Dihydro¯avonols and ¯avanones from Lonchocarpus atropurpureus roots Aderbal F. MagalhaÄes a, *, Ana Lucia T.G. Ruiz a , Ana Maria G.A. Tozzi b , Eva G. MagalhaÄes a a Organic Chemistry Department of Chemistry Institute, UNICAMP, P.O. Box 6154, 13081-970, Campinas, Sa Äo Paulo, Brazil b Botany Department of Biology Institute, UNICAMP, P.O. Box 6154, 13081-970 Campinas, Sa Äo Paulo, Brazil Received 1 December 1998; received in revised form 3 April 1999 Abstract From the petroleum extract of Lonchocarpus atropurpureus Benth. roots, 5,2 '-dihydroxy-3-methoxy-6,7-(20,20- dimethylchromene)-8-(30 ',30 '-dimethylallyl)-¯avanone and 2 ',3,5-trihydroxy-6,7-(20,20-dimethylchromene)-8-(30 ',30 '-dimethyl- allyl)-¯avanone were isolated, together with three known ¯avanoids and a mixture of two pentacyclic triterpenes. Their molecular structures were determined by spectral analyses (UV, IR, MS and 1D- and 2D-NMR experiments). # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Leguminosae; Lonchocarpus atropurpureus; Flavonoids; Flavanones; Dihydro¯avonols; Minimi¯orin; Mundulinol; Mundulin 1. Introduction The genus Lonchocarpus belongs to the subfamily Papilionoideae of the Leguminosae. Lonchocarpus atro- purpureus Benth. is native to Mexico (Pittier, 1917) and is cultivated in the Ecological Park of Campinas State University (UNICAMP). It belongs to Lonchocarpus subgenus Lonchocarpus, section Lonchocarpus. As part of a chemosystematic study of the genus Lonchocarpus (MagalhaÄes, Tozzi, Sales & MagalhaÄes, 1996; MagalhaÄes, Tozzi, MagalhaÄes & Nogueria, 1997) the root extract of L. atropurpureus was subjected to a detailed laboratory investigation. We report herein ®ve prenylated ¯avonoids (1±5) and a mixture of two pen- tacyclic triterpenes (6).Two of these compounds (2 and 3) are described for the ®rst time. 2. Results and discussion Two ¯avanones (1 and 5), three dihydro¯avonols (2±4) and a mixture of pentacyclic triterpenes (6) (Fig. 1) were isolated through chromatographic fraction- ation techniques (column, TLC and preparative TLC) from the petroleum extract of L. atropurpureus roots. Compounds 1 (C 25 H 26 O 5 ), 4 (C 25 H 26 O 5 ) and 5 (C 25 H 26 O 4 ) were identi®ed as the known minimi¯orin (Mahmoud & Waterman, 1985) mundulinol and mun- dulin (van Zyl, Rall & Roux, 1979) respectively, by comparison of their spectral data with those previously published. The mixture of pentacyclic triterpenes was analyzed by 1 H-NMR, 13 C-NMR data (Olea & Roque, 1990; Seo, Tomita & Tori, 1975; Wenkert, Baddeley, Bur®tt & Moreno, 1978) and GC/MS (Shannon, 1963; Muccino & Djerassi, 1974) to reveal a mixture of b- amyrin and lupeol. Compound 2, obtained as the major constituent, was deduced as having an elemental formula of C 26 H 28 O 6 by HREI-MS (observed. M :  436:1886; required M :  436:1886). It showed characteristic sig- nals for a dihydro¯avonol at dH 5.43 (1H, d, J = 11 Phytochemistry 52 (1999) 1681±1685 0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0031-9422(99)00401-X * Corresponding author.