Isabel Rivero-Cruz

ROS scavenging capacity and neuroprotective effect of α-mangostin against 3-nitropropionic acid in cerebellar granule neurons.

Alpha-mangostin is a xanthone with antioxidant properties isolated from mangosteen fruit. The reactive oxygen species (ROS) scavenging capacity and the potential protective effect of alpha-mangostin against the mitochondrial toxin 3-nitropropionic acid (3-NP) in primary cultures of cerebellar granule neurons (CGNs) were studied in the present work. It was found that alpha-mangostin was able to scavenge in a concentration-dependent way singlet oxygen, superoxide anion and peroxynitrite anion. In contrast, alpha-mangostin was unable to scavenge hydroxyl radicals and hydrogen peroxide. Furthermore, alpha-mangostin was able to ameliorate in a concentration-dependent way the neuronal death induced by 3-NP. This protective effect was associated with an amelioration of 3-NP-induced reactive oxygen species formation. It is concluded that alpha-mangostin is able to scavenge directly several ROS and has a neuroprotective effect against 3-NP in primary cultures of CGNs, which is associated with its ability to ameliorate 3-NP-induced ROS production.

Mexican Antidiabetic Herbs: Valuable Sources of Inhibitors of α-Glucosidases

Type II-diabetes mellitus (TII-DM) has been regarded as one of the most important public health problems in all nations in the 21st century. Although allopathic therapies remain the most important for the initial management of TII-DM, herbal remedies have gained wide acceptance for treating this condition. These alternative therapies are particularly valued in countries such as Mexico, rich in medicinal plants strongly attached to the cultural values of the population. Medicinal plants are prized sources of α-glucosidase inhibitors, which delay the liberation of glucose from complex carbohydrates, retarding glucose absorption, and thus controlling the characteristic hyperglycemia of TII-DM. Among the plant species used for treating diabetes in Mexico only 38 have been analyzed for their inhibitory activity of α-glucosidases. Most of these studies, reviewed in the present work, have focused on the evaluation of different types of extracts on the activity of α-glucosidases from diverse sources. Four species have been thoroughly analyzed in order to discover novel α-glucosidase inhibitors, namely, Hintonia latiflora and Hintonia standleyana (Rubiaceae), Ligusticum porteri (Apiaceae), and Brickellia cavanillesii (Asteraceae). Their ethnomedical uses, pharmacological and toxicological studies, chemical composition, and antihyperglycemic principles with α-glucosidase inhibitory activity are summarized.

The natural xanthone α-mangostin reduces oxidative damage in rat brain tissue

Abstract The antiperoxidative properties of α-mangostin, a xanthone isolated from mangosteen fruit, were tested for the first time in nerve tissue exposed to different toxic insults. Two reliable biological preparations (rat brain homogenates and synaptosomal P2 fractions) were exposed to the toxic actions of a free radical generator (ferrous sulfate), an excitotoxic agent (quinolinate), and a mitochondrial toxin (3-nitropropionate). α-Mangostin decreased the lipoperoxidative action of FeSO4 in both preparations in a concentration-dependent manner, and completely abolished the peroxidative effects of quinolinate, 3-nitropropionate and FeSO4 + quinolinate at all concentrations tested. Interestingly, when tested alone in brain homogenates, α-mangostin significantly decreased the lipoperoxidation even below basal levels. α-Mangostin also prevented the decreased reductant capacity of mitochondria in synaptosomal fractions. Our results suggest that α-mangostin exerts a robust antiperoxidative effect in brain tissue preparations probably through its properties as a free radical scavenger. In light of these findings, this antioxidant should be tested in other neurotoxic models involving oxidative stress.

Antimycobacterial agents from selected Mexican medicinal plants

As part of the ICBG program Bioactive Agents from Dryland Biodiversity of Latin America, the present investigation was undertaken to explore the possible antimycobacterial potential of compounds derived from selected Mexican medicinal plants. Bioassay‐guided fractionation of the crude extracts of Rumex hymenosepalus (Polygonaceae), Larrea divaricata (Zygophyllaceae), Phoradendron robinsonii (Loranthaceae) and Amphipteryngium adstringens (Julianiaceae) led to the isolation of several antimycobacterial compounds. Four stilbenoids, two flavan‐3‐ols and three anthraquinones were isolated from R. hymenosepalus. Two flavonols and nordihydroguaiaretic acid were obtained from L. divaricata. Sakuranetin was the antimycobacterial agent isolated from P. robinsonii. Two known triterpenoids and the novel natural product 3‐dodecyl‐1,8‐dihydroxy‐2‐naphthoic acid were obtained from A. adstringens. In general, the isolates were identified by spectral means. The antimycobacterial activity of the secondary compounds isolated from the analysed species, as well as that of nine pure compounds previously isolated in our laboratories, was investigated; the MIC values ranged from 16 to 128μ mL−1. Among the tested compounds, the glycolipids, sesquiterpenoids and triterpenoids showed the best antimycobacterial activity. The antimycobacterial property of the glycolipids is reported for the first time. Although the tested compounds showed moderate antimycobacterial activity, their presence in the analysed species provides the rationale for their traditional use in the treatment of tuberculosis.

Phytotoxic compounds from Flourensia cernua

Bioassay-directed fractionation of a CH(2)Cl(2)-MeOH (1:1) extract of the aerial parts of Flourensia cernua led to the isolation of three phytotoxic compounds, namely, dehydroflourensic acid (1), flourensadiol (2) and methyl orsellinate (3). Dehydroflourensic acid is a new natural product whose structure was established by spectral means. In addition, the known flavonoid ermanin and seven hitherto unknown gamma-lactones were obtained, these being tetracosan-4-olide, pentacosan-4-olide, hexacosan-4-olide, heptacosan-4-olide, octacosan-4-olide, nonacosan-4-olide, and triacontan-4-olide. Compounds 1-3 caused significant inhibition of radicle growth of Amaranthus hypochondriacus and Echinochloa crus-galli, interacted with bovine-brain calmodulin and inhibited the activation of the calmodulin-dependent enzyme cAMP phosphodiesterase.

Chemical Composition and Antimicrobial and Spasmolytic Properties of Poliomintha longiflora and Lippia graveolens Essential Oils

UNLABELLED In the present study, we reported a comparative analysis of the chemical composition and pharmacological properties of the essential oils obtained from 2 Mexican oreganos, Poliomintha longiflora and Lippia graveolens. The gas chromatography-mass spectrometry (GC-MS) profiles of the oils showed high amounts of oxygenated monoterpenes, mainly carvacrol (%[mg/100 g dry matter]) (18.36 [459.0] in P. longiflora and 13.48 [164.7] in L. graveolens). In addition, these oils contained marked quantities of p-cymene (14.09 [352.2] and 7.46 [37.3], respectively), β-caryophyllene oxide, β-caryophyllene, and carvacrol acetate. Headspace analyses of the leaves of both species using different coated fibers revealed that γ-terpinene, eucalyptol, and p-cymene were the principal light volatile components. Chromatographic fingerprints and a suitable analytical method for quantifying the main components of both essences were established using high-performance liquid chromatography (HPLC) as analytical tool. The essential oils of both species were not toxic in the acute toxicity studies in mice performed according to the Lorke procedure (DL(50) > 5000 mg/kg). The oils and the major constituents, carvacrol and p-cymene, displayed a moderate in vitro antibacterial activity, with minimum inhibitory concentration values ranging from 128 to 512 μg/mL. In addition, these samples demonstrated a marginal antispasmodic activity in vivo and provoked a concentration-dependent inhibition of the carbachol- and histamine-induced contractions using the isolated guinea-pig ileum preparation. In particular, p-cymene exerts good selective inhibitory activity on the carbachol-induced contractions (IC(50) = 9.85 μg/mL). PRACTICAL APPLICATION The analytical methods using GC-MS and HPLC techniques will be useful for establishing quality control as well as preclinical pharmacological and toxicological parameters of the crude drug P. longiflora, which is widely used as substitute of L. graveolens for medicinal and flavorings purposes. This overall information will be also useful for elaborating scientific and pharmacopoeic monographs of this very Mexican medicinal plant.

Antinociceptive activity of the essential oil from Artemisia ludoviciana

ETHNOPHARMACOLOGICAL RELEVANCE Aerial parts of Artemisia ludoviciana are widely used in Mexico for treating gastrointestinal disorders, painful complaints and diabetes. AIM OF THE STUDY To establish the preclinical efficacy as antinociceptive agent of the essential oil (EO) from the aerial parts of A. ludoviciana using well-known animal models. MATERIALS AND METHODS Acute antinociceptive effect of EO (1, 10, 31.6, 100, and 316mg/kg, i.p.) was evaluated using the hot plate and paw formalin models in mice. The motor effects were assessed with the rota-rod and open field assays. The volatile components obtained by headspace solid phase microextraction (HS-SPME) and hydrodistillation were determined using gas chromatography coupled with mass spectrometry (GC-MS) analysis. RESULTS EO decreased first and second phases of formalin test; in the first stage, the better effect was obtained with the treatment of 316mg/kg but in the second phase, time licking was attenuated at the doses of 31.6, 100 and 316mg/kg. The effectiveness of EO (ED50=25.9mg/kg) for attenuating neurogenic pain was corroborated using the hot plate test. The antinociceptive action of EO was blocked by naloxone suggesting that its mode of action involved an opioid mechanism. Furthermore, EO (316mg/kg) did not affect animal motor and coordination functions when tested by the rota-rod and open field tests. The latter results indicated that the pharmacological effects exerted by EO during the hot plate and formalin test are truly antinociceptive. GC-MS analysis of EO revealed that (±)-camphor, γ-terpineol, 1,8-cineole and borneol were the major volatile compounds of the plant. CONCLUSION EO from A. ludoviciana showed significant antinociceptive effect, which appeared to be partially mediated by the opioid system. These findings could support the long-term use of A. ludoviciana for treating painful complaints in Mexican folk medicine.

Quality control tests for the crude drug of Conyza filaginoides

Abstract Context. Conyza filaginoides (D.C.) Hieron (Asteraceae) is a medicinal Mexican plant highly prized in contemporary Mexico for the treatment of upset stomach and diabetes. Objective: This work was undertaken to develop a suitable high performance liquid chromatography (HPLC)-diode array detection (DAD) method for quantifying rutin (1), the main active principle from the aerial parts of C. filaginoides. Materials and methods: The method was performed using a LiChrospher 100 RP-18 column. The mobile phase was water (containing 0.1% phosphoric acid)-methanol-acetonitrile (80:5:15, v/v) at a flow rate of 1.2 mL min−1. Results: Limits of detection and quantification were 7.5 and 22.8 μg mL−1, respectively. The main recoveries measured at three concentrations were higher than 98%, with RSD <2%. Quantitative analysis of a few samples showed the presence of high concentrations of 1 (3.6 ± 0.2 g/100 g of dry plant material). The volatile components were extracted by hydrodistillation or head space solid-phase microextraction (HS-SPME), and thereafter analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Forty-three chemical constituents representing 90% of the total content of the oil were identified. The major light volatile compounds obtained by HS-SPME revealed a high content of monoterpene hydrocarbons. Conclusions: A precise, reliable, and accurate analytical HPLC method to detect and quantify 1 in the crude drug and some preparations were developed and fully validated. The volatile components of the plant are described for the first time. The proposed method would be useful for quality control assurance of this important Mexican plant.

Antinociceptive activity of Ligusticum porteri preparations and compounds

Abstract Context: The roots and rhizomes of Ligusticum porteri Coulter & Rose (Apiaceae) are widely used in Mexican folk medicine for several purposes, including painful complaints. Objective: The main goal of this work was to demonstrate the analgesic action in mice of some preparations and major compounds from L. porteri. Materials and methods: The extracts, aqueous (AE) and organic (OE), the essential oil (EO) and major compounds (10–316 mg/kg) from L. porteri were evaluated as potential antinociceptive agents using the acetic acid-induced writhing and hot plate tests in ICR mice. Results: All preparations tested exhibited significant antinociceptive effect in the two animal pain models selected. AE and EO were more effective in the writhing test while OE had a better effect in the hot-plate model. On the other hand, Z-ligustilide (1) provoked an increment in the latency period to the thermal stimuli in the hot-plate test at a dose of 31.6 mg/kg, and a decrease in the number of abdominal writhes at 10 mg/kg. Z-3-butylidenephthalide (2) induced a dose-dependent antinociceptive action in the hot-plate assay; this compound was also effective for controlling the pain provoked by chemical irritation at the doses of 10 and 31.6 mg/kg. Finally, diligustilide (3) inhibited the number of writhing responses at all doses tested but was inactive in the hot-plate model. Conclusion: The present investigation provides in vivo evidence supporting the use of L. porteri to treat painful conditions in folk medicine.

Dioxomorpholines and Derivatives from a Marine-Facultative Aspergillus Species

Two new dioxomorpholines, 1 and 2, three new derivatives, 3-5, and the known compound PF1233 B (6) were isolated from a marine-facultative Aspergillus sp. MEXU 27854. Their structures were established by 1D and 2D NMR and HRESIMS data analysis. The absolute configuration of 1 and 2 was elucidated by comparison of experimental and DFT-calculated vibrational circular dichroism spectra. Compounds 3, 5, and 6 were noncytotoxic to a panel of human cancer cell lines with different functional status for the tumor-suppressor protein p53, but were inhibitors of P-glycoprotein-reversing multidrug resistance in a doxorubicin-resistant cell line.