Abordagem quimiométrica e avaliação físico-química, bioativa e biológica in vitro da acerola (Malpighia emarginata) in natura e liofilizada
Brazil is an important producer of tropical fruits. Among them, acerola (Malpighia emarginata) is recognized for its high content of ascorbic acid (AA), total phenolic compounds (TPC), carotenoids, anthocyanins and potent antioxidant capacity. Considering the bioactive and commercial value of thi...
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| 格式: | doctoralThesis |
| 语言: | por |
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| 在线阅读: | https://repositorio.ufrn.br/jspui/handle/123456789/26636 |
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| 总结: | Brazil is an important producer of tropical fruits. Among them, acerola (Malpighia
emarginata) is recognized for its high content of ascorbic acid (AA), total phenolic
compounds (TPC), carotenoids, anthocyanins and potent antioxidant capacity. Considering
the bioactive and commercial value of this fruit, the present work aimed to evaluate acerola
using different approaches, which are presented in the six chapters of this thesis. A general
introduction opens this document and discusses keytopics covered throughout the research.
The second chapter shows the evaluation of the whole acerola fruit in regard to its
concentration of bioactive compounds (AA, TPC) and antioxidant activity (DPPH), by the
near infrared (NIR) technique and application of chemometric analysis. In the third chapter,
freeze-drying was applied to acerola pulp and acerola pomace in order to compare the final
products to the fresh fruit, as well as to monitor the stability of the acerola powders along the
storage. In the fourth chapter, commercially purchased freeze-died acerola was evaluated and
compared to selected freeze-dried fruits (camu-camu, apple and pineapple) in regard to in
vitro biological analyzes. Selected phytochemical compounds (AA, TPC, anthocyanins,
phenolic acids) and antioxidant activity (by two methods of detection: reducing iron potential
- FRAP and capturing the radicals of 2,2 - diphenyl - 1 - picrylhydrazyl - DPPH) of the fruit
extracts were analyzed. In addition, the effects of these extracts on reducing the production of
reactive oxygen species (ROS) and nitric oxide (NO) in RAW 264.7 macrophages were
investigated. Initially, the toxicity of the samples (reduction method of 3- (4,5-
dimethylthiazol-2yl) -2,5-diphenyl tetrazolium bromide - MTT) to RAW 264.7 cells was
assessed. The anti-inflammatory activity of acerola extracts was tested by analysing enzymes
and mediators with proinflammatory activity (inducible nitric oxide synthase - iNOS,
cyclooxygenase – COX-2, interleukins - IL1β and IL-6, tumor necrosis factor - TNFα), in addition to an in vitro assay to investigate the cell migration properties of freeze-dried extracts
in adult human dermal fibroblast cells (HDFα). The final chapters 5 and 6 show the
conclusion and the literature sources used hrere. The results show that the NIRS model is a
fast and reliable non-destructive analytical strategy to evaluate the ascorbic acid, however did
not show good settings to the phenolic and antioxidant capacity in acerola fruits. It has also
been demonstrated that freeze-dried acerola powders retain high ascorbic acid concentration
and the preservation of ascorbic acid and anthocyanins is more effective under refrigerated
storage. The results of the in vitro biological tests showed that acerola extracts, camu-camu,
apple and pineapple are able to reduce the production of reactive oxygen species (ROS). Only
freeze-dried acerola and camu-camu extracts reduced the production of reactive nitrogen
species (NO). Extracts of these fruits also suppressed the expression of IL1β and IL6, and
freeze-dried acerola is the only one capable of reducing the expression of COX-2 enzyme.
The acerola was also able to enhance cell migration, based on the in vitro results obtained in
HDFa cells, which reflects the skin cells' ability to regenerate after injury. The high ascorbic
acid content in acerola seems to play an important role in the observed in vitro biological
effects. Overall, it is concluded that acerola presents relevant bioactive and in vitro biological
potential, which can justify its exploitation as a functional ingredient in food and
pharmaceutical formulations. |
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