Identification of Anti-Inflammatory and Anti-Proliferative Neolignanamides from Warburgia ugandensis Employing Multi-Target Affinity Ultrafiltration and LC-MS.

Xiao-Cui Zhuang,Ming-Quan Guo,Xiao-Lan Hu,Gui-Lin Chen,Yong-Li Zhang,Na Li,Ye Liu,Jian-Lin Wu

doi:10.3390/ph14040313

Abstract

Previous reports have illustrated that the incidence and mortality of cancer are increasing year by year worldwide. In addition, the occurrence, development, recurrence and metastasis of cancer are closely related to inflammation, which is a kind of defensive response of human body to various stimuli. As an important medicinal plant in Africa, Warburgia ugandensis has been reported to have certain anti-inflammatory and anti-proliferative activities, but its specific components and mechanisms of action remain elusive. To tackle this challenge, affinity ultrafiltration with drug targets of interest coupled to high-performance liquid chromatography-mass spectrometry (AUF-HPLC-MS/MS) could be utilized to quickly screen out bioactive constituents as ligands against target enzymes from complex extracts of this plant. AUF-HPLC-MS/MS with four drug targets, i.e., cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), topoisomerase I (Top I) and topoisomerase II (Top II) were used to rapidly screen and characterize the anti-inflammatory and anti-proliferative natural ligands from W. ugandensis, and the resulting potential active compounds as ligands with specific binding affinity to COX-2, 5-LOX, Top I and Top II, were isolated with modern separation and purification techniques and identified with spectroscopic method like NMR, and then their antiinflammatory and anti-proliferative activities were tested to verify the screening results from AUF-HPLC-MS/MS. Compounds 1 and 2, which screened out and identified from W. ugandensis showed remarkable binding affinity to COX-2, 5-LOX, Top I and Top II with AUF-HPLC-MS/MS. In addition, 1 new compound (compound 3), together with 5 known compounds were also isolated and identified from W. ugandensis. The structure of compound 3 was elucidated by extensive 1D, 2D NMR data and UPLC-QTOF-MS/MS. Furthermore, compounds 1 and 2 were further proved to possess both anti-inflammatory and anti-proliferative activities which are in good agreement with the screening results using AUF-HPLC-MS/MS. This work showcased an efficient method for quickly screening out bioactive components with anti-inflammatory and anti-proliferative activity from complex medicinal plant extracts using AUF-HPLC-MS/MS with target enzymes of interest, and also demonstrated that neolignanamides (compounds 1 and 2) from W. ugandensis would be the active components responsible for its anti-inflammatory and anti-proliferative activity with the potential to treat cancer and inflammation.

Highlights

Warburgia ugandensis, a traditional medicinal plant commonly known as pepper bark tree and greenheart in Eastern and Southern Africa, has been widely used as conventional therapeutic medicine to treat various diseases by local people for a long time [1]
Air-dried powders of stem barks from W. ugandensis were extracted with 95%
Dried crude extracts were homogeneously dispersed in ultrapure water, and successively partitioned with equal volumes of different solvents to get other four fractions for further isolation, purification, affinity ultrafiltration, and activity assays

Summary

Introduction

A traditional medicinal plant commonly known as pepper bark tree and greenheart in Eastern and Southern Africa, has been widely used as conventional therapeutic medicine to treat various diseases by local people for a long time [1]. Many reports have illustrated the traditional uses of W. ugandensis in aches with pains, and inflammation, for example, stomachache, toothache, headache and joint ache, etc. Its specific chemical components responsible for the activities above and their corresponding mechanisms of action remain need to be explored. In the last few years, there has been ever-increasing interest in its active components responsible for the anti-cancer and anti-inflammatory effects [2,3], since cancer and inflammation are becoming a growing threat to people’s health [13,14,15,16].

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Conclusion