Bacterial endophytes are found in the internal tissues of plants and have intimate associations with their host. However, little is known about the diversity of medicinal plant endophytes (ME) or their capability to produce specialised metabolites that may contribute to therapeutic properties. We isolated 75 bacterial ME from 24 plant species of the Western Ghats, India. Molecular identification by 16S rRNA gene sequencing grouped MEs into 13 bacterial genera, with members of Gammaproteobacteria and Firmicutes being the most abundant. To improve taxonomic identification, 26 selected MEs were genome sequenced and average nucleotide identity (ANI) used to identify them to the species-level. This identified multiple species in the most common genus as Bacillus. Similarly, identity of the Enterobacterales was also distinguished within Enterobacter and Serratia by ANI and core-gene analysis. AntiSMASH identified non-ribosomal peptide synthase, lantipeptide and bacteriocin biosynthetic gene clusters (BGC) as the most common BGCs found in the ME genomes. A total of five of the ME isolates belonging to Bacillus, Serratia and Enterobacter showed antimicrobial activity against the plant pathogen Pectobacterium carotovorum. Using molecular and genomic approaches we have characterised a unique collection of endophytic bacteria from medicinal plants. Their genomes encode multiple specialised metabolite gene clusters and the collection can now be screened for novel bioactive and medicinal metabolites.

In the current scenario, nanoparticle synthesis has been fascinated by biogenic approaches than the chemical methods. However, reproducibility of the source stands essentially in nanoparticle synthesis. Nanoparticle synthesis by fungi has more advantages such as the potential for bioaccumulation, immunity towards toxicity, relatively easier to handle, simpler in synthesis and downstream processing. In this study, biogenic copper nanoparticles (CuNPs) were embedded within graphene oxide-chitosan (GO-CS) polymer to endure the biocompatibility and toxicological effects on both normal and cancer cells. The characteristics of the copper nanoparticles/graphene oxide-chitosan (CuNPs/GO-CS) nanocomposites was found to be superior to the GO-CS. This is evident from the results obtained from X-ray diffraction technique, UV-visible spectroscopy, atomic force microscope, fourier transform infrared spectroscopy, fluorescence spectroscopy, confocal laser scanning microscope and scanning electron microscopy. The synthesized new copper nanoparticles/graphene oxide-chitosan (CuNPs/GO-CS) nanocomposites were studied for their anti-bacterial activity against Escherichia coli MTCC 443 and anti-cancer activity on breast cancer MCF7 cell lines.