Endogenous production of specific flavonoids and verbascoside in agar and agitated microshoot cultures of Scutellaria lateriflora L. and biotransformation potential

Abstract

Methanolic extracts of microshoots from agar cultures and of microshoots and media from agitated cultures of Scutellaria lateriflora grown on identical five variants of the Murashige-Skoog (MS) and Linsmaier-Skoog (LS) media with different 6-benzyladenine (BA) and 1-naphthaleneacetic acid (NAA) concentrations (0.5-3.0 mg/l) were analyzed for flavonoids (27 compounds), phenylpropanoid glycosides (2 compounds) and phenolic acids (19 compounds) using the DAD-HPLC method. The amounts of individual compounds and total amounts of the above mentioned metabolite groups in the biomass from both types of the tested cultures were dependent on the composition of basal media and concentrations of BA and NAA in the media variants. In media extracts, no metabolites were confirmed. Higher total amounts of flavonoids were obtained in agar cultures (max. 722.04 and 2989.55 mg/100 g DW on MS and LS media variants, respectively), which were 1.1 and 1.7 times higher, respectively, than in agitated cultures. In both types of cultures, glycosidic conjugates: baicalin and wogonoside were the main flavonoids (max. amounts: 513.93 and 1838.18 mg/100 g DW, and 305.92 and 700.85 mg/100 g DW in agar cultures on MS and LS variants, respectively). High amounts of verbascoside in agar cultures were also confirmed (max. 384.99 and 543.17 mg/100 g DW on MS and LS media variants, respectively). The cells grown in agitated cultures converted exogenous precursors, i.e. hydroquinone (HQ) and 4-hydroxybenzoic acid (4-HBAc) into arbutin (β-d-glucoside of HQ). The highest amount of this product reached 5.63 and 1.45 g/100 g DW after the addition of these two precursors, respectively. This is the first large-scale report documenting in vitro biosynthetic potential of Scutellaria lateriflora microshoots cultivated in two tested culture. Key message After testing of 10 media variants in two types of in vitro cultures high amounts of flavonoids (app. 3 g%) and verbascoside (0.54 g%) were obtained. Additionally, 5.6 g% of arbutin as hydroquinone β-d-glucosylation product was confirmed. Keywords American skullcap • In vitro culture • Scutellaria specific flavonoids • Verbascoside • Arbutin • HPLC analysis Abbreviations BA 6-Benzyladenine 3,4-DAc 3,4-Dihydroxyphenylacetic acid DAD-HPLC Diode-array detector-high performance liquid chromatography DW Dry weight FM Fresh biomass 4-HBAc 4-Hydroxybenzoic acid HQ Hydroquinone LS Linsmaier and Skoog MS Murashige and Skoog NAA 1-Naphthaleneacetic acid Communicated by Nokwanda Pearl Makunga.

Antioxidant Potential and Enhancement of Bioactive Metabolite Production in In Vitro Cultures of Scutellaria lateriflora L. by Biotechnological Methods

“…Based on the results obtained, it is evident that extract from S. lateriflora in vitro microshoot cultures acts as a weak primary antioxidant and possesses good secondary antioxidant properties. The extract contains high amounts of the flavonoids baicalin, baicalein and wogonoside, and of the phenylpropanoid glycoside, verbascoside [ 20 ]. The secondary antioxidant activity could depend mainly on high baicalein and verbascoside contents, which are considered strong iron chelators [ 24 , 25 ].…”

“…The revealed antioxidant potential of S. lateriflora microshoot extracts and the results obtained after the optimization of agar and agitated cultures [ 20 , 21 , 38 ] encouraged us to assess whether metabolite production and accumulation in biomass could be improved using different biotechnological strategies.…”

“…Compared to agitated cultures, the total content of Scutellaria -specific flavonoids and verbascoside was higher in agar cultures (max. 2986 and 543 mg/100 g dry weight (DW), respectively) [ 20 ]. We also investigated the effect of light conditions (monochromatic red and blue light, white light, UV-irradiation, and darkness) on the accumulation of secondary metabolites in agar cultures, and found that blue light had the most beneficial effect on metabolite accumulation [ 21 ].…”

“…Our previous results from the analysis of the biotransformation process also demonstrated that agitated microshoot cultures had high biosynthetic potential. Using an exogenous substrate (hydroquinone) at a concentration of 288 mg/L, we obtained the maximum content of 5.63 g/100 g DW of arbutin (hydroquinone glucoside) as the result of the β-D-glucosilation process [ 20 ].…”

The effect of feeding culture media with biogenetic precursors on high production of depsides in agitated shoot cultures of black and red aronias

“…On the other hand on LS media variants the presence of the same compounds was confirmed in agar and agitated cultures. The quantities of metabolites were higher in agar cultures (Kawka et al 2019(Kawka et al , 2020.…”