No abstract

Ocimum gratissimum L. is a perennial herbaceous plant used in the treatment of fungal and bacterial infections. Green synthesis has provided cost effective, environment friendly procedure and raising safe strategies for the synthesis of nanoparticles. This study was aimed at investigating the potential of O. gratissimum for the synthesis of selenium nanoparticles (SeNPs) and their antimicrobial activities. Phytochemical screening on aqueous extract was carried out using standard procedures. Selenium nanoparticles was biosynthesized by O. gratissimum and characterized using Visual detection, UV-Visible spectroscopy, Scanning Electron Microscope, Transmission Electron Microscope, Energy dispersive X-ray, Fourier Transform Infra-red spectroscopy and X-ray diffraction spectroscopy. Antimicrobial activity of the biosynthesized selenium nanoparticles by O. gratissimum was done using agar well diffusion method. Saponins, tannins, cardiac glycosides, terpenoids and phenols were present. The biosynthesized SeNPs had a strong plasmon resonance band at 300 nm, changes in colour from dark brown to ruby red. The SeNPs were spherical and aggregated with varying shapes and size ranged from 20 – 50 nm. Strong signal of selenium element was observed. Hydroxyl, esters, aldehyde, alkane and amine are present and responsible for the efficient stabilization and bioreduction of Selenium nanoparticle. Furthermore, biosynthesized SeNPs by O. gratissimum (OGSeNPs) exhibited higher antimicrobial activity against both Gram ositive and Gram negative bacteria. Green synthesis of nanoparticles is a promising method in the biomedical field, due to its high bioactive components.

High morbidity and mortality rate associated with pneumococcal infection globally is of major concern most especially among infant. This burden is equally worsened by multidrug resistance strains due to indiscriminate consumption of antibiotics. Hence, need for constant search for cheap and effective bioactive compounds as alternative antimicrobials for the treatment of pneumococcal infection. Bioactive compound profiling and in-vitro antibacterial activity of ginger methanol extract against two predominant pneumococcal agents; Streptococcus pneumonia and Haemophilus influenza were investigated. Gas Chromatography Mass Spectroscopy (GC-MS) was used for the identification and quantification of bioactive compounds in the ginger methanol extract. The antibacterial activity and Minimum Inhibitory Concentration (MIC) of the extract was determined using Agar well diffusion. Twenty-seven (27) matched bioactive compounds were detected in the sample. Zingerone (17.70%), α-zingiberene (13.30%), (6)-shogaol (10.84%), α-Farnesene (6.26%), β-Funebrene (5.61%), 6-gingerol (5.18%), α-curcumene (4.15%) were the major compounds present. All other identified compounds had less than 4% composition by peak area each. The antibacterial activity of the ginger crude methanol extract against S. pneumonia and H. influenza were 2.33 mm and 9.33 mm. MIC of the extract against the isolates was 10%. In conclusion ginger crude methanol extract contain an array of bioactive compounds and the extract exhibited antibacterial activity against predominant pneumococcal agents. Ginger extract can be harnessed for the production of new antimicrobials to combat pneumococcal infection.

The levels of heavy metals in soil samples from selected major roads under construction, burrow sites (a place where soil was obtained for road filling) and two roads under use have been investigated. Soil samples were collected and digested using standard methods. The digests were analyzed for Ni, Cr, Zn, Cd, Cu and Pb using Atomic Absorption Spectrophotometer. The data were subjected to descriptive statistics, non linear regression and one way analysis of variance (ANOVA). The results showed that cadmium had the highest Contamination Factor (CF). The Pollution Load Index of the roads under construction was higher than each of the Burrow siteand one of the Trunk C roads analyzed for comparison. The Ecological Risk Factor of the sampling sites was less than 40 which indicated that, the levels of heavy metals on the road construction sites did not pose ecological risks to the environment. The Ecological Risk Index of each of all the sampling sites was less than 150 indicating that they fell within the low ecological risk category. The study established that the Burrow site did not contribute to the heavy metal concentration of the road under construction and the contamination was traced to vehicular activities.