Sesquiterpene lactones of Tithonia diversifolia. Stereochemistry of the tagitinins and related compounds

Abstract

The d in the structural label indicates that the compound bears a deuterium substituent, Z = D. For the sake of clarity; the absolute configurations of these labeled species have been assigned without any consideration of the deuterium atom. Therefore, the structural labels for the deuterated and the corresponding protiated compounds differ only in the presence or absence of d following the number for that structure. Although the compounds bearing deuterium are mixtures of diastereomers, no evidence has been observed which indicates a diastereomeric composition which is not equal to 1:1. (20) J.

Sesquiterpenoids and Flavonoids from the Aerial Parts of Tithonia diversifolia and Their Cytotoxic Activity

“…1,10,11) As part of our systematic survey of bioactive compounds from higher plants, we have now conducted a detailed phytochemical screening of the 80% EtOH extract of T. diversifolia using a cytotoxicity-guided fractionation method, which has resulted in the isolation of twelve sesquiterpenoids (1-12), including three new ones (4, 10, 12), and three known flavonoids (13)(14)(15). This paper deals with the structural identification and determination of the sesquiterpenoids and flavonoids, and with their cytotoxic activity.…”

“…tirotundin (1), 12) tirotundin 3-O-methyl ether (2), 13) tagitinin A (3), 14) tagitinin C (5), 12) deacetylviguiestin (6), 15) tagitinin F (7), 12) 1b-methoxydiversifolin (8), 1) 1b-methoxydiversifolin 3-O-methyl ether (9), 1) 4b,10a-dihydroxy-3-oxo-8b-isobutyroyloxyguaia-11(13)-en-6,12-olide (11), 16) luteolin (13), 16) nepetin (14), 16) and hispidulin (15), 16) respectively. (Table 1), signals for an acetalic carbon and a quaternary carbon with an oxygen atom were observed at d 108.8 and 81.3, respectively.…”

Supercritical carbon dioxide extraction of tagitinin C from Tithonia diversifolia

“…1), a known sesquiterpene lactone [2,3], from the aerial parts of the plant and discovered its antimalarial activity against Plasmodium falciparum. Gu et al recently showed significant antiproliferative activity of tagitinin C [4].…”

Sesquiterpenes and Other Constituents from Dendranthema zawadskii var. latilobum

“…24,25) The stereochemistry of the epoxide ring was deduced to be 1β,10α on the basis of the low field displacement of the doublet of H-6 (δ H 5.54; δ H 5.12 br d in 2). 20,[24][25][26] Thus, compound 3 was identified as 3β-acetoxy-1β,10α-epoxy-15-hydroxy-germacr-4Z-en-6β,7α,11αH-12,6-olide and named zawadskinolide C (15-hydroxyajanolide A epoxide). 25) The IR spectrum of 4 suggested the presence of a hydroxyl group (3388 cm H-NMR spectrum, which correlated with C-1, C-10, and C-9 in the HMBC spectrum, and the signals at δ C 116.3 and δ 148.4 in the 13 C-NMR spectrum were characteristic signals of an exocyclic methylene group at C-10.…”