total phenolics and flavonoids contents of aqueous extract of stinging nettle and in vitro antiproliferative effect on hela and bt- 474 cell lines

phenolic compounds including flavonoids and phenolic acids are plants secondary metabolites. due to their ability to act as antioxidant agents, there is a growing interest to use those components in traditional medicine for cancer prevention or treatment. the aim of this study was to measure the amounts of total phenolics and flavonoids as well as anti-proliferative effect of aqueous extract of stinging nettle on bt-474 and hela cell lines. the amounts of phenolics content and total flavonoids were determined by folin ciocalteu and aluminium chloride methods, respectively. the free radical scavenging activity was measured by using diphenyl - picrylhydrazyl (dpph). the reducing power of the extract was measured in the presence of potassium hexacyanoferrate and its antiproliferative activity was assessed on bt-474 and hela cell lines using mtt assay. total phenolic content was 322.941± 11.811 mg gallic acid/g extract. total flavonoid content was 133.916±12.006 mg catechin/g. the ic50 of dpph radical was 1.2 mg/ ml and the reducing power was 218.9± 15.582 μg ascorbic acid/ g. cell viability of bt-474 cells decreased to less than half of the control (no added extract) at the presence of 3 mg/ ml extract while no significant changes were detected for hela cells at similar conditions. there was no significant difference in the percentage of surviving cells between consecutive days (day 1, 2 and 3) for both bt-474 and hela cells (p>0.05). although the relatively high amount of phenolic and flavonoid contents of the aqueous extract make this plant a promising candidate for diseases treatment however, there is not a direct relationship between the amounts of these antioxidant components and the efficiency in in vitro cancer treatment.