Marine algae offer environmentally friendly platforms for green nanoparticle synthesis. This study reports the biosynthesis of silver nanoparticles using polysaccharides isolated from the brown alga Chnoospora minima (PAgNPs) and evaluates their therapeutic potential. Fourier Transform Infrared Spectroscopy (FTIR) confirmed algal polysaccharide functional groups. Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis characterized the nanoparticles as spherical (~84 nm average size), stable (zeta potential −18.5 mV), and containing elemental silver without nitrogen. The PAgNPs exhibited potent antioxidant activity (~100% DPPH scavenging) and significant antimicrobial efficacy, particularly against Staphylococcus aureus and Candida species. Crucially, PAgNPs displayed potent antiproliferative activity against human lung cancer cells (A549, IC₅₀: 13.59 µg/mL). In contrast, toxicity to normal Vero cells was significantly lower (IC₅₀: 300.2 µg/mL), demonstrating notable cancer cell selectivity (SI 22.1). Moderate activity was observed against MCF-7 breast cancer cells (IC₅₀: 100.7 µg/mL). These results demonstrate that C. minima polysaccharide facilitates the synthesis of biocompatible AgNPs with promising antimicrobial and selective anticancer capabilities, highlighting their potential for further development as nanotherapeutics.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder requiring safer and more effective therapeutic alternatives. This study investigates a novel fucoxanthin derivative isolated from the marine brown alga Chnoospora minima using a comprehensive in silico approach. Molecular docking revealed that the derivative exhibited higher binding affinities toward α-amylase (–9.4 kcal/mol) and α-glucosidase (–8.0 kcal/mol) compared to the reference drug acarbose (–8.5 and –7.4 kcal/mol, respectively). Pharmacokinetic analysis predicted good intestinal absorption and P-gp inhibition (0.894) and moderate plasma clearance (7.864 mL/min/kg), while toxicity predictions classified it in toxicity class 3, with no respiratory or ocular toxicity. Drug-likeness evaluation showed only one Lipinski and one Veber rule violation, common for natural products. Molecular dynamics simulations conducted for 100 ns using NAMD 3.0 confirmed stable protein–ligand complexes with average RMSD values of ~1.3 Å and ~1.8 Å for α-amylase and α-glucosidase, respectively, and consistent hydrogen bonding profiles. Structural analysis identified a substitution of the allene bond with an unsaturated ketone at the C8′ position as a key contributor to enhanced enzyme interaction. The findings suggest that this fucoxanthin derivative is a promising natural candidate for T2DM therapy and warrants further investigation through lab experiments (in vitro and in vivo).