant, although no evidence in the literature substantiates the safety of its use.

AIM OF THE STUDY

The aim of this study was to investigate the safety of the ethanolic extract and the ethereal fraction of B. platypetala leaves.

MATERIALS AND METHODS

The identification of chemical compounds from the B. platypetala ethanolic extract and its ethereal fraction was performed by GC/MS and ESI-MS/MS. The plant's toxicological, cytotoxic, mutagenic and genotoxic properties were determined in Saccharomyces cerevisiae strains and V79 cell culture by survival assays and comet assay.

RESULTS

The major compound identified in the B. platypetala ethanolic extract is palmitic acid, kaempferitirin and quercitrin, while the B. platypetala ethereal fraction was found to be rich in phytol, gamma-sitosterol and vitamin E. Moreover, the results indicated that the B. platypetala ethanolic extract has an anti-oxidative effect against H(2)O(2) in yeast. In addition, the B. platypetala ethanolic extract did not induce mutagenic effects on the S. cerevisiae N123 strain, but the ethereal fraction of B. platypetala at higher concentrations (250-500 μg/mL) induced cytotoxicity and mutagenicity. A slight cytotoxic effect was observed in mammalian V79 cells; however, both the B. platypetala ethanolic extract and its ethereal fraction were able to induce DNA strand breaks in V79 cells, as detected by the alkaline comet assay.

CONCLUSION

The B. platypetala ethanolic extract has antioxidant action and showed absence of mutagenic effects in yeast S. cerevisiae. On the other hand B. platypetala ethereal fraction is mutagenic and does not show antioxidant activity in yeast. In mammalian cells B. platypetala ethanolic extract and it's ethereal fraction induce cyotoxic and genotoxic action.

Genotoxicity assessment of Garcinia achachairu Rusby (Clusiaceae) extract in mammalian cells in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia achachairu Rusby (Clusiaceae) is popularly known as "achachairu", and is used in Bolivian folk medicine for its healing, digestive, and laxative properties, and in the treatment of gastritis, rheumatism and inflammation. Despite its widespread therapeutic use, there is a lack of data regarding its in vivo genotoxic effects. Therefore, in this study, we used the comet assay and the micronucleus test, respectively, to evaluate the possible genotoxic and clastogenic effects of Garcinia achachairu seed extract (GAE) on different cells of mice.

MATERIAL AND METHODS

The GAE was administered by oral gavage at doses of 500, 1000 and 2000 mg/kg. For the analysis, the comet assay was performed on the leukocytes (collected 4 and 24 h after treatment), liver, bone marrow and testicular cells (collected 24 h after treatment), and the micronucleus test (MN) on bone marrow cells. Cytotoxicity was assessed by scoring 200 consecutive polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio).

RESULTS AND CONCLUSION

The results showed that GAE did not induce significant DNA damage in leukocytes (4 h and 24 h samples), liver, bone marrow and testicular cells (24 h samples). GAE also did not show any significant increase in micronucleated polychromatic erythrocytes (MNPCEs) at the three tested doses. The PCE/NCE ratio indicated no cytotoxicity. Under our experimental conditions, the data obtained suggest that a single oral administration of G. achachairu extract does not cause genotoxicity and clastogenicity in different cells of mice.

Evaluation of genotoxicity and DNA protective effects of mangiferin, a glucosylxanthone isolated from Mangifera indica L. stem bark extract

Mangiferin is a glucosylxantone isolated from Mangifera indica L. stem bark. Several studies have shown its pharmacological properties which make it a promising candidate for putative therapeutic use. This study was focused to investigate the in vitro genotoxic effects of mangiferin in the Ames test, SOS Chromotest and Comet assay. The genotoxic effects in bone marrow erythrocytes from NMRI mice orally treated with mangiferin (2000 mg/kg) were also evaluated. Additionally, its potential antimutagenic activity against several mutagens in the Ames test and its effects on CYP1A1 activity were assessed. Mangiferin (50-5000 μg/plate) did not increased the frequency of reverse mutations in the Ames test, nor induced primary DNA damage (5-1000 μg/mL) to Escherichia coli PQ37 cells under the SOS Chromotest. It was observed neither single strand breaks nor alkali-labile sites in blood peripheral lymphocytes or hepatocytes after 1h exposition to 10-500 μg/mL of mangiferin under the Comet assay. Furthermore, micronucleus studies showed mangiferin neither induced cytotoxic activity nor increased the frequency of micronucleated/binucleated cells in mice bone marrow. In short, mangiferin did not induce cytotoxic or genotoxic effects but it protect against DNA damage which would be associated with its antioxidant properties and its capacity to inhibit CYP enzymes.

Genotoxic effects of Tabebuia impetiginosa (Mart. Ex DC.) Standl. (Lamiales, Bignoniaceae) extract in Wistar rats

Tabebuia sp. is native to tropical rain forests throughout Central and South America. Although the biological and pharmacological effects of bark extracts have been intensely studied, little is known on the extract obtained from the flower. Herein, the genotoxic potential of a flower extract from T. impetiginosa ("ipê roxo") on the blood and liver cells of Wistar rats was evaluated. Experimental procedures involved only male animals. Graduated concentrations of the extract, viz., 100, 300 and 500 mg kg(-1) of body weight, were gavage-administered and 24 h latter cells were collected and processed for analysis. With the exception of the 100 mg kg(-1) dose, a significant increase in DNA damage was noted, when compared with a negative control group. Although the genotoxic potential of this extract was higher in liver cells, the response in both tissues was related to dose-dependency. Even though DNA damage can be corrected before conversion into mutations, further study is recommended to arrive at a better understanding of incurred biological effects.

2-[2-(Trifluoro-meth-yl)phen-yl]-2H-1-benzopyran-4(3H)-one

In the title compound, C₁₆H₁₁F₃O₂, the γ-pyran­one ring adopts an envelope conformation with the chiral C atom standing out of the ring plane. In the crystal, molecules are linked by C—H⋯O and C—H⋯F inter­actions.

Synthesis and evaluation of novel analogues of mangiferin as potent antipyretic

OBJECTIVE

To screen different analogues of mangiferin pharmacologically for antipyretic activity.

METHODS

The naturally occurring xanthone glycoside mangiferin was isolated by column chromatography from the ethanolic extract of stem bark of Mangifera indica. Mangiferin was further converted to 5-(N-phenylamino methyleno) mangiferin, 5-(N-p-chlorophenylamino methyleno) mangiferin, 5-(N-2-methyl phenylamino methyleno) mangiferin, 5-(N-p-methoxy phenylamino methyleno) mangiferin, 5-(N, N-diphenylamino methyleno) mangiferin, 5-(N-α-napthylamino methyleno) mangiferin and 5-(N-4-methyl phenylamino methyleno) mangiferin analogues. The synthesized compounds were further screened for antipyretic activity along with mangiferin at a dose level of 100 and 200 mg/kg. Mangiferin and its analogues were characterized by melting point andR(f)value determination and through spectral technique like UV, IR, and NMR spectral analysis.

RESULTS

The antipyretic activity of mangiferin as well as all analogues was found to be more significant in at higher dose ie. 200 mg/kg which was depicted through a decrease in rectal temperature up to 3 h.

CONCLUSIONS

The antipyretic activity of mangiferin and its analogues may be attributed to inhibition in synthesis of TNF-α and anti-oxidant activity associated with amelioration of inflammatory actions of cytokines.

Evaluation of the mutagenicity of sesquiterpenic compounds and their influence on the susceptibility towards antibiotics of two clinically relevant bacterial strains

Sesquiterpenic compounds are natural chemicals present in organisms from different Phylae or Divisions, which have proved to be important bioactive products, namely in potentiating the action of antibiotics. In the first step, the mutagenicity of nine sesquiterpenic compounds (hydrocarbons and alcohols) was screened in a Salmonella typhimurium his(-)-reversion test with strains TA98 and TA100, in the presence or absence of in vitro metabolic activation. Under the test conditions, none of the compounds showed mutagenicity up to a concentration of 222μg/plate. trans-Farnesol, nerolidol, and α-bisabolol displayed cytotoxicity when tested at concentrations ranging from 14 to 222μg/plate. Then, the combined effect of antibiotic-sesquiterpenic compounds was evaluated on two clinically relevant pathogens, Escherichia coli and Staphylococcus aureus, with well-defined resistance-sensitive profiles. The agar-disc diffusion assay revealed that all the combinations of antibiotic-sesquiterpenic compounds increased the antibacterial activity of the antibiotics tested against S. aureus. For E. coli, an antagonistic effect was observed for various combinations on the growth of this bacterium.

Piplartine induces genotoxicity in eukaryotic but not in prokaryotic model systems

Piplartine {5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propen-1-yl]-2(1H)-pyridinone} is an alkamide present in Piper species that exhibits promising anticancer properties. It was previously shown that piplartine is mutagenic in yeast and cultured mammalian cells. This study was performed to increase the knowledge on the mutagenic potential of piplartine using the Salmonella/microsome assay, V79 cell micronucleus and chromosome aberration assays, and mouse bone-marrow micronucleus tests. Piplartine was isolated from the roots of Piper tuberculatum. This extracted compound was unable to induce a mutagenic response in any Salmonella typhimurium strain either in the presence or absence of metabolic activation. Piplartine showed mutagenic effects in V79 cells, as there was an increased frequency of aberrant cells and micronuclei formation. In addition, piplartine administered at 50mg/kg did not induce micronucleus formation in vivo, but a dose of 100mg/kg induced an increase in the levels of micronucleus polychromatic erythrocytes (MNPCEs). Overall, these results provide further support that piplartine induces in vivo and in vitro mutagenicity in eukaryotic models.

Anti-proliferation, cell cycle arrest and apoptosis induced by a natural xanthone from Gentianopsis paludosa Ma, in human promyelocytic leukemia cell line HL-60 cells

1-hydroxy-3,7,8-trimethoxyxanthone (xanthone 1) was isolated from Gentianopsis paludosa Ma and identified by MS and NMR in our laboratory. In this study, the results showed that xanthone 1 is a potent inducer of anti-proliferation and apoptosis in HL-60 cells. When the cells treated with lower concentrations of xanthone 1 (12.4-74.4microM), significant proliferation inhibition was detected by cell viability assay and morphological analyses, and conspicuous G1 and G2/M cell cycle arrest were observed by flow cytometric (FCM) analysis. However, when the cells treated with higher doses of xanthone 1 (82.7-330.8microM), significant apoptosis was observed by double sequential AO/EB staining, DNA fragmentation assay and FCM analysis. In addition, conspicuous DNA damage was detected by comet assay. In short, all the results showed that xanthone 1 had a significant cytotoxic effect and could induce proliferation inhibition and apoptosis in HL-60 cells in a time- and dose-dependent manner. It was possible that xanthone 1 could induce DNA damage in HL-60 cells, which resulted in G1 phase arrest at the lower concentrations and G2/M phase arrest at the higher concentrations, thus inhibiting the cell proliferation, and irreparable DNA damage at the higher concentrations might be responsible for the occurrence of apoptosis.

In vivo assessment of DNA damage and protective effects of extracts from Miconia species using the comet assay and micronucleus test

The genus Miconia comprises approximately 1000 species belonging to the Melastomataceae family. Several crude plant extracts from Miconia and their isolated compounds have shown biological activities, such as analgesic and anti-neoplastic action; however, no studies concerning their effects on DNA are available. The present study aimed to evaluate, in vivo, the genotoxic and mutagenic effects of four species of plants from Miconia genus using the comet assay and micronucleus test. Their possible protective effects were also evaluated in experiments associating the plant extracts with cyclophosphamide (CPA). The methanolic extracts of Miconia albicans, Miconia cabucu, Miconia rubiginosa, Miconia stenostachya and the chloroformic extract of M. albicans were investigated. For genotoxic and mutagenic evaluations, three concentrations were tested, 200, 400 and 540 mg/kg body weight (bw), based on the solubility limit of the extract in distilled water. For the protective effects, only the highest dose was evaluated against 40 mg/kg bw of CPA. Blood was removed from mice tails pre- (T0) and post-treatment (T1-30 h) for the micronucleus test and 24 h post-treatment for the comet assay. The Student's t-test was used to compare data obtained at T0 and T1, the analysis of variance-Tukey test was used to compare between groups in the micronucleus test and the Kruskal-Wallis and Dunn's test were used to compare different groups in the comet assay. All the extracts induced alterations in DNA migration (comet assay); however, no mutagenic effect was observed in the micronucleus assay. All extracts showed a protective effect against CPA in both assays. Our study showed that the use of crude extracts could be more advantageous than the use of isolated compounds. The interaction between phytochemicals in the extracts showed efficacy in reducing mutagenicity and improving the protective effects.

Lack of in vivo embryotoxic and genotoxic activities of orally administered stem bark aqueous extract of Mangifera indica L. (Vimang)

Mango (Mangifera indica L.) stem bark aqueous extract (MSBE) is a new natural product with antioxidant, anti-inflammatory and immunomodulatory effects known by the brand name of its formulations as Vimang. Previously, the oral toxicity studies of the extract showed a low toxicity potential up to 2000 mg/kg. This work reports the results about teratogenic and genotoxicologic studies of MSBE. For embryotoxicity study, MSBE (20, 200, or 2000 mg/kg/day) was given to Sprague-Dawley rats by gavage on days 6-15 of gestation. For genotoxicity, MSBE was administered three times during 48 h to NMRI mice. Cyclophosphamide (50 mg/kg) was used as a positive control. No maternal or developmental toxicities were observed when the rats were killed on day 20th. The maternal body-weight gain was not affected. No dose-related effects were observed in implantations, fetal viability or external fetal development. Skeletal and visceral development was similar among fetuses from all groups. No genotoxicity was observed in bone marrow erythrocytes and liver cells after administration. MSBE appears to be neither embryotoxic nor genotoxic as measured by bone marrow cytogenetics in rodents.