Antiproliferative Activity, Antioxidant Capacity and Tannin Content in Plants of Semi-Arid Northeastern Brazil

Abstract

The objective of this study was to evaluate antiproliferative activity, antioxidant capacity and tannin content in plants from semi-arid northeastern Brazil (Caatinga). For this study, we selected 14 species and we assayed the methanol extracts for antiproliferative activity against the HEp-2 (laryngeal cancer) and NCI-H292 (lung cancer) cell lines using the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazole) (MTT) method. In addition, the antioxidant activity was evaluated with the DPPH (2,2-diphenyl-2-picrylhydrazyl) assay, and the tannin content was determined by the radial diffusion method. Plants with better antioxidant activity (expressed in a dose able to decrease the initial DPPH concentration by 50%, or IC50) and with higher levels of tannins were: Poincianella pyramidalis (42.95 ± 1.77 µg/mL IC50 and 8.17 ± 0.64 tannin content), Jatropha mollissima (54.09 ± 4.36µg/mL IC50 and 2.35 ± 0.08 tannin content) and Anadenanthera colubrina (73.24 ± 1.47 µg/mL IC50 and 4.41 ± 0.47 tannin content). Plants with enhanced antiproliferative activity (% living cells) were Annona muricata (24.94 ± 0.74 in NCI-H292), Lantana camara (25.8 ± 0.19 in NCI-H292), Handroanthus impetiginosus (41.8 ± 0.47 in NCI-H292) and Mentzelia aspera (45.61 ± 1.94 in HEp-2). For species with better antioxidant and antiproliferative activities, we suggest future in vitro and in vivo comparative studies with other pharmacological models, and to start a process of purification and identification of the possible molecule(s) responsible for the observed pharmacological activity. We believe that the flora of Brazilian semi-arid areas can be a valuable source of plants rich in tannins, cytotoxic compounds and antioxidant agents.

Antioxidant activity of various extracts of selected gourd vegetables

“…Recent interest in tannins has been stimulated by the potential health benefits arising from the antioxidative activity. Good contribution of tannins in antioxidant activity has been observed by Gomes de Melo et al (2010). The results showed that the carotenoids content of L. siceraria, M. charantia and L. cylindrica measured as β-carotene was significantly higher when compared to remaining gourd vegetables (P < 0.05) with M. charantia exhibiting the highest content in all types of extracts.…”

Anticancer mechanisms of Strobilanthes crispa Blume hexane extract on liver and breast cancer cell lines

“…Stigmasterol and β-sitosterol extracted from S. crispa have been demonstrated to possess anti-cancer effects on liver, breast, and colon carcinoma (22). Other anti-cancer compounds that may be extracted include alkaloids and tannins (20), which have been documented to exhibit anti-cancer properties (37)(38)(39)(40). In order to identify the compounds responsible for the anti-cancer effects, further studies on the isolation and purification of the bioactive compounds from S. crispa are required.…”

Efecto gastroprotector y capacidad antioxidante del extracto acuoso de las vainas de Caesalpinia spinosa ‘tara’, en animales de experimentación

“…Dicha capacidad antioxidante se atribuiría al alto contenido de fenoles totales que presenta, esto de acuerdo con estudios previos que indican una relación directa entre actividad antioxidante y contenido de fenoles totales en hierbas, vegetales y frutos (18) , y esta a su vez con el contenido de taninos y su eficiencia antirradical (19,20) . De acuerdo con la clasificación de Gomes de Melo y col. (21) , el EAVT muestra una buena actividad antioxidante, y resultados similares han sido reportados en otros estudios referentes a los extractos de vainas de tara (4,22) . La influencia del medio ambiente, nutrición y genotipo, así como el tiempo de la cosecha y su tratamiento post-cosecha pueden afectar la calidad y niveles de antioxidantes en las plantas.…”