21beta-Hydroxy-oleanane-type triterpenes from Hippocratea excelsa.
Stem bark of Hippocratea excelsa afforded six pentacyclic triterpenes, five oleanane and one ursane types. They were identified as 11beta,21beta-dihydroxy-olean-12-ene-3-one (2), 3alpha,11alpha,21beta-trihydroxy-olean-12-ene (3), 3alpha,21beta-dihydroxy-11alpha-methoxy-olean-12-ene (4), 3alpha,21beta-dihydroxy-olean-9(11),12-diene (5), 3alpha,21beta-dihydroxy-olean-12-ene (6) and 3alpha,21beta-dihydroxy-11alpha-methoxy-urs-12-ene, isolated as its diacetate derivative (7), as well as 3alpha,21beta-dihydroxy-olean-12-ene (1) previously isolated from the root bark. The known alpha- and beta-amyrin, oleanoic and ursolic acids, trans-polyisoprene, and the ubiquitous beta-sitosterol were also isolated. Structures were elucidated on the basis of spectroscopic analyses, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC and HMBC) and comparison with literature data. The antigiardial activity of compounds 2-5 was not significant.
Laboratorio de Química Orgánica de Investigación, Facultad de Química, Universidad Autónoma de Yucatán, Calle 41 No. 421, Col. Industrial, C.P. 97150 Mérida, Yucatán, México.
David
D
Cáceres-Castillo
Gonzalo J
GJ
Mena-Rejón
Roberto
R
Cedillo-Rivera
Leovigildo
L
Quijano
D031320:Hippocrateaceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000737:chemistry* / Q000302:isolation & purification; D053978:Pentacyclic Triterpenes / Q000737:chemistry / Q000302:isolation & purification; D024301:Plant Bark / Q000737:chemistry; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification; D000097245:Ursolic Acid
D009828:Oleanolic Acid; D053978:Pentacyclic Triterpenes; D014315:Triterpenes; D000097245:Ursolic Acid; C036380:beta-amyrin