Chemical constituents from the leaves of Pseuderanthemum tunicatum (Afzel.) Milne-Redhead (Acanthaceae).

Phytochemical study of the ethanol extract of the leaves of Pseuderanthemum tunicatum afforded eleven known compounds including madagascin ( 1 ), harunganol B ( 2 ), eicosanoic acid ( 3 ), dotriacontanoic acid ( 4 ), friedelin ( 5 ), lupeol ( 6 ), β-sitosterol ( 7 ), stigmasterol ( 8 ), β-sitosterol 3- O -β- d -glucopyranoside ( 9 ), stigmasterol 3- O -β- d -glucopyranoside ( 10 ) and apigenin 7- O -β- d -glucopyranoside ( 11 ). Acetylation of compound 1 afforded madagascin diacetate ( 1a ), described here for the first time. The structures were established by interpretation of their spectral data, including IR, UV, MS, 1D- and 2D- NMR ( 1 H, 13 C, DEPT 135, 1 H– 1 H COSY, HMQC, HMBC and NOESY), as well as by comparison with literature data. In the present study all the compounds are isolated for the first time from the species P. tunicatum . Compounds 1 and 2 have never been reported from the Acanthaceae family. Compounds 4 and 6–11 have been previously isolated from the genus Pseuderanthemum , and compounds 3 and 5 from the family Acanthaceae. The chemotaxonomic significance of the isolated compounds is discussed. [ABSTRACT FROM AUTHOR]