Insecticidal, antimicrobial, phyto- and cytotoxicity of Chassalia kolly plant extract

By Patricia Akpomedaye Onocha and Shaiq Muhammad Ali

Chassalia kolly (Schumach.) Hepper (Rubiaceae) is used in ethno-medical practices particularly in Nigeria and the West African sub-region for the treatment of typhoid and fevers that are endemic in Nigeria as well as in the tropics and as an insect repellant. The methanolic extract of the dried whole plant Chassalia kolly was investigated for insecticidal, antimicrobial, phyto- and cytotoxicity activities. Antifungal activity was observed against only one of the three strains investigated namely, Candida albicans The extract however inhibited the growth of all the five human pathogenic bacteria namely: Salmonella typhii, Escherica coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus tested in the agar cup plate diffusion technique, exhibiting a concentration dependent activity. Cytotoxicity was evaluated using brine shrimp lethality assay revealing its relatively non-toxicity with an LD50 value greater than 1000 µg/ml. Phytotoxicity using the Lemna bioassay showed a moderate growth inhibitory effect against Lemna minor.  The insecticidal assay by contact toxicity method also revealed a moderate insecticidal rate of 40% against Rhizopertha dominica at the concentration of 1572.7 µg/cm2.The extract contains glycosides, alkaloids and flavonoids. These results provide some scientific basis for the utilization of the plant in ethno-medicine for the treatment of typhoid fever and as an insect repellant.

Key words: Chassalia kolly, antimicrobial, insecticidal, phyto-and cytotoxicity.

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