Anti-Tumorigenic Effects of Sea Buckthorn Root Extracts on Head and Neck Cancer Cells—A Systematic Analysis

Chemotherapy is a common treatment method for cancer that is often associated with strong side effects. To reduce these, research on extracts from medicinal plants and their active ingredients has been conducted. Although sea buckthorn (Hippophae rhamnoides) is a well-established medicinal plant, little is known about the chemical components responsible for its putative anticancer activity. This study focuses on both chemical and medical analyses of methanolic sea buckthorn root extracts. Cell viability measurements were performed on head and neck cancer cell lines, as well as non-tumorigenic control cells. Microwave and classical extractions under reflux were used to prepare the methanolic extracts. LC/MS and NMR were used to determine the structures of the molecules contained within these extracts. The aqueous phase of one sea buckthorn root extract reduced the viability of cancer cells, whereas the viability of non-tumorigenic control cells remained unaltered. The cell cycle phases of cancer cells treated with the extract shifted in comparison to control treatment. After 24 h, the number of cells in proliferative phases had increased. Two fractions of the extract that evoked alterations were identified. After a 48 h treatment, one of the fractions showed a higher number of apoptotic cells than the control. LC/MS and NMR analyses were conducted to attempt to identify the active compounds. We propose that the bioactivity of this extract is caused by a mixture of 2′-hydroxyflavone isomers.