Antibacterial Activity of Chinese Red Propolis against Staphylococcus aureus and MRSA.

Suzhen Qi,Liming Wu,Gomez Escalada Margarita,Xiaofeng Xue,Kai Wang,Wenqin Yuan,Di Wu,Sha Yan,Wenwen Zhang

doi:10.3390/molecules27051693

Abstract

The antibacterial activity of propolis has long been of great interest, and the chemical composition of propolis is directly dependent on its source. We recently obtained a type of propolis from China with a red color. Firstly, the antibacterial properties of this unusual propolis were determined against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). Studies on its composition identified and quantified 14 main polyphenols of Chinese red propolis extracts (RPE); quantification was carried out using liquid chromatography triple quadrupole tandem mass spectrometry (LC-QQQ-MS/MS) and RPE was found to be rich in pinobanksin, pinobanksin-3-acetate, and chrysin. In vitro investigations of its antibacterial activity revealed that its activity against S. aureus and MRSA is due to disruption of the cell wall and cell membrane, which then inhibits bacterial growth. Despite its similar antibacterial activities against S. aureus and MRSA, metabolomic analysis further revealed the effects of RPE on bacteria metabolism were different. The untargeted metabolomic results showed that a total of 7 metabolites in 12 metabolic pathways had significant changes (Fold change > 2, p < 0.05 *) after RPE treatment in S. aureus, while 11 metabolites in 9 metabolic pathways had significant changes (Fold change > 2, p < 0.05 *) after RPE treated on MRSA. Furthermore, RPE downregulated several specific genes related to bacterial biofilm formation, autolysis, cell wall synthesis, and bacterial virulence in MRSA. In conclusion, the data obtained indicate that RPE may be a promising therapeutic agent against S. aureus and MRSA.

Highlights

Propolis is a resinous substance collected by honeybees (Apis mellifera) when they collect natural plant shoots, resinous secretions, pollen, and soil and mix it with their own glandular secretions to repair the hive and protect it from external aggression [1].The chemical composition of propolis is very complex and is directly related to the local plant source of the honeybees [2], mainly including polyphenols, flavonoids, terpenoids, quinones, minerals [3], etc
LC-MS/MS detection conditions for each of the 14 polyphenol standards MS/MS parameters were optimized with multiple reaction monitoring (MRM)
The results indicated that 12 pathways were enriched after treatment with red propolis extracts (RPE) treated on S. aureus

Summary

Introduction

Propolis is a resinous substance collected by honeybees (Apis mellifera) when they collect natural plant shoots, resinous secretions, pollen, and soil and mix it with their own glandular secretions to repair the hive and protect it from external aggression [1]. The chemical composition of propolis is very complex and is directly related to the local plant source of the honeybees [2], mainly including polyphenols, flavonoids, terpenoids, quinones, minerals [3], etc. Depending on its botanical origin and color, propolis is classified as green, red, or brown in Brazil [4]. Brazil is the main botanical source of green propolis [5]; red propolis is found in bee hives along the coast and mangroves of northeastern Brazil, and its botanical source is Dalbergia ecastophyllum (L.) Taub [6]. Most Chinese propolis is greenish-black or dark in color [7] and is typical of poplar propolis, whose main botanical source is poplar (Populus sp.) [8].

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