Volatile Components and Antioxidant Properties of the Essential Oils and Hydrosols from Three Ginger Variants

This study aims to investigate the antioxidant potential of essential oils and hydrosols derived from three ginger (Zingiber officinale) varieties based on their chemical profiles. Hydrodistillation was conducted for 5 hours to obtain both essential oils and hydrosols. The highest yields were observed in red ginger, followed by emprit ginger and elephant ginger. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that the major phytochemical constituents of both essential oils and hydrosols include camphene, cis-citral, trans-citral, α-curcumene, zingiberene, α-farnesene, β-bisabolene, and β-sesquiphellandrene. Red ginger oil was characterized by the presence of geranyl acetate and citronellyl acetate as marker compounds, while elephant ginger oil contained β-phellandrene and citronellal as distinguishing components. In contrast, emprit ginger did not exhibit unique marker compounds significantly different from the other varieties. Antioxidant activity, assessed using IC₅₀ values, indicated that red ginger essential oil exhibited the strongest activity (IC₅₀ = 49.9 ppm) compared to other samples. However, Pearson correlation analysis suggested that functional groups such as conjugated double bonds, carbonyl groups, and hydroxyl groups were not significantly associated with antioxidant activity. Furthermore, molecular docking analysis of zingiberene—a major constituent of ginger essential oils and hydrosols—demonstrated favorable binding affinities toward NADPH oxidase and inducible nitric oxide synthase (iNOS), with binding energies of −7.30 and −8.87, respectively. Key amino acid interactions were identified at Tyr88, Val124, Met120, Arg381, Trp463, Phe476, and Glu479, indicating potential mechanisms underlying its bioactivity. Overall, the findings highlight the potential of ginger-derived essential oils, particularly red ginger, as natural antioxidant sources with possible pharmacological relevance.