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Contém referências bibliográficas
Dissertação apresentada à Escola Superior Agrária do Instituto Politécnico de Castelo Branco para obtenção do Grau de Mestre em Inovação e Qualidade na Produção Alimentar
Dissertação apresentada à Escola Superior Agrária do Instituto Politécnico de Castelo Branco para obtenção do Grau de Mestre em Inovação e Qualidade na Produção Alimentar
Disponível na Biblioteca da ESACB na cota C30-26858TFCEBA.
Dissertação apresentada à Escola Superior Agrária do Instituto Politécnico de Castelo Branco para
cumprimento dos requisitos necessários à obtenção do grau de Mestre em Inovação e Qualidade na
Produção Alimentar.
Em Portugal, crescem espontaneamente espécies de Lavandula da secção
Stoechas Ging. Estas espécies são consideradas Plantas Aromáticas e Medicinais (PAM)
devido à produção de metabolitos secundários com propriedades terapêuticas e
aromáticas. Devido ao seu elevado polimorfismo e capacidade de hibridação na natureza,
torna-se importante o conhecimento e distinção entre as espécies e subespécies. Apesar
de alguns dos constituintes químicos serem compartilhados entre estas espécies, a
presença de outros e respetivas concentrações são exclusivas de cada uma e, por
conseguinte, a sua aplicação e uso também deve ser diferenciado. De forma a contribuir
para a diferenciação entre espécies e subespécies de Lavandula que crescem na região da
Beira Baixa (BB) recorreu-se aos referenciais morfológicos de Portugal e Península
Ibérica. Através da análise destes referenciais, pode-se concluir que existem alguns
parâmetros morfológicos destacados e/ou diferenciadores entre espécies e subespécies,
salientando-se o tamanho do pedúnculo e espiga e respetiva relação, o tamanho das
brácteas inférteis e a forma das brácteas férteis. Neste trabalho, são apresentados os
resultados da observação da maioria dos parâmetros diferenciadores, em 80 plantas
recolhidas na região da BB. De acordo com os resultados, entre as subespécies, a maioria
dos parâmetros são redundantes e comuns, pelo que a análise morfológica externa da
planta não demonstrou ser suficiente para distinguir as subespécies. Considerando a
evolução natural das espécies e polimorfismo, a integração de outros tipos de análises,
como a análise dos constituintes químicos e/ou estudos genéticos, tornam-se importantes
para a diferenciação das subespécies.
Disponível na Biblioteca da ESACB na cota C30-29421TFCPANH.
Disponível na Biblioteca da ESACB na cota C30-29514TFCPANH.
L. stoechas subsp. luisieri is one of the five spontaneous species of the genus Lavandula that occurs spontaneously in Portugal. The chemical profile and antifungal activity of L. stoechas subsp. luisieri essential oils were investigated. The essential oil of two phenological stages was isolated by hydrodistillation and their chemical components analyzed by GC-FID/GC-MS. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of both essential oils were determinate to verify antifungal activity against different strains of fungi isolated from strawberry tree. The fungi tested were Aspergillus carbonarius, Rhizopus stolonifer, Penicillium brevicompactum, Aureobasidium pullulans and Saccothecium rubi. Essential oils were
characterized by a high percentage of oxygenated monoterpenes (46-64%) such as trans-α-necrodyl acetate (12.58%), fenchone (5.97%), 1,8-cineole (4.84%) and 5-methylene-2,3,4,4-tetramethylcyclopenten-2-enone (10.97%) were the major compounds in essential oil from dormancy stage, while the main compounds in flowering stage were trans-α-necrodyl acetate (26.90%), trans-α-necrodol (13.02%), lavandulyl acetate (6.53%) and linalool (5.82%). A strong antifungal activity of the essential oils was found against all strains, with MIC and MFC values ranged from 0.07-0.29 µL/mL and 0.58-9.33 µL/mL, respectively.
Essential oils of Lavandula stoechas subsp. luisieri as antifungal agent against fungi from strawberry tree fruit
Documentação e informação
The morphology and physiology of plants grown in vitro are regulated by various environmental factors such as light, temperature, humidity and carbon dioxide. Light, in its various parameters such as spectral quality, photon flux and photoperiod, is an important factor among these and generally influences the overall growth and development of plants in vitro. Light sources commonly used for in vitro plant culture are fluorescent lamps, although some research and commercial laboratories also use sodium metal or incandescent metal halide lamps. The spectral of those lamps range from 350 to 750 nm and contain blend lights that differentially affect in vitro plant growth. Recently, light emitting diodes (LEDs) have been developed and are nowadays used as an alternative source of fluorescent light for the development of plants both in greenhouses and in vitro culture rooms. In order to test the influence of these two types of light during multiplication phase, a multiplicity experiment was carried out using two species: a chestnut hybrid (Castanea sativa x C. crenata), clone M2 and the prickled broom (Pterospartum tridentatum (L.) Willk.), Malcata ecotype. Two types of light were tested, "cool white" fluorescent light and LED light with blue and red colors. It was found that LED illumination exerted a significant positive effect on the differentiation of shoots in the case of prickled broom (5.6 instead of 4.9 split shoots under fluorescent light). In the parameters of shoot length, we found that this type of lighting favored the elongation in both species. Regarding the parameters of fresh and dry weight, LED lighting caused a greater effect on the chestnut than on prickled broom. Some physiological parameters (chlorophylls, carotenoids and proteins) were also analyzed and showed to be influenced by the type of light during the development of microplants.
Cistus ladanifer has a well-defined taxonomic identity. 2,2,6-trimethylcyclohexanone may be an authenticity and taxonomic marker. Its traits and applications make it a possible economic resource fitted for Mediterranean areas. Cistus ladanifer is a dominant shrub species endemic to the western Mediterranean region. Due to its dominant nature and its potential ecological, aromatic or pharmacological applications, C. ladanifer has been the object of numerous studies. In this review current knowledge on different aspects of this species is summarized, from its taxonomy to its chemical characterisation or its competitive traits. There are no doubts about the taxonomic entity of C. ladanifer, although the recognition of infraspecific taxa deserves more attention. Given that the fragrant exudate of C. ladanifer holds a very specific composition, one species specific carotenoid, 2,2,6-trimethylcyclohexanone, derivative is proposed as an authenticity marker for uses of C. ladanifer in pharmacological or aromatic industries. Evidence is also gathered on the extreme adaptation of C. ladanifer to stressful conditions in the Mediterranean region, such as the ability to survive in low hydric and high solar exposition conditions, presistence in poor and contaminated soils, and growth inhibition of several other plants through the release of allelochemicals. Thus, the finding of potential applications for this plant may contribute to enhance the economic dimension of derelict lands, such as mine tailings or poor agricultural Mediterranean areas.
Stevia rebaudiana Bertoni, Asteraceae, is an herbaceous perennial plant native to Paraguay. This species is considered since ancient times a medicinal plant with important bioactive compounds and pharmacologic and food properties, namely diterpenes glycosides. The high natural sweetener potential stevioside and rebaudioside A produced by S. rebaudiana plants are suitable sucrose substitutes, and their obtention is influenced by environmental, phytosociological, and genetic factors. The plants' genetic profile and sweet potential depiction are needed for suitable plant selection for improvement and deployment. Thirty-one S. rebaudiana accessions grown in the same plot where leaves samples were collected in early 2019, were genotyped using six microsatellite markers, including two steviol glycosides biosynthesis functionally involved markers. Additionally, an aqueous extract of each sample was obtained in a water bath and purified by SPE for stevioside and rebaudioside A quantification by normal phase HPLC. Stevioside and rebaudioside A contents varied between 0.53-7.36% (w w-1) and 0.37-3.60% (w w-1), respectively. Two genotypes displayed interesting ratios of rebaudioside A/stevioside (number 3 and 33). The level of genetic similarity between genotypes was tested through a pairwise similarity coefficient, and two groups of individuals had the same fingerprinting. Strong relatedness was found within genotypes, possibly due to cloning, thus, influx of new germplasm ought to be made to prevent mating between relatives, and for further selection and genetic improvement.
Globally, climate change and wildfires are disrupting natural ecosystems, thus setting
several endemic species at risk. The genus Lavandula is widely present in the Mediterranean region
and its species, namely, those included in the section Stoechas, are valuable resources of active
compounds with several biological assets. Since ancient times lavenders have been used in traditional
medicine and for domestic purposes. These species are melliferous, decorative, and essential oilproducing plants with a high economic interest in the pharmaceutical, flavor, fragrance, and food
industries. The essential oils of Lavandula section Stoechas are characterized by high amounts of
1,8-cineole, camphor, fenchone, and specifically for L. stoechas subsp. luisieri one of the major
compounds is trans-α-necrodyl acetate. On the other hand, the diversity of non-volatile components
like phenolic compounds, such as phenolic acids and flavonoids, make these species an important
source of phytochemicals with pharmacological interest. Rosmarinic, caffeic, and salvianolic B acids
are the major phenolic acids, and luteolin and eriodictyol-O-glucuronide are the main reported
flavonoids. However, the concentration of these secondary metabolites is strongly affected by
the plant’s phenological phase and varies in Lavandula sp. from different areas of origin. Indeed,
lavender extracts have shown promising antioxidant, antimicrobial, anti-inflammatory, and anticancer
properties as well as several other beneficial actions with potential for commercial applications.
Despite several studies on the bioactive potential of lavenders from the section Stoechas, a systematized
and updated review of their chemical profile is lacking. Therefore, we carried out the present review
that gathers relevant information on the different types of secondary metabolites found in these
species as well as their bioactive potential.
Chemical investigations of L. stoechas subsp. luisieri and L. pedunculata essential oils were
analyzed by GC-MS, and the antimicrobial activity was performed against bacteria and fungi isolated
from food sources. The cytotoxicity of the essential oil was performed in NHDF cells using the
MTT method. According to the results, the main compounds of L. stoechas subsp. luisieri essential
oil were trans-α-necrodyl acetate (40.2%), lavandulyl acetate (11%), and trans-α-necrodol (10.4%),
while fenchone (50.5%) and camphor (30.0%) in L. pedunculata essential oil. The antifungal activity
of essential oils was confirmed with MIC values ranging from 1.2 to 18.7 µL/mL; for bacteria, it
ranged from 4.7 to 149.3 µL/mL. Both the Lavandula species tested showed low or equal MIC and
MBC/MFC values for L. stoechas subsp. luisieri essential oil, revealing greater efficacy in antimicrobial
activity. The L. stoechas subsp. luisieri essential oil revealed cytotoxic effects (30 ± 2% of cell viability)
in NHDF cells at all concentrations tested.
Main conclusion: The combination of genotypic selection, targeted and improved cultivation, and processing techniques for specific applications gives C. ladanifer the potential to be used as a valuable resource in Mediterranean areas with poor agronomic advantages.
Cistus ladanifer (rockrose) is a perennial shrub, well adapted to the Mediterranean climate and possibly to upcoming environmental changes. As a sequence to a thorough review on taxonomic, morphological, chemical and competitive aspects of C. ladanifer, the research team focuses here on the economic potential of C. ladanifer: from production to applications, highlighting also known biological activities of extracts and their compounds. The use of this natural resource may be a viable solution for poor and contaminated soils with no need for large agricultural techniques, because this species is highly resistant to pests, diseases and extreme environmental factors. In addition, this species reveals interesting aptitudes that can be applied to food, pharmaceutical, phytochemical and biofuel industries. The final synthesis highlights research lines toward the exploitation of this neglected resource, such as selection of plant lines for specific applications and development of agronomic and processing techniques.
