Studies On The Chemical Constituents Of Selaginella Tamariscina And Their Bioactivities

We studied systematically on the chemical constituents of Selaginella tamariscina by using various chromatographic methods and spectral technologies,focused on the analogues of selaginellin.As a result,16 compounds were isolated and identified,including 5 new compounds.S.tamariscina is mainly distributed in Guangxi,Sichuan,Hubei,Shanxi and Shandong provinces of China.It has been widely used in Traditional Chinese Medicine for the treatment of hepatitis,hematuria,and traumatic injury.Modern scientific studies demonstrated that the plant contains flavonoids,alkaloids,phenylpropanoids,and organic acids as its major constituents.Zhang et al.isolated an unprecedented skeleton compound featuring unique alkynyl and p-quinone methide functionalities from S.sinenisis in 2007,named as selaginellin.Flavonoids and selaginellin analogues are the principal constituents of this genus,which have a variety of pharmacological activities,including antitumor and anti-inflammatory.In order to find more selaginellin analogues,16 compounds were isolated from S.tamariscina.The compounds were identified via physicochemical properties and spectroscopic data analyses,including a novel selaginellin analogue featuring the unique motif of 1H-2-benzopyran(1),a new selaginpulvilin(2),4 known selaginpulvilins(3-6),6 known selaginellin analogues(7-12),3 new phenolic compounds(13-15),and 1 known biflavone(16).Their structures were elucidated as selagintamarlin A(1),selaginpulvilin E(2),selaginpulvilins A-D(3-6),selaginellin A(7),selaginellin B(8),selaginellin E(9),selaginellin O(10),selaginellin H(11),selariscinin D(12),13,14,15,and amentoflavone(16).Among them,1,2,and 13-15 are new compounds.Compounds 1-10 were evaluated for their inhibitory activity against PDE4D2,tubulin polymerization and tumor.Compounds 1-10 potently inhibited the activity of PDE4D2 with IC50 values in the range of 40-1680 nM.In particular,1,the most active compound showed an IC50 of 40 nM,being 20-fold stronger than the positive control.The accommodation of compound 1 in the binding site is similar to colchicine,a well known tubulin polymerization inhibitor.Most of the isolates exhibited moderate antitumor activity against several human cancer cell lines,especially,compound 1(IC50 values in the range of 7.02-10.32 μM).Compound 1 showed remarkable inhibitory activity against PDE4D2 and tubulin polymerization,which indicated that 1 might be a dual inhibitor of PDE4D2 and tubulin polymerization.