In vitro Evaluation, Green Synthesis Characterization and Molecular Docking for Medicinal Target Prediction of Gumbo Limbo (Bursera simaruba)

Background: Bursera simaruba (commonly known as gumbo limbo) is a well-recognized medicinal plant traditionally employed in the treatment of inflammatory and metabolic conditions. Despite its widespread ethnomedicinal use, there is still a lack of comprehensive scientific evidence that combines phytochemical characterization, eco-friendly nanoparticle synthesis, antimicrobial assessment, and molecular docking approaches for identifying its therapeutic targets.
Objective: This study was designed to investigate the in vitro antioxidant and antimicrobial activities of the aqueous leaf extract of Bursera simaruba. It also sought to synthesize and characterize plant-mediated metallic nanoparticles (silver, copper, and zinc oxide) and to explore potential therapeutic targets through molecular docking analysis.
Materials and Methods: Bursera simaruba fresh leaves were gathered, verified, and extracted with distilled water. In addition to quantitative antioxidant tests such as DPPH radical scavenging, ferric reducing antioxidant power (FRAP), nitric oxide inhibition, total phenolic content (TPC), total flavonoid content (TFC), and vitamin C determination, preliminary phytochemical screening was carried out. Proximate composition, mineral content, and antinutritional components were assessed using standard analytical techniques. The plant extract was used as a reducing and stabilising agent in the green synthesis of silver (AgNPs), copper (CuNPs), and zinc oxide nanoparticles (ZnONPs). Fourier Transform Infrared (FTIR) analysis and UV-visible spectroscopy were used to characterise the produced nanoparticles. A few bacterial and fungal isolates were used to investigate the antimicrobial activity. Additionally, in silico ADME profiling and molecular docking experiments were carried out against dipeptidyl peptidase-4 (DPP4).
Results: The findings revealed that the leaf extract possesses notable nutritional value, with relatively high carbohydrate (33.65%) and protein (17.11%) contents, along with appreciable mineral levels. Phytochemical analysis confirmed the presence of bioactive constituents such as saponins, phenols, and alkaloids. Quantitative assays indicated elevated flavonoid (82.86 mg AAE/g) and phenolic (57.00 mg GAE/g) concentrations, accompanied by strong antioxidant performance (nitric oxide inhibition of 75.00%, FRAP value of 66.01%, and DPPH activity of 57.00%). Successful nanoparticle formation was verified through characteristic surface plasmon resonance peaks and FTIR-identified functional groups. The synthesized nanoparticles demonstrated superior antibacterial and antifungal effects compared to the crude extract, with copper and silver nanoparticles showing the highest inhibitory activity. Molecular docking analysis revealed strong binding affinities toward DPP4, particularly for compounds such as 4-dimethylamino-3,5-dinitrobenzoic acid (−6.8 kcal/mol) and squalene (−6.2 kcal/mol), indicating possible antidiabetic potential. ADME predictions further suggested that several of the identified compounds possess favorable pharmacokinetic profiles.
Conclusion: Bursera simaruba possesses significant antioxidant and antimicrobial properties and serves as an effective bio-reducing agent for green synthesis of metallic nanoparticles. Molecular docking findings provide mechanistic insight into its potential antidiabetic activity via DPP4 inhibition. These findings scientifically support its ethnomedicinal relevance and highlight its promise for pharmaceutical and nanomedicine applications.