Production of anti-inflammatory compounds in Sphaeralcea angustifolia cell suspension cultivated in stirred tank bioreactor

Abstract

Sphaeralcea angustifolia is a plant used for the treatment of inflammatory processes. Scopoletin, tomentin, and sphaeralcic acid were identified as the compounds with anti-inflammatory and immunomodulatory effects. Successful establishment of the cell culture in Erlenmeyer flasks has been reported previously. The aim of this study was to evaluate the ability of cells in suspension from S. angustifolia grown in a stirred tank bioreactor and demonstrate their capacity to produce bioactive compounds. Cells in suspension grown at 200 rpm reached a maximal cell biomass in dry weight at 19.11 g/L and produced 3.47 mg/g of sphaeralcic acid. The mixture of scopoletin and tomentin was only detected at the beginning of the culture (12.13 μg/g). Considering that the profile of dissolved oxygen during the cultures was lesser than 15%, it is possible that the low growth at 100 rpm could be due to oxygen limitations or to cell sedimentation. At 400 rpm, a negative effect on cell viability could be caused by the increase in the hydrodynamic stress, including the impeller tip, average shear rate, and Reynolds number. The sphaeralcic acid content in the cell suspension of S. angustifolia obtained in the bioreactor was two orders of magnitude greater than that reported for the culture grown in Erlenmeyer flasks.

Keywords: Sphaeralcea angustifolia; coumarins; scopoletin; sphaeralcic acid; tomentin.

Conflict of interest statement

The authors have declared no conflict of interest.

© 2018 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Figures

Figure 1

Anti‐inflammatory compounds, such as tomentin, scopoletin, and sphaeralcic acid, produced in suspension cell cultures of Sphaeralcea angustifolia

Figure 2

Growth curves in batch of cell suspension cultures from Sphaeralcea angustifolia developed in different conditions of agitation (100, 200, and 400 rpm) with 0.1 vvm in stirred tank bioreactor. Mean ± standard error of the mean

Figure 3

Chromatograms and absorption spectrum of tomentin (λ = 343 nm, rt = 10.96 min), scopoletin (λ = 343 nm, rt = 11.5 min), sphaeralcic acid (λ = 357 nm, rt = 23.3) identified in the dichloromethane:methanol extracts from biomass of Sphaeralcea angustifolia cell suspension at day 9 in culture, as a mixture of tomentin and scopoletin (λ = 343 nm, rt = 10.99 min) and sphaeralcic acid (λ = 357 nm, rt = 23.3)

Figure 4

Accumulation (A) and excretion (B) of sphaeralcic acid in cultures of S. angustifolia suspension cells grown under different agitation conditions (100, 200, and 400 rpm) with 0.1 vvm in stirred tank bioreactor. Mean ± standard error of the mean

Figure 5

Dissolved oxygen (DO) and volumetric oxygen‐transfer coefficient (kLa), during batch cell suspension cultures of Sphaeralcea angustifolia developed in different conditions of agitation (100, 200, and 400 rpm) with 0.1 vvm in stirred tank bioreactor