Name: Flávio Maurício Perini
Type: PhD thesis
Publication date: 30/10/2020
Advisor:
Name |
Role |
|---|---|
| Viviana Borges Corte | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Antelmo Ralph Falqueto | Internal Examiner * |
| Carine Coneglian de Farias Colman | External Examiner * |
| Janaína Brandão Seibert | External Examiner * |
| Pedro Corrêa Damasceno Junior | Internal Examiner * |
| Viviana Borges Corte | Advisor * |
Summary: The researchers look at the secondary metabolites of potential allelopathic plants as an alternative for biological control, as well as the search for alternative therapeutic substances leads to an increase in the exploration of biodiversity in order to recognize alternatives that can minimize impacts and open new perspectives of biological exploration. Vegetable species for landscape and ornamental use are shown as an exploration alternative, aiming at the use of residues that would naturally be discarded, as occurs with the species Clusia fluminensis Planch. & Triana, which fits into a group of plants with special metabolites with potential to be explored for biological purposes, such as allelopathy, antioxidant activity and photoprotective activity. Ethanol extract and
hexane, dichloromethane, ethyl acetate, butanol and aqueous fractions, obtained from leaves of C. fluminensis, were tested on lettuce seeds and colonization grass, analyzing influence on germination and initial growth. Phytochemical prospecting was performed by thin layer chromatography, HPLC and gas chromatography coupled with mass spectrometry (CG / EM), biological germination and emergence tests, radicle and shoot lengths, fresh mass, enzyme activity of catalase enzymes (CAT) , peroxidase (POX) and superoxide dismutase (SOD) and pigment content (chlorophyll a, chlorophyll b and carotenoids). Analysis of the contents of total phenols, tannins and flavonoids was also
carried out, associating them to the antioxidant effects, with ABTS, DPPH, FRAP and TacPhosphomolybdenum tests, and a photoprotective effect test. The HPLC demonstrated the presence of hyperoside in the ethyl acetate fraction, in order to allow a correlation to the antioxidant activity. The tested concentrations were 0.25, 0.50, 0.75 and 1.0mg / mL. As a control, distilled water was used. The ethyl acetate fraction showed better allelopathic results, there was a significant increase in the activity of the three enzymes in lettuce seeds, a decrease in the activity of the CAT and SOD enzymes and no influence on POX in seeds of colonião grass. In the treatment of seeds with ethyl acetate extract, there was
an increase in the levels of chlorophyll a, b and carotenoids, in the total chlorophyll content and in the total chlorophyll / carotenoid ratio, in addition to no change in the chlorophyll a / b ratio. The results showed a significant presence of total phenols, tannins and flavonoids in the ethanol extract and in the fractions, with emphasis on the ethyl acetate fraction. The photoprotective activity was more significant for the dichloromethane fraction, with SPF 7.01, compatible with use as a photoprotector, in addition to identifying the ethyl acetate fraction as a possible effector of photoprotective activity due to its antioxidant effect. The results suggest that the ethyl acetate extract obtained from C. fluminensis leaves. presents promising allelopathic potential, with the possibility of exploitation as an alternative for use in biological control to replace conventional agrochemicals. They also allow us to conclude that the ethyl acetate fraction obtained from C. fluminensis leaves would be the best one to
be explored aiming at obtaining natural forms of antioxidants and photoprotection promoters, as well as the dichloromethane fraction are presented as an alternative to use as SPF.
