Pharmacokinetic Evaluation of Phytochemicals From Selected Herbs and Spices in Human Plasma Samples

Abstract

ObjectivesHerbs and spices (H/S) are rich sources of bioactive compounds with a limited understanding of their absorption and metabolism in humans. This study aimed to characterize H/S metabolites in human plasma samples over 24 h after H/S intake. MethodsPlasma samples from a randomized, single-blinded, 4-arm, 24-h, crossover clinical trial (Clincaltrials.gov NCT03926442) were used for this research. Subjects (n = 24, aged 37 ± 3 years, BMI = 28.4 ± 0.6 kg/m2) consumed a high-fat/high-carbohydrate meal with salt and pepper only (control) or with three different H/S mixtures: Italian herbs (rosemary, basil, thyme, oregano, and parsley), cinnamon, and pumpkin pie spice (cinnamon, ginger, nutmeg, and allspice), and blood samples were collected at 0, 0.5, 1, 2, 4, 5.5, 7 and 24 h. Meals contained 1 g H/S per 135 kcal and delivered 35% of each subject’s energy needed to maintain weight. Quantitative analysis of H/S metabolites was conducted using UHPLC-QQQ based on reference standards and reported multiple reaction monitoring transitions. ResultsWe have tentatively identified 58 metabolites in plasma samples, including 32 phenolic acids, 11 terpenoids, 6 flavonoids, and 9 other polyphenol metabolites. Preliminary analysis (n = 13) showed that coumarin glucuronide increased after cinnamon and pumpkin pie meals and peaked at 2 h (2656.8 ± 481.3 nmol/L and 1542 ± 275.7 nmol/L respectively), and returned to baseline concentration at 24 h. After consuming Italian herbs meal, carnosol appeared in plasma early peaking at 1 h (48.2 ± 7.0 nmol/L); carnosic acid and 12-methoxy carnosic acid peaked at 2 h (366.4 ± 142.2 nmol/L and 588.6 ± 66.3nmol/L, respectively), and these metabolites circulated in the body for up to 24 h; apigenin-7-O-glucuronide peaked at 7 h (6.0 ± 1.7 nmol/L); carnosic acid glucuronide peaked at 24 h (510.9 ± 86 nmol/L). 6- and 10-gingerol glucuronide peaked at 1 h and 2 h after consuming pumpkin pie meal (1.4 ± 0.6 nmol/L and 6.7 ± 1.7 nmol/L), and returned to baseline concentration at 5.5 and 7 h, respectively. All data are expressed as mean ± SEM. ConclusionsH/S bioactive compounds are absorbed and metabolized in the human body to early and late phase metabolites, peaking at various time-points across 24 h in response to different H/S meals. Funding SourcesThis project was supported by a gift from McCormick Science Institute and various donor funds.