Abstract
Marine algae contain many bioactive constituents. In the current research, the brown seaweed Sargassum muticum was collected from Red Sea and its extract used as a capping agent for the formulation of biocompatible stable silver nanoparticles (AgNPs). The seaweed-fabricated AgNPs were studied through UV–vis, TEM, XRD, EDX, FTIR and Zeta potential analyses. The chemical constituents of S. muticum extract were evaluated by RP-HPLC and 1H NMR. Both seaweed extract and AgNPs had mosquito larvicidal and adulticidal activities. The seaweed-fabricated AgNPs induced high larval mortality against mosquitoes from both Indian and Saudi Arabian strains when compared to the seaweed extract. The LC50 values of AgNPs against the Indian strains of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi were 43.9, 35.9 and 27.0 μg/ml, respectively; those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 110.4 and 126.2 μg/ml, respectively. In adulticidal experiments, the LC50 values of S. muticum-fabricated AgNPs against Indian strains of Cx. quinquefasciatus, Ae. aegypti and An. stephensi were 42.3, 34.3 and 29.7 µg/ml, respectively, whereas those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 86.4 and 120.0 µg/ml, respectively. Minimal doses of seaweed-fabricated AgNPs were highly effective in inhibiting the growth of Bacillus subtilis (11.25 mm inhibition zone), Escherichia coli (13.35 mm), Klebsiella pneumoniae (14.24 mm) and Salmonella typhi (12.23 mm). Additionally, the seaweed extract was highly efficient to adsorb methylene blue (MB) and methyl orange (MO) dyes. In conclusion, the S. muticum extract revealed to be an effective capping agent to fabricate AgNPs to be industrially used for the control of deadly mosquito vectors and as an antimicrobial and dye adsorbent agent.
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•Marine macroalgae, S. muticum was used as a capping agent for the synthesis of biocompatible stable AgNPs.•The phytoconstituents of seaweed extract was examined by RP-HPLC-MS, 1H NMR, and AgNPs were confirmed by UV–vis, FTIR, TEM, XRD, EDX and zeta potential analyses.•Significant larval and adult toxicity was achieved using seaweed extract and AgNPs on key mosquito vectors.•Seaweed extract and AgNPs highly inhibit the growth of all tested bacteria.•Low-cost dye adsorbent ability of seaweed extract at 0.3 g per 10 mL was obtained.