Superbanone, A New 2-Aryl-3-benzofuranone and Other Bioactive Constituents from the Tube Roots of Butea superba.

Phytochemical investigation from the tube roots of Butea superba, led to the isolation and identification of a new 2-aryl-3-benzofuranone named superbanone (1), one benzoin, 2-hydroxy-1-(2-hydroxy-4-methoxyphenyl)-2-(4-methoxyphenyl)ethanone (2), eight pterocarpans (3 - 10), and eleven isoflavonoids (11 - 21). Compound 2 was identified for the first time as a natural product. The structure of the isolated compounds was elucidated using spectroscopic methods, mainly 1D- and 2D-NMR. The isolated compounds and their derivatives were evaluated for α-glucosidase inhibitory and antimalarial activities. Compounds 3, 7, 8, and 11 showed promising α-glucosidase inhibitory activity (IC50  = 13.71 ± 0.54, 23.54 ± 0.75, 28.83 ± 1.02, and 12.35 ± 0.36 μm, respectively). Compounds 3 and 11 were twofold less active than the standard drug acarbose (IC50  = 6.54 ± 0.04 μm). None of the tested compounds was found to be active against Plasmodium falciparum strain 94. On the basis of biological activity results, structure-activity relationships are discussed.