Pesquisa das actividades antioxidante e antimicrobiana em extractos de plantas do género Plectranthus
Miniatura indisponível
Ficheiros
Data
2013
Título da revista
ISSN da revista
Título do Volume
Editora
Resumo
O uso de plantas medicinais é uma tendência generalizada na medicina popular. O género Plectranthus pertence à família das Lamiaceae tal como a salva (Salvia), o manjericão (Ocimum) e a hortelã (Mentha), que apresentam uma grande diversidade de usos etnobotânicos. No presente trabalho, foram avaliadas as atividades antimicrobiana e antioxidante de extractos de cinco espécies do género Plectranthus: P. hadiensis (vd), P. madagascarensis, P. neochilus, P. verticillatus e P. barbatus. Os extractos foram obtidos por diversos métodos: infusão, decocção, ultra-sons, micro-ondas e maceração (10% m/v de planta seca) com dois solventes diferentes (água e acetona). O método de infusão permitiu obter a maior quantidade de extrato seco a partir da planta Plectranthus barbatus (22 ± 1,0 – 33 ± 3,0 mg/mL). A actividade antimicrobiana dos extratos obtidos foi determinada usando o método da difusão em poço e foi testada contra três bactérias Gram-positivas e duas bactérias Gram-negativas. Só os extratos acetónicos de P. madagascarensis, P. verticillatus e P. hadiensis (vd) demonstraram ser ativos e exclusivamente em bactérias Gram-positivas. O extrato de P. madagascarensis demonstrou a maior actividade antibacteriana com halos de inibição entre 23 e 36 mm. A atividade antioxidante dos extratos foi determinada qualitativamente usando o método do radical 2,2-difenil-1-picril-hidrazina (DPPH) em ccd obtiveram-se resultados positivos na maioria dos extractos estudados.
The use of medicinal plants is a widespread tendency in folk medicine. The Lamiaceae family contains several genera such as sage (Salvia), basil (Ocimum) and mint (Mentha) with a rich diversity of ethnobotanical uses. This study presents the in vitro antibacterial and antioxidant activities evaluation of five species extracts of the Plectranthus genus: P. hadiensis (vr), P. madagascarensis, P. neochilus, P. verticillatus e P. barbatus. Aqueous and acetonic extracts were obtained by five different methods: infusion, decoction, ultrasounds, microwave and maceration (10% w / v of dry plant). The highest amount of dry extract was obtained by the infusion method for Plectranthus barbatus (22,0 ± 1,0 to 33,0 ± 3,0 mg/mL). The extracts obtained were tested for their antimicrobial activity against three Gram-positive bacteria and two Gram-negative bacteria using the well diffusion method. Only the acetonic extracts of P. madagascarensis, P. hadiensis (vd) and P. verticillatus showed antibacterial activity and this was exclusively against Gram-positive bacteria. The highest antimicrobial activity was exhibited by P. madagascarensis extract with inhibition zones ranging from 23 to 36 mm. The antioxidant activity of the extracts was qualitatively determined using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical assay in tlc and yielded positive results for the majority of the extracts studied.
The use of medicinal plants is a widespread tendency in folk medicine. The Lamiaceae family contains several genera such as sage (Salvia), basil (Ocimum) and mint (Mentha) with a rich diversity of ethnobotanical uses. This study presents the in vitro antibacterial and antioxidant activities evaluation of five species extracts of the Plectranthus genus: P. hadiensis (vr), P. madagascarensis, P. neochilus, P. verticillatus e P. barbatus. Aqueous and acetonic extracts were obtained by five different methods: infusion, decoction, ultrasounds, microwave and maceration (10% w / v of dry plant). The highest amount of dry extract was obtained by the infusion method for Plectranthus barbatus (22,0 ± 1,0 to 33,0 ± 3,0 mg/mL). The extracts obtained were tested for their antimicrobial activity against three Gram-positive bacteria and two Gram-negative bacteria using the well diffusion method. Only the acetonic extracts of P. madagascarensis, P. hadiensis (vd) and P. verticillatus showed antibacterial activity and this was exclusively against Gram-positive bacteria. The highest antimicrobial activity was exhibited by P. madagascarensis extract with inhibition zones ranging from 23 to 36 mm. The antioxidant activity of the extracts was qualitatively determined using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical assay in tlc and yielded positive results for the majority of the extracts studied.
Descrição
Palavras-chave
ANTIOXIDANTES, ANTIMICROBIANOS, PLANTAS MEDICINAIS, ANTIOXIDANTS, ANTIMICROBIAL, MEDICINAL PLANTS, CIÊNCIAS FARMACÊUTICAS, PHARMACEUTICAL SCIENCES