Constituents of the Essential Oil of Suregada zanzibariensis Leaves are Repellent to the Mosquito, Anopheles gambiae s.s.

In traditional African communities, repellent volatiles from certain plants generated by direct burning or by thermal expulsion have played an important role in protecting households against vectors of malaria and other diseases. Previous research on volatile constituents of plants has shown that some are good sources of potent mosquito repellents. In this bioprospecting initiative, the essential oil of leaves of the tree, Suregada zanzibariensis Verdc. (Angiospermae: Euphobiaceae) was tested against the mosquito, Anopheles gambiae s.s. Giles (Diptera: Culicidae) and found to be repellent. Gas chromatography (GC), GC-linked mass spectrometry (GC-MS) and, where possible, GC-co-injections with authentic compounds, led to the identification of about 34 compounds in the essential oil. About 56% of the constituents were terpenoid ketones, mostly methyl ketones. Phenylacetaldehyde (14.4%), artemisia ketone (10.1%), (1S)-(-)-verbenone (12.1%) and geranyl acetone (9.4%) were the main constituents. Apart from phenylacetaldehyde, repellent activities of the other main constituents were higher than that of the essential oil. The blends of the main constituents in proportions found in the essential oil were more repellent to An. gambiae s.s. than was the parent oil (p < 0.05), and the presence of artemisia ketone in the blend caused a significant increase in the repellency of the resulting blend. These results suggested that blends of some terpenoid ketones can serve as effective An. gambiae s.s. mosquito repellents

Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya

<p>Abstract</p> <p>Background</p> <p>The increasing number of multidrug-resistant <it>Plasmodium </it>strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from <it>Artemisia annua</it>. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine.</p> <p>Methods</p> <p><it>In vitro </it>anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive <it>Plasmodium berghei </it>NK65 strain in Swiss albino mice was used for monitoring <it>in vivo </it>activity of plant extracts.</p> <p>Results</p> <p>Chloroform extract of <it>H. antidysenterica </it>(HA-2) and petroleum ether extract of <it>V. canescens </it>(VC-1) plants significantly reduced parasitaemia in <it>P. berghei </it>infected mice. The extract HA-2 showed <it>in vitro </it>anti-plasmodial activity with its IC₅₀value 5.5 μg/ml using pLDH assay and ED₅₀value 18.29 mg/kg in <it>P. berghei </it>infected Swiss albino mice. Similarly petroleum ether extract of <it>V. canescens </it>(VC-1) showed <it>in vitro </it>anti-plasmodial activity with its IC₅₀value 2.76 μg/ml using pLDH assay and ED₅₀15.8 mg/kg in <it>P. berghei </it>infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of <it>V. canescens </it>was found slightly cytotoxic.</p> <p>Conclusion</p> <p>The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria.</p