Baccharis trimera (Less.) DC. essential oil: genotoxicity, mutagenicity and metabolism studies

Author(s)

Adriana Della Torre

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2018-01-30

Examining board members

Ana Lucia Tasca Gois Ruiz; Patricia Santos Lopes; Denise Gonçalves Priolli; Fabiana Regina Nonato; Cristina Pontes Vicente

• Advisor: Ana Lucia Tasca Gois Ruiz

Abstract

Baccharis trimera (Less.) DC., known as "carqueja", is a native species from tropical regions widely used in folk medicine as anti-inflammatory and to treat stomach and intestinal disorders. Considering the medicinal use of B. trimera cv. CPQBA 1 essential oil (EOBt), this research aimed to continue the phytochemical study and safety evaluation of EOBt. This study compared two batches of EOs; the first one was obtained by hydrodistillation of B. trimera aerial parts collected from January to December 2014 in the CPQBA/UNICAMP experimental field (EOBt CPQBA), while the second was a commercial sample (EOBt commercial). Gas chromatography coupled to the mass detector identified as major compounds the bicyclogermacrene, E-caryophyllene, germacrene D, beta-pinene, beta-myrcene and delta-cadinene in EOBt CPQBA, whereas carquejyl acetate and palustrol were identified in EOBt commercial. The samples were compared for in vitro antioxidant capacity using 2,2-diphenyl-1-picrylhydrazyl (DPPH¿), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS¿+) and Oxygen Radical Absorbance Capacity (ORAC). In the ABTS¿+ assay, EOBt commercial was more active than EOBt CPQBA, while in the DPPH¿ assay, both samples presented similar scavenger abilities; the results also suggested the possible participation of alpha-pinene, E-caryophyllene, myrcene and beta-pinene on EOBt CPQBA activity. In the ORAC lipophilic mode, EOBt CPQBA showed higher antioxidant activity than EOBt commercial and this antioxidant potential can be attributed, in part, to E-caryophyllene. In the antiproliferative activity assay, both EOBts samples presented a similar cytostatic profile against the tumor and non-tumor cell lines. In addition, the mutagenicity of the samples was studied using the in vitro (CHO-K1 cells) and in vivo (mouse bone marrow) micronuclei induction models while the genotoxic potential was evaluated by the in vitro (CHO-K1 cells) alkaline Comet assay. EOBt CPQBA increased the micronuclei (MN) frequency in CHO-K1 cells, concentration-independent, while EOBt commercial increased the MN frequency at the highest concentrations; myrcene, E-caryophyllene and beta-pinene may have contributed in part to the EOBt CPQBA mutagenicity. The presence of an exogenous metabolic system (S9 fraction) reversed both EOBts mutagenic effects, suggesting the formation of less mutagenic compounds after metabolization. In the in vitro alkaline Comet assay, EOBt CPQBA was less genotoxic than EOBt commercial and the use of S9 fraction reduced the EOBt commercial-induced DNA fragmentation. The acute oral toxicity experiment determined 800 mg/kg as the maximum tolerable dose (MTD) for both EOBts and from this, the dose of 300 mg/kg was selected for repeated treatments. EOBt commercial was mutagenic (dose-dependent increase in micronucleated polychromatic erythrocytes, MNPCE) in the three doses evaluated, while EOBt CPQBA increased MNPCE frequency only in the two higher doses. Through the fingerprint metabolomic approach (ESI-MS followed by PLS-DA analysis with VIP score) and the solid-phase microextraction technique of headspace volatiles, it was possible to show differences in the chemical composition of EOBts CPQBA and commercial before and after treatment with S9 fraction. Concluding, EOBt CPQBA has a more evident antioxidant effect in addition to being less genotoxic/mutagenic than EOBt commercial; these biological differences are related to chemical composition variations. These results indicate potential safety in the therapeutic use of EOBt CPQBA, which can be evaluated in complementary studies (AU)

• FAPESP's process: 13/13196-0 - Baccharis trimera (Less.) DC. essential oil: genotoxicity, mutagenicity and metabolism studies
• Grantee: Adriana Della Torre
• Support Opportunities: Scholarships in Brazil - Doctorate