毛瑞香酚性成分研究

应用色谱技术从毛瑞香根的乙醇提取物中分离和纯化出6个酚性成分,通过光谱方法鉴定其分别为瑞香醇酮(1)、西瑞香素-7-O-葡萄糖苷(2)、芫花苷(3)、瑞香黄烷D1(4)、瑞香黄烷现(5)和紫丁香苷(6)。6个化合物均为首次从该植物中分得。     

Odoracin,a Nematicidal Constituent from Daphne odora

The mechanism of the stereospecific hydride conjugate addition of 7 concerned in the total synthesis of vernolepin (1) was confirmed from the fact that intramolecular hydride attack was only possible by coordinating with the two axial hydroxyl groups present. This confirmation led us to develop a new general method for stereospecific preparation of cis-fused α-methylene-γ-butyrolactones.     

金边瑞香有机相提取物库的构建及活性成分分离纯化研究

采用逆流提取-系统溶剂组分化-高效液相色谱法(high-performance liquid chromatography,HPLC)检测组分化效果-高速逆流色谱技术(High-Speed Counter-Current Chromatography,HSCCC)分离制备高纯度化合物的研究思路,对金边瑞香化学成分进行研究得到4个高纯度单体化合物.通过现代谱学方法分别鉴定为:瑞香素(daphnetin,1)、瑞香黄烷I(daphnodorin I,2)、对羟基苯甲酸(p-hydroxybenzonic acid,3)和瑞香黄烷D1(daphnodorin D1,4),化合物2～4均为首次从该种植物中分离得到.     

Resiniferonol-related Diterpene Esters from Daphne odora Thunb. and their Ornithine Decarboxylase-inducing Activity in Mouse Skin

Phosphoenolpyruvate (PEP) carboxylase purified from Brevibacterium flavum was specifically activated by fructose 1,6-bisphosphate (FBP). The other intermediates of sugar metabolism or their structural analogues did not influence the activity. FBP decreased the apparent Km for PEP but did not affect that for another substrate, bicarbonate, or the apparent maximum velocity for PEP. The dissociation constants for FBP from enzyme-FBP and enzyme-PEP-FBP complex were 63 and 32 μm, respectively, being almost equivalent to those for acetyl-CoA. Synergistic activation by FBP and acetyl-CoA was not observed with the B. flavum enzyme, unlike the Escherichia coli enzyme. FBP, like acetyl-CoA, was kinetically competitive with aspartate. With respect to another feedback inhibitor, 2-oxoglutarate, acetyl-CoA was non-competitive, whereas FBP was of mixed-type, i.e., FBP but not acetyl-CoA prevented 2-oxoglutarate from binding to the enzyme to a certain extent. Homotropic cooperativity was observed only with FBP but not with acetyl-CoA in the absence of inhibitors. Cooperativities of FBP and acetyl-CoA were increased by aspartate but not by 2-oxoglutarate. In the aspartate-overproducing mutant enzyme, the Michaelis constant for PEP was decreased, whereas the inhibitor constant for aspartate with or without simultaneous addition of 2-oxoglutarate and the activator constants for FBP and acetyl-CoA were increased. The decreased Michaelis constant for PEP was comparable to the apparent Km of the wild-type enzyme for PEP in the presence of the saturated concentration of FBP, and would result in a further decrease in the affinity of the mutant enzyme for aspartate.     

Daphne odora Exerts Depigmenting Effects via Inhibiting CREB/MITF and Activating AKT/ERK-Signaling Pathways

Daphne odora, a blooming shrub, has been traditionally used for various medicinal purposes. However, information on its anti-melanogenic activity and dermal application is limited. In this study, the Daphne odora extract (DOE), with constituents including daphnetin, was used to investigate depigmenting activity and the underlying mechanism of Daphne odora. DOE inhibited in vitro and cellular tyrosinase activity in a dose-dependent manner, and reduced the α-MSH-induced melanin biosynthesis to a control level. The protein expressions of melanin synthesis-related enzymes were also significantly reduced by DOE. Moreover, DOE decreased the phosphorylation of cAMP-response element binding proteins (CREBs) induced by α-MSH in B16F10 cells, while it activated phosphorylated extra-cellular signal-regulated kinases (ERKs) and protein kinase B (AKT) expression. These results suggest that DOE might inhibit the melanogenesis signaling pathways by activating ERK- and AKT-signaling pathways to regulate the expression of CREB and MITF and its downstream pathways. Therefore, DOE could potentially be developed as a depigmenting agent.     

Two biflavonoids from Ouratea nigroviolacea

The leaves of Ouratea nigroviolacea (Ochnaceae) afforded two biflavonoids, ouratine A and B together with agathisflavone and stigmasterol. The biflavonoids were characterized as 4'-O-methylated apigeninyl-(I-6, II-8)-4'-O-methylatedapigenin and 4'-O-methylated apigeninyl-(I-6, II-8) apigenin by spectral and chemical transformation studies.     

Tetraflavonoid and biflavonoids from Aristolochia ridicula

Biflavones, a chalcone-flavone, and a tetraflavonoid with a new carbon skeleton were isolated from the leaves of Aristolochia ridicula. Their structures were determined by chemical derivatizations and spectrometric analyses.     

Two biflavonoids from Ouratea flava stem bark

In a chemical investigation on the stem bark of Ouratea flava, two biflavonoids: 1-[3-(2,4-dihydroxy-benzoyl)-4,5,6-trihydroxy-2-(4-hydroxy-phenyl)-benzofuran-7-yl] -3-(4-hydroxy-phenyl) -propenone (flavumone A) and 3-(2,4-dihydroxy-benzoyl)-4-hydroxy-2,7-bis-(4-hydroxy-phenyl) -7,8- dihydro-furo[2,3-f]chromen-9-on (flavumone B) were isolated along with five known flavonoids. Their structures were established by various analyses including 2D-NMR spectroscopy.     

均匀设计法对超临界流体提取金边瑞香鲜花条件的优化

目的研究超临界CO2流体提取(SFE)金边瑞香鲜花中有效成份的最佳条件。方法采用均匀设计方法，以提取压力、提取温度、解析压力、解析温度四个因素，每个因素7个水平进行实验。结果在SFE中最佳提取条件：提取压力35MPa，提取温度40℃，解析压力5～8MPa，解析温度36℃。结论本法是一种简便、高选择性和高效率提取金边瑞香鲜花有效成份的方法。     

Five biflavonoids from Calycopteris floribunda (Combretaceae)

The structures of five biflavonoids, 6"-demethoxyneocalycopterone (1), calyflorenone C (2), 6"-epi-calyflorenone B (3), 6"-epi-calyflorenone C (4) and calyflorenone D (5) from the green parts of Calycopteris floribunda were established by NMR and MS. Their NMR and chiroptical properties (CD, [alpha]20D ) were compared with those of the known C. f. biflavonoids 6-11. Compound 1 represents a calycopterone derivative, 2-5 have a calyflorenone skeleton. With regard to one chiral center (C-6"), 4 and 3 are the respective epimers of 2 and 11.     

Novel urease inhibitors from Daphne oleoids

Phytochemical investigations on the chloroform and ethyl acetate soluble fractions of the roots of the Daphne oleoids led to the isolation of the coumarin glycosides 1-6. Compound 5 with IC50 values 22.05 and 26.30 microM repectively, was found to be the most active of these compounds when screened against Bacillus pasteurii and jack bean urease enzymes in a concentration-dependent fashion.     

Biflavonoids from Daphne linearifolia Hart.

Two new biflavonoids, 2″-hydroxygenkwanol A (1) and 4′-methylgenkwanol A (2), together with fourteen known compounds were isolated from the aerial parts of Daphne linearifolia Hart. Their chemical structures were elucidated by extensive NMR spectral studies, as well as by ESI-MS analysis. The affinity of all compounds towards Hsp90, one of the most promising targets for the modern anti-cancer therapy, by surface plasmon resonance was tested. Achieved results demonstrated that 1 efficiently interacts with the protein, also allowing some structure–activity relationship evaluations.     

Flavone 5-O-glucosides from Daphne sericea

The aerial parts of Daphne sericea yielded two new flavonoids, luteolin 7-methyl ether 5-β-d-glucoside and luteolin 7,3′-dimethyl ether 5-β-d-glucoside, as well as luteolin 7-methyl ether, isovitexin, apigenin and its 7-β-d-glucoside.     

Osteoblast differentiation stimulating activity of biflavonoids from Cephalotaxus koreana

Six amentoflavone-type biflavonoids, bilobetin (1), ginkgetin (2), 4',7'-di-O-methyl-amentoflavone (3), 7-O-methyl-isoginkgetin (4), sciadopitysin (5), and 7,4',7',4'-O-methyl-amentoflavone (6), were isolated from the EtOAc fraction of Cephalotaxus koreana Nakai (Cephalotaxaceae) by bioactivity-guided fractionation technique using primary cultures of mouse osteoblasts as an in vitro assay system. Among the six biflavonoids isolated, bilobetin (1), sciadopitysin (5), and 7,4',7',4'-O-methyl-amentoflavone (6) significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity, collagen synthesis, and mineralization. Considering structure-activity relationship, methoxyl groups at 4' and 4' in the B rings in amentoflavone-type biflavonoid might be important in osteoblast differentiation. Taken together, our present study suggests therapeutic potential of biflavonoids against bone diseases such as osteoporosis.     

Antimicrobial biflavonoids from the aerial parts of Ouratea sulcata

Investigation of the aerial parts of Ouratea sulcata led to the isolation of a biflavonoid named sulcatone A, together with the known compounds, 3-hydroxy-2,3-dihydroapigenyl-[I-4',O,II-3']-dihydrokaempferol, amentoflavone, lophirone A, agathisflavone, stigmasterol and stigmasteryl-3-O-beta-D-glucopyranoside. The structure of the compound was assigned as apigenyl-[I-4',O,II-3']-dihydrokaempferol, by means of spectroscopic analysis. Sulcatone A and 3-hydroxy-2,3-dihydroapigenyl-[I-4',O,II-3']-dihydrokaempferol exhibited significant in vitro antimicrobial activities against a range of microorganisms.     

Novel urease inhibitors from Daphne oleoids

Phytochemical investigations on the chloroform and ethyl acetate soluble fractions of the roots of the Daphne oleoids led to the isolation of the coumarin glycosides 1–6. Compound 5 with IC₅₀ values 22.05 and 26.30 μM repectively, was found to be the most active of these compounds when screened against Bacillus pasteurii and jack bean urease enzymes in a concentration-dependent fashion.     

Structurally unique biflavonoids from Selaginella chrysocaulos and Selaginella bryopteris

Chemical investigation of Selaginella chrysocaulos from Northeast India yielded three new (i.e., 1-3) and two known biflavonoids. From Selaginella bryopteris, collected in the southern part of India, one new (11) and eleven known biflavonoids of the amentoflavone- and hinokiflavone-type were isolated and identified. The structures of the compounds were elucidated by 1D- and 2D-NMR spectroscopy, and by mass spectrometry. The absolute configurations of chiral biflavonoids with flavanone subunits (from S. bryopteris) were determined with the aid of circular-dichroism (CD) spectroscopy. Several very rare or even unprecedented substructures in biflavonoids were found.     

Antiplasmodial and leishmanicidal activity of biflavonoids from Indian Selaginella bryopteris

A series of eleven biflavonoids containing amentoflavone and hinokiflavone derivatives from the Indian medicinal herb Selaginella bryopteris has been investigated for their antiprotozoal activity using in vitro assays against the K1 strain of Plasmodium falciparum, Leishmania donovani, Trypanosoma brucei rhodesiense and Trypanosoma cruzi. The highest antiprotozoal activity was displayed by 7,4′,7″-tri-O-methylamentoflavone which exhibited an IC₅₀ of 0.26 μM. This compound showed no significant cytotoxicity (IC₅₀ > 150 μM) evaluated using L-6 cells. The strongest activity against Leishmania was detected for 2,3-dihydrohinokiflavone (IC₅₀ = 1.6 μM), whereas for Trypanosoma no significant activity was observed (IC₅₀ > 12.5 μg/mL for the extract). To evaluate the in vivo activity against Plasmodium of the most active compound, trimethylated amentoflavones were obtained by partial synthesis starting from amentoflavone. The synthesized mixture of trimethylated amentoflavones did not show activity in the Plasmodium berghei mouse model against female NMRI mice at 50 mg/kg.