Exploring the toxicity of extracts, fractions, and their bioactive components from raw and roasted sea buckthorn seeds on selected human cells.

INTRODUCTION: With cancer being one of the leading causes of death worldwide, research into new chemical compounds that could be used in its prevention and treatment is of utmost importance. Plants are rich in diverse active compounds and can be a source of effective anticancer agents. Sea buckthorn (Hippophae rhamnoides L.) is a promising plant that shows anti-proliferative potential; however, its molecular mechanisms remain unclear. Isorhamnetin glycosides (including isorhamnetin 3-O-β-glucoside-7-O-α-rhamnoside) are major components of sea buckthorn seeds; multiple studies showed that isorhamnetin possesses anticancer properties, however, the activity of its many derivatives remains unclear. On the other hand, sea buckthorn seeds also contain serotonin (5-HT), which might stimulate the growth of several types of cancer. METHODS: Our present study assessed the in vitro cytotoxicity and genotoxicity of two extracts (from raw and roasted seeds), seven fractions (three fractions (a, b, and c) from raw sea buckthorn seeds and four fractions (d, e, f, and g) from roasted sea buckthorn seeds), and two chemical compounds (isorhamnetin 3-O-β-glucoside-7-O-α-rhamnoside, and serotonin) toward PBMC (peripheral blood mononuclear cells), HL-60 (human acute promyelocytic leukemia), and A549 (human lung adenocarcinoma) cells. Their pro-apoptotic potential, toxicity toward blood platelets, and effect on ROS generation were assessed as well. RESULTS AND DISCUSSION: Fraction b (containing mostly flavonol glycosides) had the most promising anticancer activity out of all the tested samples - at the concentration of 50 μg/mL, it decreased the viability of HL-60 cells through the induction of apoptosis. At the same time, it was safe for PBMC and blood platelets. On the other hand, fraction c (that contained serotonin, B-type proanthocyanidins, and other compounds) stimulated A549 cells and, therefore, should be treated with caution. Fractions from roasted seeds were overall weaker than fractions from raw seeds, suggesting that thermal processing might have reduced their activity. In conclusion, fraction b from raw sea buckthorn seeds showed anticancer potential against HL-60 cells, but it should be studied further to determine the activity of individual compounds contained within, their mechanisms of action, and efficiency in vivo.