| Licorice is a commonly used Chinese herbal medicine,mainly distributed in Mongolia,Xinjiang,Gansu,and Ningxia provinces of China.The pharmacopoeia stipulates that the medicinal parts of licorice are dried roots and rhizomes of Glycyrrhiza uralensis Fisch.,G.inflata Bat.,and G.glabra L.It has been reported that licorice can regulate and protect the digestive system,respiratory system,nervous system,and endocrine system.At present,more than 400 compounds have been isolated and identified from licorice.The main bioactive ingredients are triterpenoid saponins and flavonoids.These compounds have anti-ulcer,anti-inflammatory,antispasmodic,anti-oxidant,anti-viral,anti-cancer,and liver protection effects.However,there are relatively few studies on the aerial parts of licorice,which has not been well exploited,resulting in a lot of waste of licorice resources.So far,more than 100 compounds have been isolated and identified from the aerial parts of licorice.Flavonoids and stilbenes are the main bioactive constituents.The aerial part of licorice has biological activities such as anti-inflammatory,anti-oxidation,antibacterial,antivira,l and hypoglycemic effects.Although the research on the bioactivities of the aerial extracts has been mostly reported,it is steel need to carry out the detail research on the aerial parts of licorice.In order to further study the chemical constituents and pharmacological activities of leaves of licorice,we isolated and identified the chemical constituents of the ethyl acetate layer of leaf extracts of licorice,and screened the anti-inflammatory and anti-cancer activities of isolated compounds.Furthermore,the anti-inflammatory mechanism of the new compound licostilbene B has been studied.Eighteen compounds were isolated and purified from leaves of licorice by silica gel column chromatography and semi-preparative high performance liquidchromatography.Among them,four compounds,licostilbene A(1),licostilbene B(2),licofuranol A(3),and licofuranol B(4),were new compounds,whose structures were identified by physical and chemical properties,high-resolution mass spectrometry,and nuclear magnetic resonance spectroscopy;fourteen compounds,?,? '-dihydro-3,5,4'-trihydroxy-4,5'-diisopentenylstilbene(5),glycypytilbene B(6),luteolin(7),diosmetin(8),calycosin(9),scopoletin(10),quercetin-3,4'-dimethyl ether(11),echinatin(12),3',4'-dimethylquercetin(13),3,3'-dimethylquercetin(14),chrysoer iol(15),glycypytilbene A(16),gancaonin O(17)and ?-sitosterol(18),were identified as known compounds,by comparing their spectroscopic data with the literature data.In addition,the anti-inflammatory activity and anticancer activity in vitro were carried out.The licorice leaf extracts and isolated compounds significantly inhibited the production of nitric oxide(NO)in RAW264.7 cells induced by LPS.At the concentration of 10 ?g/ml,the inhibition rate was above 80%,showing good anti-inflammatory activity.Dimethoxy-substituted flavonoids quercetin-3,4'-dimethyl ether,3',4'-dimethyl quercetin,and 3,3'-dimethyl quercetin,showed toxicity to RAW264.7 cells.Furthermore,licostilbene B,a new compound,showed the inhibitory activity on the phosphorylation of p65,ERK,JNK,and p38,which suggest that licostilbene B exerts anti-inflammatory activity by inhibiting the activation of NF-?B and MAPKs pathway.Moreover,the isolated compounds had a good effect on inhibiting the proliferation of Hela cells.At the concentration of 50 ?g/ml,licostilbene A,?,?'-dihydro-3,5,4'-trihydroxy-4,5'-diisopentenylstilbene,glycyrrhizin B,quercetin-3,4'-dimethyl ether,and echinatin showed more than 80% inhibition ratio of the proliferation of Hela cells.In conclusion,we isolated and identified the chemical constituents in the leaf of Glycyrrhiza uralensis,conducting the anti-inflammatory and anti-cancer bioactivities research.It will provide a scientific basis for the screening of anti-inflammatory and anti-cancer bioactive molecules of licorice,which will promote the development and comprehensive utilization of licorice resources. |
PDF Full Text Request