Secondary metabolites from natural sources are fast growing as popular drug leads. The structural novelty and favourable biological activity that these compounds display contribute to their popularity as drugs of the future. Examples of such compounds include the potent anticancer drug paclitaxel isolated from the bark of a yew tree as well as the more commonly known analgesic aspirin which stems from the bark of the willow tree. The biological activities exhibited by these secondary metabolites are vast and range from antimicrobial to anticancer activity to mention but a few. As a result, the isolation of novel compounds from natural sources is on the rise. The South African seaboard is home to a wealth of various marine algal species which produce fascinating secondary metabolites. For example, Portierria hornemanii was shown to produce halomon, a halogenated monoterpene which has displayed promising cytotoxic activity. This study thus focused primarily on pursuing novel compounds from three endemic South African marine algal species which have never been analysed previously from a chemical perspective. These are Plocamium rigidum (Bory de Saint-Vincent), Laurencia natalensis (Kylin) and Delisea flaccida (Suhr) Papenfuss. Four known compounds and one new halogenated monoterpene, (2E,5E,7Z)-8-chloro- 7-(dichloromethyl)-4-hydroxy-3-methylocta-2,5,7-trienal, were isolated from Plocamium rigidum. The breast cancer (MCF-7 cell line) inhibitory activity for these compounds was assessed and it was observed that an increase in the lipophilic nature of the compounds produced more favourable IC50 values. A pre-cursor to bromofucin type compounds, cis-laurencenyne, was isolated from Laurencia natalensis, as well as a new acetoxy chamigrane type compound, 4-bromo- 3,10-dichloro-7-hydroxy-3,7,11,11-tetramethylspiro [6.6] undec-1-yl acetate. Delisea flaccida was seen to contain two known bromofuranone type compounds isolated as an isomeric mixture, 1-[(5Z)-4-bromo-5-(bromomethylidene)-2-oxo-2,5- dihydrofuran-3-yl] butyl acetate and 1-[(5E)-4-bromo-5-(bromomethylidene)-2- oxo-2,5-dihydrofuran-3-yl]butyl acetate. These compounds are famous for their ability to inhibit bacterial biofilm production and they have been isolated before from an Australian Delisea spp / Adobe Acrobat 9.53 Paper Capture Plug-in

Harmful algal blooms are exponential increases in autotrophic microorganisms that proliferate in such a way that the surrounding environment, the local economy and the health of regional populations are negatively affected. Among the causes of these blooms are anthropogenic inputs of excess nitrogen and phosphorus into the environment through overfertilization. Floating treatment wetlands (FTW) have emerged as a novel method of reducing the negative impacts of these nutrient inputs by using artificial rafts to float normally emergent wetland plants on the surface of water bodies to assimilate excess nutrients. Because their use is so new, only limited research has been performed on their effectiveness. This mesocosm-level study evaluated the performance of a FTW consisting of a community of yellow canna (Canna flaccida), blue flag iris (Iris hexagona) and bulltongue arrowhead (Saggittaria lancifolia) in simulated stormwater of varying nitrogen and phosphorus concentrations. The community of plants displayed nitrogen limitation, while the cyanobacteria-dominated algal community that developed displayed phosphorus limitation, leading to the conclusion that in order for this community of macrophytes to limit algal growth, nitrogen must be present to support their growth and concurrent assimilation of the algae-limiting nutrient phosphorus. Canna and iris were found to significantly outperform arrowhead in terms of biomass gains. The study also showed that the size of the plants may be of great importance in the ability of FTWs to limit algal development. Despite the fact that the community of plants in this study were unable to limit the development of algae, the use of FTWs remains promising and further research should be done to continue to enhance our understanding of their strengths and weaknesses.