Investigation of the Chemical Variability of Essential Oils from Zingiber officinale Cultivars Using Integrated GC–MS and ¹³C NMR Analytical Approaches

Abstract

Background and Aims: Zingiber officinale is grown in various regions of Côte d’Ivoire in two varieties (yellow and white). This study aims to identify the chemical markers that distinguish the essential oils of the cultivars of this aromatic plant.  Study Design: The objective was to assess the chemical variability of Zingiber officinale cultivars according to their growing region in Côte d'Ivoire. Place and Duration of Study: This study was conducted at the Laboratory of Bioorganic Chemistry and Natural Products, University Nangui ABROGOUA (Abidjan, Côte d’Ivoire) between 2021 and 2022. Methodology: Chemical analysis was performed using gas chromatography coupled with mass spectrometry (GC/MS) and nuclear magnetic resonance (NMR) on samples of essential oil extracted from the yellow and white rhizomes of Z. officinale via Clevenger hydrodistillation.  Results: The yields obtained ranged from 0.1512 to 0.1824% for the white cultivar and from 0.1452 to 0.1908% for the yellow cultivar. A total of 74 volatile compounds were identified in each sample, accounting for more than 97% of the constituents of these essential oils. The essential oils consist mainly of monoterpenes (77.26–83.68% for the white cultivar and 79.27–79.58% for the yellow cultivar), dominated by 1,8-cineole, camphene, geranial, and neral. Sesquiterpenes constitute the second largest class of compounds (11.69–17.76% and 14.43–15.39%, respectively), followed by small proportions of aliphatic compounds (~2%) and diterpenes, notably geranyl linalool (<1%). Conclusion: These results highlight a qualitative homogeneity in the chemical composition of the ginger essential oils studied, despite quantitative variations related to geographic origin and cultivar.