Ecotype Variation of Methyl Eugenol Content in Tea Tree (Melaleuca alternifolia and Melaleuca linariifolia)

Abstract

Methyl eugenol is a natural phenylpropanoid compound found in a wide range of plants used for food, flavouring, cosmetics, and health-care. As a suspected rodent carcinogen, methyl eugenol may also be harmful to humans when present in significant concentrations. Consequently, its level has been restricted in some foodstuffs and cosmetics for some markets. In order to assess the potential to breed uniformly low methyl eugenol cultivars for an essential oil crop, tea tree, the source of 'Oil of Melaleuca, terpinene-4-ol type', we examine levels in individual trees (n = 30) from two geographic regions and six terpene chemotypes. Overall, methyl eugenol levels were low in this species (Mean [SD] 354 [239] ppm, n = 30), much lower than levels predicted to be of toxicological concern. Within each chemotype, there was a lack of evidence for correlations between terpenoid constituents and methyl eugenol levels. Further support for the independence of methyl eugenol and terpene biosynthesis was evident from similar mean levels in selected (Mean [SD] 586 [339] ppm, n = 12) and undomesticated Melaleuca alternifolia trees (Mean [SD] 480 [299] ppm, n = 5) with terpinen-4-ol type oils. By contrast, methyl eugenol level varied by geographic origin and chemotype. Trees from the upland region, where there is a prevalence of terpinolene type trees, had lower average methyl eugenol levels than trees from the coastal region, where there is a prevalence of terpinen-4-ol and 1,8-cineole type trees.

Association between vitamin content, plant morphology and geographical origin in a worldwide collection of the orphan crop Gynandropsis gynandra (Cleomaceae)

“…Such genetic variation could be induced by geographic or environmental isolation of different populations adapted to local conditions and with limited gene flow among them (Kleessen et al 2012;Prunier et al 2017). Several studies documented the geographical patterns of intraspecific differentiation in plant morphology (Pucher et al 2015;Upadhyaya et al 2017) and phytochemical profiles (Bellomo and Fallico 2007;da Silva et al 2017;Masetti et al 2017;Shepherd et al 2017). We hypothesize that the observed trade-off between carotenoids and tocopherols associated with geographical origin could be explained by differential expression of some genes involved in carotenoid, chlorophyll and tocopherol synthesis.…”

Strategy for the multi‐component characterization and quality evaluation of volatile organic components in Kaixin San by correlating the analysis by headspace gas chromatography/ion mobility spectrometry and headspace gas chromatography/mass spectrometry

“…Existing studies have shown that isocalamenediol, α-asarone, β-asarone, methyl eugenol, isoeugenol methyl ether, camphor, anethol, 2,4-di-tert-butylphenol, linalool, and asarylaldehyde are the 10 main medicinal components in KXS VOCs which have good medicinal effects. For example, β-asarone and α-asarone have good effects as antidepressants, and in the treatment of anti-senile dementia and memory improvement; methyl eugenol has anesthetic effects 31,37. For the reason that quantitative analysis of the main volatile medicinal substances which provides a basis for the study of the medicinal substance basis of KXS.…”

Orphan no more : Ethnobotany and genetic analysis of leaf yield and secondary metabolites content in Gynandropsis gynandra (Cleomaceae)

“…Such genetic variation could be induced by geographic or environmental isolation of different populations adapted to local conditions and with limited gene flow among them (Kleessen et al 2012;Prunier et al 2017). Several studies documented the geographical patterns of intraspecific differentiation in plant morphology (Pucher et al 2015;Upadhyaya et al 2017) and phytochemical profiles (Bellomo and Fallico 2007;da Silva et al 2017;Masetti et al 2017;Shepherd et al 2017). We hypothesize that the observed trade-off between carotenoids and tocopherols associated with geographical origin could be also explained by differential expression of the specific genes involved in either carotenoid or tocopherol synthesis.…”