Methods For The Separation And Analysis Of Amide Alkaloids From Three Pepper Plants

Piper longum L and Piper nigrum L are the representative plants of the pepper plants with specific aroma and spicy taste.They have the effect of artificial flavor in foods and are widely used in the burning,baking,stewing and other food processing.With the wide range of pharmacological activities,P.longum can treat dyspepsia,sleep problems,asthma,nausea and other diseases.Meanwhile,P.nigrum,with warming middle-jiao to dispel cold,relieve pain and insecticidal effect,is widely used as auxiliary drugs to treat malaria,stomachache and cholera.Amide alkaloids are the main chemical constituents of pepper plants.They have various structural types and biological activities such as insect resistance,antibacterial and anti-depression.They have been one of the research hotspots in the field of pharmacology and pharmacology.In this study,the amide alkaloids in P.longum and P.nigrum were studied,and the components and structures of the components were systematically separated and analyzed.It has the significance for the development of amide alkaloids in the pepper plant.The first chapter summarizes the research progress of pepper plants,summarizes their plant classification and chemical composition,and summarizes the main methods of separation and analysis of natural products.The second chapter extracts,separates,structures and analyzes the chemical constituents of amide alkaloids in P.longum.The total amide alkaloids were enriched by adjusting the p H of the solution,and the partition coefficients of the main compounds were determined by HPLC.High-speed countercurrent chromatography(HSCCC)was used to separate the amide alkaloids from the crude extraction.The optimum solvent system was n-hexane-ethyl acetate-methanol-water(5:4:5:4,v/v).For the less polar part,gradient HSCCC mode was carried out with the initial solvent system of n-hexane-ethyl acetate-methanol-water(6:4:6:4,v/v),and gradually changed to(7:3:7:3,v/v)and(8:2:8:2,v/v)of the lower phase.The flow-rate was set2.0 m L/min and detection wavelength of 254 nm.The structures of the thirteen monomeric compounds were identified by mass spectrometry and nuclear magnetic resonance spectroscopy.The cleavage of the main amides was investigated based on the MS/MS ion fragments of the target compounds.The third chapter extracts,enriches and analyzes the structure of amide alkaloids in the white and black pepper.The HSCCC was used to separate the amide alkaloids in the two plants with a solvent system of n-hexane-ethyl acetate-methanol-water(5:4:5:4,v/v).Structural fragmentation was studied by HPLC-Q-TOF-MS/MS,and the trace amide alkaloids structure in white and black pepper were analyzed according to the MS/MS ion fragments.Seventeen amide alkaloid compounds were identified in white pepper,while 22 amide alkaloid compounds were identified in black pepper.