Comparative Mosquito Repellency of Dried Leaves of Hyptis Suaveolens, Cassia Obtusifolia, Striga Hermonthica from the Upper East Region of Ghana and Two Standard Repellants

In this study the ethnobotanical use of mosquito repelling plant leaves as a preventive measure against mosquitoes thus malaria was investigated. Phytochemical screening of ethanol and aqueous extracts, and mosquito repellency tests of powdered dried leaves of Hyptis suaveolens, Cassia obtusifolia and Striga hermonthica in an olfactometer were carried out and compared with two standard repellants. In leaves of Striga hermonthica, glycosides, flavonoids, tannins, ketones, alkaloids, reducing sugar and phlobotannins, steroids and terpenoids were present. Hyptis suaveolens leaves had glycosides, tannins, alkaloids, reducing sugar, phlobotannins, ketones and coumarins, flavonoids, terpenoids and steroids. In Cassia obtusifolia leaves, flavonoids, anthraquinone, ketones, coumarins, terpenoids and phlobotannins, glycosides, saponins, tannins, steroids, alkaloids and reducing sugar were also present. S. hermonthica was the most repellent among the three plant leaves, and repelled 11.50±0.50, 6.50±0.63 and 8.33± 0.82 mean number of mosquitoes when it was compared to empty chamber, Hyptis suaveolens leaves and Cassia obtusifolia leaves respectively. Leaves of H. suaveolens were the second efficient repellant sample. It repelled 10.17±0.52 and 8.00±0.79 mean number of mosquitoes when it was compared with empty chamber and C. obtusifolia leaves respectively. Cassia obtusifolia leaves were the least repellent and mean numbers of mosquitoes repelled were 6.58±0.42 and 5.42±0.54 respectively compared to empty chamber and Hyptis suaveolens. The repellence efficiency of Striga hermonthica, Hyptis suaveolens and Cassia obtusifolia were 83.4, 78.3 and 70.4 % respectively compared with the standard, 90.0 %. Striga hermonthica compared well with the standard repellent and could be used to repel mosquitoes to avoid their bites.