ABSTRACT
The phytochemical screening, antioxidant and photoprotective activities of dried extracts from the leaves of Neoglaziovia variegata were investigated. It was also evaluated the total phenolic and flavonoid contents by the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities of the extracts were evaluated by using of 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene-linoleic acid bleaching and compared with ascorbic acid, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) used as reference compounds. The photoprotective effect was evaluated by the spectrophotometric method. Preliminary analysis demonstrated that the extracts were found to be positive for the presence of anthracene derivatives, flavonoids, tannins, mono and diterpenes, naphthoquinones, coumarins, triterpenoids and steroids. The most significant total phenolic and flavonoid contents was of 608.50 ± 14.74 mg of gallic acid equivalent/g and 272.50 ± 9.25 mg of catechin equivalent/g, respectively, for ethyl acetate fraction (Nv-AcOEt). The Nv-AcOEt also presented the best antioxidant activity (IC50 3.51 ± 0.18 μg/ml) for DPPH scavenging. The chloroform fraction (Nv-CHCl3) and Nv-AcOEt showed characteristic absorption bands in regions UVB and UVA in a concentration-dependent manner. Nv-AcOEt presented the highest sun protection factor SPF (27. 68 ± 4.03). It shows the possibility to use this extract as sunscreen in pharmaceutical preparations.
ABSTRACT
Selaginella convoluta é uma espécie conhecida no Nordeste do Brasil como jericó, e bastante utilizada na medicina popular para tratamento de doenças. Este estudo teve como objetivo determinar o teor de compostos fenólicos e avaliar a atividade antioxidante in vitro do extrato etanólico e das frações obtidas por partição de S. convoluta. O conteúdo de fenóis totais foi determinado pelo método de Folin-Ciocalteu. O teor de flavonoides totais também foi avaliado. A atividade antioxidante dos extratos foi avaliada usando o método do sequestro do radical DPPH e inibição da auto-oxidação do sistema β-caroteno-ácido linoleico e comparada com os compostos de referência ácido ascórbico, BHA, BHT, quercetina e pirogalol. O conteúdo fenólico total foi de 209,90 ± 19,84 e 61,13 ± 2,50 mg equivalente de ácido gálico/g para os extratos AcOEt e EEB, respectivamente. O conteúdo de flavonoides totais foi de 155,70 ± 6,21 e 62,13 ± 4,10 para os dois extratos, respectivamente. Os extratos AcOEt e EEB apresentaram boas atividades antioxidantes. BHA foi o antioxidante mais efetivo, com um valor de IC50 de 1,62 ± 0,69 μg/mL. Os resultados obtidos mostram que S. convoluta pode ser uma boa fonte de compostos fenólicos antioxidantes. Estudos posteriores serão realizados para se chegar ao isolamento e identificação dos principais constituintes fenólicos dos extratos.
Selaginella convoluta is a species of "spike moss" (an order of pteridophytes) known in Northeast Brazil as "jericó" and widely used in popular medicine to treat several diseases. Phenolic compounds were determined in extracts of whole Selaginella convoluta plants. The total phenolics content was determined by the Folin-Ciocalteu method. Total flavonoid content was also measured. Antioxidant activities of the extracts were assayed by DPPH radical scavenging and inhibition of β-carotene-linoleic acid bleaching and compared with ascorbic acid, BHA, BHT, quercetin and pyrogallol, used as reference compounds. The total phenolics contents of ethyl acetate (EtOAc) and crude ethanol extract (CEE) were 209.90 ± 19.84 and 61.13 ± 2.50 mg of gallic acid equivalent/g, respectively. The total flavonoids contents were 155.70 ± 6.21 and 62.13 ± 4.10 mg of catechin equivalent/g for the two extracts, respectively. The EtOAc and CEE extracts exhibited good antioxidant activities. BHA was the most effective antioxidant, with an IC50 of 1.62 ± 0.69 μg/ml. The results show that S. convoluta could be a good source of antioxidant phenolics. Further research will be carried out to achieve the isolation and identification of the main phenolic constituents of the extracts.