Browsing by Author "Rocha, Tiago"
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- Adulteration of Dietary Supplements by the Illegal Addition of Synthetic Drugs: a reviewPublication . Rocha, Tiago; Amaral, Joana S.; Oliveira, BeatrizIn the last few years, the consumption of dietary supplements, especially those having plants as ingredients, has been increasing due to the common idea that they are natural products posing no risks to human health. In the European Union and the United States, dietary supplements are legally considered as foods/special category of foods, thus are not being submitted to any safety assessment prior to their commercialization. Among the issues that can affect safety, adulteration by the illegal addition of pharmaceutical substances or their analogs is of major concern since unscrupulous producers can falsify these products to provide for quick effects and to increase sales. This review discusses the various classes of synthetic drugs most frequently described as being illegally added to dietary supplements marketed for weight loss, muscle building/sport performance and sexual performance enhancement. Information regarding regulation and consumption is also presented. Finally, several conventional and advanced analytical techniques used to detect and identify different adulterants in dietary supplements and therefore also in foods, with particular emphasis on plant food supplements, are critically described. This review demonstrates that dietary supplement adulteration is an emerging food safety problem and that an effective control by food regulatory authorities is needed to safeguard consumers.
- Composição e abundância de macrófitas num troço do rio OvelhaPublication . Andrade, Alexandre; Azevedo, Francisca; Bessa, Catarina; Brás, Maria João; Carneiro, Tomás; Cerqueira, Maria Margarida; Geraldes, Inês; Leal, Sofia; Marinho, Ana Sofia; Monteiro, Ana Carolina; Monteiro, Nicole; Moreira, João; Nascimento, Ana Carolina; Pereira, Ilda; Pinheiro, Maria Eduarda; Pinto, Ana Rita Ferreira Leite; Pinto, David; Pinto, Fátima Raquel; Proença, André; Rangel, Tiago; Ribeiro, Teresa; Ricardo, Maria Jacinta; Rocha, Lara; Rocha, Tiago; Silva, Jéssica; Silva, Rafael; Silva, Tânia Cristina; Soares, Rui; Teixeira, Liliana; Teixeira, Marco; Teixeira, Maria Inês; Pimenta, Sofia Pimenta SaloméAs macrófitas fluviais são um grupo relevante para a avaliação ecológica dos rios. Numa amostragem realizada num troço de 100 m do rio Ovelha, localizado a 217 m de altitude, na freguesia de Fornos, Marco de Canaveses, estudou-se a abundância, composição e distribuição das macrófitas. Verificou-se que o troço estudado é pobre em macrófitas, apresentando uma riqueza específica baixa, o que poderá estar relacionado, sobretudo, com o substrato rochoso. Considerando os resultados obtidos é fundamental que, futuramente, sejam estudadas as macrófitas conjuntamente com outros elementos biológicos, no sentido de se proceder a uma correta monitorização do estado ecológico do rio Ovelha.
- Development and validation of an HPLC-DAD-FL method for the determination of food supplements adulteration with undeclared phosphodiesterase type-5 inhibitor drugsPublication . Rocha, Tiago; Santos, J.V. Araújo; Amaral, Joana S.; Oliveira, BeatrizThe consumption of food supplements has been increasing in developed countries. However, regulations and guidelines for this type of products reveal several gaps, and do not guarantee an efficient quality control, allowing for the possibility of intentional adulteration. Supplements used for improvement of male sexual performance are among the most popular food supplements. One of the major concerns in these products is the possible adulteration with synthetic drugs used for the treatment of erectile dysfunction, namely phosphodiesterase type-5 (PDE-5) inhibitor drugs, such as sildenafil, vardenafil and tadalafil. The side effects of these compounds and possible interactions with other drugs are well documented, thus its illegal addition to food supplements could pose a serious risk for consumers with known health constraints [1]. In the last years, the presence of this type of drugs have been detected by FDA in the US and reported in food supplements commercialized in Asia and the EU. Recently, Portuguese legal authorities reported the apprehension of some food supplements due to the presence of illegal PDE-5 inhibitor drugs. In this work, an high performance liquid chromatography (HPLC) based method was developed and validated for the detection of four PDE-5 inhibitors, namely sildenafil, vardenafil, tadalafil and yohimbine, in three sexual performance enhancement supplements. The analyses were performed by HPLC-DAD-FL in a JASCO chromatograph following the conditions of a previously published method [2]. A YMC-Triart C18 analytical column (3 μm, 250 × 4.6 mm) was used, together with (A) 50 mM Ammonium acetate; (B) acetonitrile/ methanol (50:50) as eluents. A simple liquid-liquid extraction with sonication using acetonitrile/methanol (50:50) was used in all samples. To validate the proposed methodology, the limits of detection (LOD) and quantification (LOQ), linearity range, intra- and inter-day precision and accuracy of the method were determined, showing high reproducibility scores and adequate recoveries for the tested compounds. One of the analyzed supplements showed the illegal addition of sildenafil.
- Food supplements adulteration with undeclared synthetic phosphodiesterase type-5 drugs (PDE-5) inhibitorsPublication . Rocha, Tiago; Amaral, Joana S.; Oliveira, BeatrizThe use ofplant food supplements (PFS) in developed countries is becoming increasingly popular mostly due to the consumers' widespread idea that natural products are safer and healthier than conventional pharmaceutical drugs [l]. However, in the last years, several studies have been showing the existence of gaps in PFS regulation that can result in insuíficient quality control and intentional adulteration ofthese products [2]. Among the issues that can aíFect PFS safety, the illegal addition of pharmaceutical substances is of major concern, since unscrupulous producers can dope PFS to provide for quick effects. Supplements used for sexual performance improvement are among the most popular PFS used by males. One of the major concerns in this type of product is the possible adulteration with drugs used for the treatment of erectile dysfunction, namely synthetic phosphodiesterase type-5 (PDE-5) inhibitor drugs, such as sildenafil, vardenafil and tadalafil which are approved prescription drugs being marketed as Viagra (Pfizer, USA), Levitra (Bayer Pharmaceuticals Co., Germany) and Cialis (Elli Lilly, USA), respectively. Since these drugs can present side eífects, its illegal addition in PFS can seriously endanger consumers' health. In particular, individuais for whom conventional PDE-5 inhibitor drugs are contraindicated and consequently use food supplements as an alternative maybe at risk ifthe clandestine addition ofthese drugs occurs. In the last years, the presence ofthis type ofdrugs have been detected by FDA in the US, and reported in food supplements commercialized in Ásia, however studies regarding this issue in the EU are almost inexistent. For the presented reasons, an analytical methodology based on the use of high performance liquid chromatography coupled to a fluorescence detector in series with a photodiode array (HPLC-FL-PDA) is proposed for the detection ofPDE-5 inhibitors, namely sildenafil and its analogue acetildenafil, vardenafil and tadalaíil, illegally added to supplements used for aphrodisiac purposes.
- Monitorização da adulteração de suplementos alimentares à base de plantas comercializados em Portugal com inibidores de fosfodiesterase tipo 5 (PDE-5)Publication . Rocha, Tiago; Santos, J.V. Araújo; Amaral, Joana S.; Oliveira, BeatrizNa ultima década, assistiu-se a um consumo crescente de suplementos alimentares pela população mundial, especialmente, no que diz respeito ao consumo de suplementos alimentares a base de plantas 1. Estes são utilizados com diversas finalidades, tais como equilibrar a dieta, compensar uma falta nutricional, manter a saúde, prevenir doenças crónicas, melhorar a aparência e o bem-estar incluindo a condição mental, sexual e desportiva, entre outras 1. São produtos frequentemente rotulados como "naturais" o que transmite uma falsa sensação de segurança aos consumidores. Contudo, recentemente foi referida a ocorrência de adulterações nestes produtos, o que compromete a sua segurança. Entre os casos de fraude detetados destaca-se a adição de substâncias ilegais. Atualmente, os suplementos para melhorar o desempenho sexual estão entre os suplementos alimentares mais populares entre os consumidores. A disfunção eréctil e uma doença que afeta 150 milhões de homens mundialmente sendo o tratamento recomendado a administração de fármacos inibidores da enzima fosfodiesterase tipo 5 (PDE-5) 2. Os inibidores PDE-5 legalmente comercializados a nível europeu são: citrato de sildenafil, tadalafil, hidrocloreto de vardenafil e avanafil 3. Estas são substâncias com efeitos secundários graves quando administrado concomitantemente com medicamentos como nitratos ou a-bloqueadores 4. 0 objetivo deste trabalho foi, por isso, a monitorização da presença de adulterantes do tipo inibidores PDE-5 em suplementos alimentares a base de plantas vendidos com o objetivo de melhorar a performance sexual. Foram analisados doze suplementos alimentares, adquiridos no mercado português. Estes suplementos foram pesquisados quanto a presença de sildenafil, acetildenafil, tiosildenafil, tadalafil, vardenafil e yombina, atraves de metodo de crornatografia líquida de elevada performance acoplada a detetor de díodos e detetor de fluorescência em série (HPLC-DAD-FL). Dos doze suplementos analisados, seis revelaram a presença de um ou mais dos inibidores PDE-5 referidos. Adicionalmente, dois outros suplementos revelaram a presença de dois compostos, cujo espectro UV-Vis leva a suspeição de uma possível adulteração com compostos análogos às substâncias pesquisadas.
- Safety concerns regarding plant food supplementsPublication . Rocha, Tiago; Amaral, Joana S.; Oliveira, BeatrizIn the last years, plant food supplements (PFS) consumption has been increasing in developed countries, in part reflecting the growing acceptance and use of alternative/traditional medicine but also due to the common idea that PFS are natural products posing no risks to human health. Being legally considered as foods under Directive 2002/46/EC, PFS are under control of the European Food Safety Agency (EFSA) and do not require the same requisites as traditional herbal medicines for legal authorization In practice, this means that several products are being sold under the umbrella of PSF, being easily avaiJable in supermarkets, .TV shops and the internet, and not under the supervision and control of the' health authorities.