In this study, we employed tannic acid (TA)-functionalized silver nanoparticles (TA@AgNPs) as colorimetric probe for the simultaneous and sensitive detection of Al(III) and F^- ions. The proposed sensor was based on the aggregation and anti-aggregation effects of target Al(III) and F^- ions on TA@AgNPs, respectively. Because of the strong coordination bond between Al(III) ions and TA, the addition of Al(III) ions to TA@AgNPs could cause aggregation and, hence, result in a significant change in the absorption and color of the test solution. Interestingly, in the presence of F^- ions, the aggregation effect of Al(III) ions on TA@AgNPs can be effectively prevented. The extent of aggregation and anti-aggregation effects was concentration-dependent and can be used for the quantitative detection of Al(III) and F^- ions. The as-proposed sensor presented the sensitive detection of Al(III) and F ions with limits of detection (LOD) of 0.2 and 0.19 μM, respectively. In addition, the proposed sensor showed excellent applicability for the detection of Al(III) and F^- ions in real water samples. Moreover, the sensing strategy offered a simple, rapid, and sensitive detection procedure and could be used as a potential alternative to conventional methods, which usually involve sophisticated instruments, complicated processes, and a long detection time.

Fruits are known as a richest source of bioactive compounds as polyphenols which are known to have significant health promoting properties. The present study investigates the total polyphenol content of some selected fruits extracted in: acidified 70 % ethanol, acidified 70 % methanol, acidified 70 % acetone, and 100 % water solvents. Standard gallic acid solution prepared in the range of 50-500 µg/L was used to plot a calibration graph. A good linearcalibration graph (r= 0.998, n=3) was obtained by plotting absorbance at 511 nm versus standard solution and all results are given as gallic acid equivalent (GAE, mg/g, dry weight). The concentration of total polyphenols varies with the solvent used and also among different samples. Higher concentration was detected in papaya fruit both in the peel and pulp (238.6±3.64, 135.2±0.09; GAE, mg/g, dry weight) respectively and lower concentration in banana peel and pulp (43.2± 0.13, 26.6±0.06; GAE, mg/g, dry weight) respectively.

Considering the harmful effects of the synthetic termiticides and resistance development in the pest population, there is a need to search for economically viable, environmentally-friendly and effective termiticides. Therefore, the screening of alternative antitermiticidal activity from plant based products could be employed as a means in the termite control strategies. The present study was carried out to evaluate the anti-termitic activity of the hexane leaf extract of Prosopis juliflora against the termites of Macrotermes spp. at concentrations of 25, 50, 75 and 100 mg/L. It was found that, the LC₅₀-LC₉₀ values were 33.3–213.98, 12.71–66.33 and 9.41–34.71 mg/L after 24, 48 and 72 h of exposure, respectively. The phytochemical study of the crude extract showed the presence of steroids, saponins, terpenoids, alkaloids and flavonoids which might be responsible for its biocidal activity. These results suggested that hexane leaf extract of P. juliflora possessed biocidal activity aginst termites.