Introduction:
One of the plants that has long been considered by humans is Equisetum arvense L. Equisetum arvense L is now recommended for external use to heal wounds and for internal use to relieve urinary tract and prostate disorders. In the current study, the antioxidant, cytotoxicity, and anti-human lung cancer properties of Equisetum arvense were investigated in in vitro conditions.

Material and methods:
Total phenolic content, total flavonoid content, radical scavenging activity, and ferrous ion chelating were assessed to evaluate the antioxidant activity. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was chosen to investigate anticancer activity of the plant extract.

Results:
The plant extract scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) as a free radical with an IC50 of 12.3 ±0.7 µg/ml better than positive controls. The plant was also rich in phenolic compounds with an amount of 396.2 ±3.2 mg GAE/g for total phenolic content. In the MTT assay, human colorectal carcinoma (HCT-8 [HRT-18], Ramos.2G6.4C10, HT-29, and HCT 116) and normal cell lines (HUVEC) were used to study the cytotoxicity and anticancer potential of Equisetum arvense L against human colorectal cancer.

Conclusions:
The cell viability of Equisetum arvense L was very low against human colorectal carcinoma cell lines without any cytotoxicity towards the normal (HUVEC) cell line. The best anti-human colorectal carcinoma properties of Equisetum arvense L against the above cell lines were observed in the case of the HT 29 cell line.