| Four medicinal plants Dracocephalum tanguticum, Malus hupehensis, Cicuta. virosa, and Dysosma versipelli and one fungus Ustilago maydis have been chemically investigated and their bioactivities have been evaluated. A total of 90 compounds were obtained, which were characterized as five alkaloids,35 flavonoids,15 coumarins, and 35 other compounds on the basis of extensive spectroscopic data, chemical transformations, and quantum chemical computation. Eleven compounds were new secondary metabolites.Five new alkaloids dracotanosides A-E (1-5) and two new flavonoids, ladanetin-6-O-β-(6"-O-acetyl)glucoside (6) and pedalitin-3'-O-β-glucoside (7), together with 25 known compounds, were isolated from the whole plants of Dracocephalum tanguticum. Their structures were established on the basis of extensive spectroscopic (IR, MS, and NMR) data analysis and by comparison with spectroscopic data reported in the literature. Antioxidant capacities of the isolated flavonoids were determined and their cytoprotective activities were also tested against doxorubicin (DOX)-induced toxicity in H9c2 cardiomyocytes. Among all the tested compounds, luteolin-7-O-β-D-glucopyranoside (12) exhibited both strong antioxidative effect and high protective activity against DOX-induced toxicity. Further investigation found that 12 could decrease DOX-induced death of H9c2 cell, reduce LDH and CK level, and inhibit the elevated intracellular concentration of ROS and [Ca2+]i. The preliminary structure-activity relationships (SAR) of these compounds revealed the△2,3-double bond on C-ring and 3',4'-di-OHs on B-ring of a flavone skeleton such as luteolin and its derivatives, were necessary for their cardioprotective effects.Three new biflavonoid glycosides (33-35) were isolated from the leaves of Malus hupehensis, along with 16 known compounds. Their structures were elucidated by spectroscopic analyses. The absolute structures of 33 and 34?? were determined by combination of CD and computational methods, and each of them was shown to be in an atropisomeric relationship.A new dimeric coumarin, diarchangelicin A (48), together with 17 known compounds, were isolated from the aerial part of Cicuta virosa and their structures were elucidated by spectroscopic methods. In addition, the known compounds were evaluated for multidrug resistance reversing activity by using doxorubicin-resistant K562/A02 cells. Archangelicin (Arc,48) was endowed with remarkable MDR reverting effects, and the maximal reversal fold (RF) was 7.36. The action of Arc was confirmed by the increase of intracellular accumulation of Dox in K562/A02 cells. The function of P-gp was blocked, and the expression of MDR1 mRNA and P-gp were also inhibited by Arc. Accordingly, Arc reversed effectively MDR via inhibiting P-gp expression and function, and may be used as MDR reversal drugs to increase the effectiveness of chemotherapy.Thirteen known compounds, including scopoletin (66), tetracosanoic acid (67), 5-hydroxyl-7,3',4'-trimethoxy flavone (68), isorhamnetin (69), (+)-medioresinol (70), 4-hydroxy-3-methoxybenzoic acid (71), podophyllotoxin (72),5,7-dihydroxychromone (24), oleanolic acid (25), ursolic acid (26),β-daucosterol (31), andβ-sitosterol (32) were isolated from Dysosma versipellis.Eighteen known compounds, including stellasterin (73),5α- cholest-7-en-3β-ol (74), peroxyergosterol (75), N-trans-p-coumaroyl tyramine (76), N-cis-p-coumaroyltyr-amine (77),N-trans-feruloyl-3-methoxytyramine (78),N-cis-feruloyl-3-methoxyty-ramine (79),5,7-dihydroxy-4-methyl-2(1H)-quinolinone (80),6-ethoxy-4-methoxy-1-naphthalenol (81),1,2-benzenedicarboxylic acid (82),1,2-benzenedipropanoic acid diethyl ester (83),3-hydroxy-p-anisic acid (84),4-ethoxybenzoic acid (85), 3,4-dimethoxysalicylic acid (86),3-methoxybenzoic acid (87),1-O-Methyl-β-D-glucopyranoside (88),1-O-ethyl-β-D-glucopyranoside (89), 1-O-n-Butyl-β-D-glucopyranoside (90) were isolated from Ustilago maydis. |
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