Isolation, identification of endophytic fungi extracts from Codiaeum variegatum and assessment of their anti-amoebic and anti-inflammatory potential

Intestinal amoebiasis (IA) remains a global public health concern. It is often confused with an inflammatory bowel disease, and is caused by Entamoeba histolytica. Although it is more widespread in tropical countries, IA is increasingly becoming a subject of concern in so-called developed countries. The limits of conventional therapy and the concern to promote phytotherapy in a sustainable and ecological manner inspired this work, during which the anti-amoebic and anti-inflammatory potential of endophyte fungi extracts isolated from Codiaeum variegatum were evaluated. C. variegatum leaves and bark was harvested at the University of Yaounde 1. Those two fragments undergo surface decontamination then were placed in petri dishes containing PDA (Potato Agar Dextrose) supplemented with amoxicillin. The cultures obtained were then subcultured in SDA (Sabouraud Dextrose Agar) and CZA (CZapek dextrose Agar) media. The resulting growth was observed using an optical microscope with an x40 objective for grouping on the basis of macroscopic and microscopic characteristics. Screening of extracts of these fungi by the Trypan blue counting method on clinical isolates of E. histolytica, made it possible to retain 4 extracts (6, 8, 14, 18) of fungi with anti-amoebic activity. Subsequently, the anti-inflammatory potential of these extracts was evaluated on a primary culture of macrophages activated by Saccharomyces cerevisiae through the inhibition of nitric oxide (NO) production, NADPH oxidase activity, and activation of alkaline phosphatase (ALP). From that culture, 28 endophytic fungi were isolated, 13 belonging to 7 genus (Absidia sp, Alternaria sp, Aspergillus sp, Trametes sp, Trichoderma sp, Fusarium sp and Geotrichum sp). Anti-amoebic tests showed that extract 14 was the most active with an inhibitory concentration 50 (IC50) of 289.87±18.57; 207.73±22.36 and 87.79±12.51µg/mL respectively after 24, 48 and 72 hours of incubation. Chemical screening of the extracts revealed the majority presence of flavonoids in the 4 extracts (6, 8, 14, and 18). The anti-inflammatory tests of these 4 extracts revealed better anti-inflammatory activity in extract 6 (IC50= 95.94 ± 21.07 µg/mL for NO; IC50= 11.78±0.27 µg/mL for NADPH oxidase). Extract 14 had the best effect on the inhibition of NO production (IC50 = 8.56±2.13 µg/mL) and on the inhibition of the growth of trophozoites. Endophytic fungi extract from C. variegatum have demonstrated promising anti-amoebic and anti-inflammatory potential and therefore deserve special attention for the development of natural and ecological alternative treatment.