Natural product derived phytochemicals as modulators of cancer stemness and drug resistance.

Natural secondary metabolites, especially Essential oils (EOs), are compounds made by aromatic plants. These oils contain a variety of bioactive molecules with distinct effects on the body and are known for their strong, low toxicity and wide-ranging biological activities. These herbal concentrates have antimicrobial, antioxidant, anti-inflammatory, antiproliferative, and anticancer effects, mainly due to their terpene and phenolic compounds. Research shows that volatile oils can target cancer cells and may boost the effectiveness of conventional chemotherapy. Using plant based compounds to target drug resistant cancer stem cells (CSCs) is a newer strategy in cancer prevention and treatment. Even though we know more about how cells turn cancerous, cancer is still a major global health issue. This is mostly because cancer cells can resist many different standard drugs. Tumours turn resistant due to their ability to adapt and their frequent exposure to anti-cancer drugs. This review summarises current preclinical evidence on the potential of EOs to modulate CSC associated signalling pathways and overcome CSC mediated drug resistance. It highlights the multitarget mechanisms by which EOs influence CSC maintenance, self-renewal and therapeutic resistance, whilst critically acknowledging that the available evidence is largely limited to preclinical studies. It also emphasises the need for standardised EO characterisation, detailed mechanistic investigations, advanced drug delivery systems to improve bioavailability and pharmacokinetics and well-designed clinical studies to establish the safety, efficacy and therapeutic value of EOs in precision oncology.