Unusual naphthoquinones, catechin and triterpene from Byrsonima microphylla

The new triterpene Delta(1)-lupenone (1), together with lupeol, beta-amyrin and betulin were isolated from the wood of Byrsoninia microphylla (Malpighiaceae). The new compounds 3-hydroxy-2-methoxy-8,8,10-trimethyl-8H-antracen-1,4,5-trione (2), 3,7-dihydroxy-2-meth oxy-8,8, 10-trimethyl-7,8-dihydro-6H-antracen-1,4,5-trione (3), (2S*,10aR*)-2,8-dihydroxy-6-methoxy-1,1,7-trimethyl-2,3,10, 10a-tetrahydro-1H-fenantren-9-one (4) and (2S,3S)-3'-hydroxy-4',5,7-trimethoxy-flavan-3-ol (5) were also isolated through monitored TLC using the antioxidant P-carotene reagent. The antioxidant potential of the compounds 2-5 was measured and none of them showed activity. The structures of these compounds were elucidated by chemical and spectroscopic analysis based on NMR techniques (H-1, C-13 NMR, COSY, nOe difference, HMQC and HMBC), UV and MS. (c) 2005 Elsevier Ltd. All rights reserved.