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The present study was undertaken to investigate the anticancer activity of flexirubin produced by Chryseobacterium artocarpi CECT8497 and to explore its mechanism of action. The effect of flexirubin on cell proliferation of MCF-7 cells were evaluated by 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyl-tetrazolium bromide (MTT), sulforhodamine B (SRB) and lactate dehydrogenase (LDH) assays. Cell apoptosis was detected by DNA fragmentation and expression of apoptosis-related genes were assessed by RT-PCR. The study was further designed to appraise the anticancer activity of flexirubin against 7,12-di methylbenz(a)anthracene (DMBA) induced breast cancer in Sprague Dawley rats for 120 days. Treatment of cells at various concentrations (25 to 400 μg/ml) inhibited cell viability in a dose dependent manner. IC50 values of flexirubin on human breast cancer MCF-7 cells obtained by MTT, SRB and LDH were 62, 71 and 48 μM respectively. DNA fragmentation was observed in MCF-7 cell line at 45 and 90 μg/ml concentration, while no DNA fragmentation was observed in untreated cells. Flexirubin treated cells exhibited considerable decrease in the level of anti-apoptotic protein BCL-2, a strong indication that the intrinsic apoptotic pathway may play a role in MCF-7 cells. The expression of p53, caspase 3 and BCL-2 was induced by flexirubin in a dose and time dependent manner. The compound flexirubin showed good affinity to the receptor due to more lipophilic character and hydrogen bonding. The results obtained in the molecular docking studies showed good correlation with in vitro and in vivo activity. Molecular docking showed that flexirubin was effective to control the over expression of anti-apoptotic protein MCL-1, suggesting its possible applications in cancer treatment. Our findings implement that flexirubin is a potential chemo-preventive agent against human breast cancer.

Nanoparticles are currently attracting increasing attention thanks to their prospective usages in diverse fields including agriculture, cosmetics, pharmaceuticals, etc. They are produced using physical and chemical approaches, and toxic substances are released in the course of the production of nanoparticles that affect the ecology, particularly the surrounding natural environment. To address this concern the alternative practice of biological synthesis of green and stable nanoparticles has emerged; plants, fungi, bacteria, yeast, algae, and their by-products are utilized as source materials in this green process. Microbial pigment, being one such key source material, is a prospective one to synthesize nanoparticles; pigment-mediated nanoparticles are prospective ones for a variety of applications such as drug delivery, cancer treatment, antibacterial agents, wastewater treatment, biodegradation, biofuels, and biosensors. This chapter chiefly centers on the biosynthesis of nanoparticles from microbes and the commonly used enzyme- and pigment-mediated metal nanoparticles. Furthermore, this chapter addresses the latest advancements in the biosynthesis of pigment-mediated nanoparticles, formation of nanoparticles, their mechanism, size, shape, and stability. Moreover, the current limitations and prospectives of microbial pigment-mediated nanoparticles are discussed also.

A bacterial strain was isolated from an oil-contaminated site and on its’ further characterization, exhibited the potential of synthesising metabolites and the ability to degrade crude oil. Its’ morphological, biochemical and 16S rRNA analysis suggested that the bacterium belongs to Dietzia maris AURCCBT01. This strain rapidly grew in the medium supplemented with n-alkanes C14, C18, C20, C28 and C32 utilizing them as a sole carbon source and produced a maximum canthaxanthin pigment of 971.37 µg/L in the n-C14 supplemented medium and produced the lowest pigment yield of 389.48 µg/L in the n-C-32 supplemented medium. Moreover, the strain effectively degraded 91.87% of crude oil in 7 days. The emulsification activity of the strain was 25% with the highest cell surface hydrophobicity (70.26%) and it showed a decrease in surface tension, indicating that the biosurfactant production lowers the surface tension. This is the first report on the characterization of the strain, Dietzia maris AURCCBT01 and its’ novelty of alkane degradation and simultaneous production of canthaxanthin pigment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02807-7.

Mangroves are the dominant ecosystems along the subtropical and tropical coastlines around the world. A mangrove is a biodiversity hot spot and one of the richest in ecosystem services in the world, but, due to the lack of data, it is often not mentioned in many global mangrove studies. Microbes, being an important component of the mangrove environment, not only play a critical role in creating and maintaining the biosphere but also serve as a source of biotechnologically valuable and important products. The mangrove ecosystem remains largely unexplored and therefore offers an excellent opportunity for finding rare microbes with unique properties, capable of producing many novel bioactive compounds such as antibiotics, enzymes, pigments, vitamins, immunosuppressants, immune modulators, and antitumor agents. It is suggested that these unique strains of mangrove microbes be further studied in the search for broad-spectrum, novel antibiotics that could be effective in pharmacological applications. The mangrove ecosystem is very rich in microbial diversity, and less than 5% of it has been described. Hence, the present chapter makes an attempt to review the microbial pigment diversity in mangrove ecosystems and its potential biotechnological applications.

There is worldwide interest in process development for the production of pigments from natural sources due to a serious safety problem with many artificial synthetic colorants, which have widely been used in foodstuff, cosmetic, and pharmaceutical manufacturing processes. Low-cost by-products and residues of agro-industrial origin have shown their potential in production of different pigments by diverse group microorganisms and to explore the possibility of pigment production by different microbial isolates from numerous sources on various substrates. The main applications of recycled wastes are enzyme production, organic acid isolation, pigment extraction, bioactive compound production, etc. Therefore, more regulatory approval and capital investments are required to bring these value-added products in the commercial market. The conversion of agro-industrial residues to important substances may not only provide future dimension to researchers but also reduce the current environmental hazards.

Microbial pigments have great interest within the healthcare industry, as they possess immunosuppressive, antifungal, antiproliferative properties, induce apoptosis, and may have potential for medical applications. The microbes such as Micrococcus, Bacillus, Rhodotorula, Monascus, Phaffia, Sarcina, and Achromobacter have the capability to produce different pigments. Biosynthesis of microbial pigments has been greatly underexplored and a multitude of potentially useful pigments still await discovery. Only less than 1% of the microbial community is estimated to be cultivated in the laboratory and vast diversity of microbial pigments and their encoding biosynthetic gene clusters remain to be exploited. The expansion of eco-friendly technologies in pigment synthesis is of considerable importance to expand their biological applications. Nanotechnology is presently employed as a tool to explore the darkest avenues of medical sciences to combat diseases caused by drug-resistant microbes. This chapter provides the state-of-art knowledge on the synthesis of nanoparticles from pigments and their pharmacological applications. The current limits and future forecasts for the synthesis of pigment-mediated nanoparticles by microorganisms are discussed.

Thymoquinone (TQ), a major bioactive compound of Nigella sativa seeds has several therapeutic properties. The main drawback in bringing TQ to therapeutic application is that it has poor stability and bioavailability. Hence a suitable carrier is essential for TQ delivery. Recent studies indicate biodegradable polymers are potentially good carriers of bioactive compounds. In this study, polyethylene glycol (PEG) modified chitosan (Cs) nanocapsules were developed as a carrier for TQ. Aqueous soluble low molecular weight Cs and PEG was selected among different biodegradable polymers based on their biocompatibility and efficacy as a carrier. Optimisation of synthesis of nanocapsules was done based on particle size, PDI, encapsulation efficiency and process yield. A positive zeta potential value of +48 mV, indicating good stability was observed. Scanning electron microscope and atomic-force microscopy analysis revealed spherical shaped and smooth surfaced nanocapsules with size between 100 to 300 nm. The molecular dispersion of the TQ in Cs PEG nanocapsules was studied using X-ray powder diffraction. The Fourier transform infrared spectrum of optimised nanocapsule exhibited functional groups of both polymer and drug, confirming the presence of Cs, PEG and TQ. In vitro drug release studies showed that PEG modified Cs nanocapsules loaded with TQ had a slow and sustained release.

Bestrophin, an integral membrane protein existing in basolateral region of the retina is a propitious target for drug discovery. Mutations in the Bestrophin protein cause Best Vitelliform Macular Dystrophy (BVMD) leading to retinal damages and loss of visual acuity. Owing to the lack of three dimensional structure and related structural homologs in the protein data bank, we modeled the bestrophin protein using Robetta ab initio method. Further, no treatment is available for the disease. In this situation, anthocyanins from natural sources are reported to combat retinal damages. Hence, we identified anthocyanins from Syzygium cumini fruit skin using Electrospray Ionization tandem mass spectrometry. These compounds were docked into the predicted bestrophin model to study the interactions within the active site. The results may provide a valuable insight into the structure of bestrophin and efficacy of anthocyanins in molecular docking studies. Abbreviations PTP - Putative transmembrane proteins, VMD - Vitelliform macular dystrophy, BVMD - Best's vitelliform macular dystrophy, RPE - Retinal pigment epithelium, ESI-MS/MS - Electrospray Ionization Tandem Mass Spectrometry, UNIPROT - Universal Protein Resource, PSIPRED - Protein secondary structure prediction, TMH - Transmembrane Helices, SCFS - Syzygium cumini fruit skin DP - Declustering Potential IFD - Induced Fit Docking.

The emergence of HIV-TB co-infection and multi-drug resistant strains of Mycobacterium tuberculosis (Mtb) drive the need for new therapeutics against the infectious disease tuberculosis. Among the reported putative TB targets in the literature, the identification and characterization of the most probable therapeutic targets that influence the complex infectious disease, primarily through interactions with other influenced proteins, remains a statistical and computational challenge in proteomic epidemiology. Protein interaction network analysis provides an effective way to understand the relationships between protein products of genes by interconnecting networks of essential genes and its protein-protein interactions for 5 broad functional categories in Mtb. We also investigated the substructure of the protein interaction network and focused on highly connected nodes known as cliques by giving weight to the edges using data mining algorithms. Cliques containing Sulphate assimilation and Shikimate pathway enzymes appeared continuously inspite of increasing constraints applied by the K-Core algorithm during Network Decomposition. The potential target narrowed down through Systems approaches was Prephanate Dehydratase present in the Shikimate pathway this gives an insight to develop novel potential inhibitors through Structure Based Drug Design with natural compounds.