Isoprenoid pterocarpans, isoflavonoids and flavonoids from Erythrina stricta

Abstract

• Three new isoprenoid pterocarpans, erystrictins A-C, were isolated from Erythrina stricta . • Alkaloid 22 was isolated from Erythrina genus for the first time. • Several compounds exhibited certain degrees of cytotoxic activity. A pair of diastereoisomeric pterocarpans, erystrictins A/B (1a/1b), possessing a highly oxidized 3-hydroxy-2-(1-hydroxy-1-methylethyl)- 2,3-dihydro furan substituent, and erystrictin C (2), along with seven known pterocarpans ( 3 - 9 ), eleven known flavonoids ( 10 - 20 ), and two known alkaloids ( 21 - 22 ) were isolated from Erythrina stricta. Their structures were established by extensive spectroscopic analyses, including HRESIMS, 1D and 2D NMR, and electronic circular dichroism (ECD) calculations. Using the MTS method, compounds 1 - 12 were tested for their cytotoxicity against the HL-60, SMMC-7721, A-549, MCF-7 and SW-480 human tumor cell lines, compounds 4, 10 and 12 showed moderated cytotoxicity. All the compounds, except for 10 and 12 were isolated from this plant for the first time. Compound 21 was isolated from Erythrina genus for the first time.