CHARACTERISATION AND IDENTIFICATION OF KAEMPFERIA PARVIFLORA, CURCUMA CAESIA AND CURCUMA AERUGINOSA BY MULTI-STEPS INFRARED SPECTROSCOPY AND CHEMOMETRIC ANALYSIS

Abstract

Kaempferia parviflora, Curcuma caesia, and Curcuma aeruginosa, belonging to the Zingiberaceae family (Tribe Hedychieae), have not only been utilised for medicinal purposes in Malaysia, but also in traditional Chinese and Ayurvedic medicine. They share great similarities in morphology and external appearance with certain genera; hence, their identification is sometimes difficult. In addition, the raw materials that are distributed or sold are usually pulverised into small pieces, which hinders morphological identification. Herbal suppliers, manufacturers, and consumers often encounter confusion when purchasing rhizomes using vernacular names such as kunyit hitam, temu ireng, and temu hitam, which can be used interchangeably among the three species. The controversial taxonomy of these species of the tribe Hedychieae further complicates their correct identification, which is crucial for ensuring their pharmacological and clinical efficacy. In this study, we employed a multi-step infrared (IR) spectroscopy method combined with a chemometrics approach to distinguish these closely related species. We analysed 53 samples (19 K. parviflora, 17 C. caesia, and 17 C. aeruginosa) collected from 23 locations across Peninsular Malaysia. The species were effectively differentiated using one-dimensional IR (1D-IR), second derivative IR, and two-dimensional correlation infrared (2D-IR) spectra. Principal component analysis (PCA) of the 1D-IR spectra further confirmed the clear separation of the three species. Our findings demonstrate that macroscopic IR spectroscopy, when paired with chemometrics, is a useful and nondestructive approach for the initial quality control and identification of herbal raw materials.