Phytochemical profiling of Prunus armeniaca kernel extracts and exploration of their multifaceted antioxidant and antibacterial effects through in vitro and in silico studies

Introduction

Prunus armeniaca "Apricot" kernels are considered a by-product widely employed in traditional medicine for treating various ailments due to their potential therapeutic properties. The current investigation sought to assess the properties of aqueous and methanol extracts of Prunus armeniaca kernels (PAK).

Methods

The phytochemical composition of the studied extracts was evaluated using high-performance liquid chromatography with a diode array detector (HPLC-DAD). Total antioxidant capacity (TAC), β-carotene bleaching, reducing power (RP), and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays were used to assess antioxidant activity. Using the disc diffusion method and the microdilution test in 96-well microplates against four bacterial strains, the antimicrobial activity of the aforementioned extracts was evaluated. The potential of several phenolic compounds as bacterial inhibitors was assessed through extensive density functional theory (DFT) calculations and molecular docking analyses.

Results

The phytochemical analysis revealed the identification of several phenolic constituents, with tocopherol (11.61 ± 0.9 mg/g of dry extract) and resveratrol (25.3 ± 0.4 mg/g of dry extract) emerging as the major compounds in the aqueous and methanolic extracts, respectively. Both extracts exhibited remarkable antioxidant activity with IC₅₀ values of 1.47 ± 0.08 and 1.97 ± 0.15 mg/mL (DPPH), EC₅₀ = 3.682 ± 0.123 and 12.415 ± 0.344 mg/mL (RP), TAC values of 6.486 ± 0.275 and 5.323 ± 0.826 mg AAE/g, and β-carotene values of 56 ± 0.553 % and 50 ± 0.645 % respectively. Moreover, the aqueous extract showed the highest antibacterial activity against Staphylococcus aureus with a MIC value of 0.625 mg/mL, and an inhibition zone diameter of 11.5 ± 0.71 mm. The combined analysis of docking results and DFT calculations for various phenolic compounds against Staphylococcus aureus (Glycyl-penicillin-binding protein 2a) and Escherichia coli (DNA Gyrase B) revealed significant interactions and reactivities.

Conclusion

These results clearly indicate that PAK contains a high concentration of bioactive compounds, especially tocopherol and resveratrol, and may serve in the treatment of various diseases thanks to its extracts' promising antioxidant and antimicrobial activities.