Larvicidal and IGR activity of extract of Tanzanian plants against malaria vector mosquitoes

• Published in: Journal of vector borne diseases Vol. 46; no. 2; pp. 145 - 152
• Main Authors: Kihampa, Charles, Joseph, Cosam C, Nkunya, Mayunga H H, Magesa, Stephen M, Hassanali, Ahmed, Heydenreich, Matthias, Kleinpeter, Erich
• Format: Journal Article
• Language: English
• Published: India Indian Council of Medical Research 01-06-2009; Medknow Publications & Media Pvt. Ltd; Wolters Kluwer Medknow Publications
• Subjects: Animals; Annona - chemistry; Annonaceae - chemistry; Annonaceae - classification; Anopheles - drug effects; Anopheles - growth & development; Anopheles gambiae s.s; botanical mosquitocides; Control; Disease; Fabaceae - chemistry; Health aspects; IGR activity; Insect Vectors - drug effects; Insect Vectors - growth & development; Insecticides - pharmacology; Juvenile Hormones - pharmacology; Larva - drug effects; Malaria; Malaria - transmission; Materia medica, Vegetable; Mortality; Mosquitoes; Plant extracts; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plant Leaves - chemistry; Plant Roots - chemistry; Plant Stems - chemistry; Prognosis; Studies; Tanzania; Uvaria - chemistry; Uvaria - classification; Tanzania
• ISSN: 0972-9062

This paper reports the larvicidal activity of seventeen Tanzanian plant species against the malaria vector, Anopheles gambiae s.s. Giles larvae. Some of the plants are used traditionally as sources of insecticidal materials.
The crude extracts from the leaves, stem and root barks of the investigated plants were obtained by solvent extraction and then bio-assayed following WHO protocols showed LC50 values 10 to 400 ppm after 24 h exposure. The structures were determined on interpretation of spectroscopic data.
The most active extracts were those from the stem and root barks of Annona squamosa, Uvaria faulknerae, U. kirkii and Uvariodendron pycnophyllum, all of which had LC50 values between 10 and 100 ppm. Long-term exposure beyond 24 h also showed more susceptibility of the larvae to the extracts. Larvae deformities by forming tail-like structures were observed for the methanol extracts of Tessmannia martiniana var pauloi.
The results suggest that the investigated plant extracts are promising as larvicides against An. gambiae s.s. Giles mosquitoes and could be useful leads in the search for new and biodegradable plant derived larvicide products.