| dc.description |
This research evaluated larvicidal potencies and phytochemical analysis of Hypoestes
forskaolii (vahl) R. Br root extracts. Larvicidal activities were tested to Anopheles gambiae,
Aedes aegypti and Culex quinquefasciatus. World Health Organization protocol for
evaluating and testing insecticides was adopted with minor modification. Larvae of these
mosquitoes were allowed to interact with extracts prepared in different concentration ranging
between 25 to 750 μg/mL and the death rate were noted subsequent to 24 h, 36 h and 72 h.
Root extracts of H. forskaolii displayed its effectiveness towards larva’s of A. gambiae, A.
aegypti and C. quinquefasciatus 3
rd
instars having LC
50
between 3.8989 to 220.4789 μg/mL
for A. aegypti, LC
50
of 2.0322 to 69.6596 μg/mL for A. gambiae and LC
50
of 6.0004 to
177.5595 μg/mL for C. quinquefasciatus. The chloroform extract results indicated high
mortality of larvae subsequent to 72 h of contact for the three species of mosquitoes tested.
Anopheles gambiae had the LC
50
of 2.0322 μg/mL where by A. aegypti had LC50 of 3.8989
μg/mL while C. quinquefasciatus showed LC50 of 6.0004 μg/mL. Analysis of the organic
compounds found in Hypoestes forskaolii chloroform extract was performed using gas
chromatography-mass spectrometry technique (GC-MS). Twenty three compounds were
identified namely; piperonal, caryophyllene, caryophyllene oxide, β-humulene, α-farnesene,
Nerolidol, patchoulane, γ-cadinene, viridiflorol, n-hexadecanoic acid, octadecanoic acid,
bicyclo [5.2.0] nonane, 2-methylene-4,8,8-trimthyl-4vinyl, Kaurene, 9,12-octadecadienoic
acid Z, Z, eicosane, allo- aromadendrene oxide, Epiglobulol, Longipinane, curcumene,
Globulol, Calamenene, α-cedrene and Copaene. The larvicidal activity of Hypoestes
forskaolii extracts is likely due to the presence of one or some of these compounds. Further
study is needed to establish the compound(s) responsible for the displayed larvicidal
potencies. |
|