Influência da época de colheita e estado fenológico na composição fenólica e propriedades bioativas de infusões de tomilho-limão, hortelã-vulgar, limonete e erva-príncipe

Mestrado em cooperação com a Universidade de SalamancaRecentemente, com a evolução do mercado do chá e devido à crescente procura pela novidade por parte dos consumidores, as empresas de plantas têm vindo a desenvolver novos produtos de valor acrescentado, com características exclusivas. Entre estes produtos, os lotes de reserva de plantas aromáticas, surgem como uma seleção de partes específicas de plantas, preparadas através de técnicas de colheita distintas, que lhes confere características organoléticas singulares. No presente estudo foram avaliados quatro espécies de plantas amplamente consumidas em Portugal, entre elas a Mentha spicata L., Cymbopogon citratus (DC.) Stapf, Aloysia citriodora (L’Herit.) Britton, e Thymus × citriodorus L., de forma a explorar as diferenças entre infusões preparadas a partir dos lotes normais e reserva, no que respeita à sua composição fenólica e às suas propriedades antioxidantes. As infusões obtidas pelos lotes reserva de M. spicata, C. citratus e A. citriodora revelaram uma maior concentração em compostos fenólicos do que os preparados através dos lotes normais. Por outro lado, a infusão obtida através do lote normal de T. citriodorus apresentou maiores quantidades de ácidos fenólicos do que o lote reserva, no entanto, a quantidade de flavonoides totais e compostos fenólicos não foi significativamente diferente do lote reserva. Ambos os lotes de M. spicata apresentam o ácido rosmarínico como sendo o composto fenólico maioritário, no entanto o lote reserva foi o que apresentou maior teor em compostos fenólicos totais. C. citratus revelou uma prevalência de flavonoides, com uma elevada contribuição de luteolina 2”-O-deoxi-hexosil-6-C-glucósido, mas o composto mais abundante foi o ácido 5-O-cafeoilquínico em ambos os lotes. Relativamente à A. citriodora a luteolina-7-O-diglucurónido e verbascósido foram os compostos maioritários identificados. Em T. citriodorus, em ambos os lotes registou-se uma prevalência de ácidos fenólicos, sendo o ácido rosmarínico o mais abundante, seguido do ácido litospérmico A e de um hexósido de ácido rosmarínico. Em termos de atividade antioxidante, as diferenças entre lotes foram mais evidentes nas infusões de C. citratus e M. spicata do que nas restantes infusões, sendo o lote reserva, aquele que apresentou maior atividade antioxidante. Em geral, a atividade antioxidante das infusões preparadas a partir de diferentes lotes de plantas está correlacionada positivamente com a sua composição fenólica.Recently, with the evolution of the tea market, given the increasing consumers demand for novelty, tea companies have been presenting new added value products with alternative traits. Among these products, the reserve lots of aromatic plants arise as a selection of specific parts of the plants, prepared through distinct harvesting techniques that confer them singular organoleptic characteristics. In the present study, four widely consumed specimens in Portugal, Mentha spicata L., Cymbopogon citratus (DC.) Stapf, Aloysia citriodora (L’Herit.) Britton, and Thymus × citriodorus L. were assessed to explore the differences between infusions prepared from their standard and reserve lots, in what concerns the phenolic composition and related antioxidant properties. The infusions obtained from M. spicata, C. citratus and A. citriodora reserve lots revealed higher concentration in phenolic compounds than those prepared from the respective standard lots. Otherwise, the infusion of T. citriodorus standard lot presented higher amounts of phenolic acids than the reserve lot, nonetheless, total flavonoids and phenolic compounds were not significantly different between both lots. The two types of M. spicata lots presented rosmarinic acid as the most abundant phenolic compound, but the reserve lot had the highest total phenolic compounds content. C. citratus revealed a prevalence of flavonoids, with the highest contribution of luteolin 2”-O-deoxyhexosyl-6-C-glucoside, but the most abundant compound was 5-O-caffeoylquinic acid in both lots. Regarding A. citriodora, luteolin-7-O-diglucuronide and verbascoside were the major compounds identified. In T. citriodorus, both lots revealed the prevalence of phenolic acids, with rosmarinic acid as the most abundant, followed by lithospermic acid A and rosmarinic acid hexoside. In terms of antioxidant activity, the differences between both lots were more noticeable in C. citratus and M. spicata than in the other plants infusions, with the reserve lot presenting the highest activity. In general, the antioxidant activity of the infusions prepared from the different lots of the plants was positively correlated to their phenolic composition.Este trabalho foi financiado pelo programa FEDER-Interreg España-Portugal através do projeto 0377_Iberphenol_6_

Exploring reserve lots of Cymbopogon citratus, Aloysia citrodora and Thymus x citriodorus as improved sources of phenolic compounds

Given the increasing consumers demand for novelty, tea companies have been presenting new added value products such as reserve lots of aromatic plants. Herein, infusions from different lots of three aromatic plants were assessed in terms of phenolic composition (HPLC-DAD-ESI/MS) and antioxidant properties (reducing power, free radical scavenging and lipid peroxidation inhibition capacity). Cymbopogon citratus (C. citratus; main compound 5-O-caffeoylquinic acid) and Aloysia citrodora (A. citrodora; prevalence of verbascoside) reserve lots revealed higher phenolic compounds concentration than the respective standard lots. Thymus×citriodorus (T. citriodorus; main compound rosmarinic acid) standard lot presented higher amounts of phenolic acids than the reserve lot, nonetheless, total flavonoids and phenolic compounds were not significantly different. The differences between both lots antioxidant activity were more noticeable in C. citratus, with the reserve lot presenting the highest activity. This study provides evidence of the differences between these plants chemical composition and bioactivity depending on the harvesting conditions.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013); to FCT for L. Barros research contract; to FCT for the grant attributed to C. Pereira (SFRH/BPD/122650/2016) through the Programa Operacional Capital Humano (POCH) supported by the European Social Fund and National Funds of MCTES (Ministério da Ciência, Tecnologia, e Ensino Superior). The authors are grateful to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

Bioactive properties of Mentha spicata L. infusions: a comparison between standard and reserve lots

Mentha spicata L., commonly known as spearmint and belonging to the Lamiaceae family, is widely used as infusion due to its exquisite and outstanding flavour [1]. This medicinal and aromatic plant is also known for its antioxidant properties due to naturally occurring active compounds, such as phenolic compounds including flavonoids. [2] Recently, with the increased consumption of herbal infusions, several novel products are emerging and different lots with distinct compositions of the same plant are available for herbal infusions preparation [3]. As an outstanding example, the standard lots have evolved to "reserve lots", which are prepared from the apical leaves of the plant, presenting different compositions and sensorial characteristics. In the present study, the aim was to evaluate and compare the antioxidant activity as well as the bioactive compounds (phenolics and flavonoids) content of M. spicatae infusions prepared from standard and reserve lots, in order to understand the potential differences between both batches. The antioxidant activity was assessed by different assays (free radicals scavenging activity, reducing power, and lipid peroxidation inhibition), whereas total phenolics and flavonoids were estimated by colorimetric assays. The best results of antioxidant activity were achieved with the reserve lot that presented the lowest EC50o values in all the assays performed (152 to 336 μg/mL) in comparison to the standard lot (173 to 546 μg/mL). Both the infusions revealed higher potential in lipid peroxidation inhibition, in concentrations of 173 (standard tot) and 152 μg/mL (reserve lot), followed by reducing power (301 and 198 μg/mL, respectively) and free radicals scavenging activity (546 and 336 μg/mL). As expected from the antioxidant assays results, the amounts of total phenolics and flavonoids were higher in the reserve lot (2. 86 and 0. 378 mg GAE/mL, respectively) when compared to the standard lot (1. 83 and 0.268 mg GAE/mL), which is in accordance with the well-known bioactivity of these compounds. Thus, in our perspective, this study represents a major contribution of scientific information, allowing the consumer to understand the increased benefits of these new emerging tea products

Mentha spicata L. infusions as sources of antioxidant phenolic compounds: emerging reserve lots with special harvest requirements

Mentha spicata L., commonly known as spearmint, is widely used in both fresh and dry forms, for infusion preparation or in European and Indian cuisines. Recently, with the evolution of the tea market, several novel products with added value are emerging, and the standard lots have evolved to reserve lots, with special harvest requirements that confer them with enhanced organoleptic and sensorial characteristics. The apical leaves of these batches are collected in specific conditions having, then, a different chemical profile. In the present study, standard and reserve lots of M. spicata were assessed in terms of the antioxidants present in infusions prepared from the different lots. The reserve lots presented the highest concentration in all the compounds identified in relation to the standard lots, with 326 and 188 μg mL−1 of total phenolic compounds, respectively. Both types of samples presented rosmarinic acid as the most abundant phenolic compound, at concentrations of 169 and 101 μg mL−1 for reserve and standard lots, respectively. The antioxidant activity was higher in the reserve lots which had the highest total phenolic compounds content, with EC50 values ranging from 152 to 336 μg mL−1. The obtained results provide scientific information that may allow the consumer to make a conscientious choice.info:eu-repo/semantics/publishedVersio

Standard versus reserve lots of Thymus x citriodorus L. and Mentha spicata L. : nutritional contribution of the infusions

Nowadays we can notice a significant increase in the consumption of tea and herbal infusions, in such a way that their daily worldwide consumption is valuated in more than three million cups. Hence, as expected, the tea market became a highly competitive and sophisticated sector, where a wide range of products continue to be developed for added-value [1, 2]. An example in the tea industry of a new range of emerging products, are the designated "reserve lots" exclusively made up by the younger parts (apical leaves) of the plant collected in the hot summer months, unlike the standard lots, which have no harvest specific requirements. In this context, the present study was accomplished to understand the differences between infusions made from reserve lots and standard lots, in an attempt to contribute for the consumer best choice. For that purpose, we studied the nutritional value and energetic contribution of the infusions of two important species widely used either by their health benefits or their organoleptic properties, Thymus x citriodorus L. and Mentha spicata L., available in standard and reserve lots. Ali of the infusions revealed the presence of fructose, glucose and sucrose (determined by high performance liquid chromatography coupled to a refraction index detector) in very low concentrations, but in the reserve lots slightly higher amounts were detected in comparison to the standard lots. Nonetheless, T. citrodorus revealed the most relevant differences between the carbohydrates level (6.2 and 15.4 mg/100 mL, for the standard and reserve lots, respectively) and, consequently, the energetic contribution (24. 6 and 61 cal/100 mL). Regarding to the infusions of M. spicata, the carbohydrates and energy ranged from 13.2 mg/100 mL and 53 cal/100 mL (in the standard lot) to 16. 9 mg/100 mL and 67.4 cal/100 mL (in the reserve lot), respectively. Sucrose was the most abundant sugar in M. spicata (5. 9 and 8.4 mg/100 mL), whereas glucose prevailed in T. citrodorus (2. 2 and 5.75 mg/100 mL). The results here described are of great interest once they elucidate the consumer about the main differences between the nutritional contributions of the infusions obtained from different lots available on the market, allowing making a conscientious choice

Lotes normais e de reserva de hortelã-vulgar: composição fenólica e propriedades antioxidantes das infusões

A hortelã-vulgar (Mentha spicata L.) é uma planta da família das Laminaceae amplamente utilizada na preparação de infusões e na cozinha Europeia e Indiana, tanto em fresco como seca [1]. É reconhecida como fonte de antioxidantes, de entre os quais se destacam os compostos fenólicos pelas suas propriedades protetoras em situações de stresse oxidativo [2]. Com o crescimento dos produtores de plantas aromáticas e medicinais, têm surgido no mercado novos produtos de valor acrescentado. Por exemplo, os lotes normais evoluíram para lotes de reserva, preparados com folhas apicais colhidas em condições específicas que lhes conferem características organoléticas e sensoriais melhoradas. No presente trabalho, pretendeu-se avaliar e comparar a atividade antioxidante, nomeadamente a capacidade captadora de radicais livres, o poder redutor, e a capacidade de inibição da peroxidação lipídica, de lotes normais e de reserva de hortelã-vulgar, bem como os respetivos perfis fenólicos, determinados por HPLC-DAD-ESI/MS. Relativamente aos compostos fenólicos identificados, o lote de reserva apresentou teores mais elevadas do que o lote normal, com concentrações de 326 e 188 μg/mL de compostos fenólicos totais, respetivamente. O ácido rosmarínico foi o mais abundante em ambos os lotes, estando presente em concentrações de 169 e 101 μg/mL nos lotes de reserva e normal, respetivamente. Os ácidos isosalvianolico A e salvianolico L não foram comuns aos dois lotes analisados, tendo sido detetados apenas no lote normal em concentrações de 13 e 6 μg/mL, respetivamente. Para além do teor mais elevado de compostos fenólicos, o lote de reserva revelou ainda a melhor atividade antioxidante, com valores de EC50 inferiores aos do lote normal, respetivamente entre 152 e 336 μg/mL e entre 173 e 546 μg/mL. Os resultados obtidos neste estudo permitem ao consumidor uma escolha mais consciente com base nas diferentes propriedades destes lotes de hortelã-vulgar.Os autores estão gratos à Fundação para a Ciência e Tecnologia (FCT, Portugal) pelo apoio financeiro a C. Pereira (UID/AGR/00690_BI/CIMO/15/AromPlants) e L. Barros (SFRH/BPD/107855/2015).info:eu-repo/semantics/publishedVersio

Lotes de reserva de Aloysia citrodora (L’Herit.) Britton e Cymbopogon citratos (DC.) Stapf como fontes melhoradas de compostos fenólicos com propriedades bioativas

Aloysia citrodora (L'Herit.) Britton e Cymbopogon citratus (De.) Stapf são plantas pertencentes à família das Verbenaceae e Poaceae, respetivamente. São comummente conhecidas como limonete (A. citrodora) e erva-príncipe (C. citratus) e as infusões das suas folhas têm vindo a ser amplamente utilizadas pelas suas reconhecidas propriedades terapêuticas e características sensoriais, especialmente o característico aroma cítrico [1,2]. Para além dos lotes normais destas plantas, surgem agora os lotes de reserva, com características organoléticas diferenciadas, preparados a partir das folhas apicais colhidas em condições específicas [3]. Nesse sentido, este trabalho teve como objetivo caracterizar e comparar em termos de perfil fenólico (analisado por HPLC-DADESI/ MS) e capacidade antioxidante (atividade captadora de radicais livres, poder redutor e capacidade de inibição da peroxidação lipídica) das infusões obtidas a partir dos dois lotes (normal e de reserva) de limonete e erva-príncipe. As infusões de limonete apresentaram perfis fenólicos semelhantes em termos de compostos identificados, mas o teor total de compostos fenólicos encontrados na infusão do lote de reserva (230 llg/mL) foi superior ao do lote normal (182 llg/mL). Ambos os lotes apresentaram como compostos maioritários o verbascósido (93 e 73 llg/ml nos lotes de reserva e normal, respetivamente) e a luteolina-7-0-diglucurónido (88 e 68~-tg/mL) . O lote de reserva revelou ser mais rico tanto em ácidos fenólicos (1,91 e 1,65 llg/ml nos lotes de reserva e normal, respetivamente) como em flavonóides (117 e 94 ~-tg/ml) e derivados do ácido cafeico (112 e 86 llg/mL). Relativamente às infusões de erva-príncipe, o lote de reserva apresentou uma concentração total de compostos fenólicos muito superior à do lote normal (88 e 12,3 llg/ml, respetivamente), revelando teores mais elevados de ácidos fenólicos (26,2 e 5,00 llg/mL) e flavonóides (62 e 7,3 llg/mL). O ácido 5-0-cafeoilquínico foi o mais abundante em ambas as infusões (23,3 e 3,87 llg/ml nos lotes de reserva e normal, respetivamente). Relativamente à atividade antioxidante, a infusão do lote de reserva de limonete revelou melhores resultados que a do lote normal, com valores de ECso significativamente inferiores no caso do ensaio do poder redutor (0,169 e 0,205 mg/ml, respetivamente). Apresentou ainda melhores resultados na atividade captadora de radicais livres e na inibição da peroxidação lipídica, ainda que com diferenças menos acentuadas. No que respeita às infusões de erva-príncipe, o lote de reserva revelou uma capacidade antioxidante significativamente superior à do lote normal, com valores de EC50 muito inferiores em todos os ensaios realizados: poder redutor (1,01 e 2,33 mg/ml, respetivamente), atividade captadora de radicais DPPH (1,43 e 3,49 mg/ml), inibição da descoloração do β-caroteno (2,01 e 3,66 mg/ml) e inibição da peroxidação lipídica (0,37 e 0,75 mg/ml). Os resultados obtidos neste estudo permitem um melhor conhecimento das propriedades bioativas de infusões obtidas a partir de diferentes lotes destas plantas.FCT e FEDER sob o Programa PT2020 pelo apoio financeiro ao CIMO (UID/ AGR/00690/2013), bolsa de C. Pereira (SFRH/BPD/122650/2016) e contrato de L Barros. lnterreg Espana-Portugal pelo apoio financeiro através do projeto 0377 lberpheno1_6_E.info:eu-repo/semantics/publishedVersio

Antioxidant activity and nutritional value of Mentha spicata L.: a comparison between reserve and standard lots

Currently, the consumption of tea and herbal infiisions is increasing só much that its daily worldwide consumption is evaluated in more than three million cups. Therefore, in a competitive and sophisticated sector as the tea market, the innovation and development of new products is imperative (Hicks, 2009; Li et al., 2013). Nowadays, we have at our disposal a new range of emerging products, such as the designated "reserve lots" exclusively prepared by using the younger parts (apical leaves) ofthe plant collected in the hot summer months; the standard lots do not have these harvest specific requirements. In this perspective, the present study was accomplished to understand the differences between two lots of Mentha spicata L. (spearmint) for infusion preparation, widely used due to its exquisite and outstanding flavour, as well as for its antioxidant properties (Goméz-Prieto et al., 2007). The nutritional value, the energetic contribution, and the antioxidant activity, as well as the bioactive compounds (phenolics and flavonoids) content of both standard and reserve lots, were evaluated. The nutritional value was determined through the infüsion sugars content, once these were the only nutrients present in the preparations; the analysis was carried out by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI). The presence of fmctose, glucose and sucrose was detected in very low concentrations on both infüsions, with the reserve lot revealing slightly higher amounts. Sucrose was the most abundant sugar, present in a concentoration of 5.9 mg/100 mL in the standard lot and 8.4 mg/100 mL in the reserve lot. Total sugars and energy were 13.2 mg/100 mL and 53 cal/100 mL, respectively, in the standard lot; and 16.9 mg/100 mL and 67.4 cal/100 mL, respectively, in the reserve lot. The antioxidant activity of the infüsions was assessed by different assays (free radicais scavenging activity, reducing power and lipid peroxidation inhibition), whereas total phenolics and flavonoids were estimated by colorimetric assays. The reserve lot presented the lowest EC50 values, corresponding to a higher antioxidant activity, in ali the assays performed (152 to 336 |ig/mL), in comparison to the standard lot (173 to 546 |^g/mL). Both the iníüsions revealed higher potential in lipid peroxidation inhibition, in concentrations of 173 (standard tot) and 152 [ig/mL (reserve lot), followed by reducing power (301 and 198 l^g/mL, respectively) and free radicais scavenging activity (546 and 336 |^g/mL, respectively). In agreement with the antioxidant activity results, the amounts of total phenolics and flavonoids were higher in the reserve lot (2. 86 and 0.378 mg gallic acid equivalents- GAE/mL) when compared to the standard lot (1. 83 and 0.268 mg GAE/mL). Overall, in our perspective, these results represent a major contribution to elucidate the consumer about the bioactive effects of new emerging tea products such as reserve lots, which actually showed a higher antioxidant activity