Volatile Metabolomic Composition of Vitex Species: Chemodiversity Insights and Acaricidal Activity

Abstract

The Vitex genus (Lamiaceae) produces a plethora of metabolites that include ecdysteroids and terpenoids, some of which have demonstrated insect repellent properties. The volatile composition of several members of this genus has not been chemically defined, as many taxa are endemic to remote ecosystems. In this study, leaves were collected from the northeast of Brazil from Vitex capitata, V. megapotamica, V. gardneriana, and V. rufescens plants and examined for their chemical profile via GC-MS/FID of essential oil extracts. The analyses showed a diversity of terpenoids. Of particular note were seven-member ring sesquiterpenes which were present in great abundance; a dendrogram showed clades separating by the production of bicyclogermacrene, aromadendrane and 5,10-cycloaromadendrane sesquiterpenoids for the four species. Comparison of volatile metabolite profiles to 13 other Vitex species showed strong similarities in the production of some monoterpenes, but varied by their production of larger terpenes, especially those with gem-dimethylcyclopropyl subunits on seven-member ring compounds. From this work, we suggest that the sesquiterpene skeleton with seven member rings is a good chemosystematic biomarker candidate for the Vitex genus. Separation using this biomarker was then validated using Inter-Simple Sequence Repeat profiling. Lastly, experiments examining the toxicity of these four oils against the coconut mite Aceria guerreronis showed that only the oil of V. gardneriana had strong acaricidal activity, with an LC50 of 0.85 mg/mL, thus demonstrating its potential for use as a natural pesticide.

Variation of Secondary Metabolite Profile of Zataria multiflora Boiss. Populations Linked to Geographic, Climatic, and Edaphic Factors

“…For instance, cluster analysis on Verbascum songaricum resulted into nine groups (Selseleh et al, 2019) and for lemon balm populations three different chemotypes could be identified (Pouyanfar et al, 2018). Also grouping based on EO constituents of four Vitex specimens revealed different clusters (de Sena Filho et al, 2017).…”

“…For instance, cluster analysis on Verbascum songaricum resulted into nine groups ( Selseleh et al., 2019 ) and for lemon balm populations three different chemotypes could be identified ( Pouyanfar et al., 2018 ). Also grouping based on EO constituents of four Vitex specimens revealed different clusters ( de Sena Filho et al., 2017 ). In the present study, the components of the EO measured at full flowering stage underpin the presence of the three chemotypes (carvacrol, thymol, linalool).…”

Essential Oils and Biological Activities of the Genus Vitex (Lamiaceae) – A Review

“…(Nyiligira et al, 2004) The major components of Vitex essential oils mainly consist of sesquiterpene hydrocarbons. Caryophyllene was identified as the major component of four Vitex species which are; V. limonifolia (Thailand) (Suksamrarn al., 1990), V. polygama (Brazil) (Leitao et al, 1999), V. rufescens (Brazil), and V. megapotamica (De Sena Filho et al, 2017). Besides, germacrene D was found in two different Vitex species which are; V. ferruginea (South Africa) (Cabral et al, 2008) and V. rivularis (Cameroon) (Cabral et al, 2009).…”

“…Besides, germacrene D was found in two different Vitex species which are; V. ferruginea (South Africa) (Cabral et al, 2008) and V. rivularis (Cameroon) (Cabral et al, 2009). In addition, the other sesquiterpene hydrocarbons were δ-cadinene (De Sena Filho et al, 2017), cis-calamenene (Vale et al, 2019;Silva et al, 2019;Pereira et al 2018), 6,9-guaiadiene (De Sena Filho et al, 2017, which were found in the leaf oil of Brazillian V. capitata, V. gardneriana, and V. gardneriana, respectively. Meanwhile, spathulenol was found its richness in the oil of V. rehmannii (Nyiligira et al, 2004).…”

“…The toxicity against the coconut mite Aceria guerreronis showed that V. gardneriana essential oil had strong acaricidal activity, with an LC50 of 0.85 mg/mL. However, the essential oils of V. capitata, V. megapotamica, and V. rufescens plant did not kill adults of A. guerreronis over a period of 24 h. As a way of toxicity comparison, the acaricide abamectin, sprayed at its label rate, inflicted 100% mortality to A. guerreronis (De Sena Filho et al, 2017). Nat.…”