Phytochemical profiling, antioxidant activity and molecular docking analysis in Chinese cabbage (Brassica rapa ssp. pekinensis) germplasm

Chinese cabbage, a leafy vegetable is extensively cultivated and consumed in many parts of the world, especially in Eastern Asian countries. The crop contains glucosinolates, the most abundant specialized bioactive compounds in Brassicaceae plants. Glucosinolates and their hydrolysis products are crucial in plant defense against stressors, and also serves as human health-promoting agents. This study aimed to evaluate glucosinolates profile, total polyphenol and total flavonoids contents, and antioxidant activities in Chinese cabbage, as well as to investigate the molecular interactions of selected glucosinolate-derived compounds through in silico molecular docking analysis. The Ultra-performance liquid chromatography mass spectrometry was used for analysis glucosinolate content in diverse Chinse cabbage germplasm. The glucosinolates were then used for molecular docking study against three protein targets, cytochrome P450, the human myeloperoxidase-thiocyanate complex, and cyclindependent protein kinase 2. The results revealed a wide variation of total glucosinolate content within the germplasm, ranging from 692.85 to 21,211.92 mu mol/kg DW, with average content of 6601.09 mu mol/kg DW in the germplasm. Gluconapin and glucobrassicanapin with average contents exceeding 1000 mu mol/kg DW were the predominant compounds detected. Principal component analysis revealed three distinct clusters and highlighted significant variability in the glucosinolate profiles. The highest total polyphenols and flavonoids contents were found in accession IT248400. Antioxidant activity, measured using DPPH center dot and ABTS(center dot+) assays ranged from 1.45 to 3.64 mg AEAC/g and from1.78 to 5.78 mg AEAC/g, respectively. Strong correlations were observed for progoitrin and epiprogoitrin (r = 0.99, p < 0.01), and between glucocheirolin and glucoraphanin (r = 0.97, p < 0.01). In silico molecular docking studies revealed that glucosinolates may play a role in physiological and cellular defense mechanisms in humans. In particular, gluconasturtiin and glucotropaeolin exhibited the highest binding affinities when docked against cytochrome P450, the human myeloperoxidase-thiocyanate complex, and cyclin-dependent protein kinase 2. The predicted LD50 values and toxicity class of gluconasturtiin and glucotropaeolin indicated relatively low acute toxicity. Post-docking analysis based on fastDRH revealed differential binding strengths and energetics of glucosinolates with myeloperoxidase, Cytochrome P450, and cyclindependent protein kinase 2. These findings suggest that glucosinolate compounds may have potential as pharmacological agents in disease intervention and drug development.