1,2,3-Triazole-totarol conjugates as potent PIP5K1α lipid kinase inhibitors.

The human phosphatidylinositol 4-phosphate 5-kinase type I α (hPIP5K1α) plays a key role in the development of prostate cancer. In this work, seventeen derivatives of the natural diterpene totarol were prepared by copper(I)-catalysed Huisgen 1,3-dipolar cycloaddition reaction of the correspondingO-propargylated totarol with aryl or alkyl azides and screened for their inhibitory activities toward hPIP5K1α. Five compounds, 3a, 3e, 3f, 3i, and 3r, strongly inhibited the enzyme activity with IC50 values of 1.44, 0.46, 1.02, 0.79, and 3.65 µM, respectively, with the most potent inhibitor 3e 13-[(1-(3-nitrophenyl)triazol-4yl)methoxy]-totara-8,11,13-triene). These compounds were evaluated on their antiproliferative effects in a panel of prostate cancer cell lines. Compound 3r inhibited the proliferation of LNCaP, PC3 and DU145 cells at 20 µM, strongly, but also has strong cytotoxic effects on all tested cells.

Bio-Guided Isolation of New Compounds from Baccharis spp. as Antifungal against Botrytis cinerea.

Baccharis genus Asteraceae is widely used in traditional treatment against fever, headache, hepatobiliary disorders, skin ulcers, diabetes, and rheumatism, as well as an antispasmodic and diuretic. Its phytochemistry mainly shows the presence of flavonoids and terpenoids such as monoterpenes, sesquiterpenes, diterpenes, and triterpenes. Some of them have been evaluated for biological activities presenting allelopathic, antimicrobial, cytotoxic, and anti-inflammatory properties. In this paper, our research group reported the isolation, characterization, and antifungal evaluation of several molecules isolated from the dichloromethane extract from Baccharis prunifolia, Baccharis trinervis, and Baccharis zumbadorensis against the phytopathogen fungus Botrytis cinerea. The isolated compounds have not previously been tested against Botrytis, revealing an important source of antifungals in the genus Baccharis. Six known flavones were isolated from B. prunifolia. The dichloromethane extracts of B. trinervis and B. zumbadorensis were subjected to a bio-guided isolation, obtaining three known flavones, an α-hydroxidihydrochalcone mixture, one labdane, one triterpene, and two norbisabolenes from the most active fractions. The compounds 4'-methoxy-α-hydroxydihydrochalcone (7A), 3ß,15-dihydroxylabdan-7-en-17-al (8), and 13-nor-11,12-dihydroxybisabol-2-enone (11) are novel. The most active compounds were the Salvigenin (5) and 1,2-dihydrosenedigital-2-one (10) with an IC50 of 13.5 and 3.1 µg/mL, respectively.

Preparation of a ε-caprolactonic diterpenoid derivate by unexpected oxidative cleavage/lactonization of 2-oxoaustroeupatol.

From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1. The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the substrate yielding the 2-oxoaustroeupatol (2) and 2,19-dioxoaustroeupatol (3). The treatment of 2 with sodium periodate yields a heterocyclic derivative (ε-caprolactone derivate 4) formed by oxidative cleavage and unexpected intramolecular attack of the hydroxymethylene (C-19) oxygen to the ketonic carbon (C-2). A plausible mechanistic pathway for the obtention of compound 4 is proposed.

Helenin from Stevia lucida. The first report of this natural eudesmanolide mixture in Eupatorieae tribe.

From aerial parts of Stevia lucida Lagasca was isolated the natural mixture of isomeric eudesmanolides helenin. The identification and quantification of the constituents of helenin (alantolactone 1 and isoalantolactone 2, ratio 3:7) was performed through the quantitative analysis of its 1D and 2D NMR spectra.

Artificial Triterpenoid Fatty Acid Ester Isolated From the Leaves of Phytolacca icosandra L.

The methanol extract form the leaves of Phytolacca icosandra L., afforded the unprecedented artificial triterpenoid fatty acid ester 1 derived from the new natural triterpenoid phytolaccagenic acid 3-O-myristate (1a), along with the three known triterpenoids serjanic, acinosolic and phytolaccagenic acid (2 - 4). Their structures were stablished by HR-EI-MS, 1D and 2D NMR techniques. The possible mechanistic formation of 1 is proposed, and the in vitro toxicity of all compounds was assessed using the brine shrimp lethality assay (BSLA).

Structure Determination and Mechanism of Formation of a seco-Moreliane Derivative Supported by Computational Analysis.

Basic hydrolysis of a dichloromethane extract of Stevia lucida yielded (4R,5S,7R,9R,10R,11R)-7,9-dihydroxylongipin-2-en-1-one (1), which was oxidized and subjected to acidic conditions to generate the new seco-moreliane derivative 3. The structure of 3 was established based on NMR data interpretation and confirmed computationally. A plausible mechanism for the carbocationic rearrangement of the trione 2 to the seco-moreliane 3 was supported by DFT computations.

Icosandrin, a novel peltogynoid from the fruits of Phytolacca icosandra (Phytolaccaceae).

Besides the known compounds ( ± ) 3,3-bis-demethylpinoresinol (2), americanol A (3), spergulagenic acid (4), epi-acetylaleuritolic acid (5), 6'-palmityl-α-spinateryl-d-glucoside (6a) and 6'-palmityl-δ(7)-stigmastenyl-d-glucoside (6b), a novel peltogynoid (1) named icosandrin was obtained from the dried fruits of Phytolacca icosandra. This new compound was characterised by 1D-/2D-NMR, UV, IR and HR-MS techniques as 11ξ-methoxy-6,7-methylenedioxy-[2]benzopyrano-[4,3-b][1]-benzopyran-4-one. Toxicity of 1 was assessed through the Brine Shrimp Lethality Assay. Lignan 2 is reported for the first time in Phytolaccaceae family.

Chemical composition of the essential oil of Gynoxys meridana from Mérida, Venezuela.

The volatile components from the fresh leaves of Gynoxys meridana Cuatrec. were obtained by hydrodistillation and analyzed by GC/MS. A total of 25 compounds, representing 99.3% of the oil, were identified. The dominant compounds were γ-curcumene (31.9%), fukinanolide (22.3%), ß-pinene (9.5%), α-phellandrene (7.1%) and α-pinene (5.7%).

Acylated oleanane-type saponins from Ganophyllum giganteum.

Five oleanane-type saponins, 3-O-ß-D-glucuronopyranosylzanhic acid 28-O-ß-D-xylopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-(4-O-acetyl)-ß-D-fucopyranosyl ester (1), 3-O-ß-D-glucopyranosylzanhic acid 28-O-ß-D-xylopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-(4-O-acetyl)-ß-D-fucopyranosyl ester (2), zanhic acid 28-O-ß-D-xylopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-(4-O-acetyl)-ß-D-fucopyranosyl ester (3), zanhic acid 28-O-α-L-rhamnopyranosyl-(1→2)-4-O-[(3'-hydroxy-2'-methyl-butyroyloxy)-3-hydroxy-2-methyl-butyroyloxy]-ß-D-fucopyranosyl ester (4), medicagenic acid 28-O-α-L-rhamnopyranosyl-(1→2)-4-O-[(3'-hydroxy-2'-methyl-butyroyloxy)-3-hydroxy-2-methyl-butyroyloxy]-ß-D-fucopyranosyl ester (5), were isolated from the root barks of Ganophyllum giganteum. Compounds 4 and 5 possessed an unusual substitution of the C-4 position of the ß-D-fucopyranosyl moiety by a C10 ester group formed by two symmetrical C5 nilic acid. From a chemotaxonomic point of view, their structures are in accordance with the previous saponins isolated from the Doratoxyleae tribe of the Sapindaceae family. Their cytotoxicity and anti-inflammatory activity were also evaluated.

Vasorelaxant effects in aortic rings of eight diterpenoids isolated from three Venezuelan plants

Vasorelaxant activity Vasorelaxant effects of eight diterpenoids isolated from three Venezuelan plants [(+)-manool [(+)-labda-8(17),14-dien-13-ol], (+)-manoyl oxide, (+)-2-oxomanoyl oxide, sandaracopimara-8(14), 15-dien-3β, 19-diol, jhanidiol acetate (18-acetoxy-1βhydroxymanoyl oxide), jhanidiol (1β,18-dihydroxymanoyl oxide), ent-kaur-16-en-19ol and grandiflorenic acid (ent-kaur-9(11),16-dien-19-oic acid)] aortic rings were assessed in intact endothelium and endothelium-denuded isolated rat. Thw cumulative addition (10-6 to 10-4 M) of each product were carried out after contraction with phenylephrine (10-6 M). Jhanidiol acetate and ent-kaur-9,16-en-19-oic acid at 10-4 M dose concentration, exhibit the maximal vasorelaxant effect in endothelium-intact rings (51.61 ± 7.62% and 79.27 ± 7.41%, respectively). In endothelium-denuded aortic rings, the maximum vascular response exerted by both compounds was not abolished (64.14 ± 5.64% and 84.84 ± 3.62%, respectively). In denuded aortic rings, the half-maximal inhibitory concentration (IC50) Jhanidiol was obtained by the ethyl less than those obtained in rings endothelium (1.09 × 10-4 vs 7.29 × 10-5 M, respectively), although this difference was not significant. These results suggested that the mechanism behind the vasorelaxant effect of the two diterpene is mediated by endothelium-independent pathways.

Microbiological transformation of two 15α-hydroxy-ent-kaur-9(11),16-diene derivatives by the fungus Fusarium fujikuroi.

The incubation of 15α-hydroxy-ent-kaur-9(11),16-dien-19-oic acid (15α-hydroxy-grandiflorenic acid) with the fungus Fusarium fujikuroi gave as main metabolite its 3ß,6ß-dihydroxy derivative, which by an oxidative decarboxylation afforded a 19-nor compound with a 4,18-double bond. Other substances obtained were a 3α-hydroxy-19,6α-lactone, 3ß-hydroxy-6ß,7ß-epoxy-ent-kaur-9(11),16-dien-19-oic acid and 3ß-hydroxy-6-oxo-ent-kaur-9(11),16-dien-19-oic acid. Moreover, the biotransformation of 15α,18-dihydroxy-ent-kaur-9(11),16-diene led to the isolation of the corresponding 3ß-, 6ß-, 7α- and 12ß-hydroxy derivatives. Two metabolites formed by 16ß,17-epoxidation of the last compound and of the substrate were also obtained. These results indicated that the presence of the 9,11-double bond in the substrate impedes its 7ß-hydroxylation, which is necessary for the formation of gibberellins and seco-ring B ent-kaurenoids. However, this 9,11-unsaturation does not hinder a 6,7-dehydrogenation and further 6ß,7ß-epoxidation, characteristic steps of the kaurenolide biosynthetic pathway.

Xanthones from aerial parts of Hypericum laricifolium Juss.

From the aerial parts of Hypericum laricifolium Juss., twelve compounds were isolated and identified. They were the xanthones: 1-hydroxy-7-methoxy-xanthone (1), 1,7-dihydroxy-xanthone (2), 2-hydroxy-xanthone (3), 6-deoxyisojacareubin (4), 1,3-dihydroxy-6-methoxy-xanthone (6), and 1,5,6-trihydroxy-7-methoxy-xanthone (7), together with beta-sitosterol, betulinic acid, vanillic acid, isoquercitrin and a mixture of quercetin and isorhamnetin. All the compounds were characterized by spectroscopic and mass spectrometric methods, and by comparison with literature data. Thisis the first report on the presence of xanthones in H.laricifolium. 1,3-Dihydroxy-6-methoxy-xanthone has been previously synthesized, but this is the first report of its isolation from a natural source.

Synthesis and anti-inflammatory activity of ent-kaurene derivatives.

A series of kaurene derivatives (1-63) were prepared and evaluated for anti-inflammatory activity. Thirteen of the tested compounds were able to inhibit NO production with an IC(50) between 2 and 10 µM. Compounds 11, 12, 14 and 23 showed low percentage of cell viability, whereas compounds 9, 10, 17, 28, 37, 48, 55, 61 and 62 were non-cytotoxic at the concentration up to 25 µM. Some structure-activity relationships were outlined. Compounds 28, 55 and 62, were selected as representative compounds and they potently inhibited the protein expression of NOS-2. We also determined that inhibition of NF-κB activation might be the mechanism involved in anti-inflammatory effects of these kaurene derivatives. As expected, cytokines IL-6, IL-1α, TNF-α and IFN-γ were downregulated in the presence of compound 28, 55 and 62 after stimulation with LPS. These results indicate that kaurene derivatives might be used for the design of new anti-inflammatory agents.

Steroidal saponins from the fruits of Cestrum ruizteranianum.

Seven spirostane and furostane-type glycosides were isolated from the aqueous methanolic extract of the fruits of Cestrum ruizteranianum and characterized mainly by 2D NMR spectroscopy and mass spectrometry. These known saponins belong to the delta5-spirostene and delta5-furostene series and are reported in this species for the first time.

Triterpene saponins from the fruits of Phytolacca rugosa (Phytolaccaceae).

Four known serjanic acid glycosides were isolated from the fruits of Phytolacca rugosa and characterized mainly by 2D NMR spectroscopy and mass spectrometry. This aglycon has a chemotaxonomic significance for the genus Phytolacca.

Evaluation of labdane derivatives as potential anti-inflammatory agents.

In the present study, a series of labdane derivatives (2-9) were prepared from labdanediol (1) and their potential as anti-inflammatory agents were evaluated on lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. All compounds were able to inhibit LPS-induced nitric oxide (NO), although compounds 1, 2, 5, 8 and 9 exhibited the most potent effects with a range of IC(50) values of 5-15 microM. Similarly to the inhibitory effects on NO release, these labdane derivatives also inhibited prostaglandin E(2) (PGE(2)) production. However, analysis of cell viability demonstrated that effects on NO release and (PGE(2)) production of compounds 1, 8 and 9 were due to citotoxicity, whereas compound 2 and 5 did not show any effect in the survival of RAW 264.7 macrophages. In addition to these in vitro data, compound 5 also showed anti-inflammatory activity in vivo, when tested in mice. They prevented the extent of swelling in the TPA-induced ear edema model and inhibited MPO activity, showing similar potency to that of the widely used anti-inflammatory drug indomethacin. These results indicate that compound 2 and in particular compound 5 might be used for the design of new anti-inflammatory agents.

Synthesis and induction of apoptosis signaling pathway of ent-kaurane derivatives.

Thirty one ent-kaurane derivatives were prepared from kaurenoic acid (1), grandiflorenic acid (16), 15alpha-acetoxy-kaurenoic acid (26) and 16alpha-hydroxy-kaurenoic acid (31). They were tested for their ability to inhibit cell viability in the mouse leukemic macrophagic RAW 264.7 cell line. The most effective compounds were 12, 20, 21, and 23. These were selected for further evaluation in other human cancer cell lines such as Hela, HepG2, and HT-29. Similar effects were obtained although RAW 264.7 cells were more sensitive. In addition, these compounds were significantly less cytotoxic in non-transformed cells. The apoptotic potential of the most active compounds was investigated and they were able to induce apoptosis with compound 12 being the best inducer. The caspase-3, -8 and -9 activities were measured. The results obtained showed that compounds 12, 21, and 23 induce apoptosis via the activation of caspase-8, whereas compound 20 induces apoptosis via caspase-9. Immunoblot analysis of the expression of p53, Bax, Bcl-2, Bcl-xl, and IAPs in RAW 264.7 cells was also carried out. When cells were exposed to 5 microM of the different compounds, expression levels of p53 and Bax increased whereas levels of antiapoptotic proteins such as Bc1-2, Bc1-x1, and IAPs decreased. In conclusion, kaurane derivatives (12, 20, 21, and 23) induce apoptosis via both the mitochondrial and membrane death receptor pathways, involving the Bcl-2 family proteins. Taken together these results provide a role of kaurane derivatives as apoptotic inducers in tumor cells.

On the structures of the diterpenes licamichauxiioic acids A and B.

The structures of the diterpenes licamichauxiioic acids A and B, isolated from Licania michauxii, which had been reported as 15-oxo-ent-kaur-9(11),16-dien-19-oic acid (1) and 15-oxo-ent-kaur-13,16-dien-19-oic acid (3), respectively, are not correct. Starting from grandiflorenic acid (6) we had prepared a compound with the proposed structure for licamichauxiioic acid A, and its spectroscopic data are different from those given for this acid. In the case of licamichauxiioic acid B, its NMR data are not in accordance with the proposed structure 3, which also violates Bredt's rule. In addition, we described a useful method for the separation of grandiflorenic and grandiflorolic acids.

Latazienone, a new lathyrane-type diterpenoid from Euphorbia latazi Kunth.

A new lathyrane-type diterpene 8alpha,15beta-diacetoxy-7beta-benzoyloxy-3beta-(2-methylpropanoyloxy)-4alphaH,9alphaH, 11alphaH-lathyra-5E,12E-dien-14-one (latazienone) has been isolated from the latex of Euphorbia latazi Kunth. The structure of the new diterpene was determined by a combination of ID- and 2D-NMR techniques.

Synthesis and antiparasitic properties of new 4-N-benzylamino-4-hetarylbut-1-enes.

New derivatives of 4-N-benzylamino-4-hetarylbut-1-ene containing a pyridyl nucleus were synthesized from benzylamines and pyridine aldehydes. N-oxide derivatives were obtained from these homoallylamines. Study of the antiparasitic properties of obtained pyridine derivatives as well as of four related benzazepines previously described, was carried out using cytotoxicity assays against Trichomonas vaginalis and epimastigote form of Trypanosoma cruzi protozoa. Compounds showing activity against epimastigote T. cruzi were tested against the amastigote form; unspecific cytotoxicity against macrophages was also studied.