Microbial transformation of nandrolone with Cunninghamella echinulata and Cunninghamella blakesleeana and evaluation of leishmaniacidal activity of transformed products

Therapeutic potential of nandrolone and its derivatives against leishmaniasis has been studied. A number of derivatives of nandrolone (1) were synthesized through biotransformation. Microbial transformation of nandrolone (1) with Cunninghamella echinulata and Cunninghamella blakesleeana yielded three new metabolites, 10β,12β,17β-trihydroxy-19-nor-4-androsten-3-one (2), 10β,16α,17β-trihydroxy-19-nor-4-androsten-3-one (3), and 6β,10β,17β-trihydroxy-19-nor-4-androsten-3-one (4), along with four known metabolites, 10β,17β-dihydroxy-19-nor-4-androsten-3-one (5), 6β,17β-dihydroxy-19-nor-4-androsten-3-one (6) 10β-hydroxy-19-nor-4-androsten-3,17-dione (7) and 16β,17β-dihydroxy-19-nor-4-androsten-3-one (8). Compounds 1–8 were evaluated for their anti-leishmanial activity. Compounds 1 and 8 showed a significant activity in vitro against Leishmania major. The leishmanicidal potential of compounds 1–8 (IC₅₀ = 32.0 ± 0.5, >100, 77.39 ± 5.52, 70.90 ± 1.16, 54.94 ± 1.01, 80.23 ± 3.39, 61.12 ± 1.39 and 29.55 ± 1.14 μM, respectively) can form the basis for the development of effective therapies against the protozoal tropical disease leishmaniasis.     

Exploring new chemical functionalities to improve aromatase inhibition of steroids

In this work, new potent steroidal aromatase inhibitors both in microsomes and in breast cancer cells have been found. The synthesis of the 3,4-(ethylenedioxy)androsta-3,5-dien-17-one (12), a new steroid containing a heterocycle dioxene fused in the A-ring, led to the discovery of a new reaction for which a mechanism is proposed. New structure–activity relationships were established. Some 5β-steroids, such as compound 4β,5β-epoxyandrostan-17-one (9), showed aromatase inhibitory activity, because they adopt a similar A-ring conformation as those of androstenedione, the natural substrate of aromatase. Moreover, new chemical features to increase planarity were disclosed, specifically the 3α,4α-cyclopropane ring, as in 3α,4α-methylen-5α-androstan-17-one (5) (IC₅₀ = 0.11 μM), and the Δ^9–11 double bond in the C-ring, as in androsta-4,9(11)-diene-3,17-dione (13) (IC₅₀ = 0.25 μM). In addition, induced-fit docking (IFD) simulations and site of metabolism (SoM) predictions helped to explain the recognition of new potent steroidal aromatase inhibitors within the enzyme. These insights can be valuable tools for the understanding of the molecular recognition process by the aromatase and for the future design of new steroidal inhibitors.     

Biotransformation of dianabol with the filamentous fungi and β-glucuronidase inhibitory activity of resulting metabolites

Biotransformation of the anabolic steroid dianabol (1) by suspended-cell cultures of the filamentous fungi Cunninghamella elegans and Macrophomina phaseolina was studied. Incubation of 1 with C. elegans yielded five hydroxylated metabolites 2–6, while M. phaseolina transformed compound 1 into polar metabolites 7–11. These metabolites were identified as 6β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (2), 15α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (3), 11α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (4), 6β,12β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (5), 6β,15α,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (6), 17β-hydroxy-17α-methylandrost-1,4-dien-3,6-dione (7), 7β,17β,-dihydroxy-17α-methylandrost-1,4-dien-3-one (8), 15β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (9), 17β-hydroxy-17α-methylandrost-1,4-dien-3,11-dione (10), and 11β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (11). Metabolite 3 was also transformed chemically into diketone 12 and oximes 13, and 14. Compounds 6 and 12–14 were identified as new derivatives of dianabol (1). The structures of all transformed products were deduced on the basis of spectral analyses. Compounds 1–14 were evaluated for β-glucuronidase enzyme inhibitory activity. Compounds 7, 13, and 14 showed a strong inhibition of β-glucuronidase enzyme, with IC₅₀ values between 49.0 and 84.9 μM.     

Xanthine oxidase inhibitory terpenoids of Amentotaxus formosana protect cisplatin-induced cell death by reducing reactive oxygen species (ROS) in normal human urothelial and bladder cancer cells

The diterpenoids (+)-ferruginol (1), ent-kaur-16-en-15-one (2), ent-8(14),15-sandaracopimaradiene-2α,18-diol (3), 8(14),15-sandaracopimaradiene-2α,18,19-triol (4), and (+)-sugiol (5) and the triterpenoids 3β-methoxycycloartan-24(24¹)-ene (6), 3β,23β-dimethoxycycloartan-24(24¹)-ene (7), 3β,23β-dimethoxy-5α-lanosta-24(24¹)-ene (8), and 23(S)-23-methoxy-24-methylenelanosta-8-en-3-one (9), isolated from Amentotaxus formosana, showed inhibitory effects on xanthine oxidase (XO). Of the compounds tested, compound 5 was a potent inhibitor of XO activity, with an IC₅₀ value of 6.8 ± 0.4 μM, while displaying weak ABTS radical cation scavenging activity. Treatment of the bladder cancer cell line, NTUB1, with 3–10 μM of compound 5 and 10 μM cisplatin, and immortalized normal human urothelial cell line, SV-HUC1, with 0.3–1 μM and 10–50 μM of compound 5 and 10 μM cisplatin, respectively, resulted in increased viability of cells compared with cytotoxicity induced by cisplatin. Treatment of NTUB1 with 20 μM cisplatin and 10 or 30 μM of compound 5 resulted in decreased ROS production compared with ROS production induced by cisplatin. These results indicate that 10 or 30 μM of compound 5 in NTUB1 cells may mediate through the suppression of XO activity and reduction of reactive oxygen species (ROS) induced by compound 5 cotreated with 20 μM cisplatin and protection of subsequent cell death.     

Synthesis and biological evaluation of 3-tetrazolo steroidal analogs: Novel class of 5α-reductase inhibitors

In the present study, a series of steroidal tetrazole derivatives of androstane and pregnane have been prepared in which the tetrazole moiety was appended at C-3 and 17a-aza locations. 3-Tetrazolo-3,5-androstadien-17-one (6), 3-tetrazolo-19-nor-3,5-androstadien-17-one (10), 3-tetrazolo-3,5-pregnadien-20-one (14), 17a-substituted 3-tetrazolo-17a-aza-d-homo-3,5-androstadien-17-one (26–31) and 3-(2-acetyltetrazolo)-17a-aza-d-homo-3,5-androstadien-17-one (32) were synthesized from dehydroepiandrosterone acetate (1) through multiple synthetic steps. Some of the synthesized compounds were evaluated for their in vitro 5α-reductase (5AR) inhibitory activity by measuring the conversion of [³H] androstenedione in human embryonic kidney (HEK) cells. In vivo 5α-reductase inhibitory activity also showed a significant reduction (p <0.05) in rat prostate weight. The most potent compound 14 showed 5AR-2 inhibition with IC₅₀ being 15.6 nM as compared to clinically used drug finasteride (40 nM). There was also a significant inhibition of 5AR-1 with IC₅₀ 547 nM compared to finasteride (453 nM).     

Triterpene compounds isolated from Acer mandshuricum and their anti-inflammatory activity

In our preliminary screening study on the anti-inflammatory activity, a new triterpene compound, aceranol acetate (1), was isolated along with five known compounds: β-amyrin acetate (2); glutinol acetate (3); friedelin (4); glutinol (5); (3β)-d-glucopyranoside-stigmast-5-en-3-yl (6), from the stems and leaves of Acer mandshuricum. The structure of the new triterpene was determined to be 5α,6α-epidioxy-5β,6β-epoxy-9,13-dimethyl-25,26-dinoroleanan-3β-ol acetate by spectroscopic studies. Compounds 2–6 were isolated from this plant for the first. Five triterpene compounds (1–5) showed significant cytotoxic activity with GI₅₀ in the range of 11.1–17.9 μM, whereas steroid compound (6) exhibited moderate activity against four human cancer cell lines (HL-60, SK-OV-3, A549, and HT-29). Furthermore, the anti-inflammatory effects of compounds 1–6 in the non-cytotoxic concentrations (1–100 nM) were evaluated for the inhibitory activity of TNF-α secretion in the lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophage cell line. Among the compounds tested, compound 2 showed the strongest anti-inflammatory activity with the inhibition rate up to 38.40% at the concentration of 100 nM, whereas other five compounds (2–6) exhibited moderate activity.     

Triterpenes from the roots of Lantana montevidensis with antiprotozoal activity

Bioassay guided fractionation of the roots of Lantana montevidensis (Verbenaceae) has resulted in the isolation and identification of three new triterpenoids; 13β-hydroxy-3-oxo-olean-11-en-28-oic acid (1), 12β,13β-dihydroxyolean-3-oxo-28-oic acid (2) and 12β,13β,22β-trihydroxyolean-3-oxo-28-oic acid (3) in addition to nine known compounds: oleanonic acid (4), oleanolic acid (5), 3β,25β-dihydroxy-olean-12-en-28-oic acid (6), lantadene A (7), 19α-hydroxy-3-oxo-olean-12-en-28-oic acid (8) pomolic acid (9), camaric acid (10) together with β-sitosterol (11) and β-sitosterol-3-O-β-d-glucoside (12). The structures of the isolated metabolites were elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as HR-ESI–MS. The extracts and the isolated metabolites were evaluated for their antiprotozoal and antimicrobial activities. Compound 2 showed antibacterial activity against Staphylococcus aureus and methicillin resistant S. aureus with IC₅₀ values against both organisms of 2.1 μM and compound 10 showed activity against same organisms with IC₅₀ values 8.74 and 8.09 μM, respectively, compared to the positive control ciprofloxacin (IC₅₀ = 0.3 μM against S. aureus and MRSA). Compounds 1, 4, 5, 6, and 10 showed moderate antileishmanial activity with IC₅₀ values ranging between (2.54–14.95 μM) and IC₉₀ values ranging between (11.90–19.47 μM), using pentamidine as a control (IC₅₀ values 2.09 ≥ 16.8 μM) and IC₉₀ values ranging between (4.72 ≥ 16.8 μM). These compounds also showed highly potent antitrypanosomal activity with IC₅₀ values ranging between (0.39–7.12 μM) and IC₉₀ values ranging between (1.91–10.51 μM), which are more efficient than the DFMO, the antitrypanosomal drug employed as positive control (IC₅₀ and IC₉₀values 11.82 and 30.82 μM).     

Design,synthesis and anticholinesterase activity of a novel series of 1-benzyl-4-((6-alkoxy-3-oxobenzofuran-2(3H)-ylidene) methyl) pyridinium derivatives

A novel series of benzofuranone-ylidene-methyl benzylpyridinium derivatives (6a–u) were synthesized as acetylcholinesterase inhibitors. The anticholinesterase activity of synthesized compounds was measured using colorimetric Ellman’s method. It was revealed that some synthesized compounds exhibited high anticholinesterase activity, among them compound 6b was the most active compound (IC₅₀ = 10 ± 6.87 nM).     

Chemical constituents from Tribulus terrestris and screening of their antioxidant activity

Two oligosaccharides (1, 2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4–8). The structures of the compounds were established as O-β-d-fructofuranosyl-(2 → 6)-α-d-glucopyranosyl-(1 → 6)-β-d-fructofuranosyl-(2 → 6)-β-d-fructofuranosyl-(2 → 1)-α-d-glucopyranosyl-(6 → 2)-β-d-fructofuranoside (1), O-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 2)-β-d-fructofuranoside (2), 4,5-di-p-cis-coumaroylquinic acid (3) by different spectroscopic methods including 1D NMR (¹H, ¹³C and DEPT) and 2D NMR (COSY, TOCSY, HMQC and HMBC) experiments as well as ESI-MS analysis. This is the first report for the complete NMR spectral data of the known 4,5-di-p-trans-coumaroylquinic acid (4).The antioxidant activity represented as DPPH free radical scavenging activity was investigated revealing that the di-p-coumaroylquinic acid derivatives possess potent antioxidant activity so considered the major constituents contributing to the antioxidant effect of the plant.     

Methanolysis of triterpenoid saponin from Ardisia gigantifolia stapf. and structure–activity relationship study against cancer cells

Thirteen 13,28-epoxy triterpenoid saponins were isolated from Ardisia gigantifolia stapf. and one potential anti-tumor saponin was methanolysised by H₂SO₄ to afford four new compounds. The seventeen compounds were evaluated for their anti-proliferative activity on A549, HCT-8 and Bel-7402 cells. The structure–activity relationship analysis indicated that the incorporation of O group at C-16, l-rhamnose at R⁵ and acetyl group at OH-6 of the d-glucose lead to a significant increase of the cytotoxic activity on A549 and HCT-8 but significant reduction of the cytotoxic activity on Bel-7402 cells. The synthesized saponins losing 13,28-epoxy and CHO at C-30, losed their cytotoxicities on A549 and HCT-8 cells, suggesting that the two moieties play an essential role for activity. 3β-O-α-l-rhamnopyranosyl-(1 → 3)-[β-d-xylopyranosyl-(1 → 2)]-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)]-α-l-arabinopyranoside-16α-hydroxy-13,28-epoxy-oleanane (2) showed better inhibitory activity to Bel-7402 (IC₅₀ 0.86 μM) than that of 5-FU (IC₅₀ 8.30 μM), which indicate that five saccharide and methyl moiety at C-30 are important for anti-proliferative activity. The activities of saponins 15 > 14, 17 > 16, suggested that the configuration of 28,30-epoxy is preferable to be 30(R) rather than 30(S) on Bel-7402 cells. Further molecular mechanism studies of saponins 1 and 2 were carried out on the cell cycle distribution of Bel-7402 cells.     

New triterpene saponins from the seed cake of Camellia Oleifera and their cytotoxic activity

Two new oleanane-type triterpene saponins, identified as 16α-hydroxy-22-O-angeloyl-23-formyl-28,31-dihydroxymethylene-olean-12-ene-3β-O-{β-d-galactopyranosyl-(1 → 2)[β-d-xylopyranosyl-(1 → 2)-α-l-arabinopyranosyl(1 → 3)]-β-d-glucopyranosiduronic acid} (oleiferasaponin B₁, 1) and 22-O-hydrocinnamoyl-23-formyl-28-dihydroxymethylene-olean-12-ene-3β-O-{β-d-glucopyranosyl-(1 → 2)[β-d-xylopyranosyl-(1 → 2)-α-l-arabinopyranosyl(1 → 3)]-β-d-glucopyranosiduronic acid} (oleiferasaponin B₂, 2), were isolated from the seed cake of Camellia oleifera Abel. Their structures were established by extensive 1D- and 2D-NMR experiments along with TOF-MS analysis and acid hydrolysis. The cytotoxicity of the isolated compounds was evaluated in four human carcinoma cell lines: A 549, SK-OV-3, SK-MEL-2 and HCT15. Both compounds 1 and 2 exhibited significantly cytotoxic activity with IC₅₀ values of 18.5 μM (A549), 11.3 μM (SK-OV-3), 13.9 μM (SK-MEL-2) and 1.6 μM (HCT15) for 1 and IC₅₀ values of 8.4 μM (A549), 6.3 μM (SK-OV-3), 9.2 μM (SK-MEL-2) and 0.8 μM (HCT15) for 2. In addition, compound 2 showed more effective cytotoxic activity than compound 1.     

The synthesis of cholestane and furostan saponin analogues and the determination of sapogenin's absolute configuration at C-22

A facile and efficient way for the synthesis of cholestane and furostan saponin analogues was established and adopted for the first time. Following this strategy, starting from diosgenin, three novel cholestane saponin analogues: (22S,25R)-3β,22,26-trihydroxy-cholest-5-ene-16-one 22-O-[O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside] 11, (25R)-3β,16β,26-trihydroxy-cholest-5-ene-22-one 16-O-[O-α-l-rhamnopyranosyl-(1 → 2)-α-d-glucopyranoside] 14 and (25R)-3β,16β,26-trihydroxy-cholest-5-ene-22-one 16-O-[O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside] 17, three novel furostan saponin analogues: (22S,25R)-furost-5-ene-3β,22,26-triol 22-O-(α-d-glucopyranoside) 23, (22R,25R)-furost-5-ene-3β,22,26-triol 22-O-(α-d-glucopyranoside) 24 and (22S,25R)-furost-5-ene-3β,22,26-triol 22-O-[O-α-l-rhamnopyranosyl-(1 → 2)-α-d-glucopyranoside] 26, were synthesized ultimately. The structures of all the synthesized analogues were confirmed by spectroscopic methods. The S-chirality at C-22 of cholestane was confirmed by Mosher's method. The absolute configuration at C-22 of furostan saponin analogues was distinguished by conformational analysis combined with the NMR spectroscopy. The cytotoxicities of the synthetic analogues toward four types of tumor cells were shown also.     

Beilschglabrines A and B: Two new bioactive phenanthrene alkaloids from the stem bark of Beilschmiedia glabra

Two new phenanthrene alkaloids, beilschglabrines A (1) and B (2) were isolated from the stem bark of Beilschmiedia glabra, together with lupeol, taraxerol, and 24-methylenelanosta-7,9-diene-3β-15α-diol. The structures of the isolated compounds were elucidated by extensive spectroscopic data analysis and comparison with respective literature data. The compounds were tested for DPPH radical scavenging, acetylcholinesterase and lipoxygenase inhibitory activities. Compound 1 displayed considerable activity in the acetylcholinesterase (IC₅₀ 50.4 μM), the DPPH radical scavenging (IC₅₀ 115.9 μM) and the lipoxygenase (IC₅₀ 32.8 μM) assays.     

Cytotoxicity of cardenolides and cardenolide glycosides from Asclepias curassavica

A new cardenolide, 12β,14β-dihydroxy-3β,19-epoxy-3α-methoxy-5α-card-20(22)-enolide (6), and a new doubly linked cardenolide glycoside, 12β-hydroxycalotropin (13), together with eleven known compounds, coroglaucigenin (1), 12β-hydroxycoroglaucigenin (2), calotropagenin (3), desglucouzarin (4), 6′-O-feruloyl-desglucouzarin (5), calotropin (7), uscharidin (8), asclepin (9), 16α-hydroxyasclepin (10), 16α-acetoxycalotropin (11), and 16α-acetoxyasclepin (12), were isolated from the aerial part of ornamental milkweed, Asclepias curassavica and chemically elucidated through spectral analyses. All the isolates were evaluated for their cytotoxic activity against HepG2 and Raji cell lines. The results showed that asclepin (9) had the strongest cytotoxic activity with an IC₅₀ value of 0.02 μM against the two cancer cell lines and the new compound 13 had significant cytotoxic activity with IC₅₀ values of 0.69 and 1.46 μM, respectively.     

Three new benzophenone glycosides with MAO-A inhibitory activity from Hypericum thasium Griseb.

Purification of n-BuOH fraction from 80% ethanol extract of Hypericum thasium Griseb. resulted in the isolation of three new compounds 3′,4,5′-trihydroxy-6-methoxy-2-O-α-l-arabinosylbenzophenone (1), 3′,4,5′,6-tetrahydroxy-2-O-α-l-arabinosylbenzophenone (2), and 3′,4-dihydroxy-5′-methoxy-2-O-α-l-arabinosyl-6-O-β-d-xylosylbenzophenone (3) along with a known flavonoid glycoside quercetin-3-O-α-l-arabinofuranoside (4). The structures of the new compounds were elucidated by 1D and 2D NMR analysis as well as HRESIMS. The isolated compounds (1–4), as well as quercetin, and kaempferol previously isolated from EtOAc fraction were screened against MAO-A inhibitory activity. When tested against the MAO-A quercetin and kaempferol displayed IC₅₀ values of 19.6, and 17.5 μM, respectively. The IC₅₀ values for MAO-A inhibition by compounds (1–4) were 310.3, 111.2, 726.0, and 534.1 μM, respectively. Standard inhibitor (clorgyline) exhibited MAO-A inhibition with an IC₅₀ value of 0.5 μM.     

Constituents of Nelumbo nucifera leaves and their antimalarial and antifungal activity

From the leaves of Nelumbo nucifera (an aquatic plant), one new compound, 24(R)-ethylcholest-6-ene-5α-ol-3-O-β-d-glucopyranoside (1), along with 11 known metabolites (2–12), were isolated and identified by spectroscopic methods including 1D- and 2D NMR. Antifungal activity for (R)-roemerine (3) (IC₅₀/MIC = 4.5/10 μg/mL against Candida albicans) and antimalarial activity for (R)-roemerine (3) and N-methylasimilobine (5) (IC₅₀ = 0.2 and 4.8 μg/mL for the D6 clone, respectively, and 0.4 and 4.8 μg/mL for the W2 clone, respectively) was observed. None of the compounds were cytotoxic to Vero cells up to a concentration of 23.8 μg/mL. NMR data for 10-eicosanol (7) and 7,11,15-trimethyl-2-hexadecanone (10) are presented for the first time. An analysis of the structure–activity relationship shows that the substituents in position C-1 and C-2 of aporphine alkaloids are crucial for the antimalarial activity.     

Active compounds from a diverse library of triazolothiadiazole and triazolothiadiazine scaffolds: Synthesis,crystal structure determination,cytotoxicity, cholinesterase inhibitory activity,and binding mode analysis

In an effort to identify novel cholinesterase candidates for the treatment of Alzheimer’s disease (AD), a diverse array of potentially bioactive compounds including triazolothiadiazoles (4a–h and 5a–f) and triazolothiadiazines (6a–h) was obtained in good yields through the cyclocondensation reaction of 4-amino-5-(pyridin-3-yl)-4H-1,2,4-triazole-3-thiol (3) with various substituted aryl/heteroaryl/aryloxy acids and phenacyl bromides, respectively. The structures of newly prepared compounds were confirmed by IR, ¹H and ¹³C NMR spectroscopy and, in case of 4a, by single crystal X-ray diffraction analysis. The purity of the synthesized compounds was ascertained by elemental analysis. The newly synthesized conjugated heterocycles were screened for cholinesterase inhibitory activity against electric eel acetylcholinesterase (EeAChE) and horse serum butyrylcholinesterase (hBChE). Among the evaluated hybrids, several compounds were identified as potent inhibitors. Compounds 5b and 5d were most active with an IC₅₀ value of 3.09 ± 0.154 and 11.3 ± 0.267 μM, respectively, against acetylcholinesterase, whereas 5b, 6a and 6g were most potent against butyrylcholinesterase, with an IC₅₀ of 0.585 ± 0.154, 0.781 ± 0.213, and 1.09 ± 0.156 μM, respectively, compared to neostigmine and donepezil as standard drugs. The synthesized heteroaromatic compounds were also tested for their cytotoxic potential against lung carcinoma (H157) and vero cell lines. Among them, compound 6h exhibited highest antiproliferative activity against H157 cell lines, with IC₅₀ value of 0.96 ± 0.43 μM at 1 mM concentration as compared to vincristine (IC₅₀ = 1.03 ± 0.04 μM), standard drug used in this study.     

Triterpenoid saponins and C-glycosyl flavones from stem bark of Erythrina abyssinica Lam and their cytotoxic effects.

Six new compounds including two oleanane-type triterpenoid saponins (1, 2) and four C-glycosyl flavones (3–6), along with a known saponin (7), three di-C-glycosyl flavones (8–10) and a glycosyl auronol (11), were isolated from the stem bark of Erythrina abyssinica Lam. The structures of the new compounds, identified as 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (1), 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (2), 6-C-β-glucopyranosyl-8-C-β-quinovopyranosyl apigenin (3), 6-C-β-quinovopyranosyl-8-C-β-glucopyranosyl apigenin (4), 8-C-[6″-O-α-l-rhamnopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (5) and 8-C-[6″-O-β-d-xylopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (6), were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and acid hydrolysis. These new compounds together with the known saponins 7 were evaluated for their cytotoxic activity against MCF-7 (estrogen dependent) and MDA-MB-231 (estrogen independent) cell lines. The new saponin 2 exhibited the highest cytotoxic activity among tested compounds, exerting a selective inhibitory effect against the proliferation of MCF-7 cells, with lower IC₅₀ value (12.90 μM) than that of the positive control, resveratrol (13.91 μM). Structure–activity relationship of these compounds is also discussed.     

Design,synthesis and neuroprotective evaluation of novel tacrine–benzothiazole hybrids as multi-targeted compounds against Alzheimer’s disease

Alzheimer’s disease (AD) is a multifactorial disorder with several target proteins contributing to its etiology. In search for multifunctional anti-AD drug candidates, taking into account that the acetylcholinesterase (AChE) and beta-amyloid (Aβ) aggregation are particularly important targets for inhibition, the tacrine and benzothiazole (BTA) moieties were conjugated with suitable linkers in a novel series of hybrids. The designed compounds (7a–7e) were synthesized and in vitro as well as in ex vivo evaluated for their capacity for the inhibition of acetylcholinesterase (AChE) and Aβ self-induced aggregation, and also for the protection of neuronal cells death (SHSY-5Y cells, AD and MCI cybrids). All the tacrine–BTA hybrids displayed high in vitro activities, namely with IC₅₀ values in the low micromolar to sub-micromolar concentration range towards the inhibition of AChE, and high percentages of inhibition of the self-induced Aβ aggregation. Among them, compound 7a, with the shortest linker, presented the best inhibitory activity of AChE (IC₅₀ = 0.34 μM), while the highest activity as anti-Aβ₄₂ self-aggregation, was evidenced for compound 7b (61.3%, at 50 μM. The docking studies demonstrated that all compounds are able to interact with both catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. Our results show that compounds 7d and 7e improved cell viability in cells treated with Aβ₄₂ peptide. Overall, these multi-targeted hybrid compounds appear as promising lead compounds for the treatment of Alzheimer’s disease.     

Chemical constituents from the fruit of Gardenia jasminoides and their inhibitory effects on nitric oxide production

Three new iridoid glycosides, 6″-O-trans-caffeoylgenipin gentiobioside (1), genipin 1-O-β-d-apiofuranosyl (1→6)-β-d-glucopyranoside (2), genipin 1-O-α-d-xylopyranosyl (1→6)-β-d-glucopyranoside (3), three new monocyclic monoterpenoids, jasminoside R (4), jasminoside S (5), jasminoside T (6), together with nine known iridoid glycosides (7–15) and three crocetin glycosides (16–18), were isolated from the fruit of Gardenia jasminoides. Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. Inhibitory effects of the isolated compounds on nitric oxide production in lipopolysaccaride-activated macrophages were evaluated. Compounds 8 and 18 showed strong inhibitory activity on NO production with IC₅₀ values of 11.14 ± 0.67 and 5.99 ± 0.54 μM, respectively.