Bioactive compounds of citrus as health promoters

Citrus are a group of fruit species, quite heterogeneous in many aspects, including chemical composition of the fruit. Since ancient times, some citrus fruits were used to prevent and cure human diseases. In the recent decades, it has been demonstrated that fruits can actually help prevent and cure some diseases and above all, they are essential in a balanced diet. Citrus fruits, as one of the groups of fruit species, with greater importance in the world, have been studied for their effects on human health. Some species of citrus were referred as potential antioxidant based therapy for heart disease, cancer and inflammation. Fruit peels and seeds have also high antioxidant activity. The health benefits of citrus fruit have mainly been attributed to the high level of bioactive compounds, such as phenols (e.g., flavanone glycosides, hydroxycinnamic acids), carotenoids and vitamin C. These compounds are present in the fruit pulp and hence in the juice. But some bioactive compounds can be found in parts of the fruit which usually are not used for human food. The content of bioactive compounds depends on the species and cultivar, but also depends on the production system followed in the orchard. Citrus fruits, their derivatives and their by-products (peel, pulp and oil) are reach in different bioactive compounds and its maturity, postharvest and agroindustry processes influence their composition and concentration. The aim of this chapter was to review the main bioactive compounds of the different components of citrus and their relationship to health.

Molecular characterization of Citrus tristeza virus isolates from Cyprus on the basis of the coat protein gene

Within the context of a program in Cyprus for the control of Citrus tristeza virus (CTV), the coat protein (CP) genes of 12 local isolates of the virus that induced different symptoms on host trees, were compared to those of known isolates. The CP genes were reverse-transcribed (RT) and amplified by polymerase chain reaction (PCR) and the resulting amplicons were cloned and sequenced. Nucleotide sequence analysis revealed no signs of geographic speciation. All the sequences obtained clustered close to those of previously known isolates of worldwide origin that are in five distinct groups. The nucleotide diversity was high compared to that found using a worldwide database of CP gene sequences. These data support the existence of different CTV introductions into Cyprus or an introduction from a location in which CTV is relatively diverse. Some of the isolates induced stem pitting on branches of grapefruit and sweet orange. Such isolates have not been noted often in the Mediterranean basin. They were close in CP sequence to isolate B249 from Venezuela, which induces stem pitting, and are of particular concern for the whole region.

First report of Citrus tristeza virus in the State Union of Serbia and Montenegro.

Citrus production in the State Union of Serbia and Montenegro has a strategic importance to the agricultural sector. Approximately 400,000 trees are now grown in the major citrus producing region, which is the Montenegrin Coastal Region. Satsuma mandarins and lemons grafted on Poncirus trifoliata are the most cultivated varieties. In December 2003, eight samples taken from the coastal region close to the towns of Bar and Ulcinj were analyzed using enzyme- linked immunosorbent assay (ELISA) with SP7 antibodies produced at Universidade do Algarve, Portugal (3). Further analysis was done using immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) targeting the entire coat protein (CP) gene (forward primer CTV1: 5(prime)- ATGGACGACGAAACAAAGAA-3(prime) and reverse primer CTV10: 5 (prime)-ATCAACGTGTGTTGAATTTCC-3(prime)). Using both techniques, seven of eight samples analyzed were found to be infected by Citrus tristeza virus (CTV), including samples from five trees that exhibited chlorosis, gummosis, and fruit deformation, and two trees that were symptomless.

Occurrence of stem-pitting strains of Citrus tristeza virus in Croatia

Citrus is grown in Croatia (approximately 1,500 ha of citrus groves) on the Dalmatian Coast and Islands between 42 and 43°30'N. The major species, Citrus unshiu Marc. (Satsuma mandarin), is grafted on trifoliate rootstock. The presence of Citrus tristeza virus (CTV) in Satsumas in the Neretva Valley Region was previously reported (3). During the course of a biomolecular characterization of isolates from Croatia, 15 budsticks were collected from field- infected, enzyme-linked immunosorbent assay (ELISA)-positive sources during the autumn of 2003 near Kaštela, Split, Metković (Neretva Valley), and on the island of Vis. Isolates were propagated by graft transmission to Madam Vinous sweet orange (SwO) and maintained in an insect-proof greenhouse at 21 to 33° C.

Antioxidant and phenolic compounds in sweet potato peels and leaves: food applications and health benefits

Tese de doutoramento, Ciências Biotecnológicas (Biotecnologia Alimentar), Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Citrus as a component of the Mediterranean Diet

Citrus are native to southeastern Asia, but are present in the Mediterranean basin for centuries. This group of species has reached great importance in some of the Mediterranean countries and, in the case of orange, mandarin and lemon trees, they found here soil and climatic conditions which allows them to achieve a high level of fruit quality, even better than in the regions where they came from. Citrus fruits are present in the diet of the peoples living on the Mediterranean basin, at least since the time of the Roman Empire. In the 20th century they became the main crop in various agricultural areas of the Mediterranean, playing an important role in the landscape, in the diet of the overall population, and also in international trade. They are present in the gardens of palaces and monasteries, but also in the courtyards and orchards of the poorest families. Their fruits are not only a refreshing dessert, but also a condiment, or even a major component of many dishes. Citrus fruits have well-documented nutritional and health benefits. They can actually help prevent and cure some diseases and, above all, they are essential in a balanced and tasty diet.

Determinação da qualidade do fruto em citrinos de diferentes modos de produção

Dissertação mest., Agricultura Sustentável, Universidade do Algarve, 2007

Caracterização fisiológica e nutritiva da clorose férrica em citrinos

Tese dout., Ciências Agrárias, Produção Vegetal, Unidade de Ciências e Tecnologias Agrárias, Universidade do Algarve, 2000

Evaluation of fruit and seed diversity and characterization of carob (Ceratonia siliqua L.) cultivars in Algarve region

The genetic diversity of 15 carob ( Ceratonia siliqua L.) cultivars located in an experimental field from Algarve (Portugal) was evaluated over 7 years using 12 fruit and seed phenotypic characters, in order to characterize carob cultivars. The values of morphological traits obtained by cultiv ar were compared with those from other countries of the Mediterranean basin. Statistically significant differences were found between cultivars for al l characters which were examined, what indicates a high genetic diversity. The relationship among these characters was analyzed by principal component analysis (PCA) resulting in the separation of these cultivars classed in four groups (clusters I–IV) and in four ungrouped cultivars. A three dimension of the model was found to be significant and explained 74.5% of the total variation, in which the first component accounting for 34.6% of the total variation is dominated by fruit characters, while the second component is dominated by seed characters. Cultivars plotted on the left-lower quadrant on the space determined by principal components 1 and 2 are characterized by fruits with high seed yield more appropriated for industrial rentability. The correlation analyses established by cultivar provided a specific understanding about the way how fruit and seed characteristics correlate within each cultivar. This approach can be useful for the development of a breeding programme, aiming to increase the seed yield, seed thickness, individual and total seed weight by fruit, characteristics that are determinant to improve the industrial exploitation of carob.

Effect of N-nutrition and irrigation on carob (Ceratonia siliqua L.) fruit production

Carob is a traditional crop in Mediterranean areas. It exhibits drought resistance (Lo Gullo and Salleo 1988. Nunes et al. 1989) and tolerates different edaphic conditions (Martins-Loução and Brito de Carvalho 1990).

Variabilidade genómica de Citrus tristeza virus e transformação genética de Citrus aurantium L. com vista à obtenção de resistência

Tese de dout., Biologia, Faculdade de Engenharia de Recursos Naturais, Univ. do Algarve, 2003

Estudo preliminar do efeito supressor de genes do Citrus tristeza virus (CTV) no silenciamento pós-transcripcional em Nicotiana benthamiana

Dissertação de mest., Engenharia Biológica, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011

The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storage

The effect of coating Arbutus unedo fresh fruit with alginate-based edible coatings enriched with the essential oils compounds (EOC) eugenol (Eug) and citral (Cit) was studied. The minimum inhibitory concentrations (MIC) against the main postharvest pathogens were determined for Eug and Cit giving values of 0.10 and 0.15 (w/v), respectively. Twelve formulations of edible coatings were used: sodium alginate (AL) was tested at 1 and 2% (w/v) with incorporation of Eug and Cit at MIC and double MIC or their combination at MIC. Arbutus berries were dipped in those solutions for 2 min, and then stored at 0.5 degrees C. Control consisted of uncoated fruit. On days 0, 14 and 28, samples were taken to perform physicochemical and biochemical analysis [color CIE (L*, h degrees), firmness, soluble solids content (SSC), weight Loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels]. Results showed that edible coatings of 1% AL were the best to maintain most quality attributes of the commodity through storage at 0.5 degrees C. The incorporation of Cit and Eug into the alginate edible coatings improved the coatings in most cases, AL 1% + Eug 0.20% and AL 1% + Cit 0.15% + Eug 0.10% being those that better preserved sensory and nutritional attributes and reduced microbial spoilage. Thus, these coatings may be useful for improving postharvest quality and storage life of fresh arbutus fruit. (C) 2014 Elsevier B.V. All rights reserved.

Ascorbic acid and flavanone glycosides in citrus: Relationship with antioxidant activity

The effects of cultivar and orchard on the content of ascorbic acid and flavanone glycosides as well as on the antioxidant activity of citrus juices were studied. Ascorbic acid and flavanone glycosides were determined using HPLC method. For antiradicalar activity evaluation, TAEC and ORAC methods were used. Citrus of 'Valencia late' from Faro and 'D. Joao' presented the highest levels of hesperidin in contrast to the citrus of 'Valencia late' from Silves with 0.4 mg/ml, a value closer to those of Navel oranges 'Navelate' and 'Lanelate'. Citrus of 'Valencia late' from Silves and 'D. Joao' presented the lowest levels of narirutin. 'Ortanique' and 'Encore' cultivars were poorer in ascorbic acid compared with the oranges. When the TEAC method was used for the determination of antioxidant activity, 'Valencia late' from Faro presented the best activity. A good relation was observed between antiradical activity measured through the TEAC method and the amount of ascorbic acids in samples. None relation was found between the levels of flavanones and antiradical activity. When the ORAC method was applied, the best activity was found for 'Navelate' and 'Encore' samples and practically none relation between this method and the amounts of ascorbic acid and flavanones was found.

Caraterização dos supressores p20 e p23 do Citrus tristeza virus e avaliação da possibilidade da sua inibição

No presente trabalho pretendeu-se caracterizar a capacidade supressora das proteínas p20 e p23 de diferentes grupos filogenéticos do CTV e o possível silenciamento da p23 de forma a ser incluída numa estratégia de proteção. A atividade supressora local da proteína p23 de todos os grupos filogenéticos foi caracterizada em Nicotiana benthamiana da linha 16C. Todas as proteínas testadas foram capaz de suprimir o silenciamento local, mas não o silenciamento a curta distância. A supressão local mais eficiente verificou-se para a p23 do Gp 5 e a menos eficiente para os isolados dos Gps 2 e M. Surpreendentemente, a p23 do Gp 5 aboliu completamente o silenciamento sistémico, sugerindo que existe uma relação entre a intensidade do silenciamento local e sistémico. A capacidade supressora local conjunta das proteínas p20 e p23 foi avaliada. A coexpressão de ambas as proteínas revelou atividade supressora mais forte comparada com a capacidade de cada proteína individual, mesmo quando inoculada com metade da densidade ótica, sugerindo a existência de sinergismo entre as proteínas p20 e p23. Para analisar as propriedades supressoras a longo prazo, as proteínas p20 e p23 foram inseridas no vetor viral TRV que assegurou a sua disseminação pela planta e expressão por um período mais alargado. Foram observados sintomas em N. benthamiana para todas as modalidades testadas, tais como, nanismo da planta, lesões necróticas severas nas folhas inoculadas e nas folhas novas ligeiros sintomas de mosaico e enrolamento. Contudo, sistemicamente não foram registadas diferenças na capacidade supressora das proteínas p20 e p23. A possibilidade para silenciar sistemicamente a proteína p23 quando incluída num genoma viral foi avaliada através do uso de plantas e enxertos transgénicos para a p23. A estratégia que envolve o uso de enxertos transgénicos parece indicar resultados promissores que conduzem ao silenciamento da p23, contudo, são resultados que devem ser encarados como preliminares.