Assessment of the terpenic profile of Callistemon citrinus (Curtis) Skeels from Mexico

Abstract

Callistemon species are well known due to its medicinal properties and due to, among others, the relevant health benefits of their terpenic components. This paper aims to in-depth study the terpenic profile of the leaf and flower extracts of Callistemon citrinus with two ages. To fulfill this objective, initially, a screening of the terpenic composition of ethanolic extracts of C. citrinus was performed using GC–MS, and a total of 17 terpenic components were identified in leaf and flower ethanolic extracts. In order to obtain a deeper knowledge, comprehensive two dimensional gas chromatography with time of flight mass spectrometry detection (GC×GC–ToFMS) was also applied, allowing to identify a total of 100 terpenic components in the analyzed ethanolic extracts, from which 77 were identified for the first time in C. citrinus species. A total of 74 and 64 terpenic components were identified in the 4 years old leaf and flower ethanolic extracts, respectively, and 68 and 70 in 20 year old ethanolic extracts, respectively. Moreover, the most abundant terpenic components detected in leaf extracts were 1,8-cineole, α-terpineol, linalool, 4-terpineol, spathulenol, β-gurjunene and viridiflorol, and in flowers were p-cymene, myrtanol, 1,8-cineole, linalool, spathulenol and rosifoliol. Flowers and leaves extracts present a different terpenic profile, with significant differences concerning the type and level of their components, also differences may be noticed related to the extract from 4 and 20 years old. This work allowed achieving a deep characterization of the terpenic composition of leaf and flower C. citrinus, a crucial step in the bioprospection of this plant raw-material as a source of terpenic compounds.