Sesquiterpenoid lactones as potential anti-cancer agents: an update on molecular mechanisms and recent studies

Plants-based natural compounds are well-identified and recognized chemoprotective agents that can be used for primary and secondary cancer prevention, as they have proven efficacy and fewer side effects. In today's scenario, when cancer cases rapidly increase in developed and developing countries, the anti-cancerous plant-based compounds become highly imperative. Among others, the Asteraceae (Compositae) family's plants are rich in sesquiterpenoid lactones, a subclass of terpenoids with wide structural diversity, and offer unique anti-cancerous effects. These plants are utilized in folk medicine against numerous diseases worldwide. However, these plants are now a part of the modern medical system, with their sesquiterpenoid lactones researched extensively to find more effective and efficient cancer drug regimens. Given the evolving importance of sesquiterpenoid lactones for cancer research, this review comprehensively covers different domains in a spectrum of sesquiterpenoid lactones viz (i) Guaianolides (ii) Pseudoguaianolide (iii) Eudesmanolide (iv) Melampodinin A and (v) Germacrene, from important plants such as Cynara scolymus (globe artichoke), Arnica montana (wolf weeds), Spilanthes acmella, Taraxacum officinale, Melampodium, Solidago spp. The review, therefore, envisages being a helpful resource for the growth of plant-based anti-cancerous drug development.