title: Liquid chromatographic determination of caffeine and adrenergic stimulants in food supplements sold in Brazilian e-commerce for weight loss and physical fitness.
abstract: Methyl-xanthines and adrenergic stimulants, such as caffeine and synephrine, are commonly added to food supplements due to their stimulating and thermogenic effects. In addition, the abusive consumption of food supplements with ergogenic and aesthetic purposes has been observed worldwide. This work describes the study of caffeine, p-synephrine, hordenine, octopamine, tyramine, ephedrine and salicin as stimulants in dietary supplements marketed in Brazil for weight loss and physical fitness claims. A total of 94 different products were acquired from 30 Brazilian websites. Thus, the sampling of marketed supplements was performed in virtual commerce (e-commerce) with claims of weight loss, appetite reduction, fat burning and metabolism acceleration. The developed analytical method involved the separation of the stimulants by HPLC with diode array detection (HPLC-DAD) by using a gradient elution of flow rate (0.7-2.5 ml min(-1)) and mobile phase composition (0.1% H3PO4/methanol). The validated method was applied to the study of 46 dietary supplements. Caffeine, p-synephrine and ephedrine were found to be present as stimulants in 52% of the studied samples marketed as encapsulated or bulk forms. Caffeine was found to be present in concentrations that represent doses from 25.0 to 1476.7 mg day(-1). Synephrine was found in concentrations that represent doses from 59.1 to 127.0 mg day(-1). Ephedrine was found to be associated with caffeine in one formulation at a concentration representing a 26.1 mg day(-1) dosage.
authors.affiliation: a Graduate Program in Pharmaceutical Sciences , Federal University of Santa Maria (UFSM) , Santa Maria - RS , Brazil.|b Center of Health Sciences , UFSM , Santa Maria - RS , Brazil.
authors.forename: Carine
authors.initials: C
authors.lastname: Viana
authors.affiliation: a Graduate Program in Pharmaceutical Sciences , Federal University of Santa Maria (UFSM) , Santa Maria - RS , Brazil.
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Zemolin
authors.affiliation: a Graduate Program in Pharmaceutical Sciences , Federal University of Santa Maria (UFSM) , Santa Maria - RS , Brazil.
authors.forename: Larissa S
authors.initials: LS
authors.lastname: Müller
authors.affiliation: a Graduate Program in Pharmaceutical Sciences , Federal University of Santa Maria (UFSM) , Santa Maria - RS , Brazil.
authors.forename: Thaís R
authors.initials: TR
authors.lastname: Dal Molin
authors.affiliation: b Center of Health Sciences , UFSM , Santa Maria - RS , Brazil.
authors.forename: Helena
authors.initials: H
authors.lastname: Seiffert
authors.affiliation: a Graduate Program in Pharmaceutical Sciences , Federal University of Santa Maria (UFSM) , Santa Maria - RS , Brazil.|c Department of Chemistry , UFSM , Santa Maria - RS , Brazil.
authors.forename: Leandro M
authors.initials: LM
authors.lastname: de Carvalho
mesh_terms: D001938:Brazil; D002110:Caffeine / Q000032:analysis*; D000697:Central Nervous System Stimulants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements / Q000032:analysis*; D005504:Food Analysis; D020407:Internet / Q000191:economics*; D010809:Physical Fitness; D015431:Weight Loss
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine
keywords: HPLC-DAD; adrenergic stimulants; caffeine; food supplements; weight loss