The aims of nano oncology are to detect, target and treat cancer cells without any side effects. The present study describes the microbial synthesis of biocompatible nanoparticles of silver (AgNPs), gold (AuNPs) and their alloy (Ag/AuNPs) for hepatoprotective activity against diethylnitrosamine (DEN)-induced liver cancer in a Sprague Dawley (SD) rat model. The crystalline nature and physicochemical features of the nanoparticles were identified by Fourier transform infra-red (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) analysis. Based on the instrumental analysis, the synthesised nanomaterials were found to be spherical in shape and have an average size in the nano region. Nitrate reductase was characterized after partial purification of the culture filtrate via polyacrylamide gel electrophoresis and its molecular weight was determined as ∼45 kDa. Furthermore, the IC₅₀ values of the AgNPs, AuNPs and Ag/AuNPs on HepG2 cells were determined as 38.42 μg ml⁻¹, 43.25 μg ml⁻¹ and 39.20 μg ml⁻¹, respectively, and the antioxidant potential of the nanoparticles was also systematically analyzed. The No-Observed-Adverse-Effect-Level (NOAEL) for the AgNPs was determined to be 2000 mg per kg of body weight (bw) from an acute toxicity test. Similarly, the NOAEL of AuNPs and Ag/AuNPs were calculated as 1000 mg per kg bw. Based on the in vivo studies, a significant tumour reduction (∼45 to 65%) was observed in the nanoparticle-treated animals, which was further confirmed by hematological, biochemical, TEM and histopathological analysis. Immunohistochemistry analysis confirmed the presence of BAX antibodies, up to immunoreactive (3+) level in treated animals. These results strongly suggest the potential anticancer activities of AgNPs, AuNPs and Ag/AuNPs against DEN-induced liver cancer and they could be potential candidates for effective nano drug development.

The therapeutic use of metal and alloy nanoparticles is claimed to have reduced side effects and enhanced curative activity as compared to its ionic counterpart. With this view, the present study focused on the synthesis of silver (Ag), gold (Au) and silver/gold (Ag/Au) nanoparticles (NPs) by using actinobacterial metabolites as a reducing agent for enhanced in vitro antimicrobial and in vivo wound healing activities. Physico-chemical parameters of the synthesised nanoparticles were systematically assessed by using X-ray based spectroscopic, zeta potential, dynamic light scattering (DLS), atomic and electron microscopic analysis. The average sizes of the AgNPs, AuNPs and Ag/AuNPs were found to be 30.5 nm, 14.5 nm and 41.5 nm respectively. The synthesized AgNPs and Ag/AuNPs showed better antibacterial activity on Gram negative bacterial pathogens (Escherichia coli, Pseudomonas aeruginosa and Aeromonas hydrophila) than Gram positive bacterial pathogens. A Minimum Inhibitory Concentration (MIC) value of 6.25 μg ml⁻¹ was observed for E. coli, P. aeruginosa and Candida albicans. AgNP and Ag/AuNP based ointments of about 10% concentration heal (100%) the excision wound within 19 and 21 days in contrast with standard ointment. Further, the complete healing process was evaluated by histopathological analysis, and estimation of tensile strength, inflammatory cytokines (IL-6, TNFα, IL-10) and collagen constituents (hexosamine, hydroxyproline and hyaluronic acid). Metal and alloy nanoparticle use may provide a new and effective therapeutic direction for achieving development of novel antimicrobial drugs and scarless wound healing in clinical practice.

Objectives: Evaluation of Streptomyces isolated from Udhagamandalam, The Nilgiris, Tamilnadu, India for the biocontrol potential against the phytopathogen Ralstonia solanacearum and its metabolite profiling. Methods: Streptomyces strains were screened for plant growth promotion and antagonistic activity against R. solanacearum in in-vitro. The metabolite profiling of strain UT4A49 was studied through gas chromatography coupled with mass spectroscopy (GC–MS) analysis. Further, the identified lead compound 2,4-Di-tert-butylphenol (2,4-DTBP) was analyzed for its mechanism of action through in-silico docking study. The bioorganic fertilizer (BOF) amended potential Streptomyces strain UT4A49 was studied for biocontrol activity against R. solanacearum on tomato seedlings through pot culture experiments. Results: The Streptomyces strain UT4A49 showed the promising production of indole acetic acid (IAA) (76.0 ± 2.0 µg/ml), siderophore, ammonia, amylase, protease, cellulase as well as it solubilized the phosphate in-vitro. The strain UT4A49 showed strong in vitro antagonistic activity against R. solanacearum with the inhibition zone of 19.83 ± 0.44 mm in diameter. The isolated major compound, 2,4-Di-tert-butylphenol was showed strong inhibition against R. solanacearum. In silico docking study revealed that the 2,4-DTBP showed lower binding energy score with all targeted proteins which found better protein–ligand binding stability. In the pot experiment, biocontrol activity of BOF amended Streptomyces strain UT4A49 showed significant biocontrol efficacy was 78.5% against R. solanacearum in tomato seedlings. The strain UT4A49 was identified as Streptomyces sp. based on its morphological and molecular properties. Conclusions: The detailed literature survey revealed that this is the first report on strong bioactive properties of 2,4-DTBP against R. solanacearum. This present study proved that bioorganic fertilizer amended with Streptomyces sp. UT4A49 is a promising biocontrol agent for tomato bacterial disease control.