Toxic metals (As and Pb) in Sargassum elegans Suhr (1840) and its bioactive compounds

Sargassum elegans Suhr 1840 (Phaeophyta) is a brown marine macro alga, which is used both nutritionally and medicinally in the coastal areas of Southern Africa. Consequently, we conducted a phytochemical and analytical investigation on samples of this species collected from seven sites along the coast of KwaZulu-Natal, South Africa. Sargassum elegans was found to be rich in β-sitosterol, fucosterol and phaeophytin a as confirmed by spectroscopic techniques. Concentrations of essential and toxic elements varied significantly with location and were in the order of Ca > Mg> Fe > As > Cu > Zn > Mn > Ni > Pb > Co > Se > Cr > Cd. The accumulation of As by S. elegans was also evident as concentrations ranged from 42 to 105 mg kg^-1, of which, 21 to 53 mg kg^-1 was in inorganic form; consumption of this species may therefore increase dietary exposure to inorganic arsenic. Abbreviation: CRM: Certified reference material; NMR: Nuclear magnetic resonance; ICP - OES: Inductively coupled plasma - optical emission spectroscopy; PCA: Principal component analysis.