The search for novel anticancer drugs continues. Agents that can eliminate the cancerous cells but do not affect the normal cells may have a therapeutic advantage for the elimination of cancer cells. This work includes a preliminary study of the effect of two crude extracts of Greek or Mediterranean sage (Salvia triloba L.f.) on three malignant human cell lines, one malignant murine cell line, two transformed cell lines and two normal cell lines.
A boiling-water extract and a methanolic extract were prepared from dried leaves of S. triloba. Yields of extraction were 9.8 and 22.4%, respectively.
Tested cell lines included human larynx epidermoid carcinoma (HEp-2), human rhabdomyosarcoma (RD), human glioblastoma multiforme (AMGM5), murine mammary adenocarcinoma (AMN3), African green monkey kidney cells (Vero), murine L cells (fibroblasts) expressing the human poliovirus receptor (L20B), normal mouse embryo fibroblasts (MEF8) and normal rat embryo fibroblasts (REF3).
Both extracts exhibited time-dependent, cell specific inhibitory effects on HEp-2, RD and AMN3 malignant cell lines. AMGM5 cell line was resistant to the effects of either extract as inhibition could only be recorded after 72 hrs of exposure to the highest concentrations, 625 and 1250 µg/ml. In addition, growth of HEp-2, RD and AMN3 cells under treatment with either extract was biphasic during the first 48 hrs of treatment as cells were stimulated at lower concentrations and inhibited at higher concentrations.
The aqueous and methanolic extracts showed less inhibitory effects on transformed cells, Vero and L20B, compared with their effects on malignant cell lines including the most resistant cells, AMGM5, indicative of the safety both extracts towards kidney cells and non-malignant cells, respectively.
Both extracts produced little inhibitory effects on normal MEF8 and REF3 cell lines, an indication of the specificity of both extracts against malignant cells.
Finally, the aqueous and methanolic extracts of S. triloba showed immunomodulatory effects when tested on human peripheral blood lymphocytes.