Cyclodextrins have been widely used in pharmaceutical and nutritional formulations to improve bioavailability particularly for compounds with low water solubility, explained the researchers writing in the European Journal of Nutrition.
Furthermore, gamma-cyclodextrin has the advantage over other forms of being completely digested by the enzyme amylase produced by the pancreas and in saliva, the authors added.
The team reported that participants supplemented with the novel gamma-cyclodextrin curcumin formulation (CW8), showed the highest absorption of curcumin measured by blood levels over 12 hours.
Compared with a control product (unformulated standardised curcumin) those given the CW8 supplement also showed the highest blood levels of total curcuminoids and the individual curcuminoid demethoxycurcumin (DMC).
“The CW8 formulation showed a 39-fold increase in relative bioavailability compared with unformulated standard curcumin,” commented co-author Dr. Valentina Razmovski-Naumovski of the University of New South Wales .
“The data presented suggest that gamma-cyclodextrin curcumin formulation (CW8) significantly improves the absorption of curcuminoids in healthy humans,” she added.
While many approaches have tried to improve curcumin bioavailability, the 39-fold improvement versus unformulated standardised curcumin reported in the new randomised double-blind crossover trial is one of the highest results achieved to date.
However, since the trial was essentially pilot scale in size, further larger studies are needed to confirm the findings, commented the team.
The curcumin challenge
Curcumin, the principal active ingredient in the spice turmeric, has demonstrated multiple health benefits in previous research. Its properties include anti-oxidant, antimicrobial anti-inflammatory and anti-diabetic effects.
Razmovski-Naumovski and colleagues noted that realising the optimal health benefits of curcumin has historically been limited by its low solubility in water and poor intestinal absorption.
The new study examined novel curcumin formulations to identify possible ways of improving oral bioavailability in 12 people. The subjects were given four different oral supplements of curcumin, separated by a seven day washout period between formulations.
The four formulations were CW8 (mentioned above); a phytosome formulation of Curcumin: Soy Lecithin: Microcrystalline Cellulose in a ratio 1:2:2 (CSL); a formulation of curcuminoids and essential oils of turmeric rhizome (CEO); and the unformulated control product standard curcumin (StdC).
The formula products were not named in the study due to absence of consent for disclosure.
Fasting blood samples were taken at baseline and various time points up to 12 hours. The blood plasma samples were analysed for curcumin, DMC and bismethoxycurcxumin (BMC).
The subjects were given two standardised turmeric-free meals during the twelve-hour period.
The researchers calculated the relative bioavailability of the three formulated products compared to the control (StdC) using the area under the plasma concentration time curve.
Source: European Journal of Nutrition
Volume 57, Issue 3, pp 929–938, doi: 10.1007/s00394-016-1376-9
“Analysis of different innovative formulations of curcumin for improved relative oral bioavailability in human subjects”
Authors: Martin Purpura, Valentina Razmovski-Naumovski et al