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Avaliação do potencial nutricional e antioxidante de Strychnos madagascariensis poir
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Moçambique enfrenta diversos desafios na área da saúde e nutrição, pois as taxas de desnutrição continuam elevadas e com maior incidência nas áreas rurais. A carência de alimentos e défice de nutrientes contribuem para maiores fragilidades na saúde das comunidades, elevando o risco de doenças infetocontagiosas. Nas épocas de escassez de alimentos a população recorre a alimentos locais como frutos silvestres, tubérculos e cogumelos que são colhidos nas matas circundantes. Entre os alimentos colhidos, alguns têm potencial para contribuir para a melhoria da situação nutricional das comunidades, apesar de na sua maioria ainda não terem sido avaliados quanto ao seu valor nutricional.
Por outro lado, o serviço nacional de saúde ainda não consegue garantir cuidados primários de saúde para toda a população, sendo as zonas rurais as que enfrentam maiores desafios, devido à baixa cobertura existente e às distâncias entre as povoações e as unidades sanitárias, implicando tal, em conjunto com fatores socioculturais, o recurso à medicina tradicional para os cuidados primários de saúde.
Para além do recurso aos praticantes de medicina tradicional, a população faz por ela própria uso de diversas plantas com propriedades medicinais. Uma das plantas usadas é Strychnos madagascariensis Poir., fruto, localmente conhecida por macúacua ou Nkwakwa e objeto do presente trabalho. Este fruto é consumido na zona do sul de Moçambique, como alimento e como medicamento tradicional usado no tratamento e alívio dos sintomas de hipertensão e da diabetes.
Assim, este trabalho teve como base informações etnobotânicas colhidas na região de Namaacha na província de Maputo, Moçambique, a colheita do material vegetal nesta região, a preparação deste material de acordo com a metodologia tradicional (amostra Smfr-A) e a avaliação neste e numa amostra comercial (amostra Smfr-C) da mesma planta medicinal do respetivo potencial nutricional através da determinação do teor de matéria gorda total, açúcares totais, cinza total e vitamina C, foram também pesquisadas as principais classes de metabolitos secundários por TLC e por LC-UV/DAD e quantificadas por espectrofotometria UV/VIS as classes de metabolitos detetadas. Posteriormente foi determinada a atividade antioxidante pelos métodos DPPH e FRAP. Foram também determinados os parâmetros botânicos macro e microscópicos necessários à possível utilização desta planta medicinal em produtos de saúde à base de plantas.
Os resultados obtidos mostraram para as amostras Smfr-A e Smfr-C de Strychnos madagascariensis, fruto respetivamente, teores de gordura total de 27g e 18g, cinzas totais de 2,44 g e 3,96 g, hidratos de carbono totais de 6g e 6,6g, e 44 mg e 13,9 mg de vitamina C, por 100 g de amostra processada.
Os extratos hidroetanólicos (70º) preparados a partir de Smfr-A e Smfr-C possuem, respetivamente, 0,41 mg e 0,46 mg fenóis totais por 1 mg de extrato, 0,19 mg e 0,20 mg de triterpenóides por 1 mg de extrato, 0,002 mg e 0,07 mg de taninos condensados por 1 mg de extrato e 0,03 mg de taninos hidrolisáveis por 1 mg de extrato. Ambos os extratos (Smfr-A e Smfr-C) demonstraram ter atividade antioxidante superior à do ácido ascórbico pelo método DPPH, nomeadamente um valor de IC50% de 43,26 mg/ml e 40,62 mg/ml, e uma capacidade antioxidante de respetivamente 5,9 mM de Fe2SO4 por 1 mg do extrato e 6,08 mM Fe2SO4 por 1 mg do extrato.
A caracterização macroscópica e microscópica do material vegetal em natureza (Smfr-A) e pulverizado (Smfr-A e Smfr-C) permitiu a seleção de estruturas úteis para a sua identificação enquanto planta medicinal, destacando-se entre estas a presença de tricomas tetores filiformes, espessados isolados, em grupos ou inseridos em fragmentos da epiderme do tegumento.
Os resultados mostram o potencial de S. madagascariensis, fruto como alimento e como fonte de metabolitos secundários que poderão justificar a sua utilização para fins medicinais.
Mozambique faces several challenges in the area of health and nutrition, as malnutrition rates remain high and with a higher incidence in rural areas. The lack of food and nutrient deficit contribute to greater weaknesses in the health of communities, raising the risk of infectious diseases. In times of food shortages, the population uses local foods such as wild fruits, tubers and mushrooms that are harvested in the surrounding forests. Among the foods harvested, some have the potential to contribute to improving the nutritional situation of communities, although most have not yet been evaluated for their nutritional value. On the other hand, the national health service is still unable to guarantee primary health care for the entire population, with rural areas facing the greatest challenges, due to the low coverage that exists and the distances between the villages and the sanitary units, implying this, together with sociocultural factors, the use of traditional medicine for primary health care. In addition to the use of traditional medicine practitioners, the population makes by itself the use of several plants with medicinal properties. One of the plants used is Strychnos madagascariensis Poir. fruit, locally known as macúacua or Nkwakwa and object of the present work. This fruit is consumed in the southern area of Mozambique, as food and as a traditional medicine used in the treatment and relief of symptoms of hypertension and diabetes. Thus, this work was based on ethnobotany information collected in the Namaacha region in Maputo province, Mozambique, the harvesting of plant material in this region, the preparation of this material according to the traditional methodology (sample Smfr-A) and the evaluation of this and of a commercial sample (sample Smfr-C) of the same medicinal plant concerning: the nutritional potential by determining the total fat content, total sugars, total ash and vitamin C; a screening of the main classes of secondary metabolites by TLC and LC-UV/DAD were also performed and the principal classes of detected metabolites were also quantitatively determined by spectrophotometry UV/VIS. Additionally, botanical macro and microscopical parameters needed in order to allow the use of this medicinal plant in plant-based health products were also determined. The results obtained showed for the samples Smfr-A and Smfr-C of Strychnos madagascariensis, fruit respectively, a total fat contents of 27g and 18g, a total ash of 2.44g and 3.96 g, a total carbohydrates of 6g and 6.6g, and a total amount of 44 mg and 13.9 mg of vitamin C, per 100 g of processed sample. Hydroethanol extracts (70 º) prepared from Smfr-A and Smfr-C have, respectively, 0.41 mg and 0.46 mg total phenols per 1 mg extract, 0.19 mg and 0.20 mg triterpenoid for 1 mg extract, 0.002 mg and 0.07 mg condensed tannins per 1 mg extract and 0.03 mg hydrolysable tannins per 1 mg extract. Antioxidant activity evaluation by the DPPH method showed for these extracts (Smfr-A and Smfr-C) respectively, an IC50 of 43.26 mg/ml and 40.62 mg/ml, and an antioxidant capacity of 5.9 mM Fe2SO4 per 1 mg of extarct and 6.08 mM Fe2SO4 per 1 mg of extract. The macroscopic and microscopic characterization of the plant material in nature (Smfr-A) and powdered (Smfr-A and Smfr-C) allowed the selection of structures useful for its identification as herbal medicine, especially among these the presence of filiform trichomes thickened, in groups or inserted in fragments of the tegument epidermis. The results show the potential of S. madagascariensis,fruit as food and as a source of secondary metabolites that may justify its use for medicinal purposes.
Mozambique faces several challenges in the area of health and nutrition, as malnutrition rates remain high and with a higher incidence in rural areas. The lack of food and nutrient deficit contribute to greater weaknesses in the health of communities, raising the risk of infectious diseases. In times of food shortages, the population uses local foods such as wild fruits, tubers and mushrooms that are harvested in the surrounding forests. Among the foods harvested, some have the potential to contribute to improving the nutritional situation of communities, although most have not yet been evaluated for their nutritional value. On the other hand, the national health service is still unable to guarantee primary health care for the entire population, with rural areas facing the greatest challenges, due to the low coverage that exists and the distances between the villages and the sanitary units, implying this, together with sociocultural factors, the use of traditional medicine for primary health care. In addition to the use of traditional medicine practitioners, the population makes by itself the use of several plants with medicinal properties. One of the plants used is Strychnos madagascariensis Poir. fruit, locally known as macúacua or Nkwakwa and object of the present work. This fruit is consumed in the southern area of Mozambique, as food and as a traditional medicine used in the treatment and relief of symptoms of hypertension and diabetes. Thus, this work was based on ethnobotany information collected in the Namaacha region in Maputo province, Mozambique, the harvesting of plant material in this region, the preparation of this material according to the traditional methodology (sample Smfr-A) and the evaluation of this and of a commercial sample (sample Smfr-C) of the same medicinal plant concerning: the nutritional potential by determining the total fat content, total sugars, total ash and vitamin C; a screening of the main classes of secondary metabolites by TLC and LC-UV/DAD were also performed and the principal classes of detected metabolites were also quantitatively determined by spectrophotometry UV/VIS. Additionally, botanical macro and microscopical parameters needed in order to allow the use of this medicinal plant in plant-based health products were also determined. The results obtained showed for the samples Smfr-A and Smfr-C of Strychnos madagascariensis, fruit respectively, a total fat contents of 27g and 18g, a total ash of 2.44g and 3.96 g, a total carbohydrates of 6g and 6.6g, and a total amount of 44 mg and 13.9 mg of vitamin C, per 100 g of processed sample. Hydroethanol extracts (70 º) prepared from Smfr-A and Smfr-C have, respectively, 0.41 mg and 0.46 mg total phenols per 1 mg extract, 0.19 mg and 0.20 mg triterpenoid for 1 mg extract, 0.002 mg and 0.07 mg condensed tannins per 1 mg extract and 0.03 mg hydrolysable tannins per 1 mg extract. Antioxidant activity evaluation by the DPPH method showed for these extracts (Smfr-A and Smfr-C) respectively, an IC50 of 43.26 mg/ml and 40.62 mg/ml, and an antioxidant capacity of 5.9 mM Fe2SO4 per 1 mg of extarct and 6.08 mM Fe2SO4 per 1 mg of extract. The macroscopic and microscopic characterization of the plant material in nature (Smfr-A) and powdered (Smfr-A and Smfr-C) allowed the selection of structures useful for its identification as herbal medicine, especially among these the presence of filiform trichomes thickened, in groups or inserted in fragments of the tegument epidermis. The results show the potential of S. madagascariensis,fruit as food and as a source of secondary metabolites that may justify its use for medicinal purposes.
Descrição
Tese de mestrado, Qualidade Alimentar e Saúde, 2019, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Antioxidantes Composição química Medicina tradicional Monkey orange Nkwakwa Nutrição Strychnos madagascariensis Tese de mestrado - 2019