Comparative Analysis of the Chemical Composition and Cytotoxic Activity of Broccoli By-products as a Source of Bioactive Compounds

Broccoli is one of the most widely consumed cruciferous vegetables worldwide; however, only about 30%—primarily the florets—are consumed, while the remaining parts are considered waste. In this study, we analyzed broccoli by-products from Mexican crops, specifically evaluating the ethanolic extracts of bagasse (BB) and residual leaves (BL) for their growth-inhibitory effects on PC-3, HeLa, and Hep3B cancer cell lines. Both BB and BL selectively inhibited cervical cancer cell proliferation by approximately 50%. A principal component analysis (PCA) of volatile compounds identified three main groups: fatty acids, methyl esters, sterols, and diterpenoids. Notably, sterols were the predominant components in the hexane fraction of broccoli bagasse (BB-H) (>90%), whereas fatty acids were the most abundant in the hexane fraction of broccoli leaves (BL-H) (>50%). Furthermore, two phytoalexins, caulilexin C (1) and 3-indoleacetonitrile (2), were isolated and characterized by NMR, exhibiting IC50 values of 23.43 and 33.65 μg/mL, respectively, against the HeLa cell line. Also, they showed desirable drug-like properties. These findings provide valuable insights into the chemical composition of broccoli by-products from Mexican crops, emphasizing their potential as a source of bioactive compounds with pharmaceutical and food applications.