Bioactive compounds from the roots of Morinda coreia, Millingtonia hortensis and Cordia globiferaThinley Gyeltshen
( M.Sc. )
Nine known anthraquinones (162-170), scopoletin (171) and squalene (172) were isolated from the methanol extract of the inner root of Morinda coreia Ham. Compounds 165-168 and 170 exhibited cytotoxic activity, while compounds 165, 166, and 171 had antioxidant activity with oxygen radical absorbance capacity (ORAC) 3.8, 6.7, and 14.8 units, respectively. Two known flavonoids, sorbifolin (173) and acacetin-7-O-β-D-glucuronide (174) were isolated from the root barks of Millingtonia hortensis. Sorbifolin (173) scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals (IC50 = 45.4 µM), inhibited superoxide anion formation in the xanthine/xanthine oxidase (XXO) assay (IC50 = 0.6 µM), inhibited aromatase enzyme (IC50 = 2.7 µM) and exhibited 3.2 ORAC units. Acacetin-7-O-β-D-glucuronide (174) exhibited activity in XXO assay with IC50 value of 55.6 µM. Chemical investigation of the CH2Cl2 extract of Cordia globifera roots led to the isolation of three new compounds, globiferane (176) and two glutarimide alkaloids, cordiarimide A (177) and cordiarimide B (178), together with a known compound, globiferin (175). Globiferane (176) exhibited cytotoxic activity, while cordiarimides A (177) and B (178) inhibited the superoxide anion formation in XXO assay with IC50 values of 54.1 µM and 21.7 µM, respectively. The structural elucidation of the isolated compounds was performed by analysis of spectroscopic data. The absolute configuration of cordiarimide B (178) was determined by modified Mosher’s method.