BIOACTIVITIES OF EXTRACTS, DEBROMOLAURINTEROL AND FUCOSTEROL FROM MACROALGAE SPECIES

Abstract

Parasitic diseases including malaria, and other numerous microbial infections and physiologicaldiseases are threatening the global population. Tanzanian coast shores are endowed with avariety of macroalgae (seaweeds), hitherto unsystematically explored to establish their biomedicalpotentials. Thus, antiplasmodial activity using malarial imaging assay, antimicrobial activityusing microplate dilution technique, antioxidant activity using DPPH radical scavenging methodand cytotoxicity using brine shrimp test were carried out on crude extracts from the selectedspecies of algae (Acanthophora spicifera, Cystoseira myrica, Cystoseira trinodis, Laurenciafiliformis, Padina boryana, Sargassum oligocystum, Turbinaria crateriformis, Ulva fasciata andUlva reticulata) occurring along the coast of Tanzania. The extracts showed antimicrobialactivities with MIC ranging from 0.3- 5.0 µg/mL against Staphylococcus aureus, Streptococcuspyogenes, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Cryptococcusneoformans; DPPH radical scavenging activity at EC50 1.0- 100 µg/mL and cytotoxicity on brineshrimp larvae with LC50 value ranging from20 - 1000 µg/mL. The extracts from C. myrica and P.boryana inhibited growth of Plasmodium falciparum (3D7 strain) by 80 and 71%, respectively at40 µg/mL while a sesquiterpene debromolaurinterol (1) which was chromatographically isolatedfrom C. myrica exhibited antiplasmodial activity with IC50 20 µM whereas a sterol fucosterol (2)from P. boryana showed weak activity at 40 µM. Bioactivities portrayed by the investigatedextracts indicate their ingredients as potential sources of bioactive agents that warrant furtherexplorations.