Abstract:
Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy with poor prognosis and
limited treatment options. Sea buckthorn (Hippophae rhamnoides) berries, dog rose (Rosa canina)
rosehips, and garden sage (Salvia officinalis) and oregano (Origanum vulgare) aerial parts are widely used
in traditional medicine and exhibit antitumor effects in preclinical models. However, these plants remain
scarcely tested for antileukemic activity. Here, we show that their water-ethanol leaf extracts reduced the
growth and viability of AML cells and, at non-cytotoxic doses, potentiated cell differentiation induced by
a low concentration of 1a,25-dihydroxyvitamin D3, the hormonal form of vitamin D, in a cell typedependent
manner. The latter effect was accompanied by upregulation of the vitamin D receptor protein
components and its transcriptional activity. Furthermore, at minimally effective doses the extracts
cooperated with one another to produce marked cytostatic effects associated with a partial S-phase
arrest and a modest induction of apoptosis. In contrast, these combinations only slightly affected the
growth and viability of proliferating normal human peripheral blood mononuclear cells. In addition, the
extracts strongly inhibited microsomal lipid peroxidation and protected normal erythrocytes against
hypoosmotic shock. Our results suggest that further exploration of the enhanced antileukemic effects of
the combinations tested here may lead to the development of alternative therapeutic and preventive
approaches against AML.
