Studies On The Chemical Constituents And Bioactivities Of The Stems Of Clausena Emarginata

Clausena emarginata Huang is a bush of the Rutaceae, widely distributed in Yunnan and Guangxi Provinces in China.The roots and leaves of them can be used as medicine in folk. Our research group has previously characterized a variety of limonoids, carbazole alkaloids, amide alkaloids and coumarins from the CHCl3 and EtOAc fractions, and some compounds exhibited moderate neuroprotective activities and hepatoprotective activities.At a part of our ongoing research for the bioactive constitutes of the stems of Clausena emarginata systematically, a detailed phytochemical investigation on the petroleum ether and acetone fractions of the 95% ethanol extract led to 60 compounds with a variety of chromatographic techniques such as silica gel, MPLC and HPLC. Among them there were 7 new compounds, and their structures were elucidated on the basis of NMR, ESIMS, HRESIMS, UV, IR and ECD. Clauemarmarins I-M (1*,2*,3a*, 3b,4) were new coumarins, clauemargines M-N (5*-6*) were new limonoids. The known compounds were identified as citrusarin A (7), nordentatin (8), dentatin (9),5-hydroxy-8,8-dimethyl-10-(7-hydroxy-3,7-dimethylocta-1,5-dien-3-yl)-pyranocoumarin (10),5-methoxy-8,8-dimethyl-10-(7-hydroxy-3,7-dimethylocta-1,5-dien-3-yl)-pyran-coumarin (11),5-methoxy-8,8-dimethyl-10-(3’,7’-dimethylocta-1,6’-dien-3’-yl)-pyran-coumarin (12), clausmarin A (13), clausmarin B (14),7-hydroxycoumarin (15), skimmin (16),7-{[6-0-(6-deoxy-α-L-mannopyranosyl)-β-D-glucopyranosyl]oxy}-2H-1-benzo-pyran-2-one (17), zapoterin (18),21,23-dihydro-21-hydroxy-23-oxozapoterin (19), 21,23-dihydro-23-hydroxy-21-oxozapoterin (20), clauemargine A (21), clauemargine B (22), clauemargine C (23), clauemargine D (24), clauemargine E (25), clauemargine F (26), clauemargine G (27), clauemargine H (28), clauemargine I (29), clauemargine J (30), clauemargine K (31), clauemargine L (32), loliolide (33), hydroxydihydrobovolide (34),3-methylcarbazole (35), murrayafoline-A (36), murrayanine (37), clausine Z (38), claulansine B (39), claulansine G (40), mafaicheenamine A (41), indizoline (42), y-fagarine (43), dictamnine (44), 1H-Indole-3-carboxaldehyde (45), hortiamide (46), clauemaramide A (47), N-benzoyltyramine (48), dehydroconiferyl alcohol (49), (-)-syringaresinol (50), tortoside A (51), magnolol (52), honokiol (53), dictagymnin (54), evofolin-B (55), evofolin-C (56),2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glucopyranoside (57), echipuroside A (58), zhebeiresinol (59).In the in vitro assays, compounds 15,16,19,37,38 and 42 exhibited moderate neuroprotective activities against rotenone induced PC 12 cell damage at 10 μM with significance compared to the blank control group. Compounds 1*,5*,6*,19,20 and 42 showed neuroprotective effects against L-Glutamic acid-induced cellular damage in human neuroblastoma SK-N-SH cells at 10μM, while compound 40 increased this kind of damage. Compounds 2,17,35,37 and 46 exhibited hepatoprotective activities against the damage of APAP at 10μM.