PHARMACOGNOSTICAL, PHYTOCHEMICAL AND PHARMACOLOGICAL EVALUATION FOR THE ABORTIFACIENT POTENTIAL OF THE SEEDS OF NIGELLA SATIVA L.

Abstract

Nigella sativa L (Ranunculaceae family) or commonly known as black cumin has long been used as a phytomedicine for antidiarrhea, appetite enhancer, diuretic, antibacterial, analgesic, anthelmintic, various skin diseases, anti-inflammatory, back pain, hemiplegia (paralysis of the hands or feet) and rheumatism. The objective of this study was to investigate pharmacognostical, phytochemical features, antioxidant activity and abortifacient effects of ethanol and aqueous extracts of Nigella sativa seed by using DPPH assay method and pregnancy maintenance model respectively. The different pharmacognostical parameters were evaluated as per standard protocols with some modifications. The preliminary phytochemical studies were performed with various reagents and chemicals on seed extracts in order to determine the various secondary metabolites. The ethanol and aqueous extracts of Nigella sativa seeds were screened for in-vitro antioxidant activity by oxygen radical scavenging such as 1, 1-diphenyl-2- picrylhydrazyl (DPPH) method. Abortifacient activity was studied in rats at 400 mg/kg doses administered orally from 8thto 20thdayof pregnancy. Rats were laparotomised on 21st day. Weight of fetus, percentage of abortion and thelive and dead fetuses were observed in both horns of the uterus. Pharmacognostical studies reveal the macroscopical characters of Nigella sativa seeds. Phytochemical screening of the ethanol and aqueous extracts of Nigella sativa seeds revealed the presence of secondary metabolites like alkaloids, carbohydrates, proteins and amino acids, tannins, saponins, glycosidesand flavonoids. The ethanol and aqueous extracts showed good dose dependent free radical scavenging property. IC50 values for aqueous and ethanol extracts were calculated by DPPH method. Aqueous extract have shown more free radical scavenging power as compared to ethanol extract. Ascorbic acid was used as standard. In this experiment, abortion is induced by using pregnancy maintenance model. In contrast, no live foetus was recorded in the animals treated with mifepristone as well as the 400 mg/kg, p.o. body weight of the ethanolic and aqueous extract having live foetus. Whereas ethanolic and aqueous extract having dead foetus and there was no dead foetus in the mifepristone treated animals. The ethanolic and aqueous extract of Nigella sativa at doses of 400 mg/kg has abortifacient effects, supporting its uses in traditional medicine. Further studies on the isolation of bioactive phytoconstituents of Nigella sativaseeds and their mechanism of action are strongly recommended before its application to humans.