Bioproduction, purification, partial characterization and phenol removal efficacy of tyrosinase enzyme from Streptomyces sp. strain MR28.

The study focused on the production of the tyrosinase enzyme from Streptomyces sp. MR28 and its potency in removal of phenol content from water using free and immobilized tyrosinase enzyme. The tyrosinase was produced by Streptomyces sp. MR28 in liquid tyrosine broth medium, and it was further purified to near its homogeneity by employing, precipitation, dialysis, and column chromatography. After the purification, 44.49% yield with a 4 fold purification was achieved. The characterization of the purified enzyme showed a single major peak on HPLC and a solitary band on SDS-PAGE. The purified tyrosinase enzyme was active at a pH of 7.0 and a temperature of 30 °C. Further immobilization of purified tyrosinase was performed using the sodium alginate entrapment method. The capacity of the purified tyrosinase to remove phenol in water was evaluated by spectrophotometric method. The free tyrosinase enzyme-treated solutions showed a gradual decrease in the concentration of phenol with increased incubation time at 30 °C and 40 °C, at 90 min of the incubation time, it showed maximum efficacy in removing phenol from the solution. At 50 °C and 60 °C, the free tyrosinase enzyme exhibited very less capacity to remove the phenol. The immobilized enzyme showed good capacity for the removal of phenol from the solutions; the concentration of phenol in the solution decreased with an increase in the incubation time. At temperatures of 40 °C and 50 °C, the immobilized tyrosinase enzyme beads showed significant removal of phenol from the solution, and at temperatures of 30 °C and 60 °C, they also exhibited good capacity for the removal of phenol. At the end of the 90 min incubation period, it exhibited good capability. The current study suggests using immobilized microbial tyrosinase enzyme can be used for the removal of phenol from the contaminated water in a greener manner.

Eicosane: An antifungal compound derived from Streptomyces sp. KF15 exhibits inhibitory potential against major phytopathogenic fungi of crops.

In the present scenario, food security is of major concern due to exponentially increasing population and depleted crop production. The fungal diseases have contributed majorly to the scarcity of staple food products and economic loss worldwide. This problem could be tackled by preventing the crop loss during both pre and post-harvest seasons. During the current investigation, the bioactive compound eicosane was extracted from Streptomyces sp. KF15, subjected to purification and identified based on mass spectrometry and NMR analysis. The evaluation of in-vitro antifungal activity was done by poisoned food method, SEM analysis and growth pattern analysis. The bioactive compound eicosane with molecular weight of 282.5475 g/mol was purified by column chromatography and the straight chain hydrocarbon structure of CH3CH2(18)CH3 was elucidated by NMR analysis. In poisoned food assay, eicosane effectively inhibited the radial growth of all tested fungal pathogens; F. oxysporum was found to be the most sensitive with 24.2%, 33.3%, 42.4%, and 63.6% inhibition at 25-100 µg/ml concentrations. The SEM micrograph established clear differences in the morphology of eicosane treated fungi with damaged hyphae, flaccid mycelium and collapsed spores as compared to the tubular, turgid and entire fungi in control sample. Finally, the growth curve assay depicted the right side shift in the pattern of eicosane treated fungi indicating the delay in adapting to the conditions of growth and multiplication. The findings of this study encourage further research and development towards the novel antifungal drugs that can act against major phytopathogens.

In-vitro investigation on the biological activities of squalene derived from the soil fungus Talaromyces pinophilus.

The consistent increase in multidrug resistance among pathogens and increased cancer incidence are serious public health concerns and threaten humans by killing countless lives. In the present study, Talaromyces pinophilus CJ15 was characterized and evaluated for its antibacterial, candidicidal and cytotoxic activities. The selected isolate Talaromyces pinophilus CJ15 with 18S rRNA gene sequence of 1021 base pairs exhibited antifungal activity on plant pathogens via dual culture. The GC-MS profiling of crude extract illustrated the existence of many bioactive macromolecules which include squalene belonging to the terpenoids family. The biological macromolecules in the bioactive fraction of CJ15 exhibited increasing antibacterial activity with an increase in concentration such that the highest activity was recorded against Shigella flexneri with 15, 18, 20, and 24 mm inhibition zones at 25, 50, 75 and 100 µl concentrations, respectively. The squalene, having a molecular weight of 410.718 g/mol, displayed candidicidal activity with a right-side shifted log phase in the growth curve of all the treated Candida species, indicating delayed exponential growth. In cytotoxic activity, the extracted squalene exhibited an IC50 concentration of 26.22 µg/ml against JURKAT cells and induced apoptosis-induced cell death. This study's outcomes encourage the researchers to explore further the development of new and improved bioactive macromolecules that could help to prevent infections and human blood cancer.

Efficacy of Penicillium limosum Strain AK-7 Derived Bioactive Metabolites on Antimicrobial, Antioxidant, and Anticancer Activity against Human Ovarian Teratocarcinoma (PA-1) Cell Line.

Natural metabolites from beneficial fungi were recognized for their potential to inhibit multidrug-resistant human and plant fungal pathogens. The present study describes the isolation, metabolite profiling, antibacterial, and antifungal, antioxidant, and anticancer activities of soil fungi. Among the 17 isolates, the AK-7 isolate was selected based on the primary screening. Further, the identification of isolate AK-7 was performed by 18S rRNA sequencing and identified as Penicillium limosum (with 99.90% similarity). Additionally, the ethyl acetate extract of the Penicillium limosum strain AK-7 (AK-7 extract) was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and a Gas Chromatography-Mass Spectroscopy (GC-MS) analysis, and the results showed different functional groups and bioactive metabolites. Consequently, a secondary screening of antibacterial activity by the agar well diffusion method showed significant antibacterial activity against Gram-negative and Gram-positive bacterial pathogens. The AK-7 extract exhibited notable antifungal activity by a food poisoning method and showed maximum inhibition of 77.84 ± 1.62%, 56.42 ± 1.27%, and 37.96 ± 1.84% against Cercospora canescens, Fusarium sambucinum and Sclerotium rolfsii phytopathogens. Consequently, the AK-7 extract showed significant antioxidant activity against DPPH and ABTS•+ free radicals with IC50 values of 59.084 µg/mL and 73.36 µg/mL. Further, the anticancer activity of the AK-7 extract against the human ovarian teratocarcinoma (PA-1) cell line was tested by MTT and Annexin V flow cytometry. The results showed a dose-dependent reduction in cell viability and exhibited apoptosis with an IC50 value of 82.04 µg/mL. The study highlights the potential of the Penicillium limosum strain AK-7 as a source of active metabolites and natural antibacterial, antifungal, antioxidant, and anticancer agent, and it could be an excellent alternative for pharmaceutical and agricultural sectors.

Unveiling the Pharmacological Significance of Marine Streptomyces violaceusniger KS20: Isolation, Characterization, and Assessment of Its Biomedical Applications.

Marine actinomycetes represent a highly favorable source of bioactive compounds and have been the mainstay of much research in recent years. Recent reports have shown that marine Streptomyces sp. can produce compounds with diverse and potent biological activities. Therefore, the key objective of the study was to isolate and screen a potential actinomycete from marine ecosystems of Devbagh and Tilmati beaches, Karwar. Streptomyces sp. KS20 was characterized and the ethyl acetate extract (EtOAc-Ex) was screened for biomedical applications. Streptomyces sp. KS20 produced grayish-white aerial and pale-yellow substrate mycelia and revealed an ancestral relationship with Streptomyces violaceusniger. Optimum growth of the organism was recorded at 30 °C and pH 7.0. The metabolite profiling of EtOAc-Ex expressed the existence of several bioactive metabolites, whereas the functional groups were indicated by Fourier transform infrared (FTIR) spectroscopy. A considerable antioxidant activity was shown for EtOAc-Ex with IC50 of 92.56 µg/mL. In addition to this, Streptomyces sp. KS20 exhibited significant antimicrobial properties, particularly against Escherichia coli, where a zone of inhibition measuring 36 ± 0.83 mm and a minimum inhibitory concentration (MIC) of 3.12 µg/mL were observed. The EtOAc-Ex even revealed significant antimycobacterial potency with IC50 of 6.25 µg/mL. Finally, the antiproliferative potentiality of EtOAc-Ex against A549 and PC-3 cell lines revealed a constant decline in cell viability while raising the concentration of EtOAc-Ex from 12.5 to 200 µg/mL. The IC50 values were determined as 94.73 µg/mL and 121.12 µg/mL for A549 and PC-3 cell lines, respectively. Overall, the exploration of secondary metabolites from marine Streptomyces sp. KS20 represents an exciting area of further research with the potential to discover novel bioactive compounds that could be developed into therapeutics for various medical applications.

Antimicrobial Efficacy of 7-Hydroxyflavone Derived from Amycolatopsis sp. HSN-02 and Its Biocontrol Potential on Cercospora Leaf Spot Disease in Tomato Plants.

The actinomycete strain HSN-02 was isolated from the soil of a mining field in the Sandur region, Bellary, Karnataka, India. According to the morphological, cultural, physiological, and biochemical characteristics and the 16S rDNA sequence analysis, the strain HSN-02 was identified as Amycolatopsis sp. The antimicrobial activity strain HSN-02 presented stable and moderate inhibitory activity against human pathogens. In pot experiments in the greenhouse, the development of Cercospora leaf spot was markedly suppressed by treatment with the purified compound from the strain HSN-02, and the control efficacy was 45.04 ± 1.30% in Septoria lycopersici-infected tomato plants. A prominent compound was obtained from the fermentation broth of the strain HSN-02 using column chromatography and HPLC. The chemical structural analyses using UV, FTIR, HR-ESI-MS, and NMR confirmed that the compound produced by the strain HSN-02 is 7-hydroxyflavone. This investigation showed the role which the actinomycete strain can play in controlling leaf spots caused by S. lycopersici to reduce treatments with chemical fungicides.

Isolation, Characterization of Pyraclostrobin Derived from Soil Actinomycete Streptomyces sp. HSN-01 and Its Antimicrobial and Anticancer Activity.

The present study demonstrated the isolation, characterization, and antimicrobial and anticancer activity of active metabolite produced from mining-soil-derived actinomycetes. Among the 21 actinomycete isolates, the isolate HSN-01 exhibited significant antimicrobial activity in primary screening and was identified as Streptomyces sp. through 16S rRNA gene sequencing. The active metabolite was separated, purified, and confirmed through UV-Vis spectroscopy, FTIR, HR-ESI-MS, and NMR analysis and identified as pyraclostrobin. Further, the active metabolite pyraclostrobin was tested for antimicrobial and anticancer activity against the hepatocellular carcinoma (HepG2) cell line. The metabolite exhibited maximum antimicrobial potential with 17.0, 13.33, 17.66, 15.66, 14.66, and 14.0 mm of inhibition against B. cereus, S. aureus, E. coli, P. aeruginosa, S. flexneri, and C. glabrata. The active metabolite exhibited dose-dependent anticancer potential against the hepatocellular carcinoma (HepG2) cell line with the IC50 56.76 µg/mL. This study suggests that Streptomyces sp. HSN-01 is an excellent source of active secondary metabolites with various biological activities.

Exploring the Antimicrobial, Anticancer, and Apoptosis Inducing Ability of Biofabricated Silver Nanoparticles Using Lagerstroemia speciosa Flower Buds against the Human Osteosarcoma (MG-63) Cell Line via Flow Cytometry.

Biosynthesized nano-composites, such as silver nanoparticles (AgNPs), can be engineered to function as smart nano-biomedicine platforms for the detection and management of diverse ailments, such as infectious diseases and cancer. This study determined the eco-friendly fabrication of silver nanoparticles using Lagerstroemia speciosa (L.) Pers. flower buds and their efficacy against antimicrobial and anticancer activities. The UV-Visible spectrum was found at 413 nm showing a typical resonance spectrum for L. speciosa flower bud extract-assisted silver nanoparticles (Ls-AgNPs). Fourier transform infrared analysis revealed the presence of amines, halides, and halogen compounds, which were involved in the reduction and capping agent of AgNP formation. X-ray diffraction analysis revealed the face-centered cubic crystals of NPs. Energy dispersive X-ray verified the weight of 39.80% of silver (Ag), TEM analysis revealed the particles were spherical with a 10.27 to 62.5 nm range, and dynamic light scattering recorded the average particle size around 58.5 nm. Zeta potential showed a significant value at -39.4 mV, and finally, thermo-gravimetric analysis reported higher thermal stability of Ls-AgNPs. Further, the obtained Ls-AgNPs displayed good antimicrobial activity against clinical pathogens. In addition, a dose-dependent decrease in the anticancer activity by MTT assay on the osteosarcoma (MG-63) cell line showed a decrease in the cell viability with increasing in the concentration of Ls-AgNPs with an IC50 value of 37.57 µg/mL. Subsequently, an apoptotic/necrosis study was conducted with the help of Annexin-V/PI assay, and the results indicated a significant rise in early and late apoptosis cell populations. Therefore, green synthesized Ls-AgNPs were found to have potent antimicrobial and anticancer properties making them fascinating choices for future bio-medical implementations.

Penicillium citrinum NP4 mediated production, extraction, physicochemical characterization of the melanin, and its anticancer, apoptotic, photoprotection properties.

The biopolymer melanin is reported for many biological processes to secure biological entities over unfavorable environmental factors. The present study aimed to isolate soil fungi and screen for melanin production. The potent fungus was identified as Penicillium citrinum NP4 based on morphological and molecular characterization with accession number OP070954. Using standardized tyrosine broth conditions melanin was produced by NP4 and extracted by acidification. Extracted melanin exhibited maximum UV-visible absorption at 223 nm; FTIR peaks validate the occurrence of CO, CN, CH, and CC functional groups present in the indole/pyrrole structure. TLC analysis exhibited a prominent single band with a Retardation factor (Rf) of 0.68, resonance peaks at 6.621, 7.061, and 7.185 ppm exhibited aromatic hydrogen in the indole/pyrole system in 1H NMR. The EDX peaks confirm the presence of carbon, oxygen, sulfur, and nitrogen elements which are the key factors in melanin structure, and TGA reports the thermal stability of the melanin. An in silico molecular docking approach on lung cancer causing proteins EGFR (3g5z), KRAS (6vc8), and TP53 (8 dc4) were conducted to determine the active binding sites of the melanin, and proteins exhibited binding affinity of -8.0 for 3g5z, -9.8 for 6vc8, and - 10.1 kcal/mol for TP53 protein with melanin. Anticancer activity of the melanin showed significant inhibition of A549 cells in dose-dependent mode with significant IC50 of 65.49 µg/mL; apoptotic examination reveals 46.14 % apoptosis for melanin and 46.36 % apoptosis for standard drug (cisplatin). Melanin exhibited good photoprotection capacity at 1 µg/mL. In conclusion, the extracted melanin exhibited significant results on many biological applications and it can be used in the pharmaceutical field to avoid chemical-based drugs.

GC-MS Based Characterization, Antibacterial, Antifungal and Anti-Oncogenic Activity of Ethyl Acetate Extract of Aspergillus niger Strain AK-6 Isolated from Rhizospheric Soil.

Rhizospheric soil is the richest niche of different microbes that produce biologically active metabolites. The current study investigated the antimicrobial, antifungal and anticancer activities of ethyl acetate extract of the potent rhizospheric fungus Aspergillus niger AK6 (AK-6). A total of six fungal isolates were isolated, and isolate AK-6 was selected based on primary screening. Further, it exhibited moderate antimicrobial activity against pathogens such as Klebsiella pneumonia, Candida albicans, Escherichia coli, Shigella flexneri, Bacillus subtilis and Staphylococcus aureus. The morphological and molecular characterization (18S rRNA) confirmed that the isolate AK-6 belonged to Aspergillus niger. Further, AK-6 showed potent antifungal activity with 47.2%, 59.4% and 64.1% of inhibition against Sclerotium rolfsii, Cercospora canescens and Fusarium sambucinum phytopathogens. FT-IR analysis displayed different biological functional groups. Consequently, the GC-MS analysis displayed bioactive compounds, namely, n-didehydrohexacarboxyl-2,4,5-trimethylpiperazine (23.82%), dibutyl phthalate (14.65%), e-5-heptadecanol (8.98%), and 2,4-ditert-butylphenol (8.60%), among the total of 15 compounds isolated. Further, the anticancer activity of AK-6 was exhibited against the MCF-7 cell line of human breast adenocarcinoma with an IC50 value of 102.01 µg/mL. Furthermore, flow cytometry depicted 17.3%, 26.43%, and 3.16% of early and late apoptosis and necrosis in the AK-6 extarct treated MCF-7 cell line, respectively. The results of the present analysis suggest that the isolated Aspergillus niger strain AK-6 extract has the potential to be explored as a promising antimicrobial, antifungal and anticancer drug for medical and agricultural applications.

Exogenous application of antagonistic Streptomyces sp. SND-2 triggers defense response in Vigna radiata (L.) R. Wilczek (mung bean) against anthracnose infection.

Anthracnose is a devastating disease caused by the fungus Colletotrichum lindemuthianum (CL) in Vigna radiata (L.) R. Wilczek (mung bean). In the present study, an eco-friendly approach to control anthracnose infection, growth promotion and enhancement of defense response in mung bean plants using endophytic actinomycetes was performed. Among the 24 actinomycetes isolates from the Cleome rutidosperma plant, the isolate SND-2 exhibited a broad spectrum of antagonistic activity with 63.27% of inhibition against CL in the dual culture method. Further, the isolate SND-2 was identified as Streptomyces sp. strain SND-2 (SND-2) through the 16S rRNA gene sequence. In-vitro screening of plant growth trials confirmed that SND-2 has the potential to produce indole acetic acid, hydrogen cyanide, ammonia, phosphate solubilization, and siderophore. The in-vivo biocontrol study was performed with exogenous application of wettable talcum-based formulation of SND-2 strain to mitigate CL infection in mung bean seedlings. The results displayed maximum seed germination, vigor index, increased growth parameters, and lowest disease severity (43.63 ± 0.73) in formulation treated and pathogen challenged mung bean plants. Further, the application of SND-2 formulation with pathogen witnessed increased cellular defense through the maximum accumulation of lignin, hydrogen peroxide and phenol deposition in mung bean leaves compared with control treatments. Biochemical defense response exhibited upregulation of antioxidant enzymes such as phenylalanine ammonia-lyase, ß-1,-3-Glucanase, and peroxidase enzymes activities with increased phenolic (3.64 ± 0.11 mg/g fresh weight) and flavonoid (1.14 ± 0.05 mg/g fresh weight) contents in comparison with other treatments at 0, 4, 12, 24, 36, and 72 h post pathogen inoculation. This study demonstrated that formulation of Streptomyces sp. strain SND-2 is a potential source as a suppressive agent and plant growth promoter in mung bean plants upon C. lindemuthianum infestation and witnesses the elevation in cellular and biochemical defense against anthracnose disease.

Aspergillus niger CJ6 extract with antimicrobial potential promotes in-vitro cytotoxicity and induced apoptosis against MIA PaCa-2 cell line.

Nowadays, the increased number of multidrug-resistant strains among pathogens is a severe public health concern and cancer is posing a great threat for humans. These problems should be tackled with the development of novel and broad-spectrum antimicrobials from microbial origin. During the present study, the bioactive secondary metabolites from Aspergillus niger CJ6 were extracted, characterized; their biological properties were evaluated by subjecting them for antimicrobial, antifungal and anticancer activities. The potent isolate Aspergillus niger CJ6 with nucleotide sequence of 959 base pairs showed antagonistic activity against fungal pathogens in dual culture. The chemical profiling of crude ethyl acetate extract indicated the presence of various bioactive molecules belonging to phenolic, hydrocarbons, and phthalate derivative classes. In antimicrobial activity, the crude extract displayed increasing activity with increased concentration; the highest activity observed against Shigella flexneri with 15 ± 1.0, 19 ± 0.5, 20 ± 1.0 and 24 ± 1.0 mm zones of inhibition at 25, 50, 75 and 100 µl concentrations. The MTT assay illustrated deformed cells of MIA PaCa-2 cell line in in-vitro cytotoxic activity; outflow of cell matrix and membrane rupture; the IC50 of 90.78 µg/ml suggested moderate potential of extract to prevent cancer cell growth. The apoptosis/necrosis study by flow cytometer exhibited 8.98 ± 0.85% early and 73 ± 0.7% of late apoptotic population with 3.8 ± 1.1% necrotic cells; only 14.22 ± 0.6% of healthy cells suggested the increased apoptosis inducing capacity of Aspergillus niger CJ6 crude extract. The outcomes of this study persuade further exploration on the identification, purification and development of novel bioactive agents that could help battle fatal diseases in humans.

Biosynthesis and characterization of polysaccharide-capped silver nanoparticles from Acalypha indica L. and evaluation of their biological activities.

Biosynthesized silver nanoparticles (AgNPs) are gaining popularity due to their distinctive biological applications. In this research work, an eco-friendly method of synthesizing AgNPs from the leaf polysaccharide (PS) of Acalypha indica L. ( A. indica) was carried out. Synthesis of polysaccharide-AgNPs (PS-AgNPs) was indicated by visual detection of colour change from pale yellow to light brown. The PS-AgNPs were characterized with different techniques and further evaluated for biological activities. The Ultra violet-visible (UV-Vis.) spectroscopy expressed a sharp absorption peak at 415 nm confirmed the synthesis. Atomic force microscopy (AFM) analysis revealed the size range of particles from 14 nm to 85 nm. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The cubic crystalline structure of PS-AgNPs was confirmed by X-ray diffraction (XRD) and the particles were found to be oval to polymorphic shaped through transmission electron microscopy (TEM) with sizes from 7.25 nm to 92.51 nm. Energy dispersive X-ray (EDX) determined the presence of silver in PS-AgNPs. The zeta potential was -28.0 mV, which confirmed the stability and an average particle size of 62.2 nm was calculated through dynamic light scattering (DLS). Lastly, the thermo gravimetric analysis (TGA) showed the PS-AgNPs were resistant to high temperature. The PS-AgNPs exhibited significant free radical scavenging activity with an IC50 value of 112.91 µg/ml. They were highly capable of inhibiting the growth of different bacterial and plant fungal pathogens and also active to reduce the cell viability of prostate cancer (PC-3) cell line. The IC50 value was 101.43 µg/ml. The flow cytometric apoptosis analysis revealed the percentage of viable, apoptotic and necrotic cells of PC-3 cell line. According to this evaluation, it can be concluded that these biosynthesized and environmentally friendly PS-AgNPs are helpful to improve therapeutics because of significant antibacterial, antifungal, antioxidant, and cytotoxic properties to open up new possibilities for euthenics.

Myco-Nanofabrication of Silver Nanoparticles by Penicillium brasilianum NP5 and Their Antimicrobial, Photoprotective and Anticancer Effect on MDA-MB-231 Breast Cancer Cell Line.

Currently, the exploration of fungal organisms for novel metabolite production and its pharmacological applications is much appreciated in the biomedical field. In the present study, the fungal strains were isolated from soil of unexplored Yellapura regions. The potent isolate NP5 was selected based on preliminary screening and identified as Penicillium brasilianum NP5 through morphological, microscopic, and molecular characterizations. Synthesis of silver nanoparticles from P. brasilianum was confirmed by the color change of the reaction mixture and UV-visible surface plasmon resonance (SPR) spectra of 420 nm. Fourier transform infrared (FTIR) analysis revealed the functional groups involved in synthesis. Atomic force microscopy (AFM) and transmission electron microscope (TEM) analysis showed aggregation of the NPs, with sizes ranged from 10 to 60 nm, an average particle size of 25.32 nm, and a polydispersity index (PDI) of 0.40. The crystalline nature and silver as the major element in NP5-AgNPs was confirmed by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The negative value -15.3 mV in Zeta potential exhibited good stability, and thermostability was recorded by thermogravimetric analysis (TGA). NP5-AgNPs showed good antimicrobial activity on selected human pathogens in a concentration-dependent manner. The MTT assay showed concentration-dependent anticancer activity with an IC50 of 41.93 µg/mL on the MDA-MB-231 cell line. Further, apoptotic study was carried out by flow cytometry to observe the rate of apoptosis. The calculated sun protection factor (SPF) value confirms good photoprotection capacity. From the results obtained, NP5-AgNPs can be used in the pharmaceutical field after successful in vitro clinical studies.

Cave Soil Streptomyces sp. strain YC69 Antagonistic to Chilli Fungal Pathogens Exhibits In Vitro Anticancer Activity Against Human Cervical Cancer Cells.

Cancer is one of the fatal diseases and has high mortality worldwide, and the major drawback with the cure is the side effects from the chemotherapeutic agents. The increased multidrug resistance among microbial pathogens is a serious threat to plant and animal health. There is an urgent need for an alternative that can battle against pathogens and can be used for cancer treatment. Presently, actinomycetes were isolated from cave soil, and the crude extract obtained from the potent isolate was analyzed with gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC) to identify bioactive metabolites. The crude extract was examined for in vitro antimicrobial activity on human pathogens and antifungal activity on plant pathogens. The isolate Streptomyces sp. strain YC69 exhibited antagonistic activity and antimicrobial activity in a dose-dependent manner, with the highest inhibition in Staphylococcus aureus. GC-MS revealed many bioactive compounds, and HPTLC depicted metabolite fingerprints. The antifungal activity exhibited a delayed lag phase in growth curve assay and distorted and collapsed cells of Fusarium oxysporum in scanning electron microscopy (SEM) images. In the MTT assay, the IC50 of 41.98 µg/ml against HeLa cells was obtained with clear evidence for deformed cells and blebbing of the cell membrane. The results from the current study suggest that the crude extract from Streptomyces sp. strain YC69 contains antimicrobial metabolites that can inhibit pathogenic microbes in plants and humans. The MTT assay results conclude that further studies on purification may lead to the use of Streptomyces sp. strain YC69 as a source for anti-oncogenic compounds.

In Silico Molecular Docking Approach of Melanin Against Melanoma Causing MITF Proteins and Anticancer, Oxidation-Reduction, Photoprotection, and Drug-Binding Affinity Properties of Extracted Melanin from Streptomyces sp. strain MR28.

Melanin is a biopolymer reported for diverse biological actions to secure organisms over adverse environmental factors. In the last decade, melanin attributed considerable attention for its use in bioelectronics, photoprotection, environmental bioremediation, and drug discovery. Molecular docking study is the emerging trend in drug discovery for drug designing by targeting proteins. Considering the therapeutic nature of the melanin, we extracted melanin from Streptomyces sp. strain MR28, and it was tested for various biological activities, viz., DPPH free radical scavenging potency, sun protection factor (SPF), drug likeness by SwissADME, molecular docking of melanin on melanocyte-inducing transcription factor (MITF) proteins, cytotoxic activity on A375 malignant melanoma with induction of apoptosis study by flow cytometry, and adsorption study of melanin on doxorubicin and camptothecin drug for drug uptake by melanin. The melanin showed good scavenging potency of DPPH free radicals in a concentration-dependent manner. SPF of 38.64 ± 0.63, 55.53 ± 0.53, and 67.07 ± 0.82 were recorded at 0.06, 0.08, and 0.1 µg/mL, concentrations, respectively. SwissADME screening confirms the drug likeness of melanin. Docking of melanin with MITF proteins exhibited a maximum of - 9.2 kcal/mol binding affinity for 4ATK protein. Cytotoxicity of the melanin drug exhibited good inhibition of melanoma cells in dose-dependent way with significant IC50 of 65.61 µg/mL; apoptotic study reveals melanin showed 64.02% apoptosis for melanin and 33.8% apoptosis for standard drug (doxorubicin). The maximum adsorptions for selected drugs camptothecin and doxorubicin to melanin were recorded at 90 min. In conclusion, the extracted melanin showed significant results over many biological applications and it can be used in the pharmaceutical field to avoid chemical-based drugs.

Formulation-based antagonistic endophyte Amycolatopsis sp. SND-1 triggers defense response in Vigna radiata (L.) R. Wilczek. (Mung bean) against Cercospora leaf spot disease.

In the present work, Amycolatopsis sp. SND-1 (SND-1) was isolated from Cleome chellidonii Linn. (C. chellidonii) was performed as biocontrol and resistance elicitor in Vigna radiata (L.) R. Wilczek (mung bean) plants against Cercospora leaf spot causing pathogen Cercospora canescens (C. canescens). The SND-1 isolate showed 74% of inhibition against C. canescens in dual culture and GC-MS analysis revealed the presence of antifungal compounds. Molecular characterization through 16S rRNA showed that the isolated SND-1 belongs to Amycolatopsis sp. The in vitro plant growth trials exhibited production of indole acetic acid, gibberellic acid, cytokinin, ammonia, hydrogen cyanide, and siderophore and phosphate solubilization. In vivo study with talcum formulation of SND-1 revealed a significant increase in plant root length, shoots length, root and shoot fresh weight, and reduced the disease severity in treated mung bean plants. Triggering of resistance by SND-1 formulation was studied by histochemical depositions and biochemical defense enzymes that resulted in the acceleration in defense response in comparison with control plants. The bioactive endophytic Amycolatopsis sp. SND-1 enhanced the defense against C. canescens infection; hence, it can be used as a biological control agent in mung bean cultivars.

Phytochemical Analysis, GC-MS Profiling, and In Vitro Evaluation of Biological Applications of Different Solvent Extracts of Leonotis nepetifolia (L.) R.Br. Flower Buds.

Leonotis nepetifolia (L.) R.Br. is a medicinally important herb belonging to the family Lamiaceae. The plant is typically found in tropical regions, and its leaf and root extracts are renowned for their ethno-botanical and therapeutic applications. This study was designed to determine the presence of various bioactive components, and to evaluate antibacterial, antifungal, antioxidant, and anti-proliferative activities. The preliminary phytochemical screening and gas chromatography-mass spectrometry (GC-MS) analysis of different solvent extracts revealed the presence of various bioactive compounds, of which methanol extract showed 24 compounds, petroleum ether extract revealed 26 compounds, and 24 compounds in hexane extracts. The major bioactive components including λ-sitosterol (16.20 %) in methanol extract, 1-nonadecanol (15.48 %) in petroleum extract, and eicosane (13.22 %) in hexane extract have been reported with various bio-therapeutic applications. In addition, the flower bud methanolic extract of L. nepetifolia exhibited inhibitory potential against all tested bacterial and fungal pathogens. The DPPH radical scavenging assay revealed that methanolic extract possessed the highest antioxidant activity. The scavenging activity increased in a concentration-dependent manner, as indicated by a 74 % inhibition rate at 1000 µg/ml. Furthermore, the in vitro cytotoxic effects of the methanolic extract on the HepG2 cell line were evaluated. The IC50 value of methanolic extract against HepG2 cells was determined to be 83.28 µg/ml. The findings reveal that different solvent extracts of L. nepetifolia flower buds contain a significant amount of various bioactive phytochemicals with antioxidant and anticancer activities; and thus, the plant could serve as a potential source of pharmacological applications.

Leonotis nepetifolia Flower Bud Extract Mediated Green Synthesis of Silver Nanoparticles, Their Characterization, and In Vitro Evaluation of Biological Applications.

Biosynthesis of silver nanoparticles (AgNPs) using the green matrix is an emerging trend and is considered green nanotechnology because it involves a simple, low-cost, and environmentally friendly process. The present research aimed to synthesize silver nanoparticles from a Leonotis nepetifolia (L.) R.Br. flower bud aqueous extract, characterize these nanoparticles, and perform in vitro determination of their biological applications. UV-Vis spectra were used to study the characterization of biosynthesized L. nepetifolia-flower-bud-mediated AgNPs (LnFb-AgNPs); an SPR absorption maximum at 418 nm confirmed the formation of LnFb-AgNPs. The presumed phytoconstituents subjected to reduction in the silver ions were revealed by FTIR analysis. XRD, TEM, EDS, TGA, and zeta potential with DLS analysis revealed the crystalline nature, particle size, elemental details, surface charge, thermal stability, and spherical shape, with an average size of 24.50 nm. In addition, the LnFb-AgNPs were also tested for antimicrobial activity and exhibited a moderate zone of inhibition against the selected pathogens. Concentration-dependent antioxidant activity was observed in the DPPH assay. Further, the cytotoxicity increased proportionate to the increasing concentration of the biosynthesized LnFb-AgNPs with a maximum effect at 200 µg/mL by showing the inhibition cell viability percentages and an IC50 of 35.84 µg/mL. Subsequently, the apoptotic/necrotic potential was determined using Annexin V/Propidium Iodide staining by the flow cytometry method. Significant early and late apoptosis cell populations were observed in response to the pancreatic ductal adenocarcinoma (PANC-1) cell line, as demonstrated by the obtained results. In conclusion, the study's findings suggest that the LnFb-AgNPs could serve as remedial agents in a wide range of biomedical applications.

A swamp forest Streptomyces sp. strain KF15 with broad spectrum antifungal activity against chilli pathogens exhibits anticancer activity on HeLa cells.

During the investigation, soil actinomycetes were isolated from Kathlekanu swamp forest and the crude ethyl acetate extract from the potent isolate KF15 was analysed with GC-MS and HPTLC to identify bioactive metabolites. The crude extract was examined for in-vitro antifungal activity on pathogens of chilli; MTT cytotoxicity assay was performed against HeLa cell line to determine the anticancer potential. The isolate Streptomyces sp. strain KF15 exhibited antagonistic activity against fungal pathogens by inhibiting growth and altering growth pattern with increased antimicrobial activity in dose-dependent manner. GC-MS revealed many bioactive compounds and HPTLC depicted metabolite fingerprint. The IC50 of 99.85 µg/ml indicated the high potential of KF15 extract to prevent proliferation of HeLa cells. Therefore, the findings of this study indicate that the crude extract from Streptomyces sp. strain KF15 contains antifungal and anticancer metabolites; further study on purification could help in controlling many fungal diseases as well as cervical cancer in humans.