Phytochemical Analysis and In Vitro Cytotoxic Activity against Colorectal Adenocarcinoma Cells of Hippophae rhamnodies L., Cymbopogon citratus (D.C.) Stapf, and Ocimum basilicum L. Essential Oils

Colorectal carcinoma (CRC) is one of the most frequently diagnosed cancer types with current deficient and aggressive treatment options, but various studied alternative therapies are able to efficiently contribute to its management. Essential oils (EOs) contain valuable compounds, with antibacterial, anti-inflammatory, and anticancer properties, which might serve as effective solutions in CRC prophylaxis or treatment. The aim of the present work was to evaluate the phytochemical composition and in vitro biological activity of essential oils derived from Hippophae rhamnoides (Hr_EO), Cymbopogon citratus (Cc_EO), and Ocimum basilicum (Ob_EO) species on HT-29 and Caco-2 human colorectal adenocarcinoma cell lines. The main compounds identified by GC-MS analysis were estragole (Hr_EO, Ob_EO), alpha- and beta-citral (Cc_EO). All tested EOs exerted a dose-dependent cytotoxicity on both cell lines by reducing the cell viability, especially in the case of Cc_EO, where at 75 µg/mL the viability percentages reached the values of 62.69% (Caco-2) and 64.09% (HT-29), respectively. The nuclear morphology evaluation highlighted significant dysmorphologies on both lines after their treatment with EOs at 75 µg/mL.