Chandrasekaran Rajasekaran

Free Radical Scavenging, Cytotoxic and Hemolytic Activities from Leaves of Acacia nilotica (L.) Wild. ex. Delile subsp. indica (Benth.) Brenan

Dietary intake of phytochemicals having antioxidant activity is associated with a lower risk of mortality from many diseases. Therefore, the aim of this study was to determine the free radical scavenging, cytotoxic and hemolytic activities of leaves of Acacia nilotica by using various methods. The results of the present study revealed that ethanol extract was the most effective and IC50 value was found to be 53.6 μg mL−1 for Vero cell lines and 28.9 μg mL−1 for Hela cell lines in cytotoxicity assays. The zone of color retention was 14.2 mm in β-carotene bleaching assay, which was as significant as positive control, butylated hydroxy toluene. None of the tested extracts possessed any hemolytic activity against rat and human erythrocytes revealing their cytotoxic mechanism and non-toxicity. Thus, only the ethanol extract could be considered as a potential source of anticancer and antioxidant compounds. Further phytochemical studies will be performed for specification of the biologically active principles.

Free Radical Scavenging, Cytotoxic, and Hemolytic Activities of an Active Antioxidant Compound Ethyl Gallate from Leaves of Acacia Nilotica (L.) Wild. Ex. Delile Subsp. Indica (Benth.) Brenan

UNLABELLED In the present study, free radical scavenging, cytotoxic, and hemolytic activities of the polyphenolic compound ethyl gallate isolated from ethanol extract of Acacia nilotica Wild. Ex. Del. leaves were determined. The free radical-scavenging activities of the ethyl gallate were demonstrated in several in vitro assays in order to evaluate the possible antioxidant mechanism. The results revealed ethyl gallate as hydrogen donor, metal chelator, and free radical scavenger. Ethyl gallate was effective in scavenging 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals and the IC₅₀ value was lower than all the positive controls used in this study. Deoxyribose degradation assay revealed that ethyl gallate had more iron-chelating ability than the direct hydroxyl radical-scavenging ability. The results of the cytotoxic study revealed that the compound was moderately active and IC₅₀ value was found to be >100 μg/mL for Vero cell lines and 72 μg/mL for Hela cell lines. The compound possessed no hemolytic activity against rat and human erythrocytes revealing its cytotoxic mechanism and nontoxicity. The results from this work will provide an important information for the food and pharmacological industries with respect to the use of the compound as an antioxidant and a health-related drug. PRACTICAL APPLICATION Antioxidant from plant sources is safe to use, as compared to synthetic products. It also can be used as a supplement to alleviate most of the diseases because of its free radical-scavenging activity.

In vitro flowering in Oldenlandia umbellata L.

Background Oldenlandia umbellata L. (Indian madder) is an antique Ayurvedic Indian herb and a source of various anthraquinone derivatives. The red dye from its roots has been used in diverse applications since ancient times. Objectives To establish reliable and effective protocols for in vitro flowering of O. umbellata. Materials and methods For in vitro flowering, organogenic calli were subcultured onto Murashige and Skoog (MS) medium supplemented with various concentrations of Naphthalene acetic acid (NAA) (0.15–1.0 mg/l) and Benzyladenine(BA) (0.5–1.5 mg/l) with and without 0.4% of coconut milk (CM). Results The highest number of in vitro flowers (22.8%) and best response (92.73%) was achieved on MS medium supplemented with 0.7 mg/l NAA + 1.5 mg/l BA with 0.4% CM. It was found that MS medium devoid of BA promoted best root development (47.3 per calli) as well as response (100%). It was also observed that when embryogenic calli grown in depletion of required nutrition transferred to fresh media induced more flowering. In vivo and in vitro floral comparative analysis revealed that in vitro flower induction was required for short time duration (20.67 days) than in vivo flower. Conclusion To the best of our knowledge, this is the first report on in vitro flowering and this study will help to overcome problems associated with flower development and seed production. As a result, this study may be a potent conservation tool to restore innate population size in its natural habitat.

Characterization of sorption sites and differential stress response of microalgae isolates against tannery effluents from ranipet industrial area—An application towards phycoremediation

ABSTRACT Phycoremediation ability of microalgae namely Oscillatoria acuminate and Phormidium irrigum were validated against the heavy metals from tannery effluent of Ranipet industrial area. The microalgae species were cultured in media containing tannery effluent in two different volumes and the parameters like specific growth rate, protein content and antioxidant enzyme activities were estimated. FTIR spectroscopy was carried out to know the sorption sites interaction. The antioxidant enzymes namely superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) contents were increased in microalgae species indicating the free radical scavenging mechanism under heavy metal stress. SOD activity was 0.502 and 0.378 units/gram fresh weight, CAT activity was 1.36 and 0.256 units/gram fresh weight, GSH activity was 1.286 and 1.232 units/gram fresh weight respectively in the effluent treated microalgae species. Bio sorption efficiency for Oscillatoria acuminate and Phormidium irrigum was 90% and 80% respectively. FTIR analysis revealed the interaction of microalgae species with chemical groups present in the tannery effluent. From the results, the microalgae Oscillatoria acuminate possess high antioxidant activity and bio sorption efficiency when compared to Phormidium irrigum and hence considered useful in treating heavy metals contaminated effluents.

Toxicity study of dibutyl phthalate of Rubia cordifolia fruits: in vivo and in silico analysis

Natural toxins from plant sources with wide ranges of biological activities reflect the upswing of drug design in the pharmaceutical industry. Rubia cordifolia L. is one of the most important red dye yielding plants. Most of the former researches have focused on the bioactive compounds from the roots of R. cordifolia, while no attention was paid towards the fruits. For the first time, here we report the presence of dibutyl phthalate in the fruits of R. cordifolia. Structural characterization was carried out using Ultraviolet–Visible spectrophotometer (UV–Vis), Fourier transform infrared (FTIR), gas chromatography–mass spectrophotometer (GC–MS), Nuclear magnetic resonance (NMR). Acute toxicity of the crude ethanolic extracts of the R. cordifolia fruits was examined in Swiss albino mice. No mortality was observed in all treated mice with 100, 500, 1000 mg/kg body weight of crude extract of R. cordifolia fruit and it indicates that the LD50 value is higher than 1000 mg/kg body weight. This study exhibited a significant change in the body weight. Alanine transaminase (ALT), total protein, triglycerides, glucose, and also the histopathological analysis of liver for all treated mice showed difference from the control group. The dibutyl phthalate was further evaluated for the toxicity study through in silico analysis. Together, the results highlighted that the toxic potential of R. cordifolia fruits extracts and also the toxicity profile of the fruit should be essential for the future studies dealing with the long term effect in animals.

Sorption sites of microalgae possess metal binding ability towards Cr(VI) from tannery effluents—a kinetic and characterization study

AbstractProminent microalgal species, namely Anabaena, Oscillatoria, Phormidium, and Spirogyra, were isolated from estuaries polluted with tannery effluents and studied to determine their Cr(VI) bio-sorption potential. The bio-sorption potential was determined by studying the effect of growth, biomass, reduction of Cr(VI) levels, and Cr(VI) absorption by the microalgal species. The respective values for Anabaena, Oscillatora, Phormidium, and Spirogyra compared with the control were as follows: growth in BG 11 medium containing tannery effluent was 53.99, 60.03, 55.76, and 55.85%; the biomass was 60.65, 77.61, 67.16, and 76.01%; the Cr(VI) reduction potential was 70.96, 80.64, 76.12, and 74.83%; and the bio-sorption potential was 75.48, 80.64, 79.35, and 77.41%. The removal of heavy metals by microalgal biomass involves bio-reduction and bio-sorption. Fourier-transform infrared spectroscopy and nuclear magnetic resonance results revealed the presence of microalgal sorption sites. All four species showed ma...

Molecular docking and molecular dynamics to identify a novel human immunodeficiency virus inhibitor from alkaloids of Toddalia asiatica

Background: Acquired immunodeficiency syndrome caused by human immunodeficiency virus (HIV) is an immunosuppressive disease. Over the past decades, it has plagued human health due to the grave consequences in its harness. Objective: For this reason, anti-HIV agents are imperative, and the search for the same from natural resources would assure the safety. Materials and Methods: In this investigation we have performed molecular docking, molecular property prediction, drug-likeness score, and molecular dynamics (MD) simulation to develop a novel anti-HIV drug. We have screened 12 alkaloids from a medicinal plant Toddalia asiatica for its probabilistic binding with the active site of the HIV-1-reverse transcriptase (HIV-1-RT) domain (the major contributor to the onset of the disease). Results: The docking results were evaluated based on free energies of binding (ΔG), and the results suggested toddanol, toddanone, and toddalenone to be potent inhibitors of HIV-1-RT. In addition, the alkaloids were subjected to molecular property prediction analysis. Toddanol and toddanone with more rotatable bonds were found to have a drug-likeness score of 0.23 and 0.11, respectively. These scores were comparable with the standard anti-HIV drug zidovudine with a model score 0.28. Finally, two characteristic protein-ligand complexes were exposed to MD simulation to determine the stability of the predicted conformations. Conclusion: The toddanol-RT complex showed higher stability and stronger H-bonds than toddanone-RT complex. Based on these observations, we firmly believe that the alkaloid toddanol could aid in efficient HIV-1 drug discovery. SUMMARY In the present study, the molecular docking and MD simulations are performed to explore the possible binding mode of HIV 1 RT with 12 alkaloids of T. asiatica. Molecular docking by AutoDock4 revealed three alkaloids toddanol, toddanone, and toddalenone with highest binding affinity towards HIV 1 RT. The drug likeness model score revealed a positive score for toddanol and toddanone which is comparable to the drug likeness score of the standard anti HIV drug zidovudine. Results from simulation analysis revealed that toddanol RT complex is more stable than toddanone RT complex inferring toddanol as a potential anti HIV drug molecule. Abbreviations used: HIV: Human immunodeficiency virus, HIV 1 RT: HIV 1 reverse transcriptase, RNase H: Ribonuclease H, MD: Molecular dynamics, PDB: Protein databank, RMSD: Root mean square deviation, RMSF: Root mean square fluctuation.