Potassium acetate

The Folin–Ciocalteu method [30 ] was used to determine the TPC from date palm cell suspension culture, with some modifications [31 (link)]. Methanolic extract (20 µL) was mixed with 1.58 mL of deionized water and 100 µL of Folin–Ciocalteu reagent (SRL, Mumbai, India, AR grade); then, it was allowed to stand for 8 min before 20% of 300 µL sodium carbonate solution (HiMedia, Mumbai, India, AR grade) was added. After shaking and mixing the solution well, we left it for 2 h at 20 °C, after which the color was developed and the absorbance was measured at 765 nm using a UV-visible spectrophotometer (Shanghai Yoke, Shanghai, China). The TPC of cell extract was expressed as mg GAE/100 g of DW. The colorimetric method as explained by Thiruvengadam et al. [32 (link)] was used to determine the TFC of date palm cell suspension culture extracts, with some modifications [31 (link)]. Methanolic extracts (100 µL), 10% of 50 µL aluminum chloride (SRL, Mumbai, India, AR grade), 1 M of 50 µL potassium acetate (HiMedia, Mumbai, India, AR grade), and distilled water (1.8 mL) were mixed. After incubation for 30 min at room temperature, the absorbance was measured at 415 nm using a UV-visible spectrophotometer (Shanghai Yoke, Shanghai, China). The TFC of cell extract was expressed as mg QE/100 g of DW.