Efficient extraction methods and callus culture of quercetin from Indian white radish: yield analysis via HPLC quantification and assessment of cytotoxic activity.

Summary: Indian white radish Co. 1 (Raphanus sativus L.) contains medicinal quercetin, and its commercial value supports large‐scale quercetin isolation. Various extraction methods, including ultra‐assisted extraction (UAE), maceration extraction (ME), Soxhlet extraction (SE), conventional extraction (CSE) and serial maceration extraction (SME), were employed to extract quercetin from radish leaf sections. RP‐HPLC‐optimising key experimental parameters yielded a linear response for the individual target compounds in the concentration range, with a limit of quantification (LOQ) of 2.2 μg mL−1 (r2 = 0.9995), a limit of detection (LOD) of 2.2 μg per 1.0 g of crushed leaves and repeatability within the relative standard deviation (RSD) of 0.23–0.37%. For in vitro callus cultures, 2,4‐dichlorophenoxyacetic acid (2,4‐D), 6‐benzylaminopurine (BAP) and zeatin were used for callus induction from in vitro leaf segments of radish. MS medium enriched with 2,4‐D (0.5 mg) induced the highest percentage of callus at 4 weeks. Among the extraction methods, the SME method yielded the highest recovery of quercetin (96.9%; 1.92 mg g−1 DW), phenolic (26.07 mg g−1 DW) and flavonoid (34.03 mg g−1 DW), compared to other methods and solvents. The callus extract included 0.5 mg of 2,4‐D, 32.07 mg of phenolic, 42.03 mg of flavonoid and 6.46 mg of quercetin. The presence of phytocompounds and quercetin was confirmed by GC–MS/MS and RP‐HPLC. The isolated quercetin (57.9 μg) also showed lethal effects on HT‐29 human colon cancer cells. This method may be effective for evaluating quercetin in radish extracts. [ABSTRACT FROM AUTHOR]