The golden spice turmeric with its main bioactive component curcumin is one of the most popular and extensively studied nutraceuticals. Despite numerous pre-clinical studies reporting positive pharmacodynamics of turmeric extracts and curcumin, the main issues in translating the pharmacological effects to clinical efficacy have been to overcome its poor pharmacokinetics and to deliver significant amounts of the biologically relevant forms of the actives to various tissues. This review is aimed at providing a first critical evaluation of the current published literature with the novel curcumagalactomannoside (CGM) formulation of curcumin using fenugreek galactomannan dietary fibre, specifically designed to address curcumin poor pharmacokinetics. We describe CGM and its technology as a food-grade formulation to deliver ‘free’ unconjugated curcuminoids with enhanced bioavailability and improved pharmacokinetic properties. The therapeutic relevance of improving bioavailability of ‘free’ curcuminoids and some of the technical challenges in the measurement of the ‘free’ form of curcuminoids in plasma and tissues are also discussed. A total of twenty-six manuscripts are reviewed here, including fourteen pre-clinical and twelve clinical studies that have investigated CGM pharmacokinetics, safety and efficacy in various animal models and human conditions. Overall current scientific evidence suggests CGM formulation has improved bioavailability and tissue distribution of the biologically relevant unconjugated forms of turmeric actives called ‘free’ curcuminoids that may be responsible for the superior clinical outcomes reported with CGM treatments in comparison with unformulated standard curcumin across multiple studies.

Fisetin, a polyphenol found in several fruits and vegetables, has shown potential health benefits in many pre-clinical studies for neuroprotection, cardioprotection, chemoprevention, diabetes, inflammation and oxidative stress. However, the clinical effectiveness of fisetin may be limited by its poor bioavailability when ingested. Using a novel green technology of Hybrid-FENUMAT™, a food-grade fisetin formulation (FF-20) was developed through encapsulation of fisetin micelles into fenugreek galactomannan (FG) hydrogel scaffold to improve its physical characteristics and bioavailability. This is the first human pharmacokinetic study of fisetin following a single-dose, comparative, double-blinded, cross-over protocol, supplementing with FF-20 and unformulated fisetin (UF). Fifteen healthy volunteers were given a single dose of 1000 mg UF or 1000 mg FF-20 (delivering 192 mg fisetin) with a 10-d washout period between each dose. Blood samples were taken at 0⋅5, 1, 2, 3, 5, 8 and 12 h after both days of supplementation to quantify fisetin and geraldol, an active metabolite. The plasma concentration of fisetin when individuals consumed FF-20 was 26⋅9-fold greater than UF as determined by the area under the curve over 12 h [AUC0–12 h (FF-20) = 341⋅4 v. AUC0–12 h (UF) = 12⋅67]. The maximum plasma concentration (Cmax) was also more than twenty-three times higher when supplemented with FF-20 (238⋅2 ng/ml) compared to UF (9⋅97 ng/ml). The encapsulation also reduced the amount of conversion of fisetin to geraldol. No adverse events were reported during the study. Therefore, the encapsulation of fisetin into FG dietary fibre hydrogel scaffold could improve its delivery and bioavailability in human subjects.