Shivanand D. Jolad

Grindelane diterpenoids from Grindelia campórum and Chrysothamnus paniculatus

Abstract The structures of nine grindelic acid related diterpenes isolated as methyl esters from Grindelia camporum and Chrysothamnus paniculatus , were elucidated based on their spectral properties.

Cardenolides and a lignan from Asclepias subulata

Abstract Four new glycosides (three cardenolides and a lignan), nine previously reported cardenolide glycosides and a known triterpenoid were isolated from the ethyl acetate extract of the aerial parts of Asclepias subulata . The elucidation of the structures and stereochemistry of the new glycosides has been accomplished using mainly 1 H and 13 C NMR and mass (EI and FAB) spectral data of their acetyl derivatives and comparison of these data with those of known glycosides from the same plant as well as from other plants. The new compounds were identified as 16α-hydroxycalactin, 3β-(β- D -glucopyranosyloxy)-19-car coroglaucigenin 3β- D -glucoside and 4-(β- D -glucopyranosyloxy)-larciresinol.

Diterpenoids of Conyza coulteri

Abstract Four furanoditerpenoids, including three furanoclerodanes, have been identified in the extract of the aerial parts of Conyza Coulteri . One of the terpenoids, 2β-hydroxyhardwickiic acid, was found as a natural product for the first time.

Diterpenoids and flavonoids from Grindelia discoidea

Abstract A new labdane-type diterpenoid acid, discoidic acid, has been isolated from the aerial parts of Grindelia discoidea. Its structure has been deduced as 4β-hydroxymethyllabd-7-en- 15-oic acid on the basis of the spectral data of its methyl ester derivative and comparison of these data with those of the methyl ester derivative of its isomer, 3β-hydroxylabd-7-en- 15-oic acid, also isolated from the same extract. In addition, a dihydroflavonol and two flavonols have been isolated.

Antihyperglycemic activity of Teramnus labialis (Fabaceae)

In vivo bioassay-guided fractionation of the aqueous alcohol extract of the aerial parts of Teramnus labialis (Roxb.) Benth. (Fabaceae), using C57BL/Ks-db/db mice as a model for type 2 diabetes, yielded an active fraction containing a mixture of coumarins. The major coumarin present in the active fraction was identified as fraxidin.

1-Epizeylenol from Uvaria zeylanica roots

Abstract 1-Epizeylenol was isolated from Uvaria zeylanica roots and characterized, largely by 1 H and 13 CNMR spectral comparisons with zeylenol.

Five grindelane diterpenoids from Grindelia acutifolia

Abstract Five new labdane diterpenoid acids, 6α-hydroxy-17-acetoxygrindelic acid, 6-oxo-17-acetoxygrindelic acid, 6α-hydroxy-17-isovaleroxygrindelic acid, 6α-hydroxy-17-(α-methylbutyroxy)grindelic acid and 6-oxo-17-isobutyroxygrindelic acid, were shown to be present in Grindelia acutifolia, mainly on the basis of comparisons of the spectra of their methyl ester derivatives with those of their 6-deoxy derivatives, several of which are major constituents of this plant species.

Grindelane diterpenoids from Grindelia squarrosa and G. Camporum

Abstract An acid fraction of the dichloromethane extract of Grindelia squarrosa and a neutral fraction of the ethyl acetate extract of Grindelia camporum yielded a number of previously known grindelane diterpenoids and flavonoids. Along with the known isolates, two new grindelane diterpenoids, 13-isogrindelic acid and 17-grindeloxy grindelic acid, from G. squarrosa were isolated and identified spectroscopically.

Havardic acids A-F and havardiol, labdane diterpenoids from Grindelia havardii

Abstract Seven new labdane diterpenoids, designated as havardic acids A-F (as methyl esters) and havardiol, have been obtained from the dichloromethane extract of the aerial parts of Grindelia havardii , and their structures have been deduced on the basis of NMR, MS and IR data. Havardic acid E has lost carbons-14 and -15, whereas havardic acid F and havardiol have lost carbon-17.

Two grindelane diterpenoids from Grindelia camporum

Abstract Two new grindelane diterpenoids, termed camporic acid (a labdane-derived diterpenoid with a pyranoid B-ring) and 17-car☐ygrindelic acid, were isolated from Grindelia camporum as methyl esters and characterized mainly by 1 H and 13 C NMR and mass spectral analyses and comparisons with related grindelanes. Chrysolic acid methyl ester and strictanonic acid methyl ester were also obtained from this species for the first time.