Repellency and Composition of Essential Oils of Selected Ethnobotanical Plants Used in Western Kenya against Bites of Anopheles gambiae Sensu Stricto
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Date
2020
Authors
Ywaya, David O.
Birkett, Michael A.
Pickett, John A.
Ochola, John B.
Lwande, Wilber
Wachira, Benson M.
Hassanali, Ahmed
Ng’ang’a, Margaret M.
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis Group
Abstract
The essential oils of Ocimum gratissimum Linn, Hyptis suaveolens (L) Poit and Vitex keniensis,
which are used traditionally in Western Kenya for personal and space protection against mosquito bites, were
screened for repellence against Anopheles gambiae Sensu Stricto. Essential oils were extracted from their
leaves by hydrodistillation, characterised by gas chromatography linked with mass spectrophotometer and
electroantennogram detectors. The repellency of the oils and their selected blends was studied by the reduction
in probing and feeding on the human arm. The oils showed promising repellency for Anopheles gambiae, O.
gratissimum (RD50 = 2.77 × 10-5 mg cm-2, 95 % CI), Vitex keniensis (RD50 = 5.68 × 10-5 mg cm-2) and Hyptis
suaveolens (6.27× 10-5 mg cm-2) as compared to that of DEET (control) RD50 = 1.25×10-5 mg cm-2). The bioactive
constituents of each oil were identified by Gas chromatography-linked with Mass spectrometry and
Electroantennography. Some compounds were confirmed by co-injections of the oil with available authentic
standards. The results provide a scientific rationale for the traditional use of these plants in repelling disease
vectors and other biting insects, and lay down some useful groundwork for downstream development of more
effective products for personal and space protection.
Description
A research article published in Journal of Essential Oil Bearing Plants
Keywords
Anopheles gambiae, ethnobotanicals, Ocimum gratissimum, Hyptis suaveolens, Vitex keniensis, repellency, essential oils, bioactive constituents.
Citation
David O. Ywaya , Michael A. Birkett , John A. Pickett , John B. Ochola , Lwande Wilber , Benson M. Wachira , Ahmed Hassanali & Margaret M. Ng’ang’a (2020) Repellency and Composition of Essential Oils of Selected Ethnobotanical Plants Used in Western Kenya against Bites of Anophelesgambiae Sensu Stricto, Journal of Essential Oil Bearing Plants, 23:3, 432-441, DOI: 10.1080/0972060X.2020.1780954