Comparative analysis of the chemical composition and cytotoxic activity of broccoli by-products as an alternative source of bioactive compounds

Broccoli (Brassica oleracea var. italica) 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 methanolic 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 the proliferation of HeLa cervical cancer cells by approximately 50 %. A principal component analysis (PCA) of volatile compounds identified four 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), along with methyl sinapate, were isolated and characterized by NMR. These compounds exhibited IC50 values of 23.43, 33.65 and 42.47 mu g/mL, respectively, against the HeLa cell line. Additionally, they exhibited favorable drug-like properties, suggesting potential for pharmaceutical development. 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.