Triterpenes from Alisma orientalis act as farnesoid X receptor agonists

Alisma orientalis is a well-known traditional medicine exerting pharmacological effects including antidiabetes, antihepatitis, and antidiuretics, but the respective molecular mechanism is not completely clear. Farnesoid X receptor (FXR) is a member of nuclear receptor superfamily and viewed as one of the essential target proteins to develop antidiabetic treatments. In this study, the triterpenes, alisol M 23-acetate and alisol A 23-acetate, were isolated from A. orientalis and further evaluated for their activity against FXR. In the mammalian one-hybrid and transient transfection reporter assays, both triterpenes transactivated FXR to modulate promoter action including GAL4, SHP, CYP7A1, and PLTP promoters in dose-dependent manner, while they exhibited similar agonistic activity as chenodeoxycholic acid (CDCA), an endogenous FXR agonist. These results highly indicated that alisol M 23-acetate and alisol A 23-acetate acted as FXR agonists so A. orientalis might exert therapeutic effect including antihyperglycemic effect through FXR pathway.     

Studies on the lipid-regulating mechanism of alisol-based compounds on lipoprotein lipase

Studies on the lipid-regulating effects of alisol compounds are reported that include alisol B, alisol A 24-acetate (24A), alisol A and an alisol B - 24A - alisol A mixture (content ratio = 1:1:1). The effects on the activity of lipoprotein lipase (LPL), a key lipid-modulating enzyme, were studied to investigate the molecular mechanism of lipid-regulating activity of alisols. The effects of alisols on regulating blood lipids and the activities of LPL were determined using a reagent kit method. The structure of LPL was obtained by homology modeling and the interactive mechanism of alisol monomers and the mixture with LPL was investigated by molecular simulation. The alisol monomer and mixture were shown to regulate blood lipids, suggesting that alisols may decrease the level of triglyceride (TG) by improving the activity of LPL. The order of intensity was: mixture > alisol A > alisol B > 24A, indicating that alisols of alismatis rhizoma feature a synergistic effect on LPL. The N- and C-terminus of LPL both represented the catalytic active domains of this lipid-regulating effect. Cys306, Gln129 and Ser166 were the key amino acid residues resulting in the lipid-regulating effect of the alisol monomer while Ser166 and Arg18 were found to be responsible for the lipid-regulating effect of the mixture. The C-terminus of LPL was indirectly involved in the enzymatic process. A folded side chain of alisols or the parent ring was found to bind somewhat weaker to LPL than an open side chain or parent ring. The hydroxyl groups on the C14-, C22-, C28-, C30- and C31-terminus in the side chain, the ring ether structure in C23-position, and the acetyl group in C29-position represented the key sites for the lipid-regulating action of alisols. Meanwhile, the C30-site hydroxyl group played an important role in the synergistic effect of the alisol mixture.     

降脂中药复方的转运性相互作用——体外MDR1转运研究

目的:药物相互作用是影响药物安全和药效的重大因素之一。本文旨在通过体外MDR1研究方法——ATP酶法,评价降脂中药复方(Fang-2)及其单方6个饮片水提物与P-gp的相互作用,为临床中西药转运性相互作用提供参考。方法:应用标准化制备技术,制备降脂中药复方及其6个饮片水提物。利用基于MDR1膜的ATP酶法,计算MDR1细胞膜的ATP酶活性,考察药物与P-gp的相互作用。结果:1 mg·mL-1、10 mg·mL-1两个浓度中药复方的ATP酶活性分别为27.2、40.0 nmol Pi·min-1·mg-1protein,呈浓度依赖性。6个单方中,泽泻、厚朴、夏枯草与P-gp作用显著,其强弱顺序为:泽泻夏枯草厚朴(50.642.640.0 nmol Pi·min-1·mg-1protein)。泽泻单体23-乙酰泽泻醇B、24-乙酰泽泻醇A均与P-gp有较强的相互作用,ATP酶动力学研究显示其Km值和Vmax值分别为0.79±0.28μM,2.01±0.67μM和50.57±3.72 nmol Pi·min-1·mg-1protein,56.28±29.6 nmol Pi·min-1·mg-1protein。结论:Fang-2与MDR1存在相互作用,其中泽泻为主要被MDR1转运的饮片,泽泻的有效组分23-乙酰泽泻醇B和24-乙酰泽泻醇A均是MDR1底物。表明该降脂中药与临床上其他降脂药物的联用时应充分考虑MDR1介导的转运行相互作用,为临床用降脂药物提供参考和依据。     

The binding mechanisms of plasma protein to active compounds in Alismaorientale rhizomes (Alismatis Rhizoma)

Ultrafiltration and HPLC were employed to assess binding rates between rat plasma protein and two active compounds with lipid-regulating properties (alisol B 23-acetate and alisol A 24-acetate) from Alismaorientale rhizomes (Alismatis Rhizoma), a traditional Chinese medicine. SDS–PAGE was used for the evaluation of the binding between the alisol acetates and Hb in plasma. The fluorescence spectroscopy and circular dichroism spectroscopy were also combined with molecular modeling to explore binding mechanisms between Hb and the alisol acetates under imitative physiological condition. The ultrafiltration results show that alisol B 23-acetate bound more strongly than alisol A 24-acetate to plasma protein. SDS–PAGE results may suggest that alisols bind to Hb in plasma. The spectroscopy results are consisting with the molecular modeling results, and they indicate that the differences in plasma protein binding strength between the two compounds may be related to their side chains. A folded side chain/parent ring bound more strongly to Hb than an open side chain/parent ring.     

Triterpenes from Alisma orientalis act as androgen receptor agonists,progesterone receptor antagonists,and glucocorticoid receptor antagonists

Alisma orientalis, a well-known traditional medicine, exerts numerous pharmacological effects including anti-diabetes, anti-hepatitis, and anti-diuretics but its bioactivity is not fully clear. Androgen receptor (AR), progesterone receptor (PR), and glucocorticoid receptor (GR) are three members of nuclear receptor superfamily that has been widely targeted for developing treatments for essential diseases including prostate cancer and breast cancer. In this study, two triterpenes, alisol M 23-acetate and alisol A 23-acetate from Alisma orientalis were determined whether they may act as androgen receptor (AR), progesterone receptor (PR), or glucocorticoid receptor (GR) modulators. Indeed, in the transient transfection reporter assays, alisol M 23-acetate and alisol A 23-acetate transactivated AR in dose-dependent manner, while they transrepressed the transactivation effects exerted by agonist-activated PR and GR. Through molecular modeling docking studies, they were shown to respectively interact with AR, PR, or GR ligand binding pocket fairly well. All these results indicate that alisol M 23-acetate and alisol A 23-acetate from Alisma orientalis might possess therapeutic effects through their modulation of AR, PR, and GR pathways.     

Alisolide, alisols O and P from the rhizome of Alisma orientale

A nor-protostane, alisolide (1), a rearranged protostane, alisol O (2), and a 2,3-seco-protostane triterpene, alisol P (3), were isolated from the rhizomes of Alisma orientale, along with eight known protostane triterpenes. The structures were elucidated to be (17S)-3,11-dioxo-23-nor-protost-12-en-23(17)-olide, 3-oxo-11beta,23-dihydroxy-24,24-dimethyl-26,27-dinorprotost-13(17)-en-25-oic acid, and (20R,23S,24R)-23,24,25-trihydroxy-2,3-seco-protost-13(17)-en-3-oic acid 2,11beta-lactone, respectively, by interpretation of spectroscopic data.     

湖北泽泻的HPLC分析及有效成分含量测定

采用高效液相色谱方法,以乙腈和水(65?35)为流动相,图谱收集波长为210 nm。用指标成分24-乙酰泽泻醇A、23-乙酰泽泻醇B的标准品作回归曲线(利用浓度和峰面积的线性关系),对药店出售的片状干燥泽泻的含量进行测定和图谱分析,并与资料中展示的不同泽泻制品含量相比较,从而对泽泻的制作方法、有效成分含量的影响及泽泻质量进行评价,建立起成熟的质量评价的定量方法体系。     

Effects of sesquiterpenes and triterpenes from the rhizome of Alisma orientale on nitric oxide production in lipopolysaccharide-activated macrophages: absolute stereostructures of alismaketones-B 23-acetate and -C 23-acetate

The methanolic extract from a Chinese herbal medicine, the rhizome of Alisma orientale, was found to exhibit inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)activated macrophages. Novel triterpenes, alismaketones-B 23-acetate and -C 23-acetate, were isolated from the active extract together with eight sesquiterpenes and eighteen protostane-type triterpenes. The absolute stereostructures of new triterpenes were characterized on the basis of chemical and physicochemical evidence, which included the chemical correlations with known triterpenes. The guaiane-type sesquiterpenes (alismol, orientalols A and C) and protostane- and seco-protostane-types triterpenes (alisols C monoacetate, E-23-acetate, F, H, I, L-23-acetate, and M-23-acetate, alismaketones-B 23-acetate and -C 23-acetate, alismalactone 23-acetate, and 3-methylalismalactone 23-acetate) inhibited LPS-induced NO production (IC50 = 8.4-68 microM). Other triterpenes (alisols A, A monoacetate, B, B monoacetate, E, G, K-23-acetate, and N-23-acetate and 11-deoxyalisol B) also showed the potent inhibitory activity, but they showed cytotoxic effects more than 30 microM (MTT assay). In addition, alismol and alisol F were found to suppress iNOS induction.     

Sesquiterpenes and triterpenoids from the rhizomes of Alisma orientalis and their pancreatic lipase inhibitory activities

Five new terpenoids, including three sesquiterpenes 11-hydroxy-8-ox-alismoxide (1), 11-oxo-13-nor-alismol (2), and 1β,11-dihydroxy-β-cyperone (3), and two protostane-type triterpenoids 16β-acetoxy alisol B (4) and 16α-acetoxy alisol B (5) were isolated from the rhizomes of Alisma orientalis together with 11 known compounds. Their structures were established using 1D and 2D NMR and HRESIMS spectroscopic analyses. The isolated compounds were assayed for their inhibitory activities against pancreatic lipase. Compounds 6 and 13 showed inhibitory effects with IC₅₀ values of 64.4 and 45.5 μM, respectively.     

Nucleolar protein B23 has molecular chaperone activities

Protein B23 is an abundant, multifunctional nucleolar phosphoprotein whose activities are proposed to play a role in ribosome assembly. Szebeni et al. (1997) showed stimulation of nuclear import in vitro by protein B23 and suggested that this effect was due to a molecular chaperone-like activity. Protein B23 was tested for chaperone activities using several protein substrates. The temperature-dependent and -independent aggregation of the HIV-1 Rev protein was measured using a zero angle light scattering (turbidity) assay. Protein B23 inhibited the aggregation of the Rev protein, with the amount of inhibition proportional to the concentration of B23 added. This activity was saturable with nearly complete inhibition when the molar ratio of B23:Rev was slightly above one. Protein B23 also protected liver alcohol dehydrogenase (LADH), carboxypeptidase A, citrate synthase, and rhodanese from aggregation during thermal denaturation and preserved the enzyme activity of LADH under these conditions. In addition, protein B23 was able to promote the restoration of activity of LADH previously denatured with guanidine-HCl. Protein B23 preferentially bound denatured substrates and exposed hydrophobic regions when complexed with denatured proteins. Thus, by several criteria, protein B23 behaves like a molecular chaperone; these activities may be related to its role in ribosome biogenesis.     

Vaccination with mouse mammary adenocarcinoma cells coexpressing B7-1 (CD80) and B7-2 (CD86) discloses the dominant effect of B7-1 in the induction of antitumor immunity

Nonreplicating TS/A mammary adenocarcinoma cells expressing B7-2 (CD86) (TS/A-2) are more immunogenic than those expressing B7-1 (CD80) (TS/A-1), indicating that B7-1 and B7-2 display nonredundant costimulatory effects in inducing antitumor responses. Whereas transfection of B7-2 cDNA into TS/A-1 cells does not improve their immunogenicity, transfection of B7-1 cDNA into TS/A-2 cells (TS/A-2/1) decreases their immunogenicity in a manner that is directly related to the surface levels of B7-1. Ab blocking of B7-1 on TS/A-2/1 cells before their injection in vivo restores the higher immunogenicity characteristic of single B7-2 transfectants, indicating therefore that B7-1 actively modulates the B7-2-dependent costimulation. The expression of B7-1 also modifies quantitatively the balance of endogenous IFN-gamma and IL-4 induced in vivo by TS/A-2 vaccines. In fact, we find that vaccination with TS/A-2/1 cells results in the production of more IFN-gamma and less IL-4 than TS/A-2 vaccines, a pattern comparable to that induced by TS/A-1 cells. Thus, in the TS/A model of antitumor response, B7-1 modulates B7-2-dependent costimulatory effects in a dominant, noncompetitive way.     

Biotransformation of alisol G by Penicillium janthinellum and the hCE2 inhibitory effects of its metabolites

Alisol G, also named 25-anhydroalisol A, is a major triterpene obtained from dried rhizomes of Alisma orientalis. This paper investigated the transformation of alisol G by fungi and evaluated the hCE2 inhibitory effects of the transformed products. By screening whole cells of 10 strains of filamentous fungi, Penicillium janthinellum AS 3.510 exhibited a special capability to transform alisol G. Four metabolites were obtained, which were determined to be new compounds on the basis of spectroscopic data, including UV, 1D- and 2D-NMR, and HRESIMS. In addition, in an in vitro bioassay, metabolites 1–4 showed significant hCE2 inhibitory activities with IC₅₀ values of 6.81, 16.66, 3.38, and 6.33 μM, respectively.     

In vitro effects of bovine dialyzable leukocyte extract (bDLE) in cancer cells

BACKGROUND: Bovine dialyzable leukocyte extract (bDLE) is a dialyzate of a heterogeneous mixture of low molecular weight substances released from disintegrated blood leukocytes or lymphoid tissue obtained from homogenized bovine spleen. The purpose of this study was to determine if bDLE had cytotoxic effects and modulated apoptosis gene expression in breast cancer cells. METHODS: The MCF-7, BT-474, MDA-MB-453, A-427, Calu-1, U937 and L5178Y cancer cell lines and PBMC human cells were treated with bDLE (0-0.66 U/mL) for 72 h. The bDLE effect on cell growth proliferation was evaluated by MTT assay, and the MCF-7 was evaluated by ethidium bromide-acridine orange staining; total DNA was evaluated for DNA fragmentation, and total RNA was isolated for p53, bag-1, c-myc, bim, bax, bcl-2 and bad mRNA expression. RESULTS: The bDLE had dose-dependent cytotoxic effects and demonstrated an IC50 at a dosage of 0.06 U/mL (P<0.05). The bDLE did not affect the viability of normal human PBMC. The bDLE induced DNA fragmentation at doses of 0.06 and 0.13 U/mL in MCF-7 breast cancer cells. The bDLE induced cytotoxic effects and suppressed the p53, bag-1, c-myc, bax, bcl-2, and bad mRNA expression that influences apoptosis in MCF-7 breast cancer cells. Bim mRNA expression was not detected. DISCUSSION: This may open up interesting prospects for the treatment of human breast cancer.     

Anti-HBV agents. Part 3: Preliminary structure–activity relationships of tetra-acylalisol A derivatives as potent hepatitis B virus inhibitors

Thirty-two tetra-acylated derivatives of alisol A were synthesized and evaluated for their anti-hepatitis B virus (HBV) activities and cytotoxicities in vitro. Among the series of alisol A derivatives examined, five analogues were active against HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) secretion in HepG 2.2.15 cells. These results also provide interesting structure–activity relationships of tetra-acylalisol A derivatives. Compounds tetra-acetyl alisol A (A1), tetra-methoxyacetyl alisol A (A23), and tetra-ethoxyacetyl alisol A (A24) exhibited high activities against secretion of HBsAg with IC₅₀ values of 0.0048, 0.0044, and 0.014 mM, respectively, HBeAg with IC₅₀ values of 0.011, 0.012, and 0.018 mM, respectively, and remarkable selective index values SI_HBsAg >333, SI_HBeAg >145; SI_HBsAg = 209, SI_HBeAg = 77; and SI_HBsAg >200, SI_HBeAg >156, respectively. Additional studies in rats showed that compound A1 has favorable pharmacokinetic prosperities for further development purpose, with elimination half-time (t_1/2) of 1.63 h and oral bioavailability (F) of 40.9%.     

A mechanism-based, solution-phase method for screening combinatorial mixtures of potential platinum anticancer drugs

 We report a new, mechanism-based approach to the screening of pools of potential platinum antitumor drugs. A platinum complex of L-lysine, [Pt(Lys)Cl₂] or Kplatin, was selected from mixtures of platinum-amino acid compounds based on the ability of its DNA adducts to bind HMG1 in a gel mobility shift assay. Kplatin, unlike most other platinum antitumor drug candidates, is an (N,O)-chelated complex which binds DNA forming two isomeric 1,2-d(GpG) intrastrand DNA cross-links. Kplatin-modified DNA is specifically recognized by HMG1, HMG1 domain B, and testis-specific HMG, all of which bind to the major cisplatin-DNA adducts. Kplatin is toxic towards the human tumor cell lines HeLa and KM12 with LC₅₀ values of 59.2±7.8 μM and 74 μM, respectively. Received: 16 July 1997 / Accepted 31 October 1997