Assessment of DNA damage induced by extracts, fractions and isolated compounds of Davilla nitida and Davilla elliptica (Dilleniaceae)

Synthesis, Antimicrobial and Mutagenic Activity of a New Class of d-Xylopyranosides

Eight N-[2-(2',3',4'-tri-O-acetyl-α/β-d-xylopyranosyloxy)ethyl]ammonium bromides, a new class of d-xylopyranosides containing a quaternary ammonium aglycone, were obtained. Their complete structure was confirmed using NMR spectroscopy (¹H, ¹³C, COSY and HSQC) and high-resolution mass spectrometry (HRMS). An antimicrobial activity against fungi (Candida albicans, Candida glabrata) and bacteria (Staphylococcus aureus, Escherichia coli) and a mutagenic Ames test with Salmonella typhimurium TA 98 strain were performed for the obtained compounds. The greatest activity against the tested microorganisms was shown by glycosides with the longest (octyl) hydrocarbon chain in ammonium salt. None of the tested compounds exhibited mutagenic activity in the Ames test.

Amelioration of cyclophosphamide-induced DNA damage, oxidative stress, and hepato- and neurotoxicity by Piper longum extract in rats: The role of γH2AX and 8-OHdG

Background: The identification of genoprotectants is a promising strategy for improving human health. Piper longum has drawn scientific attention because of its diverse biological effects and traditional utilization. The current investigation aims to evaluate the genome-stabilizing potential of Piper longum against cyclophosphamide-associated genotoxicity.

Methods: We adopted a funnel screening with a three-tier evaluation approach, where Piper longum was investigated in an acellular medium, peripheral blood lymphocytes, and a rodent model. The genoprotective action of the Piper longum extract was initially performed with plasmid pBluescript SK(-) DNA. Furthermore, the extract and various fractions were screened against cyclophosphamide-induced genotoxicity using a cytokinesis-block micronucleus assay and a chromosomal aberration assay in human peripheral blood lymphocytes. The genome-stabilizing action of the extract and potent (hexane) fraction was further confirmed in vivo in Wistar albino rats by evaluating them using mammalian erythrocyte micronucleus tests, DNA fragmentation, oxidative stress markers, 8-hydroxy-2-deoxyguanosine (8-OHdG), γH2AX, and histopathological lesions in the liver and hippocampus. Additionally, acute and sub-acute toxicity studies were conducted following the Organization for Economic Co-operation and Development (OECD) guidelines for rats. Furthermore, the extract was quantified and characterized by high-performance thin-layer chromatography (HPTLC), ultra-high performance liquid chromatography–mass spectroscopy (UPLC-MS), and gas chromatography–mass spectrometry (GC-MS).

Results: The Piper longum ethanol extract was shown to protect plasmid pBluescript SK(-) DNA against H2O2-induced strand breaks. In human lymphocytes, the extract and hexane fraction showed a reduction in micronucleus formation (p < 0.001) and chromosomal aberrations (p < 0.01) against cyclophosphamide. Furthermore, the extract and fraction treatment, when administered at 200 mg/kg for 28 days in Wistar rats, restored cyclophosphamide-induced genomic instability by reducing micronucleus formation and DNA fragmentation; restoring redox homeostasis; decreasing 8-OHdG, a hallmark of oxidative DNA damage; reducing γH2AX, a DNA double-strand break (DSB) marker; and preserving the liver and hippocampus against histopathological lesions. The extract and fraction revealed no signs of systemic toxicity at the used doses. Piperine and piperlongumine are the major alkaloids quantified along with the presence of flavonoids in the ethanol extract and the presence of fatty acids and terpenoids in the hexane fraction of Piper longum.

Conclusion: Our investigation confirms the genoprotective action of Piper longum by reducing cyclophosphamide-associated cytogenotoxicity, oxidative stress, hepato- and neurotoxicity, oxidative DNA damage, and DNA double-strand breaks. The outcomes are critical for mitigating the genotoxic effects of chemotherapy recipients, requiring further attention.

Modulatory effect of myricitrin against chromosome instability and cytostasis induced by bleomycin and oxaliplatin in CHO-K1 cells

Myricitrin (MYR), a flavonol consumed in the leaves and fruits of plants of the Myrtaceae family, presents anti-proliferative, anti-inflammatory, anti-diabetic, and antioxidant properties in humans. However, there are few studies regarding the cyto-genotoxicity and the chemopreventive potential of MYR. Using the in vitro Micronucleus test, the cytostasis, mutagenicity, and modulatory effect of MYR in CHO-K1 cells were assessed. The concentrations of 39 and 78 µg/mL (p < 0.001.) of MYR decrease the cytokinesis-block proliferation index (CBPI) in the short exposure treatment (4 h), while in the extended treatment (24 h), concentrations of 4.8, 9.7, 19.5, 39 and 78 µg/mL (p < 0.001.) decreased the CBPI. MYR associated with oxaliplatin decreased CBPI at all tested concentrations in the pre-(p < 0.001) and post-treatments (p < 0.001), but there was no decrease when associated with bleomycin. As for chromosome instability, MYR did not increase the frequency of micronuclei (MNi), nucleoplasmic bridges (NPBs), or nuclear buds (NBUDs) in the 4 h exposure time, however, in the 24 h treatment, MYR increased the frequency of MNi and NPBs at concentration 19.5 µg/mL (p < 0.001). As for the modulatory effect, MYR associated with bleomycin decreased the frequency of MNi, NPBs, and NBUDs at all concentrations in the pretreatment (MNi and NPBs p < 0.001, NBUDs p < 0.05) and simultaneously (MNi, NPBs and NBUDs p < 0.001). When associated with oxaliplatin, the simultaneous treatment decreased the frequency of MNi (p < 0.001) and NBUDs (p < 0.01) at all concentrations, however, in the post-treatment, MYR increased MNi (p < 0.001) and NPBs p < 0.05) in CHO-K1 cells, when compared to oxaliplatin alone. The results demonstrated that MYR could modulate the mutagenic and cytostatic actions of bleomycin and oxaliplatin, demonstrating distinct behaviors, depending on the mechanism of action of the chemotherapeutic agent.

Toxic Potential of Cerrado Plants on Different Organisms

Cerrado has many compounds that have been used as biopesticides, herbicides, medicines, and others due to their highly toxic potential. Thus, this review aims to present information about the toxicity of Cerrado plants. For this purpose, a review was performed using PubMed, Science Direct, and Web Of Science databases. After applying exclusion criteria, 187 articles published in the last 20 years were selected and analyzed. Detailed information about the extract preparation, part of the plant used, dose/concentration tested, model system, and employed assay was provided for different toxic activities described in the literature, namely cytotoxic, genotoxic, mutagenic, antibacterial, antifungal, antiviral, insecticidal, antiparasitic, and molluscicidal activities. In addition, the steps to execute research on plant toxicity and the more common methods employed were discussed. This review synthesized and organized the available research on the toxic effects of Cerrado plants, which could contribute to the future design of new environmentally safe products.

Mutagenic potential of medicinal plants evaluated by the Ames Salmonella/microsome assay: A systematic review

The Ames test has become one of the most commonly used tests to assess the mutagenic potential of medicinal plants since they have several biological activities and thus have been used in traditional medicine and in the pharmaceutical industry as a source of raw materials. Accordingly, this review aims to report previous use of the Ames test to evaluate the mutagenic potential of medicinal plants. A database was constructed by curating literature identified by a search on the electronic databases Medline (via Pubmed), Science Direct, Scopus, and Web of Science from 1975 to April 2020, using the following terms: "genotoxicity tests" OR "mutagenicity tests" OR "Ames test" AND "medicinal plants." From the research, 239 articles were selected, including studies of 478 species distributed across 111 botanical families, with Fabaceae, Asteraceae and Lamiaceae being the most frequent. It was identified that 388 species were non-mutagenic. Of these, 21% (83/388) showed antimutagenic potential, most notable in the Lamiaceae family. The results also indicate that 18% (90/478) of the species were mutagenic, of which 54% were mutagenic in the presence and absence of S9. Strains TA98 and TA100 showed a sensitivity of 93% in detecting plant extracts with mutagenic potential. However, the reliability of many reviewed studies regarding the botanical extracts may be questioned due to technical issues, such as testing being performed only in the presence or absence of S9, use of maximum doses below 5 mg/plate and lack of information on the cytotoxicity of tested doses. These methodological aspects additionally demonstrated that a discussion about the doses used in research on mixtures, such as the ones assessed with botanical extracts and the most sensitive strains employed to detect the mutagenic potential, should be included in a possible update of the guidelines designed by the regulatory agencies.

The beneficial and deleterious role of dietary polyphenols on chronic degenerative diseases by regulating gene expression

Dietary polyphenols, a natural component in many kinds of foods such as fruits and vegetables, play essential roles in a wide range of plant functions. Importantly, the discovery of the functions of polyphenols including anti-oxidant, anti-carcinogenic and anti-inflammatory has been appealing to researchers' attentions. Dietary polyphenols have shown protective effects on chronic degenerative diseases (CDD) such as cardiovascular diseases, cancers, and neurodegenerative diseases by regulating gene expression. Dietary polyphenols also affect the composition and activity of gut microbiota, in reverse, gut microbiota influences the bioavailability and physiological activity of dietary polyphenols. However, not all kinds of dietary polyphenols are beneficial for human health. The potential deleterious effects of several dietary polyphenols have been reported by inducing DNA damage and gene mutants. This review summarizes the potential therapeutic effects of dietary polyphenols on chronic degeneration diseases, the polyphenols-gut microbiota interactions, and the potential dangers of individual dietary polyphenols on human health.

Safety and clinical efficacy of tenvermectin, a novel antiparasitic 16-membered macrocyclic lactone antibiotics

Tenvermectin (TVM) is a novel 16-membered macrocyclic lactone antibiotics, which contains component TVM A and TVM B. However there is not any report on safety and clinical efficacy of TVM for developing as a potential drug. In order to understand the part of safety and clinical efficacy of TVM, we conducted the acute toxicity test, the standard bacterial reverse mutation (Ames) test and the clinical deworming test. In the acute toxicity studies, TVM, TVM A and ivermectin (IVM) were administrated once by oral gavage to mice and rats. Results showed that the oral LD₅₀ values of TVM, TVM A and IVM in mice were 74.41, 106.95 and 53.06 mg/kg respectively. The oral LD₅₀ values of TVM and TVM A in rats were determined to be 164.22 and 749.34 mg/kg respectively. TVM and IVM are moderately toxic substances, meanwhile the TVM A belongs to low toxic compounds, implying that the acute toxicity is highly related to the length of side chain of TVM at position C25. In the Ames test, results showed that TVM did not induce mutagenicity in Salmonella typhimurium TA97a, TA98, TA100, TA102 and TA1535 with and without metabolic activation system, speculating that the mutagenicity is probably not related to the side chain at position C25 of 16-membered macrocyclic lactone antibiotics. In the efficacy trail of TVM against swine nematodes, growing pigs natural infection of Ascaris suum and Trichuris suis were treated with a single subcutaneous injection 0.3 mg/kg b.w.. Results showed that TVM and IVM had excellent effect in expelling Ascaris suum, and TVM had potential efficacy against Trichuris suis, however IVM had no effect on Trichuris suis. This study suggests that the side chain of TVM at position C25 may have important biological functions, which is one of the key sites of the studies on structure-activity relationship of 16-membered macrocyclic lactone compounds. TVM is a new compound exhibited some advantages worthy of developing.

DNA Protection against Oxidative Damage Using the Hydroalcoholic Extract of Garcinia mangostana and Alpha-Mangostin

Garcinia mangostana, popularly known as “mangosteen fruit,” originates from Southeast Asia and came to Brazil about 80 years ago where it mainly grows in the states of Pará and Bahia. Although mangosteen or its extracts have been used for ages in Asian folk medicine, data on its potential genotoxicity is missing. We, therefore, evaluated genotoxicity/mutagenicity of hydroethanolic mangosteen extract [HEGM, 10 to 640 μg/mL] in established test assays (Comet assay, micronucleus test, and Salmonella/microsome test). In the Comet assay, HEGM-exposed human leukocytes showed no DNA damage. No significant HEGM-induced mutation in TA98 and TA100 strains of Salmonella typhimurium (with or without metabolic activation) was observed and HEGM-exposed human lymphocytes had no increase of micronuclei. However, HEGM suggested exposure concentration-dependent antigenotoxic potential in leukocytes and antioxidant potential in the yeast Saccharomyces cerevisiae. HEGM preloading effectively protected against H₂O₂-induced DNA damage in leukocytes (Comet assay). Preloading of yeast with HEGM for up to 4 h significantly protected the cells from lethality of chronic H₂O₂-exposure, as expressed in better survival. Absence of genotoxicity and demonstration of an antigenotoxic and antioxidant potential suggest that HEGM or some substances contained in it may hold promise for pharmaceutical or nutraceutical application.

Antioxidant and DNA damage protection potentials of selected phenolic acids

In this study, ten different phenolic acids (caffeic, chlorogenic, cinnamic, ferulic, gallic, p-hydroxybenzoic, protocatechuic, rosmarinic, syringic, and vanillic acids) were evaluated for their antioxidant and DNA damage protection potentials. Antioxidant activity was evaluated by using four different test systems named as β-carotene bleaching, DPPH free radical scavenging, reducing power and chelating effect. In all test systems, rosmarinic acid showed the maximum activity potential, while protocatechuic acid was determined as the weakest antioxidant in β-carotene bleaching, DPPH free radical scavenging, and chelating effect assays. Phenolic acids were also screened for their protective effects on pBR322 plasmid DNA against the mutagenic and toxic effects of UV and H2O2. Ferulic acid was found as the most active phytochemical among the others. Even at the lowest concentration value (0.002 mg/ml), ferulic acid protected all of the bands in the presence of H2O2 and UV. It is followed by caffeic, rosmarinic, and vanillic acids. On the other hand, cinnamic acid (at 0.002 mg/ml), gallic acid (at 0.002 mg/ml), p-hydroxybenzoic acid (at 0.002 and 0.004 mg/ml), and protocatechuic acid (at 0.002 and 0.004 mg/ml) could not protect plasmid DNA.

Safety evaluation of a triazine compound nitromezuril by assessing bacterial reverse mutation, sperm abnormalities, micronucleus and chromosomal aberration

Nitromezuril (NZL) is a novel triazine compound that exhibits remarkable anticoccidial activity. However, mutagenicity and genotoxicity of NZL have not been evaluated to date. This study evaluated the potential risks of NZL by testing for bacterial reverse mutation (Ames), mouse sperm abnormality (SA), bone marrow micronucleus (MN) and chromosomal aberration (CA). Mice were orally administered with NZL at 385, 192 and 96 mg/kg, corresponding to 0.5 ×, 0.25 × and 0.125 × the LD50 of NZL, respectively. No significant increases in SA and CA were found in mice treated with NZL for 5d and 3d, respectively (P>0.05). NZL at 96-385 mg/kg did not have significant influence on micronucleated polychromatic erythrocyte counts (P>0.05). These results suggest that NZL is not genotoxic. However, Ames test results were positive both with and without the S9 system for Salmonella typhimurium TA98 and TA100, suggesting that NZL may be mutagenic. The mutagenic effects of NZL were different in in vitro and in vivo assays. Further studies should be conducted to confirm the safety of using and developing NZL as a novel anticoccidial drug.

Characterization and quantification of the compounds of the ethanolic extract from Caesalpinia ferrea stem bark and evaluation of their mutagenic activity

Caesalpinia ferrea Martius has traditionally been used in Brazil for many medicinal purposes, such as the treatment of bronchitis, diabetes and wounds. Despite its use as a medicinal plant, there is still no data regarding the genotoxic effect of the stem bark. This present work aims to assess the qualitative and quantitative profiles of the ethanolic extract from the stem bark of C. ferrea and to evaluate its mutagenic activity, using a Salmonella/microsome assay for this species. As a result, a total of twenty compounds were identified by Flow Injection Analysis Electrospray Ionization Ion Trap Mass Spectrometry (FIA-ESI-IT-MS/MSn) in the ethanolic extract from the stem bark of C. ferrea. Hydrolyzable tannins predominated, principally gallic acid derivatives. The HPLC-DAD method was developed for rapid quantification of six gallic acid compounds and ellagic acid derivatives. C. ferrea is widely used in Brazil, and the absence of any mutagenic effect in the Salmonella/microsome assay is important for pharmacological purposes and the safe use of this plant.

Characterization and antioxidant activities of degraded polysaccharides from Poria cocos sclerotium

Poria cocos F.A.Wolf is a Chinese traditional medicine used to treat chronic gastritis, edema, nephrosis, gastric atony, and acute gastroenteric catarrh. Polysaccharides are the main active component of P. cocos. We obtained polysaccharides PCP-1, PCP-2, and PCP-3 from the degradation of P. cocos polysaccharides (PCP) with different concentrations of H2O2 solution. Molecular weights were determined by high performance size exclusion chromatography. HPLC analysis of monosaccharide composition confirmed that PCP-1, PCP-2, and PCP-3 are heteropolysaccharides composed of glucose and arabinose. IR spectra indicated obvious characteristic peaks of polysaccharides. The antioxidant activities of these polysaccharides were evaluated by established in vitro systems, including scavenging activity of hydroxyl radicals, ABTS radicals, and ferrous ions. The degradation polysaccharides exhibited obvious and concentration-dependent antioxidant properties. In addition, DNA binding analysis showed that PCP-1 had a stronger capacity than other polysaccharides to interact with DNA. However, each polysaccharide had a certain capacity for DNA damage protection.

Bioguided isolation of myricetin-3-O-β-galactopyranoside with antinociceptive activity from the aerial part of Davilla elliptica St.-Hil

ETHNOPHARMACOLOGICAL RELEVANCE

Davilla elliptica St.-Hil. (Dilleniaceae) is a medicinal plant traditionally used in Brazil to treat inflammatory processes, to relieve pain, as diuretic, gastro- and hepatoprotective agents.

AIM OF THE STUDY

To undertake the fractionation of the ethanolic extract from Davilla elliptica leaves guided by an antinociceptive assay.

MATERIALS AND METHODS

The antinociceptive activity was evaluated through the formalin test in mice. Extract fractionation was performed by percolation through silica gel and partition between immiscible solvents, followed by successive column chromatography over Sephadex LH-20 and preparative RP-HPLC. Structure elucidation of the isolated compound was accomplished by spectroscopic data.

RESULTS

The EtOAc and MeOH fractions derived from the crude extract reduced significantly the licking time in the late phase of the formalin test. The bioguided fractionation of the MeOH fraction resulted in the isolation of myricetin-3-O-β-galactopyranoside, which produced significant inhibition on nociception induced by formalin (ID50=0.26 mg/kg; p.o.).

CONCLUSIONS

These results point out that myricetin-3-O-β-galactopyranoside contributes for the antinociceptive effect of Davilla elliptica extract, a constituent considerably more potent than diclofenac, employed as reference drug.