In vitro antioxidant activity of flower, seed and leaves of Alcea hyrcana Grossh.

Objectives: Alcea hyrcana Grossh (A. hyrcana Grossh) (malvacea), is native to northern of Iran. Many of the plants belonging to the genus Alcea are known to possess ethnomedical and biological properties. In this study, antioxidant activities of methanolic extracts of flower, seed and leaves of Alcea hyrcana Grossh were evaluated by various antioxidant assays. Material and Methods: 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation test were used to evaluate antioxidant activities. The total amount of phenolic compounds was determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. Total phenolic and flavonoid contents also have been determined. Results: All extracts showed good antioxidant activities. The A. hyrcana Grossh leaves extract exhibited strong ferrous chelating activity with IC₅₀ = 0.11 ± 0.01 mg ml^-1, nitric oxide radical scavenging with IC₅₀ = 0.45 ± 0.01 mg ml^-1 and better reducing power activity than other extracts. The seeds extract showed high scavenging activity against free radicals, including both the hydrogen peroxide and DPPH radicals. Only leaves extract had good activity in linoleic acid model. Seeds extract had significant higher total phenol (68.9 ± 3.7 mg gallic acid equivalent/g of extract powder) and leaves had higher flavonoids contents (28.3 ± 2.6 mg quercetin equivalent/g of extract powder) than other parts. Conclusions: The leaves, seed and flower extracts of A. hyrcana Grossh exhibited good but different levels of antioxidant activity in all the models studied. The extracts had good iron chelation, H₂O₂ and nitric oxide scavenging activities. Antioxidant activities may be attributed, at least in part, to the presence of phenols and flavonoids. [ABSTRACT FROM AUTHOR]