Effects of the sesquiterpene lactone,helenin, on feeding rates and survival of the tundra redback vole Clethrionomys rutilus

The sesquiterpene lactone, helenin, acts as a feeding deterrent to redback voles, Clethrionomys rutilus. When given a choice between normal and treated food, these animals avoided food containing at least 0.05% of helenin. However, when only offered food with various concentrations of helenin, feeding rate and consequently body weight of voles were sharply reduced when the helenin concentration was 1.5% or higher. Voles given food containing 3.0–7.0% of helenin died in 3–5 days. It is suggested that these effects of helenin are the result of its antifeedant property and subsequent starvation of animals as well as its interference with digestive processes. The data presented support the view that helenin and other sesquiterpene lactones may play an important role in the defence of plants against herbivorous mammalian predators.     

Insect feeding deterrent property of alantolactone

The sesquiterpene lactone, alantolactone, significantly reduces feeding and survival of Tribolium confusum. These findings support the view that alantolactone may protect plants such as composites from insect attack.     

Alantolactone promotes ER stress‐mediated apoptosis by inhibition of TrxR1 in triple‐negative breast cancer cell lines and in a mouse model

Triple‐negative breast cancer (TNBC) is a subtype of breast cancer with poor clinical outcome and currently no effective targeted therapies are available. Alantolactone (ATL), a sesquiterpene lactone, has been shown to have potential anti‐tumour activity against various cancer cells. However, the underlying mechanism and therapeutic effect of ATL in the TNBC are largely unknown. In the present study, we found that ATL suppresses TNBC cell viability by reactive oxygen species (ROS) accumulation and subsequent ROS‐dependent endoplasmic reticulum (ER) stress both in vitro and in vivo. Thioredoxin reductase 1 (TrxR1) expression and activity of were significantly up‐regulated in the TNBC tissue specimens compare to the normal adjacent tissues. Further analyses showed that ATL inhibits the activity of TrxR1 both in vitro and in vivo in TNBC and knockdown of TrxR1 in TNBC cells sensitized ATL‐induced cell apoptosis and ROS increase. These results will provide pre‐clinical evidences that ATL could be a potential therapeutic agent against TNBC by promoting ROS‐ER stress‐mediated apoptosis through partly targeting TrxR1.     

Simultaneous quantification of eudesmanolides and thymol derivatives from tissues of Inula helenium and I. royleana by reversed-phase high-performance liquid chromatography

A simple and rapid isocratic reversed-phase high-performance liquid chromatographic method for the quantification of alantolactone/isoalantolactone and three thymol derivatives in roots and root cultures of Inula helenium and I. royleana has been developed. The method could be applied to screen raw materials in search for highly productive plants and in vitro cultures.     

Feeding deterrent activity of enantiomeric isoalantones

The antifeeding activities on three storage pest insects of alantolactone, isoalantolactone and ent-isoalantolactone were measured and compared.     

Antifungal activity of helenin and isohelenin

Two sesquiterpene lactones, helenin and isohelenin, were examined for their activity against 16 species of fungi. These compounds varied greatly in their antifungal activities. At concentrations of 10 μg/ml, the lactones strongly inhibited the growth of Microsporum cookei, Trichophyton mentagrophytes and Trichothecium roseum, while other fungi were only inhibited by considerably higher levels (100–1000 μg/ml). It is suggested that these secondary plant metabolites might be of potential use as antifungal agents, especially if their activity and specificity could further be enhanced through modifications in their chemical structure.