Ingredient Consistency of Commercially Available Polyphenol and Tocopherol Nutraceuticals

Pharmacokinetic Analysis of an Oral Multicomponent Joint Dietary Supplement (Phycox®) in Dogs

Despite the lack of safety, efficacy and pharmacokinetic (PK) studies, multicomponent dietary supplements (nutraceuticals) have become increasingly popular as primary or adjunct therapies for clinical osteoarthritis in veterinary medicine. Phycox® is a line of multicomponent joint support supplements marketed for joint health in dogs and horses. Many of the active constituents are recognized anti-inflammatory and antioxidant agents. Due to a lack of PK studies in the literature for the product, a pilot PK study of select constituents in Phycox® was performed in healthy dogs. Two novel methods of analysis were developed and validated for quantification of glucosamine and select polyphenols using liquid chromatography-tandem mass spectrometry. After a single oral (PO) administrated dose of Phycox®, a series of blood samples from dogs were collected for 24 h post-dose and analyzed for concentrations of glucosamine HCl, hesperetin, resveratrol and naringenin. Non-compartmental PK analyses were carried out. Glucosamine was detected up to 8 h post-dose with a Tmax of 2 h and Cmax of 9.69 μg/mL. The polyphenols were not found at detectable concentrations in serum samples. Co-administration of glucosamine in the Phycox® formulation may enhance the absorption of glucosamine as determined by comparison of glucosamine PK data in the literature.

Stereospecific quantitation of 6-prenylnaringenin in commercially available H. lupulus-containing natural health products and dietary supplements

6-Prenylnaringenin (6PN) is a chiral prenylflavonoid found most prevalently in hops (Humulus lupulus) and present in hops and hop products. It is an isomer of the potent phytoestrogen, 8-prenylnaringenin. An enantiospecific method for quantitation 6PN by LC-ESI-MS has been developed. Baseline enantiomeric resolution of 6PN was attained on a Chiralpak(®) AD-RH column with an isocratic mobile phase consisting of acetonitrile and 10 mM ammonium formate (pH 8.5) (39:61, v/v) and a flow rate of 1.25 mL/min. Quantitative MS data were obtained by selected ion monitoring of the [M-H](-)-ion of both enantiomers of 6PN (m/z 339.10) and the internal standard, 4-acetamidobenzoic acid (m/z 178.05). The method was found to be accurate and precise for enantiospecific quantification of 6PN. The method was successfully applied to the content analysis of 39 commercially available natural health products and dietary supplements reported to contain H. lupulus plant material, extracts and label claims of 6PN. 6PN was present in 25 of 34 products containing plant material or extracts of H. lupulus. Of the five products with claimed amounts of 6PN, all were found to possess <50% of label claims. Results of the content analysis indicated a lack of uniformity in botanical nutraceuticals claiming 6PN content.

Synthesis of glycosides of resveratrol, pterostilbene, and piceatannol, and their anti-oxidant, anti-allergic, and neuroprotective activities

Resveratrol was glucosylated to its 3- and 4'-β-glucosides by cultured cells of Phytolacca americana. On the other hand, cultured P. americana cells glucosylated pterostilbene to its 4'-β-glucoside. P. americana cells converted piceatannol into its 4'-β-glucoside. The 3- and 4'-β-glucosides of resveratrol were further glucosylated to 3- and 4'-β-maltosides of resveratrol, 4'-β-maltoside of which is a new compound, by cyclodextrin glucanotransferase. Resveratrol 3-β-glucoside and 3-β-maltoside showed low 2,2-diphenyl-1-picrylhydrazyl free-radical-scavenging activity, whereas other glucosides had no radical-scavenging activity. Piceatannol 4'-β-glucoside showed the strongest inhibitory activity among the stilbene glycosides towards histamine release from rat peritoneal mast cells. Pterostilbene 4'-β-glucoside showed high phosphodiesterase inhibitory activity.

The quality of commercially available nutraceutical supplements and food sources

OBJECTIVES

Nutraceuticals are components of dietary origin, with claimed beneficial therapeutic activities. The quality of nutraceuticals is paramount for efficacy and safety, and it includes quality of raw materials, different available chemical forms, complex products, lack of substitution of inappropriate materials, and the absence of contaminants. The aim of this review is to investigate the extent of substandard formulated and raw material nutraceuticals, and to highlight any consequent health concern.

KEY FINDINGS

Reports of the quality of raw materials have revealed wide variations, often as a result of lack of clear regulatory definitions with respect to size of polymeric entities and also presence of glycosidic and salt forms. Published evaluations of over 70 formulations of 25 different nutraceuticals revealed variable quality; no nutraceutical showed consistent high quality, but a number revealed consistent low quality, thereby making the case for closer regulation of manufacturers. Whole food sources have also been shown to be widely variable in constituent levels. The effect of different formulations requires consideration, as the different types have been shown to have marked effects on bioavailability.

SUMMARY

The poor quality of commercially available nutraceuticals has been highlighted. In addition, incidences of side effects and drug interactions are increasing, as consumption of nutraceuticals rises. Pharmacists and health practitioners need to be aware of the scientific literature to advise accordingly.