Polyphenolic Profile and Varied Bioactivities of Processed Taiwanese Grown Broccoli: A Comparative Study of Edible and Non-Edible Parts

Abstract

Broccoli contains a substantial amount of bioactive compounds such as glucosinolates, phenolics, and essential nutrients, which are positively linked to health-promoting effects. This work aimed to evaluate whether both edible and non-edible parts of broccoli could be effective by examining in vitro antioxidant, cytotoxic, apoptotic, and antibacterial properties of its floret, leaf, and seed extracts (FE, LE, and SE, correspondingly). High-performance liquid chromatography (HPLC) and various assays exhibited strong antioxidant activities of all samples. LE obtained the highest capacity, correlated to its polyphenolic contents. SE exerted significant cytotoxicity against A549, Caco-2, and HepG2 cancer cell lines at low inhibitory concentration (IC)50 values (0.134, 0.209, and 0.238 mg/mL, respectively), as tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry confirmed apoptosis induction of extracts in Caco-2 cells by revealing an increased subG1 population and a decreased mitochondrial membrane potential. The considerable antibacterial efficacy was observed in either LE and SE against Bacillus subtilis and Salmonella typhimurium (0.39–0.78 mg/mL) using well-agar diffusion and minimum inhibitory concentration (MIC) techniques, along with the weak activity against Staphylococcus aureus and Escherichia coli (1.56–3.13 mg/mL). The findings suggest that broccoli and its byproducts might serve as a promising source for further development of food or pharmaceutical products.