Abstract

Wild marigold (Tagetes minuta L.) is grown over a wider range of climatic conditions starting from 3000 to 11000 feet of altitude in the north and Northwestern parts of Pakistan. The plant yield strongly aromatic essential oils and other compounds, reported to be of great medicinal importance. The information regarding biological and biochemical activities of the compounds present in Tagetes grown in Northern parts of Pakistan is unknown. In current study our main goal was to carry out bioassays of bioactive extracts from the seeds of Tagetes naturally growing in north of Pakistan. The essential oils from the seeds were extracted using solvent extraction method and the crude fractions were prepared for biological (malaricidal, phytotoxic and insecticidal) activities. The crude fractions in n-hexane and ether of T. minuta were applied onPlasmodium falciparum 3D7, Lemna minor and three species of common grain pests of fungus namely Tribolium castaneum, Rhyzopertha dominica,Callosobruchus analis. The n-hexane fraction showed significantly better results tahn ether-fraction for anti-malarial activity. Both fractions showed low or no phytotoxic activity but n-hexane fraction was effective at the concentration of 1000 µg/ml. Insecticidal activity (~70%) was observed for both n-hexane and ether fractions against common grain pests especially for Rhyzopertha dominica. The present information may provide foundation for further study and improvement of wild Tagetes for extraction of more valuable compounds, decreasing the cost incurred nationally on the treatment of malaria and chemical control of insects and adding to national income by exporting the plant or its products. These results provided the first preliminary findings of anti-malarial activity of the seed extract ofT. minuta. The findings would be useful in promoting research aiming at the development of new drugs against mosquitoes based on the use of bioactive chemical compounds present in this wild plant of Northern Pakistan.

Key words: Tagetes minuta, essential oils, anti-malarial activity, phytotoxicity, insecticidal activity.