LC/HRESI-MS/MS screening, phytochemical characterization, and in vitro antioxidant and cytotoxic potential of...

Avoiding the probable dangerous side effects of synthetic drugs, this study aims the identification of natural antioxidant and antitumor agents from J. integerrima leaf and floral extracts. A highly efficient and fast UPLC/ESI-qTOF-HRMS/MS screening has led to characterization of 30 flavonoids, i.e. 12 flavonols, 6 flavones, 3 dihydroflavonols, 4 anthocyanins (flower), 2 dihydroflavonols, and 3 isoflavones from both J. integerrima extracts. In addition, six major polyphenols were identified for the first time from leaf extract, and their structures were established as apigenin 7-O-β-d-neohesperidoside (rhoifolin, 1), apigenin 8-C-β-D-⁴C₁-glucopyranoside (vitexin, 2), luteolin 6-C-β-D-⁴C₁-glucopyranoside (isoorientin, 3), 6,6″-di-C-β-D-⁴C₁-glucopyranosyl-methylene-biapigenin (Jatrophenol-I, 4), (E)-p-coumaric acid methyl ester (5), and (E)-ferulic acid methyl ester (6) with HRESI-MS and NMR analyses. The in vitro antioxidant activity of both extracts and major pure isolates was decided using DPPH, reducing power capability, FRAP, and ABTS radical scavenging assays, and their in vitro cytotoxicity was evaluated on Ehrlich ascites carcinoma cells (EACC), as well.The flower extract and compound 3 have shown the strongest antioxidant and cytotoxic effects. At low concentrations (25 µg/mL), they showed the highest DPPH radical scavenging ability (79.63 ± 0.42 and 76.20 ± 0.35%) regarding BHA (91.44 ± 0.29% at 100 µg/mL). In the parameter of absorbance, they exhibited higher reducing power ability (1.402 ± 0.025 and 1.178 ± 0.019%) than that of BHA (0.975 ± 0.013 at 100 µg/mL). Similarly, they proved superior FRAP (1427 ± 9.61 and 1377 ± 13.61 µmol Trolox/ 100 g) and highest ABTS activity (80.19 ± 0.55 and 68.38 ± 0.19%), which are higher activities compared to BHA (88.42 ± 0.24% at 100 µg/mL). Furthermore, all samples gave noticeable cytotoxicity at the same concentration (100 µg/mL), especially the flower extract and compound 3 which showed a relatively high effect on the viability of EACC (81.12 ± 0.24 and 77.21 ± 0.76 %, respectively) relative to vincristine reference drug (90.64 ± 0.39 %). Based on the findings, the extracts and isolates can be considered as potent antioxidant and cytotoxic natural agents, especially flower extract and isoorientin (3), which may supply novel insight into their likely application in pharmaceutical industries.