Study On The Chemical Constituents And Bioactivities Of Flos Populi

The male inflorescence of Populus tomentosa Carr.,Populus canadensis Moench.or other plants of Populus are all referred as Flos populi.It is widely distributed in most parts of China.It is regarded as the first drug for treating diarrhea in poultry and included in Chinese Veterinary Pharmacopoeia?2015 Edition?.Previous research had shown that the main chemical constituents of Flos populi were flavonoids and phenolics.And it had been indicated possessing anti-bacterial,antioxidant,anti-inflammatory,antiviral and some other pharmacological activities notably.In order to enrich the research materials about it,we investigated the chemical constituents of the male inflorescence of Populus tomentosa Carr.systemically.Meanwhile,we evaluated the anti-tumor,antioxidant and anti-inflammatory activities of some compounds and found two known compounds might be potential candidates for the treatment of inflammatory diseases in this study.Dried male inflorescence of Populus tomentosa Carr.?30 kg?were extracted with 70%EtOH and partitioned obtain petroleum ether extract?350 g?,EtOAc extract?500 g?and n-butanol extract?400 g?.The EtOAc and n-butanol extract were separated and purified systematically.Using chromatographic methods such as silica gel,Sephadex LH-20,preparative HPLC and recrystallization repeatedly,forty-eight compounds were isolated and forty-two were identified based on the physiochemical properties and spectroscopic data.They were identified as chrysoeriol?1?,apigenin?2?,luteolin?3?,dillenetin?4?,kaempferol?5?,quercetin?6?,myricetin?7?,rhamnazin?8?,pinocembrin?9?,naringenin?10?,isosakuranetin?11?,eriodictyol?12?,taxifolin?13?,dihydromyricetin?14?,apigenin-7-O-?-D-glucopyranoside?15?,luteolin-7-O-?-D-glucopyranoside?19?,diosmetin-7-O-?-D-glucopyranoside?17?,kaempferide-7-O-?-D-glucopyranoside?18?,5-hydroxy-flavanone-7-O-?-D-glucopy-ranoside?19?,kaempferol-3-O-{[2-O-?-L-rhamnopy-ranosyl-4-O-?-D-glucopyranosyl]-?-D-glucopyranoside}?20?,apigenin-7-O-?-6?-O-p-coumaroyl?-?-D-glucopyranoside?21?,syringin?22?,salicin?23?,p-coumaric acid glucoside?24?,tremuloidine?25?,benzyl alcohol-O-?-D-glucopyranoside?26?,tremulacin?27?,salireposide?28?,2-hydroxycyclohexyl-6?-O-p-coumaroyl-?-D-glucopyranoside?29?,4?-hydroxy-1?-O-??-D-glucoside?-benzyl-2-hydroxybenzoate?30?,ursolic acid?31?,betulonic acid?32?,daucosterol?33?,2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-?6?-O-acetyl?-?-rhamnosyl?1?2?-?-D-glucoside?34?,2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-?-rhamnosyl?1?2?-?-D-glucoside?35?,xanthopurpurin?36?,catechol?37?,3,3?,4,4?-tetrahydroxybiphenyl?38?,coumaric acid?39?,protocatechuic acid?40?,caffeic acid?41?,2-acetyl-1,3-dicaffeoylglycerol?42?.Compound 30 is a new compound.Compound 1,4,7,13-15,17-19,26,30-32,38 were isolated from the genus Populus for the first time.Compound1,4,7,8,10-15,18,19,22,26,29-32,37,38,40,42 were isolated from the plant for the first time.The cytotoxic effects in vitro of some compounds were evaluated and the flavonoid compounds had the most significant activity.Compound 3,6,9,11 exhibited significant cytotoxicities against most cell lines with IC₅₀ values of less than 15?g/mL.The antioxidant properties in vitro of some compounds were tested by the ABTS and FRAP assays.From the results,compounds 6,7 and 14 exhibited remarkable antioxidant activities.Compounds 3,12,13,16,41 and 42 exhibited obvious antioxidant activities.By contrast,compounds 1,2,4,5,17,28 and 30 were found to possess moderate activities.Moreover,we assessed the anti-inflammatory effects of other some compounds in terms of their abilities to inhibit the production of NO by LPS-stimulated the murine macrophage cell line RAW 264.7 with Griess method and found compounds 27 and 42could decrease NO level markedly.The cell viability assays had ensured the toxic doses of them.Additionally,treatment with compounds 27 and 42 attenuated the release of TNF-?,IL-6 and IL-1?in LPS-stimulated RAW 264.7 cells respectively in a concentration-dependent manner.The findings suggested that they had anti-inflammatory activities evidently and contributed to the potential underlying mechanisms of them further.