Chitosan-mediated nano-bioprocessing of Acacia seyal seed extract for enhanced antineoplastic, anti-Helicobacter pylori and antioxidant performance

Abstract

Acacia seyal is a medicinal plant rich in bioactive compounds known for their antimicrobial, antioxidant, and anticancer properties. Conventional plant extracts often suffer from poor stability and limited bioavailability, reducing their therapeutic effectiveness. The utilization of chitosan nanoparticles (CS-NPs) offers a promising strategy to enhance biological activity of plant extracts. Encapsulation of A. seyal seeds extract (ASSE) in CS-NPs (ASSE@CS-NPs) was the aim of the present investigation to compete Helicobacter pylori and HCT116 cancer cells. The phytochemical profile of ASSE revealed diverse phenolic acids and flavonoids via HPLC analysis. Methyl gallate was dominated (20.98 mg/g), followed by gallic acid, and catechin. FTIR analysis confirmed characteristic functional groups in ASSE and CS-NPs. Peak shifts and intensity variations in ASSE@CS-NPs indicated successful encapsulation through hydrogen bonding and electrostatic interactions. ASSE@CS-NPs showed the strongest anti-H. pylori effect with inhibition zone (23.7 mm) and lowest MIC/MBC (15.62 µg/mL). Compared to CS-NPs (20.7 mm, 31.25 µg/mL) and ASSE (19.7 mm, 31.25 µg/mL). ASSE@CS-NPs showed notable antioxidant activity, achieving 96% scavenging at 1000 µg/mL with IC₅₀ of 3µg/mL compared to ASSE (5 µg/mL) and CS-NPs (74 µg/mL). ASSE@CS-NPs exhibited potent cytotoxicity against HCT116 cells with IC₅₀ of 23 µg/mL, outperforming ASSE (588 µg/mL) and CS-NPs (120 µg/mL). The formulation achieved > 80% inhibition at 62.5 µg/mL. Molecular docking was performed to evaluate the binding affinity and interaction patterns of methyl gallate (a main constituent of ASSE) and chitosan against H. pylori urease (PDB ID: 6ZJA). Docking results revealed favorable binding scores for both ligands, with chitosan showing higher affinity (S score: - 6.42 kcal/mol) compared to methyl gallate (S score: - 5.45 kcal/mol). Key hydrogen bond interactions were observed with active site residues ASP362 and ALA169 for methyl gallate, and ASP223 and HIS323 for chitosan. These results suggest that ASSE@CS-NPs possess inhibitory potential against H. pylori and HCT116 cells.