A new strategy based on acid-alkali complexation for rapidly and accurately fishing phytochemicals in Sennae Folium

Objective:There are some anthraquinones,anthraquinones and flavonones in Sennae Folium which exhibited significant acidity,such as sennoside A/B and sennoside C/D.The current strategies used in separating these components are mainly based on conventional column chromatography which is time consuming,laborious and costly.This study is aimed at exploring a method of precipitation extraction of acid components in Sennae Folium.Using alkaloid as a"hook",it is reasonable to use the principle of"acid-alkali complexation"to"fish"the acidic components in Sennae Folium.Methods:Isothermal titration calorimeter(ITC)was used to measure the extraction efficiency of different alkaloids.Then,alkaloid determined by ITC was mixed with extracting solution of Sennae Folium to form complex.High performance liquid chromatography coupled with mass spectrometry(HPLC-MS2)was used to investigate the ingredients"fished"by berberine(Ber).The mechanism of"fishing"process was explained by ITC,optical activity,fluorescence spectrometry and scanning electron microscope.Results:The ITC results proved that the choice of"hook"was particularly important in the process of"fishing".Among the hooks,the fishing efficiency of the isoquinoline alkaloids(Ber)was the highest,reaching 10.3%.Nine ingredients were detected and determined by HPLC-MS2,and the main components were sennoside A/B and sennoside C/D.Based on ITC test of Ber and sennoside A,the combination mechanism of the two ingredients was a chemical reaction with a nearly binding ratio(2:1).Fluorescence and optical properties of the active ingredients were changed after complexation.By scanning electron microscope,we found that two types of components had obviously self-assembled behavior during the formation process.Conclusion:Ber successfully"fished"the main acidic components,sennoside A/B and sennoside C/D,from Sennae Folium.Combined with different characterizations,the"fishing"process was determined as a chemical association reaction induced by electrostatic interaction orπ-πstacking.Therefore,with special identification ability,the"fishing"process had the potential of practical application.

Synthesis and biological evaluation of new peroxo-bridged diosgenin derivatives

Objective： In order to find lead compound with anti-HBV activity from peroxo-bridged diosgenin deriva- tives obtained with Eosin Y as the photosensitizer. Method： Eosin Y was used as the photosensitizer to activate the oxygen in the air to synthesize novel diosgenin derivatives with peroxo-bridge. The structures of synthesized compounds were identified by NMR and HR-MS. Their cytotoxicity and antihepatitis B activity were evaluated via MTS assay and ELISA method, respectively. Results： Six diosgenin derivatives were synthesized, three of which contained peroxo-bridge, and their structures were confirmed by spectroscopy. It showed that 5a,8a-peroxo-6-alkenyl-diosgenin （7） could suppress the production of HBsAg on transfected HepG2.2.15 cells at low-toxic concentration and the in- hibition rate on HepG2.2.15 cells was 18.28% at 12.50 μg/mL, better than that of 3TC （7.30% at 12.50 μg/mL） and others. Conclusion： Due to its lower cytotoxicity and potential anti-hepatitis B activity, compound 7 could be developed as the promising candidate of anti-hepatitis B drug. It also indicated that the peroxo-bridged derivatives had potential biological values for developing clinical agents.