Chemical composition, in vitro assessment of antioxidant properties and cytotoxicity activity of ethanolic and aqueous extracts of Ajuga orientalis L. (Lamiaceae)

Abstract

Context: Ajuga orientalis L. (Lamiaceae) is an aromatic herb used in traditional medicine in Jordan and neighboring countries. Aims: To evaluate the cytotoxic potential of ethanolic and aqueous extracts from the aerial parts of A. orientalis against three cell lines MCF-7, Caco-2, and HDFa. In addition to assessing the total phenolic and flavonoid contents, antioxidant activity. Further to analyze the phytochemical constituents. Methods: The phytochemical analysis was performed using gas chromatography/mass spectrometry. The total phenolic (TPC) and flavonoid (TFC) contents were assessed using colorimetric methods. The antioxidant properties of both extracts were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power ability. Cytotoxicity was investigated using methyl thiazol tetrazolium (MTT) assay. Results: The most abundant compounds in the extract were 9-octadecenoic acid, methyl ester, (E)- (27.2%), hexadecanoic acid, methyl ester (12.8%), and methyl stearate (9.6%). The ethanolic extract demonstrated higher TPC and TFC than the aqueous extract. Also, the ethanolic extract showed higher antioxidant activity than aqueous extract using DPPH and the reducing power ability. Furthermore, the aqueous extract of A. orientalis has a potent cytotoxic effect against the Caco-2 cell line (IC50 = 2.059 ± 0.10 μg/mL). In contrast, the ethanolic extract demonstrated a cytotoxic effect against the MCF-7 cell line (IC50 = 59.32 ± 0.04 μg/mL). Both extracts did not exhibit a toxic effect against normal dermal fibroblast cell line (HDFa). Compared to non-cancerous cells, the ethanolic extract of A. orientalis demonstrated high selectivity against MCF-7 cells and limited selectivity against Caco-2 cells. In comparison, the aqueous extract was highly selective against both cancerous cells. Conclusions: A. orientalis demonstrated antioxidant properties and significant antiproliferative potential against breast and colon cancer. Therefore, additional investigations are needed to study the mechanism of the cytotoxicity for this plant.