The natural products described in the literature as constituents of Leontodon spp. are mainly sesquiterpene lactones, phenolic compounds, sterols and pentacyclic triterpenes.
The occurrence of guaiane-type sesequiterpenes lactones has been reported from some Leontodon species. Three compounds, 14-hydroxyhypocretenolide (1), 14-hydroxyhypocretenolide β-D-glucopyranoside (2) and 14-hydroxyhypocretenolide-β-D-glucopyranoside-4′-14″-hydroxyhypocretenoate (3) were isolated from Leontodon hispidus (Zidorn et al., 1998). Eight compounds were isolated from Leontodon autumnalis; two from the flowerheads (8-deoxylactucin and jacquinelin) and six from have been isolated from the aerial parts: crepidiaside A (4), crepidiaside B (5),15-glucopyranosyloxy-2-oxo-guaia-3,11(13)-dien-1α,5α,6β,7α,-10αH-12,6-olide (6); 15-glucopyranosyloxy-2-oxo-guai-3-en-1α,5α,6β,7α,10α,11βH-12,6-olide (7); 15-hydroxy-2-oxo-guai-3-en-1α,5α,6β,7α,10α,11βH-12,6-olide (8); and 15-glucopyranosyloxy-2-oxo-guaia-3,11(13)-dien-1β,5α,6β,7α,10αH-12,6-olide (9) (Fig. 103) (Zidorn et al., 2000a).
The sesquiterpene lactone glucoside glucozaluzanin C (10) (Zidorn et al., 2001a) and a germacranolide glucoside [15-β-D-glucopyranosyl-8-[p-(β-D-glucopyranosyloxy)phenylacetyl]-salonitenolide (11)] were found in the aerial parts of L. cichoraceus (Zidorn et al., 2001b).
An oleanene triterpenetetrol [2β,3β,15α,21β-olean-12-ene-2,3,15,21-tetrol (12)], was isolated from the aerial parts of Leontodon filii (Tostão et al., 2005).
The major phenolic compounds in the aerial parts of Leontodon taraxacoides were the flavonoids apigenin, luteolin and their glucosides, as well as caffeic acid, and chlorogenic and isochlorogenic acids (Giner et al., 1993).
Nine different phenolics (luteolin, luteolin-7-O-β-D-glucoside, luteolin-7-O-β-D-glucuronide, luteolin-7-O-[β-D-gentiobioside, luteolin-4′-O-β-D-glucoside, chlorogenic acid, caffeoyl tartaric acid, cichoric acid and 3,5-dicaffeoyl quinic acid]were identified in Leontodon helveticus, Leontodon autumnalis and Leontodon hispidus (Zidorn and Stuppner, 2001).