Avaliação da composição fitoquímica e da actividade antimicrobiana in vitro dos extractos das sementes da planta Nigella sativa (Cominho preto)

Abstract

N. sativa is a plant of the Ranunculaceae family. The seeds are used in medicine traditional Mozambican medicine for treating various diseases such as bronchitis, diarrhea, rheumatism, asthma, skin diseases, and others; in cooking as a seasoning, and in cultural matters and religious. The present work aimed to evaluate the phytochemical profile and activity in vitro antimicrobial activity of N. sativa seed extracts. The crude extracts were obtained by maceration, infusion and decoction methods. It took place preliminary qualitative phytochemical screening on crude extracts using colorimetric tests and precipitation tests with specific reagents and quantitative phytochemistry were used standard methods of analysis. Antimicrobial activity was determined by the disk method. agar diffusion on solid medium against two bacterial strains: Staphylococcus aureus, Escherichia coli grown in Muller Hinton medium and Candida albicans fungus grown in Sabourand Dextrose. Phytochemical analysis of the different seed extracts revealed the presence of flavonoids, alkaloids, flavonols, tannins, coumarins, saponins, steroids and triterpenes. The macerated extract ethanolic presented higher levels of total phenols (6.2914 ± 0.0059 mgEAGg -1 ), flavonoids total (11,066 ± 0.001 mgEQg -1 ) and total alkaloids (239,374 ± 1,857 mgEAg -1 ). The extracts of the seeds showed antimicrobial activity against the microorganisms under study. The results obtained revealed a susceptible antimicrobial activity, as well as existence of phytochemicals that support the use of these seeds in traditional medicine for the treatment of diseases caused by the strains studied. N. sativa seeds deserve more exploration of their activities as they have proven to be a source of different compounds.(TRADUÇAONOSSA)