Conjugation of micro/nanocurcumin particles to ZnO nanoparticles changes the surface charge and hydrodynamic size thereby enhancing its antibacterial activity against Escherichia coli and Staphylococcus aureus.

Nanobiotechnology-mediated synthesis of ZnO nanoparticles, micro/nanocurcumin, and curcumin-ZnO nanocomposites and their characterization followed by comparative study of their antibacterial, antioxidant, and iron-chelating efficiency at various dosages are discussed. Micro/nanocurcumin and ZnO nanoparticles were synthesized using curcumin and zinc nitrate as precursor and then conjugated by sonication to synthesize curcumin-ZnO nanocomposites. The synthesized nanoparticles were then characterized by using ultraviolet-visible spectroscopy, X-ray diffraction, Scanning electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering analysis. After that, the antibacterial activity of the synthesized nanoparticles was evaluated by the optical density (OD600 ) method against Escherichia coli and Staphylococcus aureus cells. The DPPH (2,2-diphenyl-1-picrylhydrazyl ), hydroxyl radical scavenging activity, and ferrous ion-chelating efficiency of synthesized nanoparticles were evaluated by spectrophotometry analysis. Nanocurcumin (mean zeta potential = -25 mV; average hydrodynamic diameter = 410 nm) based coating of ZnO nanoparticles (mean zeta potential = -15.9 mV; average hydrodynamic diameter = 274 nm) to synthesize curcumin-ZnO nanocomposites (mean zeta potential = -18.8 mV; average hydrodynamic diameter = 224 nm) exhibited enhanced zeta potential, which resulted in reduced agglomeration, smaller hydrodynamic size in water, improved aqueous solubility, and dispersion. All the aforesaid factors including the synergistic antibacterial effect of ZnO nanoparticle and micro/nanocurcumin contributed to increased antibacterial efficiency of curcumin-ZnO nanocomposites. Micro/nanocurcumin due to its better water solubility and small hydrodynamic diameter exhibited enhanced antioxidant and ferrous ion-chelating efficiency than curcumin.

Contrasting diversity of vaginal lactobacilli among the females of Northeast India.

BACKGROUND: Lactobacilli are gatekeepers of vaginal ecosystem impeding growth of pathogenic microbes and their diversity varies across populations worldwide. The present study investigated diversity of human vaginal microbiota among females of Northeast India, who are distinct in dietary habits, lifestyle, and genomic composition from rest of India. RESULTS: Altogether, 154 bacterial isolates were obtained from vaginal swab samples of 40 pregnant and 29 non-pregnant females. The samples were sequenced for 16 s rRNA gene and analysed for identification using a dual approach of homology search and maximum likelihood based clustering. Molecular identification based on 16S rRNA gene sequence confirmed the isolates belonging to 31 species. Lactobacilli constituted 37.7% of the bacterial isolates with 10 species and other Lactic Acid Bacteria (39.61%) represented another 10 species, some of which are opportunistic pathogens. The remaining of the communities are mostly dominated by species of Staphylococcus (14.28%) and rarely by Propionibacterium avidum (3.90%), Bacillus subtilis, Escherchia coli, Janthinobacterium lividum, and Kocuria kristinae (each 0.64%). Interestingly Lactobacillus mucosae and Enterococcus faecalis, which are globally uncommon vaginal microbes is found dominant among women of Northeast India. This tentatively reflects adaptability of particular Lactobacillus species, in distinct population, to better compete for receptors and nutrients in vaginal epithelium than other species. Further, intrageneric 16S rRNA gene exchange was observed among Enterococcus, Staphylococcus, and two species of Lactobacillus, and deep intraspecies divergence among L. mucosae, which pinpointed possibility of emergence of new strains with evolved functionality. Lactobacilli percentage decreased from young pregnant to aged non-pregnant women with maximum colonization in trimester II. CONCLUSION: The study highlighted importance of assessment of vaginal microbiota, Lactobacillus in particular, across different population to gain more insight on female health.

Cyathea gigantea (Cyatheaceae) as an antimicrobial agent against multidrug resistant organisms.

BACKGROUND: Rapid emergence of multidrug resistant (MDR) organisms in hospital and community settings often result into treatment failure, thus leading the clinicians with fewer treatment options. Cyathea gigantea, an ethnomedicinally important fern used in cuts and wound infections. So, if this medicinal plant is used in treating the MDR infections then it might bring certain relief in future treatment options. METHODS: Antibacterial activity of C. gigantea against MDR bacteria was assed using well diffusion and broth microdilution methods to determine the diameters of growth inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Synergistic activity was also determined with the conventional antibiotics by disc diffusion method followed by FIC index of each of the tested antibiotic was calculated. The active extract was then subjected to fractionation by column chromatography and antibacterial activity was done with each of the collected fractions. RESULTS: Crude extract of C. gigantea was found to be active against all the tested organisms. The MIC was 200 µg/ml against Gram-positive i.e., Staphylococcus aureus ATCC 25923 and 400 µg/ml against Gram-negative i.e., Escherichia coli ATCC 25922 and Pseudomonas aeruginosa PAO1, while the MBC was 400 µg/ml in case of Gram-positive and 800 µg/ml for Gram-negative. The synergistic activity revealed that the plant extract increased the antibacterial property of the studied antibiotics and the FIC index showed that significant synergistic activity was shown by ciprofloxacin followed by tetracycline, ampicillin and oxacillin. Antibacterial activity with the fractionated extract showed that the FR II, FR III and FR IV were active against both Gram-positive and Gram-negative bacteria, whereas FR I, FR V and FR VI did not show antibacterial property against any of the tested bacteria. CONCLUSIONS: Extracts of C. gigantea was found active against both selected Gram-positive and Gram-negative organisms and thus offers the scientific basis for the traditional use of the fern. The present study also provides the basis for future study to validate the possible use against multidrug resistant organisms.

Curcumin as potential therapeutic natural product: a nanobiotechnological perspective.

OBJECTIVES: Nanotechnology-based drug delivery systems can resolve the poor bioavailability issue allied with curcumin. The therapeutic potential of curcumin can be enhanced by making nanocomposite preparation of curcumin with metal oxide nanoparticles, poly lactic-co-glycolic acid (PLGA) nanoparticles and solid lipid nanoparticles that increases its bioavailability in the tissue. KEY FINDINGS: Curcumin has manifold therapeutic effects which include antidiabetic, antihypertensive, anticancer, anti-inflammatory and antimicrobial properties. Curcumin can inhibit diabetes, heavy metal and stress-induced hypertension with its antioxidant, chelating and inhibitory effects on the pathways that lead to hypertension. Curcumin is an anticancer agent that can prevent abnormal cell proliferation. Nanocurcumin is an improved form of curcumin with enhanced therapeutic properties due to improved delivery to the diseased tissue, better internalization and reduced systemic elimination. SUMMARY: Curcumin has multiple pharmacologic effects, but its poor bioavailability reduces its therapeutic effects. By conjugating curcumin to metal oxide nanoparticles or encapsulation in lipid nanoparticles, dendrimers, nanogels and polymeric nanoparticles, the water solubility and bioavailability of curcumin can be improved and thus increase its pharmacological effectiveness.