Isolation and characterization of phenolic compounds from the leaves of Salix matsudana.

Xiang Li,Yi-Nan Zheng,Zhi Liu,Chang-Chun Yuan,Guang-Zhi Sun,Li-Juan Wang,Xin-Feng Zhang

doi:10.3390/molecules13081530

Abstract

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclo-oxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (1), together with five known flavonoids – luteolin (2), isoquercitrin (3), 7-methoxyflavone (4), luteolin 7-O-glucoside (5), 4',7-dihydroxyflavone (6) – and two phenolic glycosides, leonuriside A (7) and piceoside (8). Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies, high resolution ESI mass spectroscopic analyses and comparisons with literature data. The isolated compounds 1-8 were tested for their inhibitory activities against COX-1 and COX-2. Compounds 1, 5 and 6 were found to have potent inhibitory effect on COX-2 and compounds 3-5 exhibited moderate inhibition against COX-1.

Highlights

Salix matsudana Koidz is a small to medium-sized upright spreading tree reaching up to about 30 feet in height and a 15-foot-spread, distributed around the world [1]
Compound 1 was isolated as a pale yellow amorphous powder, and its molecular formula was determined as C26H26O12 on the basis of high resolution (HR)-ESI-MS (m/z 531.1517 [M+H]+, calcd. 531.1503) and NMR data (Table 1), implying fourteen degrees of unsaturation
To our knowledge no publications have reported flavonoid pathway related genes in Salix matsudana, our results strongly suggested that the speculated enzymes (F3H, flavonoid 7-glucosyltransferase (F7GT), flavonoid 3-glucosyltransferase (F3GT) and prenyltransferase) exist in this spp

Summary

Introduction

Salix matsudana Koidz is a small to medium-sized upright spreading tree reaching up to about 30 feet in height and a 15-foot-spread, distributed around the world [1]. As part of our investigations on the chemical constituents and pharmacological activities of Salix species [7,8,9,10], a new flavonoid, named matsudone A (1), has been isolated from a 70% methanol extract of the leaves of Salix matsudana, along with seven known compounds 2-8 (Figure 1). Their structures were elucidated on the basis of high resolution (HR) ESI-MS, 1H- and 13C-NMR, together with 2D-NMR spectroscopic analyses. Bioassay and compounds 1, 5 and 6 were found to have potent inhibitory effect on COX-2, while compounds 3-5 exhibited moderate inhibition against COX-1

Results and Discussion

Bioactivity Results

Conclusions