Varibility of Flavonoid Content, Reducing and Antioxidant Activity in Althaea officinalis L. Hairy Roots

Abstract

Althaea officinalis L. is widely used as a medicinal plant due to its antiseptic, antioxidant, antimicrobial, anti-inflammatory, and gastroprotective properties. A. officinalis roots contain a great number of secondary metabolites including flavonoids which exert antioxidant and chelating abilities. Flavonoids possess protective effects against several chronic diseases, in particular neurodegeneration and cancer; they have also neuroprotective, hepatoprotective, anti-bacterial, anti-inflammatory, anti-viral, and anti-cancer effects. Tissue cultures of different plant species are a promising source of secondary metabolites with pharmacological activities, and hairy roots are one of the types. Hairy roots are known as fast-growing, genetically stable cultures, effective producers of both biomass and specialized plant metabolites including flavonoids. A. officinalis hairy roots and roots of in vitro cultured control (initial) plants were used in this research to study flavonoid content and some biochemical characteristics (antioxidant activity and ability to reduce iron ions Fe³⁺ to Fe²⁺) of their ethanolic extracts. Two groups of hairy root lines were studied. Hairy roots of one group were obtained as the result of transformation with A4 wild Agrobacterium rhizogenes strain while the second group was initiated by transformation with A. rhizogenes strain carrying human interferon-α2b gene under the control of the sugarbeet root-specific Mll promoter. Among the two groups of hairy root lines no significant differences were detected that could suggest the role of additional genes in the antioxidant status of the hairy roots: in both groups, there were lines with low, medium and high values of the studied parameters. The total flavonoid content correlated with DPPH scavenging activity and reducing capacity. The results of study confirm flavonoid participation in antiradical reactions in A. officinalis hairy root cells.