Biosynthesis of selenium nanoparticles by Aloe vera leaf extract and its biomedical applications

Aloe vera has been cultivated mainly for medicinal purposes, with over 75 biologically active compounds in its gel. Selenium nanoparticles (SeNPs) are novel selenium sources characterized by great biocompatibility, low toxicity, stability, selectivity, and extensive uses. This study emphasizes the significant role of phytofabricated SeNPs in several biomedical applications.

SeNPs were synthesized utilizing Aloe vera leaf extract. The biosynthesized SeNPs were characterized using UV-Vis, EDX, XRD, zeta potential, FTIR, and TEM analyses. The antioxidant, antibacterial, anti-inflammatory, and anticancer effects, along with the impact on antioxidant enzymes of biosynthesized SeNPs, were evaluated. The biomedical functions of SeNPs were concentration-dependent, showing antibacterial activity against both Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus, and Bacillus subtilis) and Gram-negative (Escherichia coli, Salmonella typhimurium, and Klebsiella pneumonia). Additionally, SeNPs exhibited antioxidant activity, with DPPH scavenging from 77.39 ± 0.895% at 120 µg mL^-1 to 20.75 ± 0.952% at 5 µg mL^-1. SeNPs showed anti-inflammatory activity at 31.25 µg mL^-1, inhibiting of bovine serum albumin (BSA) denaturation by 79.87 ± 1.21%, compared to 82.23 ± 1.127% for diclofenac sodium. SeNPs exhibited anticancer efficiency against MCF7 and Caco2 cells with IC50 values of 312.02 ± 3.25 and 120.96 ± 1.87 µg mL^{- 1}, respectively, and were biocompatible with the normal WI38 cells. Moreover, there was a notable decline in the enzyme activities CAT activity decreased by 48.32% and 59.39% and SOD by 43.26% and 54.52% in the Caco2 and MCF-7 cell lines, respectively.

The Bio-fabricated SeNPs exhibited nontoxicity and eco-friendliness, demonstrating notable antimicrobial efficacy, particularly against S. aureus, K. pneumonia, and B. subtilis. They also possess high DPPH scavenging capabilities, anti-inflammatory properties, and exhibit superior anticancer activity on the Caco2 cancerous cell line compared to the MCF7 cell line, while retaining WI38 normal cells, underscoring their potential in medical applications.