Study On The Chemical Constituents Of Belamcanda Chinensis And Their Antioxidant And Anti-inflammatory Activities

Belamcanda chinensis L.（DC）is a traditional Chinese medicine that has been used to manage several diseases including inflammation and upper respiratory tracts such as tonsillitis,pharyngitis,laryngitis,cough and asthma.The main objective of this study is to isolate and characterize chemical constituents from the active fraction of Belamcanda chinensis roots and evaluate their antioxidant and anti-inflammatory activities.The Belamcanda chinensis roots were collected from Nanzhao in Henan Province,China,and extracted with 95%ethanol by the soaking method and partitioned with four polar solvents;petroleum ether,dichloromethane,ethyl acetate and n-butanol.The total flavonoid and phenolic content of the ethanol and polar solvent extracts were determined by colorimetry method.In vitro,antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl（DPPH）,2,2’-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid）（ABTS）,and ferric reducing antioxidant power（FRAP）assay.Anti-inflammatory activity was evaluated using cyclooxygenase-2（COX-2）inhibition assay.Then,the fraction with the best antioxidant and anti-inflammatory activity was selected for separation and identification of active components responsible for these activities.Finally,the antioxidant and anti-inflammatory activity of the isolated compounds were evaluated.The results revealed that dichloromethane fraction had the highest flavonoid content（291.29mg RE/g）while ethyl acetate had the highest phenolic content（286.34 mg GAE/g）.The dichloromethane fraction exhibited both significant DPPH free radical scavenging activity(IC₅₀=43.92 mg/m L)and potential FRAP reducing power(1.05 mg Fe²⁺/g)while ethyl acetate exhibited potent ABTS radical scavenging ability(IC₅₀=38.72 mg/m L).In vitro COX-2 inhibition assay revealed that dichloromethane(IC₅₀=0.28μM)exhibited the highest COX-2 inhibition activity.Based on the above results,the DCM fraction was further isolated where a total of 27 compounds were isolated including 9 first time from this genus,with 26 of them identified as flavonoids and1 alkyl-phenylketone.The antioxidant and anti-inflammatory activity for these isolated compounds was screened.Compound BC-5-4（Dalspinin）with IC₅₀ of 10.44μM exhibited the strongest DPPH free scavenging activity even higher than vitamin C(IC₅₀=11.26μM),Compound BC-3-2（iristectorigenin B）exhibited the strongest ABTS radical scavenging activity(IC₅₀=13.49μM)and BC-3-8（3′,5,7-trihydroxy-8,4′-dimethoxyisoflavone）showed the strongest FRAP reducing power(4.77 m M Fe²⁺).The anti-inflammatory activity for these compounds was revealed to exhibit potential effects on COX-2 inhibition assay.Compound BC-3-8（3′,5,7-trihydroxy-8,4′-dimethoxyisoflavone）with IC₅₀ of 4.20μM exhibited the strongest COX-2 inhibition activity amongst the compounds.This study reveals the isolated compounds from the roots of Belamcanda chinensis exhibited significant antioxidant and anti-inflammatory activities.