Mohamed K.Y. Soliman, Halah H. Al-Haideri, Khairiah Mubarak Alwutayd, Mai Hamed Salem, Adil Abalkhail, Abdulkarim S. Binshaya, Jawaher J. Albaqami, Rowa K. Zarah, Hamida Hamdi
This work employed Psidium guajava leaves for biogenic titanium dioxide nanoparticles (TiO₂NPs) by environmentally friendly techniques, which were comprehensively analyzed utilizing FT-IR, SEM, TEM, XRD, and EDX techniques. The analysis of TiO₂NPs indicated that the produced TiO₂NPs possess a crystalline structure in an average particle size varying from 35.4 to 65.9 nm. The antimicrobial findings indicated that TiO₂NPs had a significant antibacterial potential towards Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, which have minimum inhibitory concentrations varied from 500 to 250 µg/mL. Additionally, TiO₂NPs displayed a spectrum of anti-biofilm actions toward B. subtilis and P. aeruginosa. Moreover, TiO₂NPs exhibit significant antioxidant activity whose IC50 was 209.4 µg/mL utilizing DPPH technique. In addition, TiO₂NPs exhibit potential anticancer action against Caco-2 cell line whose IC50 was 102.3 µg/mL, by reducing it to 96.4 and 94.7 % at 1 mg/mL and 0.25 mg/mL, respectively. In summary, TiO₂NPs synthesized from P. guajava leaf extract show antibacterial, anticancer, and antioxidant effects with great biocompatibility. KEY WORDS: TiO₂NPs, Characterization, Antimicrobial, Anti-biofilm, Anticancer Bull. Chem. Soc. Ethiop. 2026, 40(1), 65-78. DOI: https://dx.doi.org/10.4314/bcse.v40i1.6