Protection of Panel Product from Mould Using Natural Extracts – A

10 11 ABSTRACT 12 13 The aim of this research was to exploit natural products chemistry to control the incidence and extent 14 of mould growth in housing hence improving the sustainability of building products. 15 16 In this study, 7 extracts of the essential oils were screened in a nutrient medium for their antimould 17 activity against 3 common moulds, viz C. herbarum, Penicillium sp. and Alternaria sp. Subsequently, 18 the antimould activity of 3 extracts; eugenol, thymol and cinnamaldehyde were evaluated on 2 19 different types of gypsum board finished with either paint or wall paper, typical of what is used in 20 building. 21 22 In the initial in-vitro screening trial, variability in the tolerance of the tested fungi towards the essential 23 oils was apparent. Some of the essential oils such as eugenol, thymol, cinnamaldehyde and carvacrol 24 completely inhibited the growth of all test fungi at the concentration of 1% w/v of active on nutrient 25 medium, whereas, different fractions of manuka oil (manuka, manuka less triketones and extracted 26 triketones) showed varied activity against 3 mould fungi. The triketones fraction was able to 27 completely inhibit the growth of Cladosporium herbarum but not Penicillium and Alternaria sp. 28 29 Testing of selected extracts sprayed onto gypsum board confirmed the antimould activity of eugenol, 30 thymol and cinnamaldehyde against Penicillium sp. Gypsum board blocks (without any finish) 31 sprayed with 3% w/v of eugenol, thymol and cinnamaldehyde prevented the growth of Penicillium sp. 32 Gypsum blocks that were painted before spraying with these extracts allowed some growth of 33 Penicillium sp. after 12 weeks incubation. Blocks finished with wall paper and sprayed with 2 of the 34 extracts, eugenol and thymol prevented the growth. However, minor growth of Penicillium sp. was 35 noticed on cinnamaldehyde sprayed blocks. 36 37 This study identified essential oils as a potential mould inhibitor for panel products which is one of the 38 most common mould habitats in the building environment. This approach highlights the opportunity 39 for natural products to improve the indoor environment quality of buildings. 40 41