Isolation, structural elucidation of bioactive compounds and their wound-healing ability, antibacterial and In silico molecular docking applications.

Andrographis echioides has been extensively utilized in traditional Indian folk medicines for several skin disorders and other biological actions such as diuretic, antimicrobial, anthelmintic, anti-ulcer, and hepatoprotective properties. Different crude extracts were extracted from A. echioides leaves using various solvents such as methanol and water. The prepared crude extracts were utilized to formulate different herbal ointments. Further, the prepared ointments were examined against wounds and bacterial pathogens. The wound healing ability of the prepared formulations was observed for F1, F2, and F3, to be (89.84%, 95.11%, and 95.75%) respectively. Moreover, wound healing capabilities were compared with standard Betadine which exhibits 98.12%, those results indicating that the prepared herbal ointment also has a promising wound healing ability. The F2 formulations outperform the other two formulations (F1 and F2) in terms of their antibacterial ability to combat Staphylococcus aureus, Klebsiella pneumoniae Bacillus subtilis, and Escherichia coli. Moreover, there are two compounds were successfully isolated and identified from methanolic extract, which are 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol and 3-(3,4-Dihydroxyphenyl)-2-propenoic acid. Meanwhile, the molecular docking investigation exposed high binding energy Staphylococcus aureus TyrRS (-8.9 kcal/mol), Isoleucyl-tRNA synthetase (-7.5 kcal/mol), Penicillin-binding protein 2a (-8.0 kcal/mol), S. aureus DNA Gyrase (-7.2 kcal/mol), GSK-3beta (Glycogen synthase kinase-3 beta) (-8.3 kcal/mol) and TGF - Beta Receptor Type 1 Kinase Domain (-8.7 kcal/mol) indicating high degree of interaction between Compound-1 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol (DHPDHC) and 7 clinically important skin infective pathogen Staphylococcus aureus proteins at the active sites. Additionally, the standard drug Povidone iodine, Sulphothiazole, and Nitrofurazone (<-8 kcal/mol), displayed low binding affinity on targeted proteins. A molecular dynamics simulation research with high free energy showed stable interaction between the ligand and protein. Which endorses the capabilities of A. echioides derived compounds as a potential wound healer and antibacterial therapeutic candidate for drug development in the future.

Eco-friendly synthesis of Ag-NPs using Endostemon viscosus (Lamiaceae): Antibacterial, antioxidant, larvicidal, photocatalytic dye degradation activity and toxicity in zebrafish embryos.

Nanotechnology is a multidisciplinary area of study that has grown significantly in serving many functions and impacting human society. New fields of science have been facilitated by the clean, non-toxic, and biocompatible nature of plant-derived nanoparticles. The present study deals with the first green synthesis of silver nanoparticles (Ag-NPs) using Endostemon viscosus, and their synthesized Ag NPs were characterized by different spectral methods (UV-vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction Spectroscopy (XRD), Transmission Electron Microscopy (TEM) and Energy dispersive X-ray Spectroscopy (EDAX). The change initially observed the production of Ag-NPs in color from green to ash and then confirmed by SPR band at 435 nm in UV-vis spectral analysis. The FTIR findings indicate that many functional groups belong to the pharmaceutically useful phytochemicals, which interact as reducing, capping, and stabilizing agents in synthesizing silver nanoparticles. The predominant peaks in the XRD pattern belong to the planes 210°, 111°, 200°, 241°, and 311° and thus demonstrated the Ag-NPs FCC crystal structure. TEM analysis exhibited spherical-shaped particles with an average size of 13 nm, and the EDAX band showed a distinctive metallic silver peak at 3.0 keV. The antibacterial activity of Ag-NPs tested to show a maximum zone of inhibition of 19 mm for Staphylococcus aureus and 15 mm for Escherichia coli at 100 µg/mL, respectively. Bio-fabricated Ag-NPs were assessed for antioxidant activity (DPPH with % inhibition 57.54% and FRAP with % inhibition 70.89%). The biosynthesized Ag-NPs demonstrated potential larvicidal efficacy against Aedes aegypti with more than 90% at 250 µg/mL. Histological profiles were altered while treating with Ag-NPs at 250 µg/mL. The photocatalytic activity of synthesized E. viscosus Ag-NPs was tested against methylene blue (MB) and crystal violet (CV), and the maximum degradation efficiency was found as 90 and 94%, respectively. Furthermore, the toxicity test on zebrafish embryos demonstrated that aberrations have only been induced at concentrations higher than 500 µg/mL. We conclude that the greenly produced Ag-NPs may find use in biomedical applications based on bacteria and cost-effective industrial wastewater treatment.

Larvicidal Enzyme Inhibition and Repellent Activity of Red Mangrove Rhizophora mucronata (Lam.) Leaf Extracts and Their Biomolecules Against Three Medically Challenging Arthropod Vectors.

The larvicidal potential of crude leaf extracts of Rhizophora mucronata, the red mangrove, using diverse solvent extracts of the plant against the early fourth instar larvae of Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti mosquito vectors was analyzed. The acetone extract of R. mucronata showed the greatest efficacy: for Cx. quinquefasciatus (LC50 = 0.13 mg/mL; LC90 = 2.84 mg/mL), An. stephensi (LC50 = 0.34 mg/mL; LC90 = 6.03 mg/mL), and Ae. aegypti (LC50 = 0.11 mg/mL; LC90 = 1.35 mg/mL). The acetone extract was further fractionated into four fractions and tested for its larvicidal activity. Fraction 3 showed stronger larvicidal activity against all the three mosquito larvae. Chemical characterization of the acetone extract displayed the existence of several identifiable compounds like phytol, 3,7,11,15-tetramethyl-2-hexadecen-1-ol, 1-hexyl-2-nitrocyclohexane, eicosanoic acid etc. Enzyme assay displayed that R. mucronata active F3-fractions exert divergent effects on all three mosquitos' biochemical defensive mechanisms. The plant fractions displayed significant repellent activity against all the three mosquito vectors up to the maximum repellent time of 210 min. Thus, the bioactive molecules in the acetone extract of R. murconata leaves showed significant larvicidal and enzyme inhibitory activity and displayed novel eco-friendly tool for mosquito control.

Comparative extraction of Salmonella bongori derived metabolites and their toxicity on bacterial pathogens, mosquito-larvae, zebrafish-embryo and brine-shrimp: A modified approach.

The present study pertains to two different (standard and adapted) extraction-procedures to extract bacterial extracellular metabolites from the cell-free supernatant (CFS) of S. bongori. Metabolites were extracted with the different polarity solvents using lyophilized-CFS mediated procedure, which revealed more number of compounds than standard procedure. The crude-extracts (CEs) were characterized using FTIR, HPLC and GC-MS analyses. The commonly presented compounds in standard (ME, EA & HE) and lyophilization-mediated extracts (LME, LEA & LHE) were identified through Heat-map analysis. Antibacterial assay: all CEs showed considerable activity on tested MTCC-strains, in which, LME and LEA were found preponderant. Larvicidal bioassay: LME resulted maximum mortality than other CEs on Culex-larvae. Zebrafish embryo-toxicity assay: except HE, all CEs exhibited toxicity at 100 ppm after 96 hpf. Brine shrimp-toxicity assay: ME, LME, EA and LEA have shown significant mortality after 24 h. With these observations, the adapted-extraction-procedure could form significance in the drug development process.

Isolation and growth inhibition potential of entomopathogenic nematodes against three public health important mosquito vectors.

The prevalence of mosquito vector borne diseases and the resistance of mosquitoes to conventional pesticides have been of important public concern to the mosquito endemic countries. Present study was conducted to identify the native bio-larvicidal potential of the entomopathogenic nematodes; Steinernema siamkayai (KPR-4) Heterohabditis indica (KPR-8), Steinernema glaseri and Steinernema abbasi. The isolated nematodes were subsequently cultured and evaluated their larvicidal potential against the larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Among the tested four different nematode species, the S. abassi exerted the highest mortality against A. aegypti (97.33%), the H. indica (KPR-8) against A. stephensi (97.33%) and the S. siamkayai (KPR-4) against C. quinquefasciatus (98.67%). The maximal mosquito-larvicidal property of EPNs was found with the LC50 and LC90 values (IJs/larvae): S. abbasi = 12.47 & 54.35 on A. aegypti; H. indica KPR-8 = 19.88 & 66.81 on A. stephensi and S. siamkayai KPR-4 = 16.69 & 58.97 on C. quinquefasciatus, respectively. The presently generated data on the molecular and larvicidal characteristics of the entomopathogenic nematodes form an important baseline data that upon further research would lead to the development of eco-friendly mosquito-control agent.

Multipurpose efficacy of the lyophilized cell-free supernatant of Salmonella bongori isolated from the freshwater fish, Devario aequipinnatus: toxicity against microbial pathogens and mosquito vectors.

Presently, the discovery of effective drugs and pesticides from eco-friendly biological sources is an important challenge in the field of life sciences. The present research was aimed for standardizing an innovative approach in the evaluation of the biological potentiality of the metabolites of fish-associated bacteria. We have identified 17 skin-associated bacteria from the freshwater fish, giant danio, Devario aquipinnatus. They were screened through biofilm forming and extracellular enzyme producing ability. The results of preliminary antibacterial evaluation of the bacterial supernatants underlined the importance of three potential strains (BH8, BH10 and BH11) for further applied research. Hence, such strains were subsequently subjected to a novel extraction procedure to overcome the difficulties found in polar solvents mixed with the supernatant. The lyophilized cell-free supernatant (LCFS) of 3 isolates were individually extracted by using methanol. During the testing of LCFS's methanolic extract (LCFS-ME) of 3 isolates, only the extract of BH11-strain exhibited potent inhibitory activity against the pathogenic bacteria and fungi. Furthermore, the larvicidal and mosquitocidal assays on the filariasis vector, Culex quinquefasciatus also showed its potent toxicity on both the adults and developmental instars of mosquito. Through molecular and phylogenetic analyses, the BH11 strain was identified as Salmonella bongori (KR350635). The present finding emphasized that the S. bongori could be an important novel source of effective antimicrobials and mosquitocidal agents.

Bio-pesticidal effects of Trichoderma viride formulated titanium dioxide nanoparticle and their physiological and biochemical changes on Helicoverpa armigera (Hub.).

The control of agricultural pests through eco-friendly nanopesticides is a challenge of crucial environmental importance nowadays. The current study was aimed to discover a novel biopesticides through Trichoderma viride mediated synthesis of titanium dioxide nanoparticles (TDNPs). The main chemical and physical features of the TDNPs were assessed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and size distribution and shape of the NPs studied through the scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM) and dynamic light scattering (DLS). The extracellular synthesized nanoparticles were evaluated for their larvicidal, antifeedant and pupicidal activities against Helicoverpa armigera. TDNPs exhibited highest mortality rate on first (100%), second (100%) and third (92.34%), instar larvae of H. armigera at 100 ppm. The detoxifying enzymes such as, ß-glucosidase and carboxylesterase were reduced whereas glutathione S-transferase increased during the treatment of TDNPs against H. armigera at 100 ppm. No toxic effects were found on Eudrilus eugeniae filter paper and artificial soil assays treated with TDNPs at 100 ppm. However, cypermethrin was toxic to earthworms after 72 h treatment. Therefore, TDNPs could act as significant inhibitors on the development of H. armigera, although, no adverse effect was found on earthworms.