Cultura de tecidos, aspectos fitoquímicos e avaliação dos potenciais citotóxico, antibacteriano e antibiofilme de Kalanchoe pinnata (Lam.) Pers. cultivada in vivo e in vitro

Abstract

The plant tissue culture provides the in vitro production of secondary metabolites and plant biomass on a large scale, reducing the need for access to the material growing in vivo. Kalanchoe pinnata, popularly known in Brazil as saião-roxo, is used in folk medicine to treat various diseases, has also been demonstrated in vitro antibacterial activity of methanol and ethanol extracts. The production of metabolites with antimicrobial interest, such as quercetin, may be obtained by plant tissue culture. Thus, leaf explants of K. pinnata were inoculated in MS medium in the presence of the auxins PIC, 2,4-D, NAA and IBA and the cytokinins KIN, BAP and TDZ for in vitro morphogenesis. The phytochemical evaluation was performed with colorimetric and chromatographic methods for aqueous and methanolic extracts of the material obtained in vivo and in vitro. To evaluate the cytotoxic activity were used the human carcinoma cell lines HEp-2, Caco-2 and T84, cultured in the presence of extracts and the flavonoids quercetin and rutin. The antibacterial activity was evaluated by the macrodilution method and the evaluation of antibiofilm activity was performed in Enteroaggregative Escherichia coli (EAEC 042). In vitro plants were obtained and acclimatized successfully. In the presence of growth regulators were obtained calli, cell suspension cultures and roots cultures. Phytochemical analysis revealed the presence of phenols, tannins, saponins and 8 flavonoids in different extracts. The aqueous extracts of K. pinnata not show toxicity to Hep-2, but all other cells were sensitive to these extracts. Otherwise, the flavonoids quercetin and rutin showed no cytotoxicity at all the evaluated cell lines. The antimicrobial activity was observed in extract of leaves obtained in vivo, rutin and quercetin. Despite not inhibit the growth of EAEC 042, the extracts of K. pinnata was able to reduce the biofilm growth above 50%. The culture with quercetin was able to inhibit the growth of EAEC 042 and Staphylococcus aureus and to reduce the formation of simple and mixed biofilm of these two bacteria, showing that this flavonoid can be one of the active compounds in the inhibition of bacterial growth. In conclusion, K. pinnata have great potential for in vitro cultivation and can be exploited for the production of metabolites of medicinal interest.