Bacterial infections are currently a threat in Sub-Saharan Africa. Piper guineense is a commonly used spice and medicinal plant in West Africa. Fruits and leaves from this plant are used to treat infectious diseases [1]. P guineense extracts and its bioactive alkaloids, such as piperine are currently paving way as therapeutic agents in antimicrobial drug discovery, and are potential antibacterial agents for multiple human infectious diseases [2,3]. Due to increasing microbial resistance to the current antibiotics, there is a need to search for new natural antibacterial agents from P. guineense.
In our study, sequential extraction was conducted on the extracts of P. guineense, and twelve crude extracts and fractions of various polarities (hexane, chloroform, ethanol, methanol, cold water macerations and hot water decoctions) were screened for antibacterial activity against three Gram-positive and five Gram-negative bacteria. Piperine and piperlongumine were screened as representatives of the piperamide alkaloids in P. guineense. HPLC-DAD and UHPLC/Q-TOF MS analysis were conducted to characterize and identify the bioactive alkaloids present in the extracts.
Our result indicates that the extracts contain piperamide alkaloids. The extracts and pure compounds were active against P. aeruginosa, E. aerogenes, S. aureus, E. coli, S. enterica, P. mirabilis and B. cereus with MIC values ranging from 39 µg/mL- 1250 µg/mL. The piperine alkaloid-rich hexane leaf extract gave the lowest MIC of 19 µg/mL against Sarcina sp. The water extracts were not active against most of the bacterial strains. The result demonstrates that P. guineense contains antibacterial compounds, which are mostly piperamide alkaloids and which could be relevant for the discovery of new antibiotic scaffolds.
References :
1. Besong, E. E., et al., (2016). Int. J. Pharm. Pharma. Res., 6(1), 368-384.
2. Tekwu, E. M.,et al., (2012). J. Ethnopharmacol., 142(2), 374–382.
3. Chavarria, D., et al., (2016). Expert Opin. Ther. Pat., 26(2), 245-264.