NMR spectroscopy and antioxidant activity of flavanones and flavones isolated from Chromolaena tacotana (Klatt) R.M. King & H. Rob.
Fecha de publicación: 30/12/2020

Chromolaena tacotana is considered as a source of flavonoids. Here we examined the content and antioxidant properties of flavones and flavanones from the leaves of the plant. Four flavonoids, including (Cta) 5, 4′ dihydroxy-7-methoxy flavanone, (Ctb) 3,5,3′-trihydroxy-7,4′-dimethoxyflavone; (Ctc), 3,4′-dihydroxy -5,7- dimethoxyflavanone; and (Ctd) 4′-hydroxy-5,7-dimethoxyflavanone, were isolated from leaves extracts, were identified by their NMR spectroscopic data, and then free radical scavenging activities of the flavonoids were assessed against DPPH. The antioxidant activity for the flavanone Ctb was the highest even compared to that of quercetin, with IC50 of 6.27 μg/mL and 8.67 μg/mL respectively. The flavanones Cta, Ctc and Ctd presented a lowest activity against free radicals as expected according to their molecular substituents and the position within the structure. Data obtained from this study support the ethnomedicinal use of the leaves of C.

Antiproliferative activity of extracts of Gnaphalium Gracile H.B.K. against cancer cell lines
Fecha de publicación: 30/08/2018

Ethanol and n-hexane extracts obtained from the leaves and inflorescences of Gnaphalium gracile, were tested at different concentrations to evaluate their antineoplastic activities on pancreatic, colon, and prostate cancer cell lines by examining mitochondrial function. The polar extracts of both, leaves and inflorescences which contain gnaphalin, quercetin, and 3-methoxy quercetin, exhibited cytotoxicity against every cell line tested with EC50 values ranging between 20.23±1.185 µg/mL and 70.71±1.1419 µg/mL. The most remarkable values were observed in pancreatic cancer Panc 28 and androgen-dependent prostate LnCaP cells, with EC50 values of 20.23±1.185 and ˂25µg/mL, and androgen-independent prostate cancer PC-3, colon HCT-116 and pancreatic MIA PaCa cells with values ranging between 28.84±1.1766 and 34.41±1.057 µg/mL. The non-polar extract derived from leaves demonstrated significant cytotoxicity towards colon cancer HCT-116 cells, with an EC50 of 39.46±1.0617 µg/mL. However, the non-polar extract from the inflorescences did not have an appreciable effect on cell proliferation of any of the cell lines tested except for androgen-independent prostate cancer PC-3 cells with an EC50 of 62.05±1.237 µg/mL. The data obtained support the traditional use of G. gracile and suggest the polar extracts from aerial parts, as an interesting source for the development of novel antineoplastic agents. © 2018, SILAE (Italo-Latin American Society of Ethnomedicine). All rights reserved.

Chromolaena tacotana (Klatt) R. M. King and H. Rob. Source of Flavonoids with Antiproliferative and Antioxidant Activity
Fecha de publicación: 31/05/2018

Objetive: To determine the antioxidant and antiproferative activity of the flavonoids isolated from the leaves of Chromolaena tacotana. Methods: Extraction was carried out with dichloromethane (CH2Cl2) from the leaves by soxhlet, the flavonoids were isolated by column chromatography (Si gel G 60-200 microns 4 x 60cm) eluted with CHCl3, mixtures of CHCl3: MeOH and MeOH. The molecular structures were elucidated by 1HNMR, 13CNMR mono and 2D and UV spectroscopic methods with displacement reagents. Each flavonoid was evaluated for its antioxidant activity by the methods DPPH● and ABTS● + and the cytotoxic activity was evaluated by MTT analysis. Findings: These compounds were identified as 3,5,4’-trihydroxy-7- methoxyflavone (Ct1), 3,5,8-trihydroxy-7,4’dimethoxyflavone (Ct2), 5,4’-dihydroxy-7-methoxyflavanonol (Ct3) and 5, 7, 3’, 4’-tetrahydroxy-3-methoxyflavone (Ct4). The flavonoid that had the best response in antioxidant activity was Ct4 with and IC50 of 2.51mg/L of DPPH● and 2.13 mg/L of ABTS●+. Antiproliferative potential showed that MDA-MB-231 breast cancer cells were the most sensitivity cell line to the flavonoids, and Ct2 is the flavonoid with better antineoplastic potential on majority of cells, except for the most resistant SiHa cervix cancer cells. Application: The high antioxidant activity of flavonoids isolated from Chromolaena tacotana and its antiproliferative activity on different cell lines, make the species a plant with pharmacological potential.

Antiproliferative activity of chloroformic fractions from leaves and inflorescences of Ageratina gracilis
Fecha de publicación: 01/01/2017

To obtain a scientific basis and justification of plant domestication in the use of Ageratina gracilis, we did an in vitro study of the anticancer potential of extracts and fractions from its leaves and inflorescences. Firstly, cytotoxicity was evaluated against five human tumorigenic cell lines by MTT assay. Subsequently, the chloroformic fractions, considered the most cytotoxic were tested for genotoxicity by comet assay, morphological effects were analyzed by fluorescent microscopy, cell cycle arrest by flow cytometry and early apoptosis induction through fluorescein-5-isothiocyanate (FITC) labeled Annexin-V assay. Non-polar extracts with IC₅₀ values of <53μg/ml showed a high cytotoxicity. The highest cytotoxicity was achieved by chloroformic fraction from petroleum ether extract of leaves and inflorescences and chloroformic fraction from ethanolic extract of leaves, displaying a significant inhibition of cell viability particularly on A549 cells with an IC₅₀ value of 25.9 μg/mL. Chloroformic fractions caused a high percent of DNA damage above 60 percent on A549 and MDAMB-231.The fractions also induced G1/S phase arrest of the cell cycle in A549 cells, furthermore it was confirmed the apoptotic activity chloroformic fraction from petroleum ether extract of inflorescences and chloroformic fraction from ethanolic extract of leaves on those cells by Annexin-V assay. These preliminary results indicate that A. gracilis has an antiproliferative activity against cancer cells, being a starting point for forthcoming studies about the antineoplastic activity and its domestication conditions.