Abstract

IMMUNO-MODULATORY AND MEMBRANE STABILISING ACTIVITIES OF ENDOPHYTIC FUNGI ISOLATED FROM MANGROVE PLANTS: RHIZOPHORA RACEMOSA, AVICENNA ALBA AND ACROSTICHUM AUREUM

Okafor Sunday N.*, Okonkwo Onyinye B., Amarachi Helen Njoku, Enyum Iheanacho and Okonkwo Toochukwu J. N.?

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Abstract

Objective: To investigate the immuno-stimulatory and membrane stabilising activities of endophytic fungi isolated from mangrove plants: Rhizophora racemosa, Avicenna alba and Acrostichum aureum. Method: The pure endophytic fungal cultures were fermented using semi-solid rice substrate which produced the crude extract. The crude extract was then extracted using ethyl acetate and methanol and dried under controlled temperature of 37 ˚C and standard atmospheric pressure. Hypotonicity-induced and heat-induced haemolysis assays were used to evaluate the membrane stabilizing activity, and phagocytises stimulatory assay was used to evaluate the immunomodulatory activity of the isolated endophytic fungi. Results: Eight endophytes coded as 1S2, 2L1, 2S2, 3L1M, 3L2-B, 3L2-amc, 3S1 and 3S2- amc were isolated from leaves and seeds of R. racemosa, A. alba and A. aureum. Ethyl acetate extracts of 1S2, 2L1, 2S2, 3L2-B and 3S2-amc were found to stabilize the membrane more than the standard drug. Their mean percentage inhibitions at 100 μg/ml are 95.41, 86.07, 88.35, 90.65 and 76.01% respectively when compared to the standard (48.98%) in a hypotonic environment. Only 1S2, 2S2, 3L2-B and 3S2-amc showed significant membrane stabilizing activity comparable to the standard in the heat induced environment. All the ethyl acetate extracts did not show any significant immuno-stimulatory activity (p>0.05). Conclusion: 1S2, 3L2-B and 3S2-amc have promising membrane stabilizing activity and can serve as leads in the development of novel bioactive compounds.

Keywords: Immuno-stimulatory, membrane stabilising, endophytic fungi, Rhizophora racemosa, Avicenna alba and Acrostichum aureum.