Asteraceae (Achillea millefolium and Calendula officinalis) and Lamiaceae (Melissa officinalis and Origanum majorana) extracts were obtained by applying two sequential extraction processes: supercritical fluid extraction with carbon dioxide, followed by ultrasonic assisted extraction using green solvents (ethanol and ethanol:water 50:50). The extracts were analyzed in terms of the total content of phenolic compounds and the content of flavonoids; the volatile oil composition of supercritical extracts was analyzed by gas chromatography and the antioxidant capacity and cell toxicity was determined. Lamiaceae plant extracts presented higher content of phenolics (and flavonoids) than Asteraceae extracts. Regardless of the species studied, the supercritical extracts presented the lowest antioxidant activity and the ethanol:water extracts offered the largest, following the order Origanum majorana > Melissa officinalis ≈ Achillea millefolium > Calendula officinalis. However, concerning the effect on cell toxicity, Asteraceae (especially Achillea millefolium) supercritical extracts were significantly more efficient despite being the less active as an antioxidant agent. These results indicate that the effect on cell viability is not related to the antioxidant activity of the extracts.

Cancer is among the leading causes of morbidity and mortality worldwide. Many of the chemotherapeutic agents used in cancer treatment exhibit cell toxicity and display teratogenic effect on nontumor cells. Therefore, the search for alternative compounds which are effective against tumor cells but reduce toxicity against nontumor ones is of great importance in the progress or development of cancer treatments. In this sense, scientific knowledge about relevant aspects of nutrition intimately involved in the development and progression of cancer progresses rapidly. Phytochemicals, considered as bioactive ingredients present in plant products, have shown promising effects as potential therapeutic/preventive agents on cancer in several in vitro and in vivo assays. However, despite their bioactive properties, phytochemicals are still not commonly used in clinical practice due to several reasons, mainly attributed to their poor bioavailability. In this sense, new formulation strategies are proposed as carriers to improve their bioefficacy, highlighting the use of lipid-based delivery systems. Here, we review the potential antitumoral activity of the bioactive compounds derived from plants and the current studies carried out in animal and human models. Furthermore, their association with lipids as a formulation strategy to enhance their efficacy in vivo is also reported. The development of high effective bioactive supplements for cancer treatment based on the improvement of their bioavailability goes through this association.

BackgroundPancreatic cancer is one of the most aggressive and mortal cancers. Although several drugs have been proposed for its treatment, it remains resistant and new alternatives are needed. In this context, plants and their derivatives constitute a relevant source of bioactive components which might efficiently inhibit tumor cell progression.MethodsIn this study, we have analyzed the potential anti-carcinogenic effect of different Asteraceae (Achillea millefolium and Calendula officinalis) and Lamiaceae (Melissa officinalis and Origanum majorana) plant extracts obtained by different green technologies (Supercritical CO2 Extraction –SFE- and Ultrasonic Assisted Extraction –UAE-) to identify efficient plant extracts against human pancreatic cancer cells that could constitute the basis of novel treatment approaches.ResultsAsteraceae extracts showed better results as antitumoral agents than Lamiaceae by inducing cytotoxicity and inhibiting cell transformation, and SFE extracts were most efficient than UAE extracts. In addition, SFE derived plant extracts from Achillea millefolium and Calendula officinalis displayed synergism with the chemotherapeutic 5-Fluororacil.ConclusionThese results show how Yarrow and Marigold SFE-derived extracts can inhibit pancreatic cancer cell growth, and could be proposed for a comprehensive study to determine the molecular mechanisms involved in their bioactivity with the final aim to propose them as potential adjuvants in pancreatic cancer therapy.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2322-6) contains supplementary material, which is available to authorized users.