**Acknowledgements**

*Essential Oils - Oils of Nature*

reported in our study.

on *Staphylococcus aureus* (Gram+

(DC1) to durable (DC2) classes.

African padauk (*Pterocarpus soyauxii*) medium-heavy heartwood manifests a remarkable decay resistance attributed to its specific extractive compounds [33]. Moreover, extractive compounds obtained from black locust heartwood were able to increase the native durability of European beech against wood-decaying fungi

The strong antifungal activity of *T. articulata* root burl wood EOs is probably related to their alcohol fraction, rich in thymol and 3-tert-butyl-4-methoxyphenol, which confer them this significant bioactivity. The combined action of two phenolic compounds, such as thymol and carvacrol, was previously reported [17, 35]. Action of phenolic compounds on fungi is primarily based on the inhibition of fungal enzymes containing SH group in their active site

[36, 37]. The antifungal activity of the EOs of *C. atlantica* wood can be correlated to its sesquiterpene ketones, which are mainly atlantones (about 40.61%). Bioassays conducted with pure *α*-atlantones extracted from *Decalepis hamiltonii* revealed great inhibitory activity against pests and molds [38]. In our study, alcohols present in *C. atlantica* oil in significant amount (more than 26%), such as isocedranol, tumerol, himachalol, and cedrol, may also be involved in the inhibitory effect of this oil. Other compounds such as cadinenes (monoterpene hydrocarbon) could also have a great antimicrobial property [39]. However, synergistic action of two or more components of essential oils extracted from thuya and Atlas cedar woods can also be involved in the observed bioactivity

Antifungal activity of several thyme species oils was recently tested successfully against wood-decaying fungi especially those of *Thymus bleicherianus* [17]. Furthermore, EOs of *T. articulata* root burl showed an antibacterial activity two to six times greater compared to that of reference antibiotic and were more effective

bacteriostatic and bactericidal effects [40]. Regarding inhibition mechanisms of active compounds of EOs, it was reported that volatile alcohols can act on both lytic and synthetic enzyme pathways and growth inhibition consequently occurred after

Active compounds contained in oils of *T. articulata* and *C. atlantica* woods, which were successfully tested against wood-decaying fungi, may protect and ensure good natural durability levels for these woods ranging from very durable

Findings of this study could allow us to consider recovering wastes from *T. articulata* and *C. atlantica* wood processing for the extraction of bioactive oils and use them as biocide especially in preservative treatment of less-durable woods such as those of pines. Also, these results are in favor of more protection for these threatened species and for the rehabilitation in their natural environment. Natural compounds of *T. articulata* and *C. atlantica* oils can then replace the use of current petrochemical compounds that are becoming more and more criticized for their

The present study has clarified the relationship between the natural durability of *T. articulata* and *C. atlantica* woods and the antifungal activity of their EOs. According to the bioassay conducted on those oils, a significant inhibitory activity was obtained on the four wood-rotting fungi tested, mainly for oils extracted from *T. articulata* root burl. Stronger inhibitory effect was then reached by dilutions over 1/5000 v/v for this oil rich in phenols. The durability classes of *T. articulata*

breaking off natural extension hyphae of fungi [41, 42].

harmful effect on human health and the environment.

) and *Escherichia coli* (Gram<sup>−</sup>) with significant

from class 5 (not durable) to class 3 (moderately durable) [34].

**222**

**3. Conclusion**

This project is supported by Forest Research Center in Rabat (High Commission for Water and Forests and Fight against Desertification) in collaboration with Faculty of Sciences in Rabat (Mohammed V University), Morocco.
