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Aims: The present work aimed to evaluate the anti-amoebic, antibacterial, and anti-inflammatory potential of three natural polyketides from Phomopsis sp. CAM212.

Study Design: Clinical isolates of E.histolytica, E.coli ATCC25922 strain, primary peritoneal mouse macrophages and three polyketides were used.

Places and Duration of Study: Laboratory of Pharmacology and Toxicology, Laboratory of Medical Microbiology, Faculty of Science, University of Yaounde 1 between May and December 2022.

Methodology: During this work, we evaluated the ability of three natural polyketides from Phomopsis sp to inhibit the growth of germs responsible for amoebic and bacillary dysentery. First, the anti-amoebic activity was carried out on clinical isolates of E. histolytica in polyxenic culture. Subsequently, we evaluated the antibacterial potential on a strain of E. coli ATCC25922. Finally, the anti-inflammatory potentials were evaluated on a primary culture of SC activated macrophages through inhibition of nitric oxide (NO) production, activation of phosphatase alcaline (ALP) and inhibition of 5-lipoxygenase (5-LOX).

Results: It emerges from this work that among compounds, phomopsinin B, presented the highest anti-amoebic potential (84.4 % inhibition after 72h) and the highest antibacterial potential (MIC=12.5µg/mL and MBC/MIC=2). Phomopsini A and phomopsini A acetate showed moderate anti amoebic and antibacterial potentials. However, all these activities remain lower than that of metronidazole and ciprofloxacin (90% of amoebic inhibition after 72h; MIC=0.72µg/mL and MBC/MIC=4). Subsequently, all tested compounds were nontoxic on primary macrophages. Phomopsinin B exhibited a great anti-inflammatory potential through the inhibition of NO production (IC50=1.72±0.91µg/mL); inihibition of 5-LOX activity (IC50=36.97±7.12µg/mL) and activation of ALP activity (IC50=0.13±0.01µg/mL) as compared to Baicalin the standard. The anti-inflammatory potential of phomopsinin A and phomopsinin A acetate were lower compared to baicalin.

Conclusion: Ultimately, among compounds tested, phomopsinin B exhibited the best anti-amoebic, antibacterial and ant-inflammatory potential similar to the respective standards within the limits of the tests carried out.