In vitro anti-proliferative activity of clove extract on human gastric carcinoma

Background and objectives: Cancer cell resistance to common chemotherapy agents is on rise. Plants are considered valuable sources of herbal drugs for cancer therapy. The present study was conducted to investigate the in vitro antioxidant, anti-proliferative, and apoptosis-inducing properties of clove (Syzygium aromaticum L.) extract in human gastric carcinoma (AGS). Methods: Crude ethanol extract of S. aromaticum dried buds was prepared and  in vitro anti-proliferative effects of the extract on AGS and normal Human dermal fibroblasts (HDF) cell lines were studied by MTT assay. To examine apoptosis induction, AGS cells were incubated with IC50 concentrations of the extract, stained with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC), and analyzed by flow cytometry. Antioxidant activity and total phenolics and flavonoids contents were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Folin-Ciocalteu method, and aluminum chloride colorimetric method, respectively. Results: The IC50 of DPPH and total phenolics and flavonoids contents of the extract were 10.05±1.93 μg/mL, 225.6±40 mg GAE/g, and 29.30±2.35 mgRUT/g, respectively. The IC50 of the extract against HDFs was 649 µg/mL, higher than AGS cells, which was 118.7 g/mL at 48 h after treatment. Flow cytometric analysis showed that the extract induced cell apoptosis. Conclusions: Crude ethanol S. aromaticum extract had high total phenolics content, and suppressed the proliferation of human gastric cancer cells, likely due to apoptosis induction. Further studies should be conducted to determine the mechanisms of its anticancer effects.