Separation and Identification of Non-Volatile Sour and Bitter Substances in Amomum villosum L. by Ultra-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry and Electronic Tongue Analysis, as Well as Their In Vitro Anti-Tumor

Amomum villosum L. is a perennial herbaceous belonging to the ginger family. Due to its unique aroma, it is widely used in alcoholic beverages and food processing. Unfortunately, issues with bitterness and sourness occur, which affect the taste and quality of processed products. In this study, the non-volatile sour and bitter substances in Amomum villosum L. were systematically isolated, purified, and characterized through a combination of chromatographic separation techniques and ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS). The results indicate that three sour compounds (DL-malic acid, protocatechuic acid, and p-hydroxybenzoic acid) and one bitter compound (catechin) were identified for the first time in Amomum villosum L. The in vitro anti-tumor activity was screened and determined using Cell Counting Kit-8 (CCK-8) assays, a 5-Ethynyl-2′-deoxyuridine (EdU) staining experiment, and scratch assays. The results reveal that the bitter substance of catechin (25–100 μg/mL) exhibited significant inhibitory effects, which inhibited the proliferation and migration of human non-small cell lung cancer A549 cells through dose-dependent mechanisms. This investigation also reveals the influence of different traditional extraction solvents on the degree of bitterness and sourness in Amomum villosum extracts, providing a theoretical basis for improving the quality and pharmacological utilization of Amomum villosum extracts.