Study On Isolation, Identification And Anticancer Activity Of The Active Components From Chinese Herb "Xiebai"

Xiebai is an edible Chinese herbal medicine that has various benefits to health and treatment.In order to evaluate its nutritional and health value,solvent extraction was used to separate free amino acids and derivatives from its two plant sources,namely Allium chinense G.Don and Allium macrostemon Bunge,and amino acid automated analysis and ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry were used to analyze these molecules.In addition,MTT assay,colony formation assay,flow cytometry,wound healing and cell invasion assays were used to analyze the anti-cancer activity of its crude methanol extract and some of active chemical components(i.e.,isoliquiritigenin and N-trans-feruloyltyramide)in vitro.Our data show that both plants are rich in free amino acids,and the total free amino acid content of A.chinense G.Don is higher than that of A.macrostemon Bunge.The free amino acid composition in both plants is similar,including nineteen protein amino acids and four non-protein amino acids.The identified amino acids include eight essential amino acids and five semi essential amino acids.The total amount of essential amino acids and semi-essential amino acids accounted for 64.9% and 69.7% of the total free amino acids of the two plants,respectively.The main amino acids of the two plants,in a decreasing order of concentration,are arginine,glutamine,glutamic acid,asparagine,and serine.A.chinense G.Don is also rich in citrulline and lysine.Furthermore,two amino acid derivatives,N-methylproline and H-Glu-Tyr-OH dipeptide,were identified from two plants.For the first time,the presence of N-methylproline in Allium plants and H-Glu-Tyr-OH dipeptides in unprocessed foods are reported.The effects of the identified substances on the flavor,nutrition,and health value of Xiebai are discussed.Finally,the in vitro anti-cancer experiments showed that the crude methanol extract of Xiebai inhibited cell viability in non-small cell lung cancer cell lines A549 and PC-9.As compared to single drug,a combination of isoliquiritigenin and N-trans-feruloyltyramine resulted in additive anti-cancer activity in A549 and PC-9,even better in PC-9,evidenced by cell proliferation,cell cycle,apoptosis,migration,and invasion,via regulating EGFR/PI3K/mTOR and RAF/MAPK signaling pathways.Our findings highlight that targeting EGFR signaling pathway may be a novel strategy in clinical drug management and treatment of lung cancers by using the active chemical components from Xiebai.