Characterization of the phytochemical composition and cytoprotective properties of Brassica olearacea var. botrytis L. by-products: a recycling strategy for nutraceutical production

Inedible parts of vegetables are commonly discarded in environment during collection, handling, transportation and processing of food, thus posing disposal and ecological concerns [1]. Nevertheless, waste could be reduced by applying targeted prevention strategies, among which reduction, reuse and recycling [2]. Particularly, recycling strategies (e. g. composting, processing to flour, conversion into water) allow to recovery waste after major modifications and to reuse them for further applications or as starting material for extraction of specific compounds [3]. In line with this interest, in the present study, by-products of cauliflower (Brassica olearacea var. botrytis L.; Fam. Brassicaceae) have been studied, within the Ri.cicloHorto project, as possible valuable sources of bioactive phytochemicals, particularly polyphenols and glucosinolates, to be used for nutraceutical purposes. In line with literature evidence about the healing properties of Brassicaceae species [4,5], phytochemical composition and the potential cytoprotective properties have been evaluated. Methods: Plant materials, i.e. leaves, stems and flower of cauliflower, were subjected to a 80% v/v ethanolic extraction, using an ultrasonic bath; the resulted dried extracts were assessed for their phytochemical composition and bioactivities. Total polyphenols, tannins and flavonoids, and glucosinolates were measured according to previous methods [6,7], in order to identify the possible bioactive phytochemicals. Moreover, the antioxidant and cytoprotective properties towards the damage induced by tert-butyl hydroperoxide (tBOOH) in human cholangiocytes and airway cells, have been studied [8]. At last, human cancerous cell lines, including A549 (lung cancer cells), MDA-MB-468 (triple negative breast cancer cells), Mz-ChA-1 (extrahepatic cholangiocarcinoma cells) and Bx-PC3 (pancreas adenocarcinoma cells) were used to highlight possible chemopreventive effects of the tested samples. Results: Our results showed the presence of polyphenols, tannins and flavonoids, along with glucosinolates in all tested samples, especially in the extracts from leaves and flowers. These samples also exhibited cytoprotective properties against the oxidative damage of tBOOH, by counteracting both cytotoxicity and intracellular oxidative stress. Moreover, stem extracts produced antiproliferative effects in cancer cell lines, thus suggesting a possible chemopreventive power. Further studies will allow to define the mechanisms underlying the observed pharmacological activities and the potential bioactive compounds. Conclusions: Present findings strengthen the interest in cauliflower waste as source of bioactive compounds and phytocomplexes of pharmaceutical/nutraceutical interest and open up future challenges to be overcome in order to exploit these valuable by-products. References 1. Chang et al. Waste Manag. Res. 2006, 24, 354–362. 2. Plazzotta et al. Trends Food Sci. Technol. 2017, 63, 51–59. 3. Deng et al. Int. J. Mol. Sci. 2012, 13, 8308–8323. 4. Cartea et al. Molecules 2010, 16, 251. 5. Salehi et al. Phytother Res. 2021, 35, 3590. 6. Di Sotto et al. Molecules 2019, 24, 3103 7. Gallaher et al. J Agric Food Chem. 2012, 60, 1358 8. Di Sotto et al. Molecules 2018, 23, 2066.