Bog myrtle (BM) (Myrica gale L.), is a shrub with a wide occurrence across the northern hemisphere, particularly
in Irish boglands. Bogs provide critical functions for hydrology, biodiversity and
climate. Currently in Ireland there is a drive towards developing a bioeconomy, with
the discovery of sustainable natural products from Irish biodiversity being of priority.
In the quest for innovation with the natural product environment, the first step is
often rooted in ethnobotanical and ethnopharmacological uses of species. Irish and
international folklore reports use of BM for the determent of various insects such
as midges [1]
[2]
[3].
This study aimed to enrich the knowledge surrounding BM and its potential as a natural
insect repellent. After reporting systematic chemical profiling and anti-cholinesterase
activity of essential oil samples (EOs), extracted from BM from a range of locations,
plant parts and seasons [4]
[5], work was advanced to testing for repellency. EOs with varied chemical profiles,
their fractionated components, and a variety of combinations, were screened for repellency
using arm-in-cage and Y-tube assays against Aedes aegypti mosquitoes. Results for BM-EO repellency showed great variance across all samples,
dependent on chemical composition, with complete protection time (CPT) for contact
repellency ranging from 7.22 – 36.02 minutes and 0 ->240 minutes for long-distance
repellency. Furthermore, CPT for BM was altered when EOs were combined with other
oils and individual compounds. The best performing combination was BM and commercial
clove oil (1:1) ratio. This study corroborates the traditional use of BM in deterring
insects. Further studies are underway.
