Masood-ul-Hassan Balkhi

Assessment of endosulfan induced genotoxicity and mutagenicity manifested by oxidative stress pathways in freshwater cyprinid fish crucian carp (Carassius carassius L.)

Over the past few decades, endosulfan, one of the polychlorinated pesticides still in use, has received considerable attention of a number of international regulations and restriction action plans worldwide. This study aimed to evaluate the cytogenetic effects of endosulfan using robust genotoxicity assays, along with the oxidative stress pathways in order to understand biochemical mechanism, in Carassius carassius L. The LC50-96 h (95% confidence limits) value of endosulfan was 0.070 (0.046-0.093) ppm; and on its basis three test concentrations (sub-lethal I: 0.052, II: 0.035 and III: 0.017 ppm) were selected for 35 d in vivo exposure. The mean concentration of endosulfan in aquaria was always constant, when analyzed by dispersive liquid-liquid micro extraction (DLLME) followed by GC-MS. Autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28 and 35 of endosulfan exposure; the micronucleus formation (MN), authenticated by scanning electron microscopy, and chromosomal aberrations (CA), were induced significantly (p<0.05) in all the treated groups, including positive control cyclophosphamide (4 ppm), when compared to negative control. Similarly lipid peroxidation (LPO) was induced significantly with the maximal at higher concentration (SL-I) on 4th day (722.45%; p<0.01). Antioxidant biomarkers like glutathione reduced, superoxide dismutase and catalase also fluctuated significantly (p<0.01) in all treatment groups. Collective findings demonstrated that genotoxic effects were invariably accompanied and correlated with increased oxidative stress and disturbance of antioxidant enzymes; and the MN and CA assays are useful tools in determining potential genotoxicity of aquatic xenobiotics and might be appropriate as a part of monitoring program.

Pharmacological and toxicological evaluation of Urtica dioica.

Context: Medicinal plants are a largely unexplored source of drug repository. Urtica dioica L. (Urticaceae) is used in traditional medicine to treat diverse conditions. Objective: The present study describes the antidiabetic, antiinflammatory, antibacterial activity, and toxicological studies of Urtica dioica. Materials and methods: U. dioica leaves were subjected to solvent extraction with hexane, chloroform, ethyl acetate, methanol, and aqueous, respectively, and screened for antidiabetic (300 mg/kg bw by glucose tolerance test; GTT), antiinflammatory (200 mg/kg bw by rat paw edema assay) and antibacterial activities [by disc-diffusion and minimum inhibitory concentration (MIC) assays]. Toxicological studies were carried on Artemia salina and Wistar rats; phytochemical analyses were carried out, using chromatographic and spectroscopic techniques. Results: The aqueous extract of U. dioica (AEUD) significantly (p < 0.001; 67.92%) reduced the blood glucose level during GTT in Wistar rats with an effective dose of 300 mg/kg bw in dose-dependent studies. High-performance liquid chromatography with photodiode-array detection (HPLC-DAD) analysis showed the presence of hydroxycinnamic acid derivatives and flavonoids in AEUD. Hexane Fraction-2 (HF2) exhibited both antiinflammatory activity (48.83% after 3 h), comparable to that of indomethacin (53.48%), and potent antibacterial activity with MIC values ranging from 31.25–250 µg/mL against all the tested strains. Gas chromatography–mass spectrometry (GC–MS) analysis showed fatty acid esters and terpenes as the major constituents of HF2. Toxicity tests showed higher safety margin of all the solvent extracts with LC50 > 1000 μg/mL each on A. salina. Discussion and conclusion: Our results showed that the U. dioica leaves are an interesting source of bioactive compounds, justifying their use in folk medicine, to treat various diseases.

An introduction about Genotoxicology Methods as Tools for Monitoring Aquatic Ecosystem: Present status and Future perspectives

Pesticide residues with genotoxic potential reach the aquatic environment and constitute a major issue that give rise to concerns at local, regional, national and global scales. Fish serves as an excellent genetic model for the genetic hazard assessment as they are very sensitive to changes in their environment. As there is a close consortium of DNA damage, mutation and induction of various types of genetic disorders, genotoxicity tests like chromosomal aberration test, micronuclei and comet assay are gaining credence and since past few decades many tests have been developed for evaluating genetic alterations in aquatic organisms. These tests rely on the premise that any change to DNA may have enduring and ardent consequences. Thus, the first aim of the genotoxicology is to describe the outcome produced by toxic substances in various test species, but only from the genetic point of view and to draw conclusions that can be extrapolated to man. This review summarizes the genotoxicity tests developed till date and the role of piscine model in genotoxicology. The text also delves the latest knowledge and thinking on these cardinal approaches for the assessment of aquatic environmental health, management and conservation, besides providing useful repository for the researchers especially dealing with aquatic genotoxicity tests. The perspectives for further research on the use of genotoxicology tests were also highlighted.

Oxidative stress in the freshwater cyprinid crucian carp (Carassius carassius L.) upon chronic exposure to endosulfan

Oxidative stress and antioxidant responses of crucian carp, upon chronic exposure to endosulfan, were evaluated in vivo. The lethal concentration (LC50–96 h) was 70 μg L−1; on its basis, the fish were exposed to endosulfan at 20, 35, and 50 μg L−1 and autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28, and 35. Lipid peroxidation was induced in a concentration-dependent manner, being highest at 50 μg L−1 (3/4 LC50–96 h, sub-lethal concentration-I, SL-I) on day 4 (720% versus control), followed in its extent (490%) at 30 μg L−1 (1/2 LC50–96 h, sub-lethal concentration-II, SL-II) on day 7 and lowest (260%) at 10 μg L−1 (1/4 LC50–96 h, sub-lethal concentration-III, SL-III) on day 14. Glutathione showed a concentration- and time-dependent elevation in the initial phase, with highest level on day 4 (180%) at SL-I, but showed significant reduction in all test concentrations from day 21 of post-exposure. Superoxide dismutase was decreased significantly throughout the study, with highest reduction (63%) on day 4 at SL-I; catalase increased in all test concentrations up to day 14 but showed a significant decrease from the day 28 of post-exposure. The potential role of these parameters as indicators of pesticide pollution in aquatic systems is discussed.

Complete mitochondrial genome organization of Schizothorax esocinus (Heckel, 1838)

Abstract The complete mitochondrial genome of Schizothorax esocinus, an endemic coldwater fish of Himalayas, was determined for the first time. The genome is 16,583 bp in length and consists of 13 protein-coding genes, 22 tRNAs, 2rRNA genes and 1 putative control region. The gene organization and its order were similar to other vertebrates. The overall base composition was; A 29.8%, G 17.8%, C 27%, T 25.4%, A + T content 55.2% and the G + C content 44.8%. The control region was also consisted of a microsatellite locus (TA) 13 between 16,463 to 16,488 bp. The present study will provide the rationale for the management and conservation of S. esocinus.

Podophyllum hexandrum ameliorates endosulfan-induced genotoxicity and mutagenicity in freshwater cyprinid fish crucian carp.

Abstract Context: Medicinal plants continue to act as a repository for novel drug leads with novel mechanisms of action. Podophyllum hexandrum Royale (Berberideceae) treats diverse conditions in folk medicine. Objective: The antimutagenic potential of P. hexandrum was evaluated against endosulfan-induced clastogenicity in a piscine model by cytogenetic endpoints. Materials and methods: Podophyllum hexandrum rhizomes were subjected to successive solvent extraction. Fish were exposed to hexane, chloroform, ethyl acetate, methanol and aqueous extracts (15 mg/L each) of plant and endosulfan (0.05 mg/L) alone followed by their combination for antimutagenicity estimates. Chromosomal aberrations (CA) were made from kidney cells and micronuclei (MN) slides from peripheral blood erythrocytes at 48, 72 and 96 h. Antioxidant activity was analyzed by the DPPH assay. Phytochemical analyses were carried out using chromatographic and spectroscopic techniques. Results: Endosulfan induced significant (p < .05) MN, authenticated by scanning electron microscopy, and CA in a time-dependent manner. However, methanol and ethyl acetate extracts revealed ameliorating effects. The column eluted methanolic fraction-2 (ME-F2) showed highest reduction profile of 83 and 84% in CA and MN, followed in its extent (73 and 72%) by ethyl acetate fraction-4 (EE-F4). ME-F2 and EE-F4 showed three and six major peaks when analyzed by GC-MS. To explore possible mechanism of action, ME-F2 showed potent antioxidant potential and strong correlation (R2 = .900) with antimutagenic activity, whereas EE-F4 seemed to act through a different mechanism. Discussion and conclusion: This study confirms the antimutagenic potential of the subject plant with the identification of some novel compounds, justifying their use in folk medicine, and their corresponding benefit to mankind.

Complete mitochondrial genome organization of Schizopyge niger (Heckel, 1838)

Abstract The complete mitochondrial genome of Schizopyge niger, an endemic coldwater fish of Himalayas was determined for the first time. The genome is 16,585 bp in length and consists of 13 protein-coding genes, 22 tRNAs, 2rRNA genes and 1 putative control region. The gene organization and its order were similar to other vertebrates. The overall base composition was; A: 29.9%, G: 17.7%, C 27.1%, T 25.3%, A + T content 55.2% and the G + C content 44.8%. The control region was also consisted of a microsatellite locus (TA)13 between 16,471 to 16,496 bp. The present study will provide the rationale for the management and conservation of S. niger.