Untargeted Metabolomics for Sea Buckthorn (Hippophae rhamnoides ssp. carpatica) Berries and Leaves: Fourier Transform Infrared Spectroscopy as a Rapid Approach for Evaluation and Discrimination

Untargeted metabolomics coupled with chemometric analysis was applied to evaluate and discriminate six Romanian sea buckthorn (Hippophae rhamnoides L.) berries and leaves. Total carotenoids and total phenolics were determined quantitatively by UV-Vis spectrometry. The qualitative evaluation and discrimination was obtained using the FTIR fingerprints (by using Fourier Transform Infrared spectroscopy) of raw carotenoid and phenolic extracts. The average concentration of total carotenoids was 54 and 3.9 mg carotenoids/ 100g DW in berries and leaves, respectively. The average concentration of total phenolics was 746 mg GAE/100g DW in berries, approximately 1.8 times lower than total phenolics found in leaves. By PCA (Principal Component Analysis) of fingerprints (900-1800 cm-1), the responsible bands for samples discrimination were identified. In case of total carotenoids extract the biomarker bands were: 1745, 1743, 1500 cm-1 for berries and 1458 cm-1 and 1735 cm-1 for leaves, while for total phenolic extract the key bands were 1731, 1033, 1622 cm-1 for berries and 1047 cm-1, 1616, 1512 and 1454 cm-1 for leaves. FTIR spectroscopy proved to be a simple and sensitive analytical technique that can be successfully used in sample discrimination and classification.