Comparative Analysis of Hydro-Distillation and Steam-Distillation Techniques on the Chemical Composition of Turmeric (Curcuma longa Linn) Rhizomes

Turmeric (Curcuma longa Linn) is a well-known medicinal and aromatic plant, traditionally used for centuries due to its bioactive rhizomes, which offer significant health benefits. To fully harness these benefits, a suitable method capable of extracting these bioactive compounds is required. This research, therefore, seeks to compare the effect of two different techniques (hydro-distillation: HD and steam-distillation SD) on the chemical composition of Curcuma longa Linn rhizomes, which were obtained from the local market in Ijebu-Ode, Ogun State. The extracted oils were analyzed using Gas Chromatography Mass Spectrometry (GC-MS). A total of 23 compounds were found in the HD oil and 25 in the SD oil. In the HD oils, Sesquiphellandrene (18.77%), Tumerone (18.83%), and Terpinolene (13.28%) were the most abundant compounds, followed by α-Zingiberine (7.61%), Germacrene (7.43%). Other compounds were present in negligible amounts. While in Steam distillation, the order of abundance was Tumerone (24.23%), Sesquiphellandrene (11.20%), and Aromadendrene (10.07%), besides other compounds. The HD method had a higher composition of Sesquiphellandrene (18.77%), Aromadendrene oxide (2) (5.30%), and Terpinolene (13.28%), while Tumerone (24.23%) and Aromadendrene (10.07%) were more abundant in the SD oil. Although both hydro-distillation and steam-distillation successfully extracted various bioactive compounds from Curcuma longa rhizomes, the methods yielded distinct chemical profiles, with only eight compounds in common. These differences suggest that the choice of extraction method significantly influences the chemical composition and potential applications of the extracted oils.