Isolation and characterization of a novel xanthone from the hairy root cultures of Swertia chirayita (Roxb.) H. Karst. and its biological activity

Abstract

Swertia chirayita (Roxb.) H. Karst. is a well-documented traditional plant used to cure liver diseases, malaria fever, jaundice, hepatitis and diabetes. Xanthones are produced by the plant and provide a variety of health benefits. The goal of this research is to develop an efficient and reliable approach for hairy root induction and to explore the biosynthesis of xanthones in hairy root lines. Infection of S. chirayita leaves with Rhizobium rhizogenes strain (LBA 9402) resulted in distinct hairy root lines. The rolB gene integration in the root was validated by polymerase chain reaction (PCR) in four hairy root lines. Hairy root line SA produced the maximum biomass of 13.32 ± 0.50 g/flask FW (fresh weight) and 1.29 ± 0.05 g/flask DW (dry weight) after 60 days. A novel 1,2,5,6-tetrahydroxyxanthone (2) was isolated and characterized from SA hairy root line using flash chromatography. Swerchirin (1) (0.382 ± 0.089 mg/g DW) and 1,2,5,6-tetrahydroxyxanthone (2) (0.935 ± 0.02 mg/g DW) along with swertianin (0.0195 ± 0.007 mg/g DW) were accumulated higher amount in SA line. 1,2,5,6-tetrahydroxyxanthone (2) exhibited strong antioxidant activity in DPPH (IC50 = 1.60 ± 0.004 µg/mL) and FRAP (4.83 ± 0.02 Eq. to FeSO4) assay. Further, swerchirin (1) exhibited anti-proliferative activity by suppressing the growth of MDA-MB-231 cell line with IC50 of 18.82 μg/mL (65.83% at 50 μg/mL) and 1,2,5,6-tetrahydroxyxanthone (2) inhibited the growth of K562 cell line with IC50 of 22.83 μg/mL (67.82% at 50 μg/mL). The characterized compounds with promising biological activity could be taken up for its commercial production.