Effective catalysis and antibacterial activity of silver and gold nanoparticles biosynthesized by Phlogacanthus turgidus

In this work, an environmentally friendly and cost-effective synthetic method of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) was successfully performed using aqueous extract of Phlogacanthus turgidus (PT) leaves. The biosynthesis of nanoparticles was optimized for reaction conditions including concentration of metallic ions, temperature, and time using the measurement of UV–Vis spectroscopy. The nanoparticles were well characterized by analytic techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), and selected area electron diffraction (SAED). The morphological data showed that PT-AgNPs possessed the spherical shape with the size distribution ranging from 5 to 15 nm with a mean size of 10 nm while PT-AuNPs existed in the multiple shape with the size distribution ranging from 5 to 20 nm with a mean size of 12 nm. The antibacterial behavior showed that PT-AgNPs possessed high bioactivity against four bacterial strains including Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, and Escherichia coli. Moreover, the catalytic activity of the biogenic nanoparticles was investigated for catalytic reduction of 2-nitrophenol, 3-nitrophenol, and rhodamine B. The kinetic data showed that the nanoparticles were excellent catalysts with potential applications for environmental treatment.

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Synthesis of corn rootworm pheromones from commercial diols

A mixture of stereoisomers of the corn rootworm pheromones was synthesised via the Grignard coupling of protected bromohydrins with alkylcuprate as a key step. The synthesis of 8-methyldec-2-yl propanoate (I), the northern corn rootworm Diabrotica longicornis Say pheromone, was achieved from pentane-1,5-diol in four steps with an overall yield of 35.1 % and 10-methyltridecan-2-one (II), the southern corn rootworm Diabrotica undecimpunctata howardi Barber pheromone, was synthesised from octane-1,8-diol as commercially available starting material in five steps with an overall yield of 28.7 %.     

Novel biogenic silver nanoparticles used for antibacterial effect and catalytic degradation of contaminants

Research on Chemical Intermediates - The study reports a versatile, cost-efficient and ecofriendly protocol for the synthesis of biogenic silver nanoparticles (AgNPs) using the aqueous extracts of...     

Mannich aminomethylation of flavonoids and anti-proliferative activity against breast cancer cell

We herein report Mannich aminomethylation of variously structural flavonoids and their biological evaluation against human breast cancer cell. Mannich reaction showed that substitution at C-6 position depends on amine basicity and C-ring feature of flavonoids. All five flavonoid substrates reacted with strong amine bases to afford the bis(6,8-aminomethyl) derivatives, while with weak amines, the different products were obtained dependently on structural characteristic of flavonoid. 3-OH and 3-O-substituted groups on the C-ring exhibited the deactivated aminomethylation at C-6 position, whereas substitution at this position was independent on bond feature at C-2 and C-3 on the C-ring. Screening anti-proliferative activity showed six flavonoids possessed activity against breast cancer cell, MDA-MB-231. Among them, the flavonoids, luteolin (2) and 3′,4′,5,7-tetrahydroxy-6,8-bis(pyrrolidin-1-ylmethyl)-3-rutinosylflavone (3a), displayed the highest anti-proliferative activity with the lowest IC₅₀ values.     

Waste Banana Stem Utilized for Biosynthesis of Silver and Gold Nanoparticles and Their Antibacterial and Catalytic Properties

The present work presented a synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using the aqueous extract of waste banana stem (WBS), Musa paradisiaca Linn. The reduction and formation of MNPs have been characterized by several analysis techniques such as X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The techniques showed that average particle size of WBS-AgNPs and WBS-AuNPs in crystalline nature was in ranges of 7–13 nm and 11–14 nm, respectively. The synthesized nanoparticles were used to evaluate antibacterial activity and catalysis. The WBS-AgNPs showed strong antibacterial activity against B. subtilis and E. coli. The largest zone of inhibition against B. subtilis (14.2 mm) and E. coli (9.3 mm) was found at concentrations of 4.0 ppm and 2.0 ppm, respectively. The excellent catalytic application of both the nanoparticles for the reduction of 4-nitrophenol was confirmed via study on their kinetics. The normalized kinetic constants (k_nor) of WBS-AgNPs and WBS-AuNPs were found to be 1.72?×?10^–3 s^?1 mg^?1 and 2.45?×?10^–3 s^?1 mg^?1, respectively.