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

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

Publication Date:
08 September 2020 (online)

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