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| Author(s): |
Dayana Rubio Gouvea
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2013-10-08 |
| Examining board members: |
Norberto Peporine Lopes;
Cristiane Masetto de Gaitani;
Luiz Alberto Beraldo de Moraes;
Celso Vataru Nakamura
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| Advisor: | Norberto Peporine Lopes |
| Abstract | |
The species Lychnophora salicifolia Mart. popularly known as \"arnicão\" is used as an antiinflammatory and topical analgesic agent; it is also employed as flavoring in the Brazilian cachaça. Vicenin-2 is a C-glycoside flavonoid present in large amounts in the hydroalcoholic extract of the leaves of L. salicifolia and has anti-inflammatory, antioxidant, and anticancer activities. Another major substance in this extract is lychnopholic acid, which accounts for the antibacterial and trypanocidal actions of the extract. More comprehensive studies involving natural products are necessary; therefore, we studied the metabolism of the two aforementioned molecules. We did not observe the in vitro formation of metabolites from vicenin-2. In the case of lychnopholic acid, we detected the formation of two metabolites using rat liver microsomes, which possibly originated from the addition of an oxygen atom to the acid\'s molecule. The same substances may also have been produced when we employed FeTFPP as catalyst and m-CPBA as oxidizing agent. In the reactions involving human liver microsomes, we verified that lychnopholic acid conjugation with glucuronic acid and calculated the following parameters: Vmax = 272.5 ± 12.75 ?mol g-1 protein h-1; Km = 12.38 ± 1.218 ?M, and R2 = 0.9980. Studies using Caco-2 cells indicated that lychnopholic acid was quickly absorbed by passive diffusion. On the other hand, vicenin-2 was not transported, suggesting no absorption or efflux of this compound in Caco-2 cells. As for the pharmacokinetic profile, lychnopholic acid presented very low t1/2, high Cl, and very high Vd. Concerning vicenin-2, the t1/2 value was slightly larger, but still rather low, whereas Cl and Vd values were slightly lower, indicating that both substances are quickly eliminated from the body. (AU) | |
| FAPESP's process: | 10/09137-0 - "In vitro and in vivo metabolism of the major secondary metabolites present in the extract of Lychnophora salicifolia Mart. (Asteraceae: Vernonieae) leaves" |
| Grantee: | Dayana Rubio Gouvea |
| Support Opportunities: | Scholarships in Brazil - Doctorate |