A highly efficient, green, and multicomponent reaction for 32 spirooxindole derivatives via the formation of cascade C–N, C–O, and C–S bonds using starch-capped zinc oxide nanocomposite as an effective heterogeneous catalyst with the synergistic application of ultrasound and on-water synthesis has been developed.

A highly efficient, green, and multicomponent reaction method has been developed for the diversity-oriented synthesis of 32 spirooxindole derivatives via the formation of cascade C–N, C–O, and C–S bonds. The synthesis involved starch-capped zinc oxide nanocomposite as an effective heterogeneous catalyst with the synergistic application of ultrasound and on-water synthesis. By employing this approach, all desired products were successfully obtained with high yields and comparatively short reaction times. Furthermore, the catalyst employed in the process exhibited excellent recyclability, allowing for its recovery and reuse for up to eight consecutive runs without any loss of catalytic activity. The greenness of the protocol was evaluated by various green metrics such as E-factor and eco-score, and the result showed the acceptability of the present method in organic synthesis.

This study aimed to synthesize silver nanoparticles from biological method like fungi, as it is an easy, nontoxic, cost-effective process. A design expert software was utilized for optimization through Box-Behnken design. BSA AgNPs were characterized for DLS studies, antioxidant studies like DPPH, Ferrous ion chelation, lipid peroxidation were carried out and it exhibited good antioxidant results for BSA AgNPs and AgNPs. Cytotoxicity test was performed on HT-29 cells and the results exhibited that AgNPs and BSA AgNPs showed the IC₅₀ value of 120 and 100 μg/ml. Hence, our formulations are favouring the  good antioxidant and cytotoxicity leads to better clinical outcomes.

Nanobiotechnology has evolved as a promising technology in developing therapeutically active materials. This study involved the biological synthesis of silver nanoparticles (AgNPs) from extracellular filtrate from the fungal species Aspergillus fumigatus to assess their antioxidant and cytotoxic activity under in-vitro conditions. This method has become more reliable than physical and chemical approaches, attributed to its use of ecologically clean and non-toxic methods. These synthesized nanoparticles are then characterized by UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering, scanning electron microscope (SEM), differential scanning calorimetry, and X-ray diffraction (XRD). Design optimization was done to optimize the selected variables to choose the best-fit ratios for the experiment. UV spectroscopy showed the absorption peaks for AgNPs and bovine serum albumin (BSA) AgNPs at 300 and 315 nm. FTIR spectroscopy showed amide, carboxyl, and ester groups in BSA AgNPs, indicating their role in stabilizing nanoparticles. The particle size and zeta potential for AgNPs and BSA AgNPs were found to be 124.81 and 152.92 nm; zeta potentials for AgNPS and BSA AgNPs were found to be −13.3 and −15.6 mV. Various antioxidant studies like 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS), ion chelating assay, lipid peroxide assay, and malondialdehyde were carried out, indicating good antioxidant activity for synthesized nanoparticles. SEM images advocated good spherical images and are well dispersed. The cytotoxic assay performed on HT-29 colon cancer cells exhibited good inhibition activity for AgNPs and BSA AgNPs, with an IC₅₀ value of 120 and 100 μg/ml. These study results revealed that the synthesized AgNPs, on optimization through Box-Behnken design, exhibited good antioxidant and cytotoxic activity.