Pheophytin analogues from the medicinal lichen Usnea diffracta.
Hong-Bo Xu1, Tong-Hua Yang2, Pei Xie1
1a Shaanxi Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Shaanxi Province Key Laboratory of New Drugs and Chinese Medicine Foundation Research , Shaanxi University of Chinese Medicine , Xianyang , P.R. China.
Natural Product Research
|November 3, 2017
Summary
Researchers discovered a new pheophytin from the Usnea diffracta lichen, along with two known analogues. These compounds showed significant xanthine oxidase (XO) inhibitory activity, offering potential therapeutic benefits.
Area of Science:
- Natural Product Chemistry
- Pharmacology
Background:
- Lichens are a rich source of bioactive natural products.
- Pheophytins are chlorophyll derivatives with diverse biological activities.
- Xanthine oxidase (XO) is a key enzyme in purine metabolism, implicated in conditions like gout.
Purpose of the Study:
- To isolate and characterize novel and known compounds from the lichen Usnea diffracta.
- To evaluate the xanthine oxidase inhibitory potential of the isolated compounds.
Main Methods:
- Isolation of compounds using chromatographic techniques.
- Structure elucidation through extensive spectroscopic analysis (NMR, MS).
- In vitro assay for xanthine oxidase inhibition activity determination.
Main Results:
- A new pheophytin, (132S, 17S, 18S)-132-hydroxy-20-chloro-ethylpheophorbide a (3), was identified.
- Two known analogues (1-2) were also isolated from U. diffracta for the first time.
- Compounds 1-3 exhibited significant xanthine oxidase inhibitory activity with IC50 values ranging from 42.1 to 75.9 μg/mL.
Conclusions:
- Usnea diffracta is a valuable source of rare pheophytin derivatives.
- The isolated pheophytins demonstrate potent xanthine oxidase inhibition, suggesting potential therapeutic applications.
