3.5. Cell Cultures and Viability Assay

Cytotoxic activity was tested on human colon adenocarcinoma HT29 (ATCC HTB-38), colon carcinoma HCT116 (ATCC CCL-247), colon adenocarcinoma DLD-1 (ATCC CCL 221), and normal human colon epithelial CCD 841 CoN (CRL 1790) cells. Cells were grown under standard conditions (37 °C, 5% CO₂, relative humidity) and culture media (McCoy’s for HT29, DMEM high glucose for HCT116 and DLD-1), supplemented with 10% fetal bovine serum and 1% antibiotics solution (10,000 U penicillin and 10 mg streptomycin/mL). The stock solutions of the extracts were prepared in DMSO, and then diluted in the culture medium to the working concentrations (for sprouts 0–500 µg/mL, for leaves and flowers 0–100 µg/mL). Cell viability was determined after 24 h of incubation by MTT assay, as previously described [21]. Doxorubicin was used as a reference drug control. The absorbance was measured at 570 nm using a Biotek Synergy microplate reader (BioTek Instruments Inc., Winooski, VT, USA). All analyses were performed in three replicates, and the results are expressed as % of cell viability (mean ± SD) and IC₅₀ values (concentration at which viability is inhibited by 50%) where possible.