|Plants have been widely used in traditional medicine for a number of ailments, among which may
be included infectious diseases such as colds, influenza, chicken pox, TB, etc. as well as lifestyle
diseases such as diabetes and cancer. Seaweeds have also been shown to contribute to the
maintenance of health through their nutritional and medicinal properties and recently, a great deal
of interest has developed towards the isolation of bioactive compounds from marine sources due to
their numerous health benefits. Furthermore, marine algae are valuable sources of structurally
diverse metabolites with scientifically proven therapeutic claims.
Chemical constituents of red seaweed, Porphyra capensis was investigated in this present study
along with subsequent brine shrimp lethality assay analysis of the crude extracts. The compounds
isolated from the plant were from the hexane (6) and butanol (2) extracts. These compounds were
all isolated and purified by various chromatographic techniques, namely silica gel chromatography,
Sephadex LH-20 gel as well as C18 reversed phase silica gel.
The structures of the isolated compounds were analysed and characterised by NMR, GC-MS, ESI
MS and FTIR spectroscopy. Eight compounds were isolated and identified as phytol, desmosterol,
9-eicosenoic acid, 5,8,11,14,17-eicosapentanoic acid, palmitic acid, methyl (E)-hexadec-9-enoate,
glycerol and compound 1 (novel compound). All the compounds were isolated from Porphyra
capensis for the first time. The hexane, butanol and methanol extracts were found to be non-toxic
with the brine shrimp test LC50 value at least two times greater than ?g/ml.