Curcumin is a compound, derived from the Curcuma longa plant, which has shown anticancer activity and relatively low toxicity in humans. It has been a subject of significant interest in recent years as an adjuvant chemotherapy agent. Literature data for curcumin and related curcuminoids have shown discrepancies in the irreported bioactivities, and this has spurred disputes in the scientific community about their purported benefits. A possible explanation for these inconsistencies is variability between curcumin sources in purity and content. A systematic study has been conducted on the biological properties of curcumin from various sources, both naturally sourced and synthesized using neat and solvent-based methods. Bioactivities tested included antioxidative capacity and cell growth inhibition. This study has also been expanded to include curcuminoids containing varied electronic and structural features, and biological properties were also evaluated after coordination to a metal.