Silk Fibroin Nanoparticles\nas a Drug Delivery System\nof 3,3′-Diindolylmethane with Potential Antiobesogenic Activity

Obesity is a global\ndisease characterized by excessive lipid accumulation\nin the adipose tissue. There is an urgent need to explore alternative\ncompounds to treat obesity. Low-molecular-weight compounds from plants,\nlike 3,3′-diindolylmethane (DIM), are emerging as potential\nalternatives for obesity treatment. In this work, DIM is encapsulated\ninto silk fibroin nanoparticles (SFNP) to evaluate the antiobesogenic\npotential. The obtained spherical-like SFNPs have a particle size\nbetween 165 and 200 nm, a polydispersity index between 0.11 and 0.15,\nand a zeta potential from −27 to −37 mV. DIM does not\nmodify the nanoparticle shape but changes the secondary structure\nof fibroin and generates smaller nanoparticles (145 nm). DIM-loaded\nSFNP (SFNP-DIM) enhance their antioxidant capacity by 4.4-fold compared\nto SFNP. SFNP-DIM does not show cytotoxicity on white-like adipocytes,\nunlike 3T3-L1 preadipocytes, where cell viability decreased in a concentration-dependent\nmanner. The SFNP-DIM treatment (5 μM, 0.03 mg SFNP mL<sup>–1</sup>) does not modify the morphology of white-like adipocytes. It produces\nan apparent augmentation in the size and number of intracellular lipid\ndroplets and increases by 2.18 ± 0.4-fold of triglyceride content.\nThese findings demonstrated that SFNPs could be a potential delivery\nsystem of DIM, suggesting a potential therapeutic agent for treating\nobesity.