The petroleum ether, chloroform and methanol crude extracts of the two different plant parts (leaves andbark) of Mirabilis jalapa (Nyctaginaceae)were screened for cytotoxicity by brine shrimp lethality bioassay and thecrude methanol extract of the bark was screened for antioxidant activity using the 1, 1-diphenyl-2- picrylhydrazyl-hydrate (DPPH) free radical scavenging assay. The petroleum ether extract of the bark showedsignificant cytotoxic activity with the LC50 value 8.12 μg/ml compared to vincristine sulphate (LC50 0.33 μg/ml).On the other hand, the methanol crude extract of the bark showed mild antioxidant activity with the IC50 value598.02 μg/ml compared to ascorbic acid (IC50 70.985μg/ml). Above results suggest moderate cytotoxic andantioxidant activity of the extract.
Key words: Mirabilis jalapa, Nyctaginaceae, Cytotoxicity, DPPH, Antioxidant.
Plants produce a diverse range of bioactive molecules, making them a rich source of differenttypes of medicines. Higher plants, as sources of medicinal compounds, have continued to play adominant role in the maintenance of human health since ancient times. Over 50%of all modern clinical drugs are of natural product origin and naturalproducts play an important role in drug development programs in the pharmaceutical industry. The relatively lower incidence of adverse reactions to plant preparationscompared to modern conventional pharmaceuticals, coupled with their reduced cost, isencouraging both the consuming public and national health care institutions to consider plantmedicines as alternatives to synthetic drugs. Thus plants are considered as areof the most important and interesting subjects that should be explored for the discovery anddevelopment of newer and safer drug candidates. Mirabilis jalapa (Bengali name-Krishnakali,Sandhayamalati; English name 4 O’clock plant; Family- Nyctaginaceae) is a tall herbaceousclimbing plant with opposite leaves, large showy flowers, coriaceous ovoid fruits and prominenttuberous roots, planted as an ornamental plant throughout the country. Phytochemical investigations revealed that the plant contains alanine, alphaamyrins, arabinose, beta-amyrins, campesterol, daucosterol and dopamine. Previously,antimicrobial, antinociceptive and anti-gonorrheal properties of this plant have been reported. The present reportdemonstrates the cytotoxic and antioxidant properties of M. jalapa through in vivo and in vitroevaluation.
In the cytotoxicity study, the positive result of crude petroleum ether extract of bark suggests that the plant may contain antitumor or pesticidal compounds. The IC50 value of the crude methanol Extract shows that M. jalapa is an important source of natural antioxidant also.
CYTOTOXICITY AND ANTIOXIDANT ACTIVITY OF EXTRACTS FROM MIRABILIS JALAPA