Nury Pérez-Hernández

Bioactive Montanine Derivatives from Halide-induced Rearrangements of Haemanthamine-type Alkaloids. Absolute Configuration by VCD

An unexpected rearrangement of haemanthamine-type alkaloids in the presence of halogenating agents has been found. Rearranged compounds present the 5,11-methanomorphantridine framework characteristic of montanine-type alkaloids. These compounds are difficult to obtain because of their scarcity in natural sources and because the synthetic approaches developed so far require numerous steps. Vibrational circular dichroism (VCD) spectroscopy was used to determine the absolute configuration of one of the rearranged compounds. Several rearranged alkaloids showed antimalarial activity.

Interaction between Heliopsis longipes extract and diclofenac on the thermal hyperalgesia test

Heliopsis longipes is an herbaceous plant found in Mexico, used traditionally for its analgesic and anesthetic activities. Plant extracts in combined use with synthetic drugs may represent a therapeutic advantage for the clinical treatment of pain, allowing the use of lower doses, and limiting side-effects. Therefore, the main objective of this study was to determine the possible pharmacological interaction between Heliopsis longipes ethanolic extract (HLEE) and diclofenac in the Hargreaves model of thermal hyperalgesia in the mouse. HLEE, diclofenac or fixed-dose ratio HLEE-diclofenac combinations were administered systemically to mice and the antihyperalgesic effect was evaluated using the thermal hyperalgesia test. All treatments produced a dose-dependent antihyperalgesic effect. ED(30) values were estimated for all the treatments and an isobologram was constructed. The derived theoretical ED(30) value for the HLEE-diclofenac combination was 54.4+/-9.4 mg/kg body wt, significantly higher than the actually observed experimental ED(30) value, 8.6+/-4.0 mg/kg body wt. This result corresponds to synergistic interaction between HLEE and diclofenac in the Hargreaves model of thermal hyperalgesia. Data suggest that low doses of the HLEE-diclofenac combination can interact synergistically at the systemic level and that this association may therefore represent a therapeutic advantage for the clinical treatment of inflammatory pain.

Absolute configuration and 1H NMR characterization of rosmaridiphenol diacetate.

The correction of patented structure 1 of rosmaridiphenol, an antioxidant isolated from rosemary, Rosmarinus officinalis, was made recently. The correct structure is proposed as 11,12-dihydroxy-8,11,13-icetexatrien-1-one (2a) based on 2D NMR data. In order to further support the structure, this work reports the single-crystal X-ray analysis, the complete (1)H NMR assignment by full spin-spin simulation, and the absolute configuration of the diacetate 2b derived via vibrational circular dicroism measurements in comparison with density functional theory calculated data.

Antinociceptive, genotoxic and histopathological study of Heliopsis longipes S.F. Blake in mice

ETHNOPHARMACOLOGICAL RELEVANCE H. longipes S.F. Blake (Asteraceae) is a Mexican plant, whose roots are traditionally used as a condiment, as a mouth anesthetic, and as an antiparasitic. Affinin is the alkamide present in higher amounts in the roots of H. longipes. AIM OF THE STUDY To date, there are no published studies regarding the relation between the analgesic properties, in vivo cytotoxicity, and DNA-damaging potential of H. longipes ethanol extract (HLEE). MATERIALS AND METHODS The HLEE was chromatographically fingerprinted to validate its affinin contents. Biological evaluation was conducted in sets of 6-8 CD1(+) mice. Antinociceptive effect was evaluated using the writhing and hot-plate tests, and mutagenic and cytotoxic effects were evaluated with micronucleous test in CD1(+) mice. For histopathological studies, biological samples from liver, heart, kidneys, spleen, lung, and brain were collected and stained. RESULTS Oral administration of HLEE (3-100 mg/kg) produced a dose-dependent antinociceptive effect in both assays. In micronucleus assay, the variability in the number of micronucleated polychromatic erythrocytes (MNPE) induced, and PE/NE index, the ratio of polychromatic erythrocytes with respect to the number of normochromatic erythrocytes induced by HLEE in the evaluated schedule, were small and nonsignificant. After histopathological results, HLEE showed polioencephalomalacia with 1000 mg/kg dose. CONCLUSIONS This work provides evidence that HLEE exerts analgesic effects, with no genotoxic effects in vivo. These findings would be an important contribution to explain the use of H. longipes root as an effective analgesic in traditional medicine, and to establish for the first time the absence of genotoxic and cytotoxic effects of the root in bioactive doses in vivo.

Hypochlorous Acid Scavenging Activities of Thioallyl Compounds from Garlic

The hypochlorous acid (HOCl) scavenging capacities of 10 garlic compounds containing modifications in the thioallyl group (-S-CH2CH ═ CH2) were determined by a catalase protection assay, and the corresponding structure-activity relationships using molecular descriptors were calculated. This scavenging activity was enhanced by increasing the number of S atoms or by the alanyl group (-CH2CH-NH2-COOH) and decreased in the absence of the C ═ C bond or in the presence of a sulfoxide group in the thioallyl group. Interestingly, S-allylcysteine and its corresponding sulfoxide (alliin) showed the highest and lowest HOCl-scavenging capacities, respectively. Quantitative modeling by multiple regression analysis and partial least-squares projections showed that the topological descriptor polar surface area and two electronic properties, namely, highest occupied molecular orbital and total energy, contributed mainly to variations in the HOCl scavenging activity of thioallyl compounds. These observations provide new insights on the antioxidant mechanism of garlic derivatives in processes involving HOCl production.

Structure and Antimicrobial Activity of Phloroglucinol Derivatives from Achyrocline satureioides

The new prenylated phloroglucinol α-pyrones 1-3 and the new dibenzofuran 4, together with the known 23-methyl-6-O-demethylauricepyrone (5), achyrofuran (6), and 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A), were isolated from the aerial parts of Achyrocline satureioides. Their structures were determined by 1D and 2D NMR spectroscopic studies, while the absolute configuration of the sole stereogenic center of 1 was established by vibrational circular dichroism measurements in comparison to density functional theory calculated data. The same (S) absolute configuration of the α-methylbutyryl chain attached to the phloroglucinol nucleus was assumed for compounds 2-6 based on biogenetic considerations. Derivatives 7-16 were prepared from 1 and 5, and the antimicrobial activities of the isolated metabolites and some of the semisynthetic derivatives against a selected panel of Gram-positive and Gram-negative bacteria, as well as a set of yeast molds, were determined.

Evaluation of the interaction between acemetacin and opioids on the hargreaves model of thermal hyperalgesia

It has been shown that the association of opioids analgesic agents with non-steroidal anti-inflammatory drugs (NSAIDs) can increase their antinociceptive activity, allowing the use of lower doses and thus limiting side effects. Therefore, the goal of the present study was to examine the possible pharmacological interaction between acemetacin and two opioids in the Hargreaves model of thermal hyperalgesia in the mouse. Acemetacin, codeine, nalbuphine or fixed-dose ratios acemetacin-codeine and acemetacin-nalbuphine combinations were administrated systemically to mice and the antihyperalgesic effect was evaluated using the thermal hyperalgesia test. All treatments produced a dose-dependent antihyperalgesic effect. ED40 values were estimated for all the treatments and an isobologram was constructed. The derived theoretical ED40 for the acemetacin-codeine and acemetacin-nalbuphine combinations were 55.9+/-4.9 mg/kg and 40.3+/-3.8 mg/kg, respectively, being significantly higher than the actually observed experimental ED40, 14.5+/-1.7 mg/kg and 12.7+/-2.2 mg/kg, respectively. These results correspond to synergistic interactions between acemetacin and opioids on the Hargreaves model of thermal hyperalgesia. Highest doses of the individual drugs or the combinations did not affect motor coordination in the balancing test on a rota-rod. Data suggest that low doses of the acemetacin-opioids combination can interact synergistically at systemic level and therefore this drugs association may represent a therapeutic advantage for the clinical treatment of inflammatory pain.

NMR-based conformational analysis of perezone and analogues.

Complete assignment of the 1H NMR chemical shift and coupling constant values of perezone (1), O‐methylperezone (2) and 6‐hydroxyperezone (3) was carried out by total‐line‐shape‐fitting calculations using the PERCH iterative spectra analysis software (PERCH Solutions Ltd., Kuopio, Finland). The resulting simulated spectra for the three compounds showed strong similarity to their corresponding experimental spectra. Particularly, all vicinal, allylic and homoallylic coupling constant values for the side chain of the three compounds were very similar, thus revealing that the conformation of these three molecules in solution is indeed almost identical. This fact is in agreement with extended side chain conformations over folded chain conformations because 1, 2 and 3 undergo completely different intramolecular cycloaddition reactions. In addition, results of double pulsed field gradient spin echo NOESY 1D experiments performed on perezone (1) were unable to provide evidence for folded conformers. Copyright

Complete 1H NMR assignments of pyrrolizidine alkaloids and a new eudesmanoid from Senecio polypodioides

Chemical investigation of the aerial parts of Senecio polypodioides lead to the isolation of the new eudesmanoid 1β‐angeloyloxyeudesm‐7‐ene‐4β,9α‐diol (1) and the known dirhamnosyl flavonoid lespidin (3), while from roots, the known 7β‐angeloyloxy‐1‐methylene‐8α‐pyrrolizidine (5) and sarracine N‐oxide (6), as well as the new neosarracine N‐oxide (8), were obtained. The structure of 1 and 8 was elucidated by spectral means. Complete assignments of the 1H NMR data for 5, 6, sarracine (7), and 8 were made using one‐dimensional and two‐dimensional NMR experiments and by application of the iterative full spin analysis of the PERCH NMR software. Copyright

Structure-Activity Relationships of Aromadendranes in Uterus- Relaxant Activity

Aromadendranes belong to a class of sesquiterpenes present in higher plant essential oils and marine animals. Although the biological activities include antifungal, antibacterial, antiviral, plant growth regulatory, antifeedant, repellent and cytotoxic, there is only one precedent for spasmolytic effects. In a previous report we have shown that the aromadendrene molecule known as spathulenol, isolated from Lepechinia caulescens, efficiently relaxes rat uterus rings and therefore in the present work we describe structure-activity relationships of thirteen aromadendranes, most of them having the trans-fused perhydroazulene skeleton, with spasmolytic activity.