Histochemical localization and characterization of chalcones on the foliar surface of Zuccagnia punctata Cav. Insights into their physiological role

Dihydroxychalcones as well as other metabolites synthesized via the phenylpropanoid pathway have a wide range of biological activities. Although this class of phenolic compounds is found in very large amounts in some tissues, their physiological significance remains unclear.This approach focused on the chemical analysis of Zuccagnia punctata leaf rinse extract in which dihydroxychalcones (99.25 μg 2′,4′-dihydroxychalcone/cm² and 73.38 μg 2′,4′-dihydroxy-3′-methoxychalcone/cm²) are the main constituents. Histochemical analysis (fluorescence microscope and emission scanning electron microscope coupled with an energy dispersive X-ray spectrometer) revealed a high flavonoid concentration on the foliar surface. The high accumulation of phenolic compounds, flavonoids or chalcones in the cuticle of Z. punctata leaves would act as defense mechanisms against UV radiation for the protection of photosynthetic tissues against oxidative stress.     

Prenylflavone derivatives from Broussonetia papyrifera,inhibit the growth of breast cancer cells in vitro and in vivo

Two new prenylflavones 5,7,3′,4′-tetrahydroxy-3-methoxy-8-geranylflavone (1) and 5,7,3′,4′-tetrahydroxy-3-methoxy-8,5′-diprenylflavone (2), as well as four known ones, uralenol (3), papyriflavonol A (4), broussoflavonol B (5) and broussochalcone A (6) were isolated and purified from an ethyl acetate-soluble extract of the barks of Broussonetia papyrifera. Their structures were determined with the spectroscopic methods including HR-EI-MS, 1D and 2D NMR. We found that compounds 2–6 showed potent anti-proliferation effects on ER-positive breast cancer MCF-7 cells in vitro. The IC₅₀ values of compounds 2 and 5 were 4.41 and 4.19 μM respectively after the treatment of 72 h. We also found that compounds 2 and 5 strongly down-regulated expression concentrations of estrogen receptor-α (ER-α) and were able to inhibit tumor growth in a xenograft model of the human breast cancer line BCAP-37 in vivo. Our results demonstrated that prenylflavones from B. Papyrifera exhibit potent anti-tumor activity.     

Flavanoids from Dalea elegans: Chemical reassignment and determination of kinetics parameters related to their anti-tyrosinase activity

In the first chemical investigation developed on the species Dalea elegans twenty years ago, the occurrence of two prenylated derivatives of pinocembrin was reported: 2′,4′-dihydroxy-5′-(1‴,1‴-dimethylallyl)-6-prenylpinocembrin (6PP) given as a new structure in this family of compounds, and another derivative of already known structure, 6-prenylpinocembrin (6P). In the present paper, their structures were again analyzed by using spectroscopic techniques, especially 2D NMR. Based on the evidence obtained it is proposed the reassignment of both flavanones as: 2′,4′-dihydroxy-5′-(1‴,1‴-dimethylallyl)-8-prenylpinocembrin (8PP) for the first and 8-prenylpinocembrin (8P) for the last. Additionally, triangularin, demethoxymatteucinol, comptonin and 7-hydroxy-5-methoxy-6,8-dimethylflavanone were isolated from aerial parts of D. elegans and informed by the first time for this species. All of these compounds were evaluated in vitro in relation to the antityrosinase effect by using a spectrophotometric method. Compound 8PP (IC₅₀ 2.32 ± 0.01 μM) exhibited the most potency and was two times more active than Kojic acid (IC₅₀ 4.93 ± 0.01 μM) used as a positive control. Triangularin also has shown an important inhibitory activity. Kinetic studies were performed for both compounds. Hence, new tyrosinase inhibitors with potential applications in pharmacy and cosmetic industry are presented.     

Spectral lights trigger biomass accumulation and production of antioxidant secondary metabolites in adventitious root cultures of Stevia rebaudiana (Bert.)

Stevia rebaudiana (S. rebaudiana) is the most important therapeutic plant species and has been accepted as such worldwide. It has a tendency to accumulate steviol glycosides, which are 300 times sweeter than marketable sugar. Recently, diabetic patients commonly use this plant as a sugar substitute for sweet taste. In the present study, the effects of different spectral lights were investigated on biomass accumulation and production of secondary metabolites in adventitious root cultures of S. rebaudiana. For callus development, leaf explants were excised from seed-derived plantlets and inoculated on a Murashige and Skoog (MS) medium containing the combination of 2,4-dichlorophenoxy acetic acid (2, 4-D, 2.0 mg/l) and 6-benzyladenine (BA, 2.0 mg/l), while 0.5 mg/l naphthalene acetic acid (NAA) was used for adventitious root culture. Adventitious root cultures were exposed to different spectral lights (blue, green, violet, red and yellow) for a 30-day period. White light was used as control. The growth kinetics was studied for 30 days with 3-day intervals. In this study, the violet light showed the maximum accumulation of fresh biomass (2.495 g/flask) as compared to control (1.63 g/flask), while red light showed growth inhibition (1.025 g/flask) as compared to control. The blue light enhanced the highest accumulation of phenolic content (TPC; 6.56 mg GAE/g DW), total phenolic production (TPP; 101 mg/flask) as compared to control (5.44 mg GAE/g DW; 82.2 mg GAE/g DW), and exhibited a strong correlation with dry biomass. Blue light also improved the accumulation of total flavonoid content (TFC; 4.33 mg RE/g DW) and total flavonoid production (TFP; 65 mg/flask) as compared to control. The violet light showed the highest DPPH inhibition (79.72%), while the lowest antioxidant activity was observed for control roots (73.81%). Hence, we concluded that the application of spectral lights is an auspicious strategy for the enhancement of the required antioxidant secondary metabolites in adventitious root cultures of S. rebaudiana and of other medicinal plants.     

Syntheses of benzophenone-xanthone hybrid polyketides and their antibacterial activities

Muchimangins are benzophenone-xanthone hybrid polyketides produced by Securidaca longepedunculata. However, their biological activities have not been fully investigated, since they are minor constituents in this plant. To evaluate the possibility of muchimangins as antibacterial agent candidates, five muchimangin analogs were synthesized from 2,4,5-trimethoxydiphenyl methanol and the corresponding xanthones, by utilizing p-toluenesulfonic acid monohydrate for the Brønsted acid-catalysis. The antibacterial assays against Gram-positive bacteria, Staphylococcus aureus and Bacillus subtilis, and Gram-negative bacteria, Klebsiella pneumoniae and Escherichia coli, revealed that the muchimangin analogs (±)-1,3,6,8-tetrahydroxy-4-(phenyl-(2′,4′,5′-trimethoxyphenyl)methyl)-xanthone (1), (±)-1,3,6-trihydroxy-4-(phenyl-(2′,4′,5′-trimethoxyphenyl)methyl)-xanthone (2), and (±)-1,3-dihydroxy-4-(phenyl-(2′,4′,5′-trimethoxyphenyl)methyl)-xanthone (3) showed significant activities against S. aureus, with MIC values of 10.0, 10.0, and 25.0 μM, respectively. Analogs (±)-1 and (±)-2 also exhibited antibacterial activities against B. subtilis, with MIC values of 50.0 and 12.5 μM, respectively. Furthermore, (+)-3 enhanced the antibacterial activity against S. aureus, with a MIC value of 10 μM.     

Four isoflavanones from the stem bark of Platycelphium voënse

From the stem bark of Platycelphium voënse (Leguminosae) four new isoflavanones were isolated and characterized as (S)-5,7-dihydroxy-2′,4′-dimethoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (trivial name platyisoflavanone A), (±)-5,7,2′-trihydroxy-4′-methoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (platyisoflavanone B), 5,7-dihydroxy-4′-methoxy-2″-(2?-hydroxyisopropyl)-dihydrofurano-[4″,5″:3′,2′]-isoflavanone (platyisoflavanone C) and 5,7,2′,3″-tetrahydroxy-2″,2″-dimethyldihydropyrano-[5″,6″:3′,4′]-isoflavanone (platyisoflavanone D). In addition, the known isoflavanones, sophoraisoflavanone A and glyasperin F; the isoflavone, formononetin; two flavones, kumatakenin and isokaempferide; as well as two triterpenes, betulin and β-amyrin were identified. The structures were elucidated on the basis of spectroscopic evidence. Platyisoflavanone A showed antibacterial activity against Mycobacterium tuberculosis in the microplate alamar blue assay (MABA) with MIC = 23.7 μM, but also showed cytotoxicity (IC₅₀ = 21.1 μM) in the vero cell test.     

Redefining the structure–activity relationships of 2,6-methano-3-benzazocines. Part 8. High affinity ligands for opioid receptors in the picomolar Ki range: Oxygenated N-(2-[1,1′-biphenyl]-4-ylethyl) analogues of 8-CAC

N-[2-(4′-methoxy[1,1′-biphenyl]-4-yl)ethyl]-8-CAC (1) is a high affinity (K_i = 0.084 nM) ligand for the μ opioid receptor and served as the lead compound for this study. Analogues of 1 were made in hopes of identifying an SAR within a series of oxygenated (distal) phenyl derivatives. A number of new analogues were made having single-digit pM affinity for the μ receptor. The most potent was the 3′,4′-methylenedioxy analogue 18 (K_i = 1.6 pM).     

Novel oxazolinyl derivatives of pregna-5,17(20)-diene as 17α-hydroxylase/17,20-lyase (CYP17A1) inhibitors

New oxazolinyl derivatives of [17(20)E]-pregna-5,17(20)-diene: 2′-{[(E)-3β-hydroxyandrost-5-en-17-ylidene]methyl}-4′,5′-dihydro-1′,3′-oxazole 1 and 2′-{[(E)-3β-hydroxyandrost-5-en-17-ylidene]methyl}-4′,4′-dimethyl-4′,5′-dihydro-1′,3′-oxazole 2 were evaluated as potential CYP17A1 inhibitors in comparison with 17-(pyridin-3-yl)androsta-5,16-dien-3β-ol 3 (abiraterone). Differential absorption spectra of human recombinant CYP17A1 in the presence of compound 1 (λ_max = 422 nm, λ_min = 386 nm) and compound 2 (λ_max = 416 nm) indicated significant differences in enzyme/inhibitors complexes. CYP17A1 activity was measured using electrochemical methods. Inhibitory activity of compound 1 was comparable with abiraterone 3 (IC₅₀ = 0.9 ± 0.1 μM, and IC₅₀ = 1.3 ± 0.1 μM, for compounds 1 and 3, respectively), while compound 2 was found to be weaker inhibitor (IC₅₀ = 13 ± 1 μM). Docking of aforementioned compounds to CYP17A1 revealed that steroid fragments of compound 1 and abiraterone 3 occupied close positions; oxazoline cycle of compound 1 was coordinated with heme iron similarly to pyridine cycle of abiraterone 3. Configuration of substituents at 17(20) double bond in preferred docked position corresponded to Z-isomers of compounds 1 and 2. Presence of 4′-substituents in oxazoline ring of compound 2 prevents coordination of oxazoline nitrogen with heme iron and worsens its docking score in comparison with compound 1. These data indicate that oxazolinyl derivative of [17(20)E]-pregna-5,17(20)-diene 1 (rather than 4′,4′-dimethyl derivative 2) may be considered as potential CYP17A1 inhibitor and template for development of new compounds affecting growth and proliferation of prostate cancer cells.     

Structure–cytotoxic activity relationship of sesquilignan,morinol A

The cytotoxic activities of sesquilignans, (7S,8S,7′R,8′R)- and (7R,8R,7′S,8′S)-morinol A and (7S,8S,7′S,8′S)- and (7R,8R,7′R,8′R)-morinol B were compared, showing no significant difference between stereoisomers (IC₅₀ = 24–35 μM). As a next stage, the effect of substituents at 7, 7′, and 7″-aromatic ring on the activity was evaluated to find out the higher activity of (7S,8S,7′R,8′R)-7,7′,7″-phenyl derivative 18 (IC₅₀ = 6–7 μM). In the research on the structure–activity relationship of 7″-position of (7S,8S,7′R,8′R)-7,7′,7″-phenyl derivative 18, the most potent compounds were 7,7′,7″-phenyl derivative 18 (IC₅₀ = 6 μM) against HeLa cells. Against HL-60 cells, 7″-(4-nitrophenyl)-7,7′-phenyl derivative 33 and 7″-hexyl-7,7′-phenyl derivative 37 (IC₅₀ = 5 μM) showed highest activity. We discovered the compounds showed four to sevenfold potent activity than that of natural (7S,8S,7′R,8′R)-morinol A. It was also confirmed that the 7′-benzylic hydroxy group have an important role for exhibiting activity, on the other hand, the resonance system of cinnamyl structure is not crucial for the potent activity.     

Synthesis and biological evaluation of 3′,4′,5′-trimethoxychalcone analogues as inhibitors of nitric oxide production and tumor cell proliferation

A series of 23 3′,4′,5′-trimethoxychalcone analogues was synthesized and their inhibitory effects on nitric oxide (NO) production in LPS/IFN-γ-treated macrophages, and tumor cell proliferation has been investigated. 4-Hydroxy-3,3′,4′,5′-tetramethoxychalcone (7), 3,4-dihydroxy-3′,4′,5′-trimethoxychalcone (11), 3-hydroxy-3′,4,4′,5′-tetramethoxychalcone (14), and 3,3′,4′,5′-tetramethoxychalcone (15) were the most potent growth inhibitory agents on NO production, with an IC₅₀ value of 0.3, 1.5, 1.3 and 0.3 μM, respectively. The tumor cells proliferation assay results revealed that several compounds exhibited potent inhibition activity against different cancer cell lines. The chalcone 15 was the most potent anti-proliferative compound in the series with IC₅₀ values of 1.8 and 2.2 μM toward liver cancer Hep G2 and colon cancer Colon 205 cell lines, respectively. 2,3,3′,4′,5′-Pentamethoxychalcone (1), 3,3′,4,4′,5,5′-hexamethoxychalcone (3), 2,3′,4,4′,5,5′-hexamethoxychalcone (5), 2-hydroxy-3,3′,4′,5′-tetramethoxychalcone (10), 11 and 14 showed significant anti-proliferation actions in Hep G2 and Colon 205 cells with an IC₅₀ values ranging between 10 and 20 μM. Among the tested agents, compound 7 showed selective NO production inhibition (IC₅₀ = 0.3 μM), while has no effect on tumor cell proliferation (IC₅₀ >100 μM). 3,3′,4,4′,5′-Pentamethoxychalcone (2) showed selective anti-proliferation effect in Hep G2 cells, in addition to its potent NO inhibition, however has no such response in Colon 205 cells. In contrast, 3-formyl-3′,4′,5′-trimethoxychalcone (22) showed moderate growth inhibition in Colon 205 cells, while has no such effect on NO production and Hep G2 cells proliferation. These results provide insight into the correlation between some structural properties of 3′,4′,5′-trimethoxychalcones and their in vitro anti-inflammatory and anti-cancer differentiation activity.     

Homoisoflavonoids from the medicinal plant Portulaca oleracea

Four homoisoflavonoids named portulacanones A−D, identified as 2′-hydroxy- 5,7-dimethoxy-3-benzyl-chroman-4-one, 2′-hydroxy-5,6,7-trimethoxy-3-benzyl-chroman-4-one, 5,2′-dihydroxy-6,7-dimethoxy-3-benzyl-chroman-4-one, and 5,2′-dihydroxy-7-methoxy-3-benzylidene-chroman-4-one, were isolated from aerial parts of the plant Portulaca oleracea along with nine other known metabolites. Their structures were established on the basis of extensive spectroscopic analyses. Portulacanones A−D is the first group of homoisoflavonoids so far reported from the family Portulacaceae. They represent a rare subclass of homoisoflavonoids in nature with a structural feature of a single hydroxyl group substituted at C-2′ rather than at C-4′ in ring B of the skeleton. Three homoisoflavonoids and the known compound 2,2′-dihydroxy-4′,6′-dimethoxychalcone selectively showed in vitro cytotoxic activities towards four human cancer cell lines. Especially 2,2′-dihydroxy-4′,6′-dimethoxychalcone showed cytotoxic activity against cell line SGC-7901 with an IC₅₀ value of 1.6 μg/ml, which was more potent than the reference compound mitomycin C (IC₅₀ 13.0 μg/ml).     

Biotransformation of isofraxetin-6-O-β-d-glucopyranoside by Angelica sinensis (Oliv.) Diels callus

Isofraxetin-6-O-β-d-glucopyranoside, identified from traditional medicinal herbal Xanthoceras sorbifolia Bunge, has been demonstrated to be a natural neuroinflammatory inhibitor. In order to obtain more derivatives with potential anti-neuroinflammatory effects, biotransformation was carried out. According to the characteristics of coumarin skeleton, suspension cultures of Angelica sinensis (Oliv.) Diels callus (A. sinensis callus) were employed because of the presence of diverse phenylpropanoids biosynthetic enzymes. As a result, 15 products were yielded from the suspension cultures, including a new coumarin: 8′-dehydroxymethyl cleomiscosin A (1), together with 14 known compounds. Their structures were elucidated by extensive spectroscopic analysis. Furthermore, the biotransformed pathways were discussed. Among them, compound 13 was transformed from isofraxetin-6-O-β-d-glucopyranoside, while compounds 1–6, 10–12, 14–15 were derived from the culture medium stimulated by the substrate. The biotransformation processes include hydroxylation, oxidation and esterification. Furthermore, their inhibitory effects on lipopolysaccharide (LPS)-activated nitric oxide (NO) production were evaluated in BV2 microglial cells. It is worth noting that, 1, 1′-methanediylbis(4-methoxybenzene) (3), obtucarbamates A (5), 2-nonyl-4-hydroxyquinoline N-oxide (10) and 1H-indole-3-carbaldehyde (11) exhibited significant inhibitory effect against neuroinflammation with IC₅₀ values at 1.22, 10.57, 1.02 and 0.76 μM respectively, much stronger than that of the positive control minocycline (IC₅₀ 35.82 μM).     

Flavones and phenylpropanoids from a sedative extract of Lantana trifolia L.

The flavone glycosides, named scutellarein-7-O-β-d-apiofuranoside and apigenin-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-apiofuranoside, and the flavone celtidifoline (5,6,4′,5′-tetrahydroxy-7,3′-dimethoxyflavone), along with other 11 known compounds, were isolated from leaves of the ethyl acetate extract of Lantana trifolia L. using step gradient High Speed Countercurrent Chromatography (HSCCC) and High Performance Liquid Chromatography (HPLC), respectively. Their structures were elucidated by spectroscopic methods, including 2D NMR and mass spectrometry (ESI-MS) techniques. The ethanolic and ethyl acetate extracts produced an intense sedative effect in mice, one hour after oral administration of 1 mg/kg. This effect was neither due to a benzodiazepine-like effect of the three flavone derivatives neither of the phenylpropanoids, betonyoside F and verbascoside, that were tested for their affinity for the [³H] flunitrazepam binding sites.     

In vitro cultures of Silybum marianum and silymarin accumulation

In this study, a protocol for initiation of callus and shoot cultures from leaves and shoot tips explants of different silybium genotypes collected from different locations in Egypt was established. Callus cultures were initiated from leaves explants and exposed to different concentrations of the precursor (coniferyl alcohol). Shoot cultures were initiated from shoot tips explants. Moreover, the produced plants of the different Silybium shoots as well as intact plants were subjected to protein screening using SDS–PAGE analysis.Results obtained revealed that the optimum medium for growth and maintenance of friable callus was MS medium supplemented with 0.25 mg L⁻¹ 2,4-Dichlorophenoxy acetic acid (2,4-D) + 0.25 mg L⁻¹ Kinetin (Kin). The best medium for proliferation of high number of shoots was MS-medium with 0.25 mg L⁻¹ each of Benzyl Adinine (BA) and Naphthalene Acetic Acid (NAA). Coniferyl alcohol in concentration of 30 μM caused an increase in accumulation of silymarin contents in most callus cultures. SDS–PAGE of different Silybium shoots revealed that the protein profiles of 100% of in vitro produced plantlets similar to their control.     

Secondary metabolites from the leaves of the medicinal plant goldenseal (Hydrastis canadensis)

The study presented herein constitutes an extensive investigation of constituents in Hydrastis canadensis L. (Ranunculaceae) leaves. It describes the isolation and identification of two previously unknown compounds, 3,4-dimethoxy-2-(methoxycarbonyl)benzoic acid (1) and 3,5,3′-trihydroxy-7,4′-dimethoxy-6,8-C-dimethyl-flavone (2), along with the known compounds (±)-chilenine (3), (2R)-5,4′-dihydroxy-6-C-methyl-7-methoxy-flavanone (4), 5,4′-dihydroxy-6,8-di-C-methyl-7-methoxy-flavanone (5), noroxyhydrastinine (6), oxyhydrastinine (7) and 4′,5′-dimethoxy-4-methyl-3′-oxo-(1,2,5,6-tetrahydro-4H-1,3-dioxolo-[4′,5′:4,5]-benzo[1,2-e]-1,2-oxazocin)-2-spiro-1′-phtalan (8). Compounds 3–8 have been reported from other sources, but this is the first report of their presence in H. canadensis extracts. A mass spectrometry based assay was employed to demonstrate bacterial efflux pump inhibitory activity against Staphylococcus aureus for 2, with an IC₅₀ value of 180 ± 6 μM. This activity in addition to that of other bioactive compounds such as flavonoids and alkaloids, may explain the purported efficacy of H. canadensis for treatment of bacterial infections. Finally, this report includes high mass accuracy fragmentation spectra for all compounds investigated herein which were uploaded into the Global Natural Products Social molecular networking library and can be used to facilitate their future identification in H. canadensis or other botanicals.     

Cytotoxic benzophenone and triterpene from Garcinia hombroniana

Garcinia hombroniana (seashore mangosteen) in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to investigate the bioactive chemical constituents of the bark of G. hombroniana. Ethyl acetate and dichloromethane extracts of G. hombroniana yielded two new (1, 9) and thirteen known compounds which were characterized by the spectral techniques of NMR, UV, IR and EI/ESI-MS, and identified as; 2,3′,4,5′-tetrahydroxy-6-methoxybenzophenone (1), 2,3′,4,4′-tetrahydroxy-6-methoxybenzophenone (2), 2,3′,4,6-tetrahydroxybenzophenone (3), 1,3,6,7-tetrahydroxyxanthone (4), 3,3′,4′,5,7-pentahydroxyflavone (5), 3,3′,5,5′,7-pentahydroxyflavanone (6), 3,3′,4′,5,5′,7-hexahydroxyflavone (7), 4′,5,7-trihydroxyflavanone-7-rutinoside (8), 18(13 → 17)-abeo-3β-acetoxy-9α,13β-lanost-24E-en-26-oic acid (9), garcihombronane B (10), garcihombronane D (11), friedelan-3-one (12), lupeol (13), stigmasterol (14) and stigmasterol glucoside (15). In the in vitro cytotoxicity against MCF-7, DBTRG, U2OS and PC-3 cell lines, compounds 1 and 9 displayed good cytotoxic effects against DBTRG cancer cell lines. Compounds 1–8 were also found to possess significant antioxidant activities. Owing to these properties, this study can be further extended to explore more significant bioactive components of this plant.     

Synthesis and cytotoxic activity of new azepino[3′,4′:4,5]pyrrolo[2,1-a]isoquinolin-12-ones

A series of azepino[3′,4′:4,5]pyrrolo[2,1-a]isoquinolin-12-ones (3a–f), that were conformationally restricted analogs of lead compound 2, were designed as potential cytotoxic compounds and synthesized using a radical oxidative aromatic substitution reaction as the key step. Compounds 3a–f were tested on five tumor cell lines to determine the conformational requirements for biological activity of compound 2. The results show that conformational restrictions on compound 2, generating the derivatives 3a–f, do not appreciably reduce the cytotoxic activity of 2, although compound 3d (R = Br) showed good activity against U-251 cells. Preliminary structure–activity relationship studies with these compounds revealed the importance of halogens bonded to the isoquinoline moiety. Additionally, derivatives 3f (R = NO₂) and 3b (R = F) were cytotoxic to PC-3 and K-562 cells. However, none of the azepino[3′,4′:4,5]pyrrolo[2,1-a]isoquinolinones inhibited the enzymatic activity of CDK1/cyclin B, CDK5/p25, or GSK-3.     

Synthesis,evaluation of anti-HIV-1 and anti-HCV activity of novel 2′,3′-dideoxy-2′,2′-difluoro-4′-azanucleosides

A series of 2′,3′-dideoxy-2′,2′-difluoro-4′-azanucleosides of both pyrimidine and purine nucleobases were synthesized in an efficient manner starting from commercially available L-pyroglutamic acid via glycosylation of difluorinated pyrrolidine derivative 15. Several 4′-azanucleosides were prepared as a separable mixture of α- and β-anomers. The 6-chloropurine analogue was obtained as a mixture of N⁷ and N⁹ regioisomers and their structures were identified based on NOESY and HMBC spectral data. Among the 4′-azanucleosides tested as HIV-1 inhibitors in primary human lymphocytes, four compounds showed modest activity and the 5-fluorouracil analogue (18d) was found to be the most active compound (EC₅₀ = 36.9 μM) in this series. None of the compounds synthesized in this study demonstrated anti-HCV activity.     

Phenolics from Glycyrrhiza glabra roots and their PPAR-γ ligand-binding activity

Bioassay-guided fractionation of the EtOH extract of licorice (Glycyrrhiza glabra roots), using a GAL-4-PPAR-γ chimera assay method, resulted in the isolation of 39 phenolics, including 10 new compounds (1–10). The structures of the new compounds were determined by analysis of their spectroscopic data. Among the isolated compounds, 5′-formylglabridin (5), (2R,3R)-3,4′,7-trihydroxy-3′-prenylflavane (7), echinatin, (3R)-2′,3′,7-trihydroxy-4′-methoxyisoflavan, kanzonol X, kanzonol W, shinpterocarpin, licoflavanone A, glabrol, shinflavanone, gancaonin L, and glabrone all exhibited significant PPAR-γ ligand-binding activity. The activity of these compounds at a sample concentration of 10 μg/mL was three times more potent than that of 0.5 μM troglitazone.     

Production of di-d-fructofranosyl-2,6′:2′,6-anhydride (DFA IV) by recombinant Bacillus subtilis carrying heterogenous levan fructotransferase from Arthrobacter nicotinovorans GS-9

We developed di-d-fructofranosyl-2,6′:2′,6-anhydride (DFA IV) production system with single culture of Bacillus subtilis directly from sucrose. This system can avoid the purification procedure of levan which organic solvent was used for precipitation. The levan fructotransferase (LFTase) gene was cloned from Arthrobacter nicotinovorans GS-9 (AHU1840, FERM P-15285) and expressed in levan producing B. subtilis 168. LFTase activity was detected in the culture supernatant of the transformant with maximal activity of 0.062 U/ml after 15.5 h post induction. Then sucrose was added as substrate and incubated. About 78 h after addition of sucrose, 20.5 g/l of DFA IV was produced from 139.3 g/l of sucrose consumed. The yield of DFA IV from sucrose was 14.7 wt.%.