Tumor inhibitors. XXXI. Vernolepin, a novel elemanolide dilactone tumor inhibitor from Vernonia hymenolepis

Recent Advances in the Synthesis of α‐Alkylidene‐Substituted δ‐Lactones, γ‐Lactams and δ‐Lactams

“…The first α-alkylidene δ-lactones, such as vernolepin (5) or vernomenin (6, Figure 2), containing both α-methylidene δ-lactone and α-methylidene γ-lactone moieties, were isolated in the 1960s from Vernonia hymenolepis. [5] Both compounds showed significant cytotoxicities against human pharyngeal carcinoma (KB) cells.…”

“…The first α-alkylidene δ-lactones, such as vernolepin (5) or vernomenin (6, Figure 2), containing both α-methylidene δ-lactone and α-methylidene γ-lactone moieties, were isolated in the 1960s from Vernonia hymenolepis. [5] Both compounds showed significant cytotoxicities against human pharyngeal carcinoma (KB) cells. [5] Later on, some natural compounds containing only α-methylene δ-lactone moieties, such as teucrium lactone (7), [6] crassin (8a) [7] and its acetate 8b [8] or pentalenolactone E (9), [9] were also isolated.…”

“…[5] Both compounds showed significant cytotoxicities against human pharyngeal carcinoma (KB) cells. [5] Later on, some natural compounds containing only α-methylene δ-lactone moieties, such as teucrium lactone (7), [6] crassin (8a) [7] and its acetate 8b [8] or pentalenolactone E (9), [9] were also isolated. Crassin (8a) shows in vitro activity against KB cells and its acetate 8b has antibiotic activity.…”

Synthesis of DAAS derivatives and their enhancement of HL-60 leukemia cell differentiation

“…Some natural sesquiterpenes including vernolepin (Kupchan et al, 1968) and costunolide (Ohnishi et al, 1997) were reported to have remarkable antileukemic activity in vitro and to have an α-methylene-γ-lactone moiety, which is expected to function as a major structural feature. There has been an increasingly large amount of research devoted to the development of new antitumor agents in this field.…”

Approaches to the synthesis of 8-epi-vernolepin from germacrolides

“…1), isolated from the Ethiopian plant Vernonia hymenolepis, 1 is a sesquiterpene dilactone with spasmolytic, anti-aggregating and de-aggregating activities, 2 as well as antitumor activity in vitro and in vivo.…”