Planta Med 2020; 86(17): 1269-1277
DOI: 10.1055/a-1229-4565
Natural Product Chemistry and Analytical Studies
Original Papers

Phytochemical Analysis, In Vitro Anti-Inflammatory and Antimicrobial Activity of Piliostigma thonningii Leaf Extracts from Benin

Peter Marquardt
1   Department of Pharmaceutical Biology, Institute of Pharmacy, Faculty of Medicine, Leipzig University, Leipzig, Germany
,
Cica Vissiennon
2   Institute for Medical Physics and Biophysics, Faculty of Medicine, Leipzig University, Leipzig, Germany
,
Andreas Schubert
3   Antimicrobial Agents Unit, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany
,
Claudia Birkemeyer
4   Institute of Analytical Chemistry, Leipzig University, Leipzig, Germany
,
Virgile Ahyi
5   IRGIB Africa University, Inter-Regional University of Industrial Engineering, Biotechnologies and Applied Sciences, Cotonou, Benin
,
Karin Fester
1   Department of Pharmaceutical Biology, Institute of Pharmacy, Faculty of Medicine, Leipzig University, Leipzig, Germany
6   Faculty of Natural and Environmental Sciences, Zittau/Görlitz University of Applied Sciences, Zittau, Germany
› Author Affiliations
Zoom Image

Abstract

The leaves of Piliostigma thonningii are used in traditional medicine in Benin to treat inflammatory skin diseases and infections. So far, pharmacological studies of the anti-inflammatory and anti-infective effects of phytochemically characterized extracts of P. thonningii have been very limited. Therefore, we investigated the in vitro anti-inflammatory and antimicrobial effect of P. thonningii leaf extracts and analyzed the phytochemical composition of extracts of different polarities (water, 50% ethanol, and n-hexane). Quercetin-3-O-rhamnoside was confirmed as the main flavonoid in the polar extracts. GC-MS analysis identified 20 constituents of the aqueous extract and 28 lipophilic compounds of the n-hexane extract by comparison with authentic standards and spectral library data. The aqueous P. thonningii leaf extract inhibited the IL-8 and IL-6 secretion in TNF-α-stimulated HaCaT cells in a concentration-dependent manner with IC50 values of 74 µg/mL for IL-8 and 89 µg/mL for IL-6. However, an inhibitory effect of the identified quercetin-3-O-rhamnoside and its aglycone, quercetin, on the release of IL-8 and IL-6 could not be demonstrated. In the antimicrobial screening, inhibition zones for a 50% EtOH leaf extract of P. thonningii were found for Staphylococcus epidermidis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. For none of the microbial strains, however, the MIC was below 500 µg/mL, so that the antibacterial activity must be classified as low. As a result, our investigations primarily support the ethnomedical use of P. thonningii leaf extracts in topical inflammatory conditions. Further studies are required to identify the compounds responsible for the in vitro anti-inflammatory effects.

Supporting Information



Publication History

Received: 08 March 2020

Accepted after revision: 20 July 2020

Article published online:
08 September 2020

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany