Alkaloids are heterocyclic bases with widespread occurrence in nature. Plants are rich and easily accessible sources of them. Most
isoquinoline alkaloids have cytotoxic activity for different types of
cancer, including
malignant melanoma, the most aggressive type of
skin cancer. The morbidity of
melanoma has increased worldwide every year. For that reason, developing new candidates for anti-
melanoma drugs is highly needed. The aim of this study was to investigate the
alkaloid compositions of
plant extracts obtained from Macleaya cordata root, stem and leaves, Pseudofumaria lutea root and herb, Lamprocapnos spectabilis root and herb, Fumaria officinalis whole plant, Thalictrum foetidum root and herb, and Meconopsis cambrica root and herb by HPLC-DAD and LC-MS/MS. For determination of cytotoxic properties, human
malignant melanoma cell line A375, human Caucasian
malignant melanoma cell line G-361, and human
malignant melanoma cell line SK-MEL-3 were exposed in vitro to the tested
plant extracts. Based on the in vitro experiments, Lamprocapnos spectabilis herb extract was selected for further, in vivo research. The toxicity of the extract obtained from Lamprocapnos spectabilis herb was tested using an animal zebrafish model in the fish embryo toxicity test (FET) for determination of the LC50 value and non-toxic doses. Determination of the influence of the investigated extract on the number of
cancer cells in a living organism was performed using a zebrafish xenograft model. Determination of the contents of selected
alkaloids in different
plant extracts was performed using high performance liquid chromatography (HPLC) in a reverse-phase system (RP) on a Polar RP column with a mobile phase containing
acetonitrile, water and
ionic liquid. The presence of these
alkaloids in
plant extracts was confirmed by LC-MS/MS. Preliminary cytotoxic activity of all prepared
plant extracts and selected
alkaloid standards was examined using human
skin cancer cell lines A375, G-361, and SK-MEL-3. The cytotoxicity of the investigated extract was determined in vitro by cell viability assays (MTT). For in vivo determination of investigated extract cytotoxicity, a Danio rerio larvae xenograft model was used. All investigated
plant extracts in in vitro experiments exhibited high cytotoxic activity against the tested
cancer cell lines. The results obtained using the Danio rerio larvae xenograft model confirmed the anticancer activity of the extract obtained from Lamprocapnos spectabilis herb. The conducted research provides a basis for future investigations of these
plant extracts for potential use in the treatment of
malignant melanoma.