The combination of ATR-FTIR and chemometrics for discrimination of Red Ginger (Zingiber Officinale Var Rubrum) oil in West Sumatra and its antioxidant activity

Abstract

Their origin influences the chemical components and pharmacological action of essential oils. This study aimed to classify red ginger oil (RGO) based on its FTIR spectra combined with chemometrics and determine its antioxidant activity. Fresh red ginger rhizomes were collected from six West Sumatra regions and extracted using hydrodistillation. ATR-FTIR and Chemometrics were used to classify the oil, and its antioxidant activity was tested using various methods. The study found that RGO was golden yellow with a unique odor, and it had a yield range of 0.52% - 0.86%, a specific gravity of 0.83-0.94 g/ml, a refractive index of 1.4834 – 1.4880, and an optical rotation value of -36.382. However, all RGO samples had low antioxidant activity. Principal Component Analysis (PCA) showed that RGO can be separated based on the altitude of the growing locations at the wavenumber 2000-400 cm-1. Hierarchical Clustering Analysis (HCA) revealed three clusters of RGO: I; Solok, II; Kamang Magek and Batusangkar, III; Dharmasraya, Pesisir Selatan, and Pasaman Barat, with different FTIR fingerprints. In conclusion, red ginger oil from different parts of West Sumatra has unique metabolite profiling and low antioxidant activity levels.