Sesquiterpene Lactones and Thymol Esters from Vicoa pentanema

Abstract

The aerial parts of Vicoa pentanema yielded four new sesquiterpene lactones, namely, 10α-hydroxy-14H-inuviscolide (1), 4α,5α-epoxy-10α,11β,13H,14H-1-epi-inuviscolide 3-β-d-glucoside (2), 2α-O-acetyl-3β-hydroxyalantolactone (3), and 2α,3α-dihydroxyalloalantolactone (4). The structure and stereochemical assignments of all sesquiterpenes were based on their 1H and 13C-NMR spectral data, including those derived from 2D-NMR COSY, HETCOR, FLOCK, and NOESY experiments, as well as extensive NOE-difference studies. In addition, the same plant material yielded the known sesquiterpene lactones 8β-hydroxyparthenolide (5), 8-epi-confertin (6), 4α,5α-epoxy-10α,14H-1-epi-inuviscolide (7), inuviscolide (8), lipiferolide (9), and carabrone (10), the known thymol ester 7,8-epoxy-9-(isobutyryloxy)thymolisobutyrate (11), and its hydrolysis product 7-hydroxy-8,9-bis(isobutyryloxy)thymol (12).

Micropropagation and in vitro flowering in Pentanema indicum Ling

“…Ray florets 12-24, much longer than involcure and disc florets scanty. Many compounds have been isolated from P. indicum namely, sesquiterpenevicolides, monoterpenediol-vicodiol and thymol esters (Saradha Vasanth et al 1990;Mossa et al 1997), cis-cis germacranolide (Sawaiker et al 1998), 4,5,6-trihydroxy-4-7-dimethoxy flavone (Krishnaveni et al 1997). Vicolide D showed abortifacient and antifertility activities (Alam et al 1989).…”

Cytotoxic sesquiterpene lactones from Centaurothamnus maximus and Vicoa pentanema

“…c Data assigned for comparison; assignment for carbon 10 of 3 was incorrectly reported by Massiot et al (1986). germacranolides (13, 14) and one elemenolide (15), from V. pentanema (Mossa et al, 1997).…”

“…Centrifugal preparative TLC (CPTLC, using a Chromatotron 1 instrument, Harrison Research Inc. Model 7924) was run with 4 mm silica gel PF 254 disc, using a flow rate of 2 mL/min. The isolation and structure elucidation of sesquiterpene lactones (4-15) from the aerial parts of V. pentanema was described previously (Mossa et al, 1997).…”

“…& Hemsl., another Compositae plant, yielded 12 sesquiterpene lactones (4-15), of which four were reported as new compounds (Mossa et al, 1997). In this paper we wish to report the isolation and characterization of compounds 1-3 from C. maximus, and the cytotoxic and antimicrobial activities of compounds 1-15, as well as cell aggregation and adhesion studies of the cytotoxic sesquiterpene lactones.…”

Sesquiterpenoids from the Aerial Parts of Inula japonica

“…Previous phytochemical investigations of I. japonica revealed that sesquiterpenoids were the main active constituents [11] [14 -16]. To search for biologically active compounds, we investigated the chemical constituents of the aerial parts of the plant, and fourteen eudesmane sesquiterpenoids were isolated, including four new ones, (1b,5a,7b,8b,11b)-5-hydroperoxy-1-hydroxyeudesm-4(15)-eno-12,8-lactone 1 ) (1) [17], (1b,5a,7b,8b)-8-(acetyloxy)-5-hydroperoxy-1-hydroxycostic acid methyl ester 1 ) (12) [11], (1b,3b,4b,7b,8b)-1,3-dihydroxyeudesma-5,11(13)-dieno-12,8-lactone 1 ) (7) [18], (1b,3b,4b,7b,8b,11b)-1,3-dihydroxyeudesm-5-eno-12,8-lactone 1 ) (8) [18], and ten known compounds (5a)-5-hydroperoxyasperilin (2) [17], (5a)-5-hydroxyasperilin (3) [19], alantolactone (4) [11], (1b)-1-hydroxyalantolactone (5) [11] [20], (1b,11b)-11,13-dihydro-1-hydroxyalantolactone (6) [11] [21], ivangustin (9) [11], (8b)-8-hydroxysantamarin (10) [15], (1b,7b,8b)-8-(acetyloxy)-1-hydroxycostic acid methyl ester (11) [11], britannilactone (13) [22], and 1-O-acetylbritannilactone (14) [22]. To the best of our knowledge, among these known sesquiterpenoids, compounds 2 -4 were reported from I. japonica for the first time.…”