Study On The Anti-inflammatory Constituents Of Morinda Officinalis How

Ba-ji-tian,first documented at“Shennong Bencao Jing”,is the dried root of Morinda officinalis How.in Rubiaceae with a long medicinal history.As one of the“four southern medicines in China”,ba-ji-tian is not only used for treat diseases in traditional Chinese medicine,but also consumed as a tonic in nourishing soups and drinks.Modern pharmacological research showed that ba-ji-tian possessed multiple biological effects,including anti-depression,anti-osteoporosis,anti-inflammation,anti-Alzheimer’s disease,improving reproductive capacity,cardiovascular and cerebrovascular protection and so on.In this study,the 75%methanol extract of the dried roots of M.officinalis were separated and purified by various chromatographic methods.Forty-two compounds were identified as below:（1）methyl naphthoates:（-）-mornaphthoate G（1a*）,（+）-mornaphthoate G（1b*）,（+）-mornaphthoate H（2a*）,（-）-mornaphthoate H（2b*）.（2）anthraquinones:2,8-dihydroxy-1-methoxy anthracene-9,10-dione（3*）,2,5,8-trihydroxy-1-methoxyanthracene-9,10-dione（4）,3,8-dihydroxyl-1,2-dimethoxyanthracene-9,10-dione（5）,1,5,8-trihydroxy-2-methoxy anthracene-9,10-dione（6）,1,3,8-trihydroxy-2-methoxy anthracene-9,10-dione（7）,1,8-dihydroxy-2-hydroxymethyl anthracene-9,10-dione（8）,1,5-dihydroxy-2-hydroxymethylanthracene-9,10-dione（9）,1-hydroxy-2-methoxymethylanthracene-9,10-dione（10）,1-hydroxy-6-hydroxymethylanthracene-9,10-dione（11）,1-hydroxy-7-hydroxymethyl anthracene-9,10-dione（12）,2-hydroxy-1-methoxyanthracene-9,10-dione（13）,2-hydroxy-1,3-dimethoxyanthracene-9,10-dione（14）,3-hydroxy-1,2-dimethoxyanthracene-9,10-dione（15）,2-ethoxymethyl-3-hydroxy-1-methoxy anthracene-9,10-dione（16）,3-hydroxy-1-methoxy-2-methylanthracene-9,10-dione（17）,1,3-dihydroxy-2-methoxyanthracene-9,10-dione（18）,1-hydroxy-2-hydroxymethylanthracene-9,10-dione（19）,1,4-dihydroxy-2-hydroxymethyl anthracene-9,10-dione（20）,1,2-dihydroxy-3-methylanthracene-9,10-dione（21）,2-hydroxy-3-methylanthracene-9,10-dione（22）,2-dimethoxymethyl anthracene-9,10-dione（23）,2-methoxyformylanthracene-9,10-dione（24）.（3）Coumarins:scopoletin（25）,6-hydroxy-7,8-dimethoxy-coumarin（26）,fraxidin（27）,isofraxidin（28）.（4）Phytosterols:β-sitosterol（29）,7-ketositosterol（30）,（3β,7β）-7-methoxystigmast-5-en-3-ol（31）,（3β,7α）-7-methoxystigmast-5-en-3-ol（32）.（5）Others:ningpogenin（33）,1H-indole-3-carboxaldehyde（34）,4-hydroxy-3,5-dimethoxybenzaldehyde（35）,syringic acid（36）,n-hexadecanoic acid（37）,methyl hexadecanoate（38）,heptadecanoic acid（39）,octadecanoic acid（40）.Among the 42 identified compounds,compounds 1a,1b,2a,2b and 3 are five new compounds which have not been reported.Compounds 5,6 and 23 are three new natural products.Compounds 8-10,16,20,26,27,31,32 and 34-36are isolated from the dried roots of M.officinalis for the first time.In addition,in vitro anti-inflammatory activities of the methyl naphthoate and anthraquinones were tested.Except for compound 4,the methyl naphthoates（1a,1b,2a,2b）and most anthraquinones（5-23）exhibited inhibition on the NO production for different intense.Among the 26 compounds,compound 19(IC₅₀=17.17±4.13μM)and compound 2b(IC₅₀=34.32±4.87μM)showed better NO inhibition effect.Preliminary study on their anti-inflammatory mechanism showed that compound 19 exhibited the expressions of pro-inflammatory mediators of COX-2,IL-1βand IL-6 in concentration-dependent manners.Compound 2b showed suppression of the phosphorylation of NF-κB.And compounds 2b and 19 could reduce the protein expressions of i NOS,COX-2 and suppress the nuclear translocation of NF-κB.In conclusion,the in vitro anti-inflammatory activities of the two compounds were achieved by downregulating the expression of pro-inflammatory mediators i NOS,COX-2,IL-1βand IL-6,and their anti-inflammatory activities were related to NF-κB.This study not only enriched the anti-inflammatory active ingredients of M.officinalis,laid a certain chemical foundation for the further development and utilization of M.officinalis,but also provided a scientific basis for that reasonable consumption of M.officinalis as a healthcare product might be beneficial for preventing and reducing the occurrence of inflammatory-associated diseases.