Serengolam V. Govindan

New prenylated isoflavones and a prenylated dihydroflavonol from Millettia pachycarpa

Abstract Extraction of Millettia pachycarpa Benth. gave 5,7,4′-trihydroxy-6,8-diprenylisoflavone (1a), 5,7,4′-trihydroxy-6,3′-diprenylisoflavone (2a), 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (3a) and (2R, 3R)-5,4′-dihydroxy-8-prenyl-6″,6″-dimethylpyrano[2″,3″: 7,6]-dihydroflavonol (4a) whose structures were established by chemical transformations and spectroscopic means. Pectolinarigenin and salvigenin were isolated from Buddleia macrostachya Benth.

New flavonoids from Inula cappa

Abstract Extraction of Inula cappa DC. yielded three new flavonoids with an unusual ring B substitution pattern, namely (2 R ,3 R )-5′-methoxy-3,5,7,2′-tetrahydroxyflavone, (2 S )-5,7,2′,5′-tetrahydroxyflavanone and 7.5′-dimethoxy- 3,5,2′-trihydroxyflavone. Structures were established by chemical correlation, spectroscopic studies and degradation.

New melampolides and darutigenol from Sigesbeckia orientalis

Abstract Isolation and identification of darutigenol and two new melampolides from Sigesbeckia orientalis , in addition to the previously described orientalide and darutoside, are reported.

Sesquiterpene lactones and other constituents of Eupatorium lancifolium and E. semiserratum

Abstract The isolation of the cytotoxic and/or antileukaemic heliangolides eupacunolin, eupacunin, desacetyleupacunin, a new germacradienolide and a coumarin fr

Eucannabinolide and other constituents of Schkuhria virgata

Abstract Isolation of eucannabinolide, its 3-isovaleroyl analog and pectolinarigenin from Schkuhria virgata (La Llave et Lex.) DC. is reported. The identity of eucannabinolide, which exhibits in vivo antileukemic activity, with ‘hiyodorilactone A’, ‘20-hydroxychromolaenide’ and ‘schkuhrin I’ is discussed.

Rotenoids from roots of Millettia pachycarpa

Abstract Roots of Millettia pachycarpa furnished retenone, cis -12a-hydroxyrotenone, rot-2′-enonic acid and cis -12a-hydroxyrot-2′-enonic acid.

Diterpenes of helianthus rigidus and H. Salicifolius

Abstract The chloroform extract of Helianthus rigidus gave ciliaric acid and 16-hydroxy-11-kauren-19-oic acid. H. salicifolius furnished these compounds as well as (−)-kauranol.

Sesquiterpene lactones of eupatorium anomalum and eupatorium mohrii

Abstract Several new guaianolides and the previously known heliangolide eurecurvin have been isolated from Eupatorium anomalum . Eupatorium mohrii also yielded three of the new guaianolides together with eurecurvin and a new germacradienolide. The implications of these findings are discussed.

New prenylated isoflavones from Millettia pachycarpa

Abstract Isolation of four new isoflavones from a new collection of Millettia pachycarpa is reported. Proof of the structure of lupinifolol, previously isolated from M. pachycarpa , by synthesis of dehydrolupinifolol is described.

The germacradienolide isabelin from Zexmenia valerii: stereochemistry and conformation of scandenolide and deoxymikanolide☆

Abstract The isolation of the germacradienolide isabelin from Zexmenia valerii is reported. In contrast to isabelin, the closely related lactones deoxymikanolide and scandenolide exist in solution in one conformation only, which is similar to that of dihvdromikanolide in the solid state. The C-3 stereochemistry of scandenolide is revised.