A Clinical Trial to Evaluate the Chronic Safety and Tolerance of Turmipure Gold™ in Healthy Subjects

The rhizome of Curcuma longa (turmeric) is commonly used as a spice and for its medicinal proprieties traditionally in Asian countries. Turmeric has been studying in different therapeutic area. Antioxidant, anti-inflammatory (respiratory system, joints and digestive), antimutagenic, antimicrobial, neurological disease, hepatoprotective and anticancer properties are supported by in vitro and in vivo data.

Despite several data identified in the scientific literature, the community herbal monograph of the European Medicines Agency allows the traditional use only for the following therapeutic indication "Traditional herbal medicinal product used to increase bile flow for the relief of symptoms of indigestion (such as sensation of fullness, flatulence, and slow digestion)." According to the World Health Organization (WHO) Monographs on Selected Medicinal Plants, the use for treatment of acid, flatulent, or atonic dyspepsia is supported by clinical data. Treatment of peptic ulcers, and pain and inflammation due to rheumatoid arthritis and of amenorrhoea, dysmenorrhoea, diarrhoea, epilepsy, pain, and skin diseases are uses described in pharmacopoeias and in traditional systems of medicine.

Several health claims are pending for European Commission's decision (referred to the Regulation n°1924/2006). As a consequence, in European countries, claims related to antioxidant, joints, digestion, liver, etc. are tolerated for the moment.

Curcumin has been studied as the main bioactive component of turmeric associated to the potential health effect. However, besides curcumin, others components have been identified called the curcuminoids groups. Curcuminoids are natural yellow-orange pigments and hydrophobic polyphenols derived from the rhizome of the herb Curcuma longa. They are commonly isolated from the spice and food-coloring agent turmeric. Extracts of curcuminoids generally contain 75-80% curcumin, 15-20% demethoxycurcumin (DMC), and 0-10% bisdemethoxycurcumin (BDMC).

Regarding the intrinsic property, curcuminoids have higher solubility in organic solvents than in water. As a consequence, curcumin has low aqueous solubility and poor gastrointestinal absorption. It was also documented that curcumin have low absorption from the gut, rapid metabolism and rapid systemic elimination. This leads to the conclusion that turmeric has low bioavailability, which limits its use in general health care and as an adjunct in managing various diseases. Indeed, it was found low serum levels and limited tissue distribution irrespective of route of administration. In order to improve the bioavailability of curcumin, several approaches have been undertaken. The use of adjuvant like piperine that interferes with glucuronidation; liposomal curcumin, nanoparticles, phospholipid complex; and structural analogues of curcumin. The tested products are different from technology of bioavailability enhancement. Recently, Naturex has developed a dried emulsion formulation using a turmeric extract mixed together with a quillaja extract, sunflower oil and arabic gum. This formulation is highly dispersible in water and should therefore improve the bioavailability of curcuminoids.

In order to assess the bioavailability of the product Turmipure Gold™, Naturex conducted a clinical study in 2018. The plasmatic concentration profile of total curcuminoids (curcumin, DMC, BDMC and their metabolites) on a 24-hour period after consumption of a single dose of 300 mg Turmipure Gold™ 30% curcuminoids formulation in comparison to the one obtained after consumption of 1500 mg Standard turmeric powder extract 95% curcuminoids was investigated as the primary objective (unpublished yet). A statistical significant difference was observed on the primary outcome which was the dose-normalized Area Under the Curve (AUC) 0-24h of Total curcuminoids. Turmipure Gold™ formulation was significantly higher than Standard turmeric powder extract (adjusted p<0.0001) for this parameter.

Thirty subjects received the products in a cross-over design, 16 women and 14 men and no gender effect was observed on the primary outcome.

Statistical significant differences were also observed on the dose-normalized of Area Under the Cuve (AUC0)-24h of Total curcuminoids between products comparisons: Turmipure Gold™ was higher than Turmeric extract (1500mg) combined with piperine (15mg) or the phytosome formulation (1000mg) (adjusted p<0.0001 for each).

The aim of this double-blind placebo-controlled clinical trial is to evaluate the chronic safety and tolerance of Turmipure Gold™ in healthy subjects during 5 weeks +/- 3 days between visit V1 (dispensation of the product) and visit V2 (normal end-of-study). 60 healthy male and female volunteers with 40/60 ratio will be recruited for this study.

In order to assess the gastrointestinal tolerance, a composite score of gastrointestinal tolerance has been chosen as primary endpoint of the trial. The composite score of GI tolerance will be determined as the sum of the scores of the 4 GI symptoms and the composite score of stool frequency and consistency (score of GI tolerance = bloating score + abdominal cramping score + stomach noises score + flatulence score + stool score).

Regarding the safety concern, the European Medicines Agency (EMA) monograph indicate contraindication for the following pathologies: "Hypersensitivity to the active substance(s), obstruction of bile duct, cholangitis, liver disease, gallstones and any other biliary diseases" (confirmed by the WHO monograph). The only undesirable effect reported are "mild symptoms of dry mouth, flatulence and gastric irritation may occur. The frequency is not known." In addition to this, the safety profile of the comparatives products was assessed good in several published trials. This will be investigated deeper in this trial with all the safety and tolerance parameters. An additional end-of-study visit could be planned if the biological results of the V2 visit are not satisfactory, according to the opinion of the investigator.

Inclusion criteria

• Age between 18 and 60 years (limits included),
• BMI between 19 and 28kg/m² (limits included),
• Weight stable within ±3kg in the last three months,
• With routine blood chemistry values within the normal range,
• For women: Non menopausal with the same reliable contraception since at least 3 cycles before the beginning of the study and agreeing to keep it during the entire duration of the study (condom with spermicidal gel and estrogen/progestin combination contraception accepted) or menopausal without or with hormone replacement therapy (estrogenic replacement therapy begun from less than 3 months excluded),
• Non-smoking or with tobacco consumption ≤ 5 cigarettes / day and agreeing not to smoke during all experimental sessions (V1 and V2),
• Good general and mental health with in the opinion of the investigator: no clinically significant and relevant abnormalities of medical history or physical examination,
• Able and willing to participate to the study by complying with the protocol procedures as evidenced by his dated and signed informed consent form,
• Affiliated with a social security scheme,
• Agreeing to be registered on the volunteers in biomedical research file.

Exclusion criteria

• Suffering from a metabolic or endocrine disorder such as diabetes, uncontrolled or controlled thyroidal trouble or other metabolic disorder,
• Suffering from a severe chronic disease (e.g. cancer, HIV, renal failure, ongoing hepatic or biliary disorders, chronic inflammatory digestive disease, arthritis or other chronic respiratory trouble, etc.) or gastrointestinal disorders found to be inconsistent with the conduct of the study by the investigator (e.g. celiac disease),
• Suffering from liver diseases,
• Current disease states that are contraindicated to subjects with dietary supplementation: chronic diarrhea, constipation or abdominal pain, Inflammatory bowel diseases (Crohn's disease or ulcerative colitis), Cirrhosis, chronic laxatives use…,
• Suffering from Irritable Bowel Syndrome (IBS) diagnosed or not by a medical doctor and treated with chronic medication,
• Having medical history of current pathology which could affect the study results or expose the subject to an additional risk according to the investigator,
• Recent gastroenteritis or food borne illness such as confirmed food poisoning (less than 1 month),
• With a low veinous capital of blood samples according to the investigator's opinion,
• With a known or suspected food allergy or intolerance or hypersensitivity to any of the study products' ingredient (gluten intolerance, celiac disease, etc….),
• Pregnant or lactating women or intending to become pregnant within 3 months ahead,
• Exhibiting alcohol or drug dependence,
• On any chronic drug treatment (for example anticoagulant, antihypertensive treatment, treatment thyroid, asthma treatment, anxiolytic, antidepressant, lipid-lowering treatment, corticosteroids, phlebotonic, venotonic, drug with impact on blood circulation …) excepting oral and local contraceptives,
• Currently taking (and during the last month) any supplementation from botanical origins or with curcumin,
• Currently taking (and during the past 3 months) any prebiotics or probiotics supplementation from food or from dietary supplements,
• With significant change in food habits or in physical activity in the 3 months before the V0 visit or not agreeing to keep them unchanged throughout the study,
• Trying to lose weight with a current or planned in the next 3 months specific diet (hyper or hypocaloric, vegan, vegetarian…) or exercise regimen,
• With a personal history of anorexia nervosa, bulimia or significant eating disorders according to the investigator,
• Consuming more than 3 standard drinks of alcoholic beverage daily for men or 2 daily for women or not agreeing to keep his alcohol consumption habits unchanged throughout the study,
• Having a lifestyle deemed incompatible with the study according to the investigator including high level physical activity (defined as more than 10 hours of significant physical activity a week, walking excluded),
• Taking part in another clinical trial or being in the exclusion period of a previous clinical trial,
• Having received, during the last 12 months, indemnities for clinical trial higher or equal to 4500 Euros,
• Under legal protection (guardianship, wardship) or deprived from his rights following administrative or judicial decision,
• Presenting a psychological or linguistic incapability to sign the informed consent,
• Impossible to contact in case of emergency.

After V0 biological analyses the subject will be considered as non-eligible to the study on the following criteria:

• Control record (Glycaemia, Gamma glutamyl transpeptidase (GGT), ASAT, ALAT, Urea, Creatinine and Complete blood count) with clinically significant abnormality according to the investigator.