Membrane Stabilising and Phagocytosis Stimulatory Activities of Fusarium equiseti — An Endophytic Fungus of Mangrove Palm (Nypa fruticans Wurmb) Fruit

Abstract

Objective: Nypa fruticans Wrumb commonly known as mangrove palm thrives well in brackish water; and is an important medicinal plant. It was sampled, surface sterilised, sectioned into tiny chips and plated on sabrose dextrose agar (SDA) media seeded with antibiotics to isolate the endophytic fungi. Methods: Fusarium equiseti was fermented on sterilised solid rice media for 28 days, extracted with ethyl acetate, filtered and concentrated in vacuo. A high-pressure liquid chromatography (HPLC) assay was performed. While the biological effects, were evaluated by human erythrocyte membrane stabilisation against heat- and hypotonicity-induced haemolysis and stimulation of human polymorphonuclear neutrophilis (PMNs) phagocytosis. Results: Fusarium equiseti (20 – 100 μg/ml) expressed a dose-dependent effect in both bioassays, comparing significantly (p < 0.05) with reference drugs: diclofenac (100 μg/ml), indomethacin (50 μg/ml), prednisolone (100 μg/ml), for membrane stabilisation; and ascorbic acid (50 μg/ml) for the later. The HPLC assay identified an isofistularin-3 like-compound as the dominant constituent. Conclusion: This is first reported on the isolation of endophytic fungi from the Niger Delta mangrove plant species in Nigeria. It also demonstrated the potential of the mangrove palm as a source of novel lead compounds for the development of anti-inflammatory and immune-stimulatory drugs. Future studies will hopefully isolate and characterise the active principles.