The Role of the Estrogen-Related Receptor Alpha (ERRa) in Hypoxia and Its Implications for Cancer Metabolism.

Under low oxygen conditions (hypoxia), cells activate survival mechanisms including metabolic changes and angiogenesis, which are regulated by HIF-1. The estrogen-related receptor alpha (ERRα) is a transcription factor with important roles in the regulation of cellular metabolism that is overexpressed in hypoxia, suggesting that it plays a role in cell survival in this condition. This review enumerates and analyses the recent evidence that points to the role of ERRα as a regulator of hypoxic genes, both in cooperation with HIF-1 and through HIF-1- independent mechanisms, in invertebrate and vertebrate models and in physiological and pathological scenarios. ERRα's functions during hypoxia include two mechanisms: (1) direct ERRα/HIF-1 interaction, which enhances HIF-1's transcriptional activity; and (2) transcriptional activation by ERRα of genes that are classical HIF-1 targets, such as VEGF or glycolytic enzymes. ERRα is thus gaining recognition for its prominent role in the hypoxia response, both in the presence and absence of HIF-1. In some models, ERRα prepares cells for hypoxia, with important clinical/therapeutic implications.

Subclassification of B-acute lymphoblastic leukemia according to age, immunophenotype and microenvironment, predicts MRD risk in Mexican children from vulnerable regions.

Introduction: The decisive key to disease-free survival in B-cell precursor acute lymphoblastic leukemia in children, is the combination of diagnostic timeliness and treatment efficacy, guided by accurate patient risk stratification. Implementation of standardized and high-precision diagnostic/prognostic systems is particularly important in the most marginalized geographic areas in Mexico, where high numbers of the pediatric population resides and the highest relapse and early death rates due to acute leukemias are recorded even in those cases diagnosed as standard risk. Methods: By using a multidimensional and integrated analysis of the immunophenotype of leukemic cells, the immunological context and the tumor microenvironment, this study aim to capture the snapshot of acute leukemia at disease debut of a cohort of Mexican children from vulnerable regions in Puebla, Oaxaca and Tlaxcala and its potential use in risk stratification. Results and discussion: Our findings highlight the existence of a distinct profile of ProB-ALL in children older than 10 years, which is associated with a six-fold increase in the risk of developing measurable residual disease (MRD). Along with the absence of CD34+ seminal cells for normal hematopoiesis, this ProB-ALL subtype exhibited several characteristics related to poor prognosis, including the high expression level of myeloid lineage markers such as MPO and CD33, as well as upregulation of CD19, CD34, CD24, CD20 and nuTdT. In contrast, it showed a trend towards decreased expression of CD9, CD81, CD123, CD13, CD15 and CD21. Of note, the mesenchymal stromal cell compartment constituting their leukemic niche in the bone marrow, displayed characteristics of potential suppressive microenvironment, such as the expression of Gal9 and IDO1, and the absence of the chemokine CXCL11. Accordingly, adaptive immunity components were poorly represented. Taken together, our results suggest, for the first time, that a biologically distinct subtype of ProB-ALL emerges in vulnerable adolescents, with a high risk of developing MRD. Rigorous research on potential enhancing factors, environmental or lifestyle, is crucial for its detection and prevention. The use of the reported profile for early risk stratification is suggested.

Anti-inflammatory and antinociceptive effects of an ethanol extract from Senna septemtrionalis.

Senna septemtrionalis (Viv.) H.S. Irwin & Barneby (Fabaceae) is a medicinal plant used as a folk remedy for inflammation and pain. The objective of this study was to evaluate the anti-inflammatory and antinociceptive actions of an ethanol extract of Senna septemtrionalis aerial parts (SSE). The in vitro anti-inflammatory effects of SSE were assessed using LPS-stimulated macrophages and the subsequent quantification of the levels of cytokines (IL-6, IL-1ß, and TNF-α) with ELISA kits, nitric oxide (NO), and hydrogen peroxide (H2O2). The in vivo anti-inflammatory actions of SSE were evaluated with the TPA-induced ear oedema test and the carrageenan-induced paw oedema test. The antinociceptive actions of SSE (10-200 mg/kg p.o.) were assessed using three models: two chemical assays (formalin-induced orofacial pain and acetic acid-induced visceral pain) and one thermal assay (hot plate). SSE showed in vitro anti-inflammatory actions with IC50 values calculated as follows: 163.3 µg/ml (IL-6), 154.7 µg/ml (H2O2) and > 200 µg/ml (IL-1ß, TNF-α, and NO). SSE showed also in vivo anti-inflammatory actions in the TPA test (40% of inhibition of ear oedema) and the carrageenan test (ED50 = 137.8 mg/kg p.o.). SSE induced antinociceptive activity in the formalin orofacial pain test (ED50 = 80.1 mg/kg) and the acetic acid-induced writhing test (ED50 = 110 mg/kg). SSE showed no antinociceptive actions in the hot plate assay. The pre-treatment with glibenclamide abolished the antinociceptive action shown by SSE alone. Overall, SSE exerted in vitro and in vivo anti-inflammatory actions, and in vivo antinociceptive effects by the possible involvement of ATP-sensitive K + channels.

Antiviral and immunomodulatory effects of polyphenols on macrophages infected with dengue virus serotypes 2 and 3 enhanced or not with antibodies.

Background: There is a lack of specific antiviral therapy against dengue virus (DENV) in current use. Therefore, a great proportion of dengue cases progress to severe clinical forms due to a complex interplay between virus and host immune response. It has been hypothesized that heterotypic non-neutralizing antibodies enhance DENV infection in phagocytic cells, and this induces an inflammatory response that is involved in the pathogenesis of severe dengue. Purpose: To identify the antiviral and immunomodulatory effects of polyphenols on dengue virus infection. Methods: Human U937-DC-SIGN macrophages were infected with DENV serotypes 2 or 3 in the presence or not of enhancing antibody 4G2. Viral titers and the secretion of tumor necrosis factor-alpha, IL-6, IL-10 and interferon-alpha were analyzed timely. Results: DENV infection alone induced high production of IL-6 and TNF-α, but in the presence of 4G2 antibody, viral titers and TNF-α secretion were potentiated. Based on anti-inflammatory antecedents, the polyphenols curcumin, fisetin, resveratrol, apigenin, quercetin and rutin were tested for antiviral and immunomodulatory properties. Only quercetin and fisetin inhibited DENV-2 and DENV-3 infection in the absence or presence of enhancing antibody (>90%, p<0.001); they also inhibited TNF-α and IL-6 secretion (p<0.001). Conclusion: Quercetin and fisetin down-regulate the production of proinflammatory cytokines induced by DENV infection enhanced by antibodies a mechanism involved in severe dengue.

Self-medication practice in pregnant women from central Mexico.

Self-medication during pregnancy represents a serious threat for mother and child health. The objective of this study was to evaluate the prevalence and the factors associated with self-medication among Mexican women living in the central region of Mexico. This is a descriptive interview-study of 1798 pregnant women or women who were pregnant no more than 3 years ago, when the interview was carried out. Data analysis was carried out with chi-square analysis and odds ratio. The prevalence of self-medication (allopathic drugs, medicinal plants, and other products, including vitamins, food supplements, among others) was 21.9%. The factors associated (p < 0.05) with self-medication were: higher education (college and postgraduate), smoking, and consumption of alcohol. Smoking was the strongest factor (OR: 2.536; 1.46-4.42) associated to self-medication during pregnancy, followed by consumption of alcohol (OR: 2.06; 1.38-3.08), and higher education (OR: 1.607; 1.18-2.19). Medicinal plant consumption was associated with nausea, constipation, migraine, and cold (p < 0.05), whereas he self-medication of allopathy was associated with gastritis and migraine (p < 0.05). Self-medication was influenced mainly by a relative or friend, who recommended the use of herbal medicine/allopathic medication. Two of the most common medicinal plants (arnica and ruda) here informed are reported to induce abortion or toxicity during pregnancy. The findings showed that self-medication (medicinal plants and allopathic medication) is a common practice among pregnant women from central Mexico. Adequate counselling of pregnant women by healthcare professionals about the potential risks of self-medication with herbal medicine and allopathic drugs during pregnancy is strongly warranted.

Bursera copallifera Extracts Have Cytotoxic and Migration-Inhibitory Effects in Breast Cancer Cell Lines.

Plants from the Bursera genus are widely distributed in the tropical dry forests of Mexico. In traditional medicine, extracts from different species of Bursera have been used for a wide range of biological activities, including the treatment of cancer-related symptoms. Compounds present in the Bursera genus include lignans, flavonoids, steroids, short-chain aliphatic alkanes, acetates, alcohols, ketones, and terpenoids. In some instances, secondary metabolites of these classes of compounds may induce cytotoxicity, and therefore we sought to investigate the effects of B. copallifera leaf extracts in breast cancer cell lines to evaluate their potential therapeutic value for the treatment of breast cancer, one of the most prevalent types of cancer in women worldwide. Two B. copallifera leaf extracts exerted cytotoxic effects on both the MCF7 and MDA-MB-231 breast cancer cell line models. The cytotoxic effect was more evident in the MDA-MB-231 triple negative cell line inhibiting also the migration of these cells. We identified hydroxycinnamic acid and flavonol derivatives as major phenolic components of the extracts. Our results strongly suggest a potential use of the Bursera leaf extracts rich in phenolic compounds, their individual phenolic compounds, or their combinations for the treatment of breast cancer.

Antinociceptive Activity of Ent-Dihydrotucumanoic Acid Isolated from Gymnosperma glutinosum Spreng Less.

Preclinical Research The diterpene ent-dihydrotumanoic acid (DTA) was among the compounds isolated from Gymnosperma glutinosum (Spreng) Less (Asteraceae). There are no reports regarding the pharmacological effects of DTA. Cytotoxicity against cancer cells (1-250 µM), and the antibacterial (50-1400 µM) activity of DTA were evaluated using the MTT assay, and the minimum inhibitory concentration test, respectively. The antidiarrheal (1-100 mg/kg p.o.) and anti-inflammatory (2 mg/ear) effects of DTA were evaluated using castor oil and 12-O-tetradecanoylphorbol-13-acetate, respectively. The antinociceptive and sedative effects of DTA (1-100 mg/kg p.o.) were evaluated using two models of chemically-induced nociception, and the pentobarbital-induced sleeping time test, respectively. The antinociceptive mechanism of DTA was evaluated using the acetic acid writhing test with inhibitors related to pain processing pathways. The effects of DTA (10-100 mg/kg p.o.) on locomotor activity were evaluated using the rotarod test. DTA lacked cytotoxic activity (IC50 > 100 µM) on cancer cells, possessed moderate antibacterial effects against B. subtillis (MIC= 175 µM), moderate antidiarrheal and anti-inflammatory effects, and minimal vasorelaxant effects. In the formalin test, DTA showed antinociceptive effects in both phases. In the acetic acid test, DTA showed antinociceptive activity (ED50 = 50.2 ± 5.6 mg/kg) with potency similar to that of naproxen (NPX; ED50 =33.7 ± 4.5 mg/kg) an effect blocked by naloxone implicating an opioid mechanism. DTA also exerted antidiarrheal activity and showed no sedative effects or changes in locomotor activity in mice. Drug Dev Res 78 : 340-348, 2017. © 2017 Wiley Periodicals, Inc.

Magnolia dealbata seeds extract exert cytotoxic and chemopreventive effects on MDA-MB231 breast cancer cells.

CONTEXT: Cancer prevention remains a high priority for the scientific world. Magnolia dealbata Zucc (Magnoliaceae), a Mexican endemic species, is used for the empirical treatment of cancer. OBJECTIVE: To evaluate the cytotoxic and cancer chemopreventive effects of an ethanol extract of Magnolia dealbata seeds (MDE). MATERIALS AND METHODS: The cytotoxic effect of MDE, at concentrations ranging from 1 to 200 µg/ml, on human cancer cells and human nontumorigenic cells was evaluated using the MTT assay for 48 h. The apoptotic activities of MDE 25 µg/ml on MDA-MB231 breast cancer cells were evaluated using the TUNEL assay and the detection of caspase 3 using immunofluorescence analysis for 48 h, each. The chemopreventive effect was evaluated by administrating different doses of MDE, between 1 and 50 mg/kg, injected intraperitoneally daily into athymic mice which were implanted with MDA-MB231 cells during 28 days. The growth and weight of tumors were measured. RESULTS: MDE showed cytotoxic effects on MDA-MB231 cells (IC50 = 25 µg/ml) and exerted pro-apoptotic activities as determined by DNA fragmentation in MDA-MB231 cells. MDE 25 µg/ml also induces the activation of caspase 3 in MDA-MB231 cells. These results suggest that Magnolia dealbata may be an optimal source of the bioactive compounds: honokiol (HK) and magnolol (MG). MDE 50 mg/kg i.p. exerted chemopreventive effects by inhibiting the growth of MDA-MB231 tumor by 75% in athymic mice, compared to the control group. CONCLUSIONS: MDE exerts cytotoxic, apoptotic and chemopreventive activities on MDA-MB231 human cancer cells.

Rutin exerts antitumor effects on nude mice bearing SW480 tumor.

BACKGROUND AND AIMS: We previously showed that extracts from Phoradendron serotinum and Croton lechleri exerted in vitro cytotoxic and in vivo antitumor effects and that their main component was rutin (RTN; 3-rhamnosyl-glucosylquercetin). However, it is unknown whether RTN exerts in vivo antitumoral effects on human colon cancer cells. The aim of this work was to evaluate the antitumor effects of RTN on a murine model. METHODS: Cytotoxic effects of RTN on human cancer and non-tumorigenic cell lines were evaluated using the MTT assay. Different doses of RTN were injected intraperitoneally daily into nu/nu mice bearing tumors of SW480 colon cancer cells during 32 days. The growth and weight of tumors were measured. Serum levels of VEGF, survival time, increase in life span and toxicological effects on body weight and organ weight were also analyzed. RESULTS: RTN showed the highest cytotoxic effects against SW480 cells (IC50 = 125 µM) as compared to the other cancer cells lines and decreased, in a dose dependent manner, the tumor volume and weight of mice bearing SW480 tumor. RTN 20 mg/kg, the highest dose tested, lacked toxic effects on body weight and relative organ weight in mice, increased mean survival time by 50 days, and decreased by 55% the VEGF serum levels compared to untreated mice. CONCLUSIONS: RTN exerts in vitro cytotoxic effects on SW480 cells, induces in vivo antitumor effects, lacks toxic effects on mice bearing SW480 tumor and exerts antiangiogenic properties.

Kaempferitrin induces apoptosis via intrinsic pathway in HeLa cells and exerts antitumor effects.

ETHNOPHARMACOLOGICAL RELEVANCE: Justicia spicigera is used for the empirical treatment of cervical cancer in Mexico. Recently, we showed that Justicia spicigera extracts exerted cytotoxic and antitumoral effects and the major component of this extract was kaempferitrin (KM). MATERIALS AND METHODS: The cytotoxic and apoptotic effect of KM on human cancer cells and human nontumorigenic cells were evaluated using MTT and TUNEL assays, and Annexin V/Propidium iodide detection by flow cytometry. The effect of KM on cell cycle was analyzed by flow cytometry with propidium iodide. The apoptotic and cell cycle effects were also evaluated by western blot analysis. Also, different doses of KM were injected intraperitoneally daily into athymic mice bearing tumors of HeLa cells during 32 days. The growth and weight of tumors were measured. RESULTS: KM induces high cytotoxic effects in vitro and in vivo against HeLa cells. The general mechanisms by which KM induces cytotoxic effects include: cell cycle arrest in G1 phase and apoptosis via intrinsic pathway in a caspase dependent pathway. Also, KM exerts chemopreventive and antitumor effects. CONCLUSION: KM exerts cytotoxic and antitumor effects against HeLa cells.

The antitumoral effect of the American mistletoe Phoradendron serotinum (Raf.) M.C. Johnst. (Viscaceae) is associated with the release of immunity-related cytokines.

ETHNOPHARMACOLOGICAL RELEVANCE: Phoradendron serotinum is commonly used in Mexican traditional medicine for the empirical treatment of cancer. However, there are no studies regarding the antitumoral or immunomodulatory activities of Phoradendron serotinum. MATERIALS AND METHODS: The in vivo toxicity of ethanolic extracts of Phoradendron serotinum (PSE) was evaluated in mice according to the Lorke procedure. The in vitro immunomodulatory effects of PSE were evaluated estimating the effects of PSE on the pinocytosis, NO production and lysosomal enzyme activity in murine macrophages RAW 264.7. The effects of PSE on the proliferation of murine splenocytes and NK cell activity were also assayed. The cytotoxic effects on TC-1 (lung murine cancer cells) were evaluated using the MTT assay, whereas the apoptotic effect of PSE on TC-1 cells was evaluated using TUNEL assay. Also, different doses of PSE were injected intraperitoneally daily into C57BL/6 mice bearing tumors of TC-1 cells during 25 days. The growth and weight of tumors was measured. In addition, the levels of IL-2, IL-6, IL-12, IL-23 and IFN-γ in murine serum and supernatants of K562 cell-murine splenocyte cocultures were measured. RESULTS: PSE stimulated the proliferation, pinocytosis and lysosomal enzyme activity in murine macrophages with a similar potency than lypopolisaccharides 1 µg/ml. In addition, PSE stimulated the proliferation of murine splenocytes and induced the NK cell activity. PSE showed cytotoxic (IC(50)=1.9 µg/ml) and apoptotic effects against TC-1 cells. The LD(50) was 125 mg/kg by intraperitoneal route (i.p.) and 375 mg/kg by oral route. PSE administrated at 1, 5 and 10 mg/kg i.p. inhibited the tumor growth by 18%, 40% and 69%, respectively, in mice bearing TC-1 tumor. PSE increased the in vitro and in vivo release of IL-2, IL-6 and IFN-γ but lacked effect on IL-12 and IL-23 release. CONCLUSIONS: Phoradendron serotinum shows moderate toxic effects in vivo, exerts cytotoxic and apoptotic effects on TC-1 cells. Phoradendron serotinum also has antitumor effects in mice bearing TC-1 tumor and induces immunomodulatory activities in vivo. The results suggest that antitumoral effects of PSE are related with the production of immunity-related cytokines.

Antitumor and immunomodulatory effects of Justicia spicigera Schltdl (Acanthaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Medicinal plants are an important source of antitumor compounds. This study evaluated the acute toxicity in vitro and in vivo, as well as the cytotoxic, antitumor and immunomodulatory effects of ethanolic extracts of Justicia spicigera leaves (JSE). MATERIALS AND METHODS: The in vitro and in vivo toxicity of JSE was evaluated with comet assay in peripheral blood mononuclear cells (PBMC) and acute toxicity in mice, according to the Lorke procedure, respectively. The apoptotic effect of JSE on human cancer cells and human noncancerous cells was evaluated using flow cytometry with annexin-Alexa 488/propidium iodide. Also, different doses of JSE were injected intraperitoneally daily into athymic mice bearing tumors of HeLa cells during 18 days. The growth and weight of tumors were measured. The in vitro immunomodulatory effects of JSE were evaluated estimating the effects of JSE on the phagocytosis of the yeast Saccharomyces cerevisiae, NO production and H(2)O(2) release in macrophages, as well as the proliferation of splenocytes and NK activity. RESULTS: The comet assay showed that only JSE tested at 200 and 1000 µg/ml induced a significantly DNA damage in PBMC, compared to untreated cells, whereas the LD(50) was >5000 mg/kg by intraperitoneal route (i.p.) and by oral route. JSE showed pro-apoptotic (Annexin/PI) effects by 35% against HeLa cells, but lack toxic effects against human normal cells. JSE administrated at 10, 50 and 100 mg/kg i.p. inhibited the tumor growth by 28%, 41% and 53%, respectively, in mice bearing HeLa tumor. JSE stimulated, in a concentration dependent manner, the phagocytosis of Saccharomyces cerevisiae yeasts, the NO production and H(2)O(2) release by human differentiated macrophages. In addition, JSE stimulated the proliferation of murine splenocytes and induced the NK cell activity. CONCLUSION: Justicia spicigera shows low toxic effects in vitro and in vivo, exerts apoptotic effects on HeLa cells, has antitumor effects in mice bearing HeLa tumor and induces immunomodulatory activities in vitro.

Antitumor effect of Croton lechleri Mull. Arg. (Euphorbiaceae).

UNLABELLED: ETHNOPHARMAGOLOGICAL RELEVANCE: Medicinal plants are an important source of antitumor compounds. This study evaluated the acute toxicity in mice, as well as the cytotoxic and antitumoral effects of methanolic extracts of Croton lechleri leaves (CLE). MATERIALS AND METHODS: The cytotoxicity of CLE on human cancer cell lines and human non-cancerous cells was evaluated using the MTT and apoptosis assays. Apoptosis induced by CLE on human cancer cell lines was determined using flow cytometry with annexin-Alexa 488/propidium iodide. The acute toxicity in mice was performed according to the Lorke procedure. Different doses of CLE were injected intraperitoneally daily into athymic mice bearing tumor during 18 days. The growth and weight of tumors was measured. RESULTS: CLE showed low IC(50) values on HeLa (17µg/ml) cells but lack toxic effects against human normal cells. Induction of cell death in HeLa cells by CLE was confirmed by an increase of apoptosis (Annexin/PI) by 30% compared to untreated cells. The LD(50) was 356mg/kg by intraperitoneal route (i.p.) and 500mg/kg by oral route. CLE administrated at 1, 10 and 50mg/kg i.p. inhibited the tumor growth by 38%, 48% and 59%, respectively, in mice bearing HeLa tumor. CONCLUSION: Croton lechleri shows moderate toxic effects in vivo, exerts cytotoxic effects on HeLa cells and has antitumor effects in mice bearing HeLa tumor.

Antimicrobial and cytotoxic effects of Mexican medicinal plants.

The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC50 < or = 30 microg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents.

Mexican medicinal plants used for cancer treatment: pharmacological, phytochemical and ethnobotanical studies.

AIM OF THE STUDY: This review provides a summary of Mexican medicinal flora in terms of ethnobotanical, pharmacology, and chemistry of natural products related to anticancer activity. MATERIALS AND METHODS: Bibliographic investigation was carried out by analyzing recognized books and peer-reviewed papers, consulting worldwide accepted scientific databases from the last five decades. Mexican plants with attributed anti-cancer properties were classified into six groups: (a) plant extracts that have been evaluated for cytotoxic effects, (b) plant extracts that have documented anti-tumoral effects, (c) plants with active compounds tested on cancer cell lines, (d) plants with novel active compounds found only in Mexican species, (e) plants with active compounds that have been assayed on animal models and (f) plants with anti-cancer ethnopharmacological references but without scientific studies. RESULTS: Three hundred plant species belonging to 90 botanical families used for cancer treatment have been recorded, of which only 181 have been experimentally analyzed. The remaining 119 plant species are in use in empirical treatment of diseases consistent with cancer symptomatology. Only 88 of the plant extracts experimentally studied in in vitro cellular models have demonstrated active cytotoxic effects in at least one cancer cell line, and 14 out of the 88 have also been tested in vivo with the results that one of them demonstrated anti-neoplasic effects. A total of 187 compounds, belonging to 19 types of plant secondary metabolites, have been isolated from 51 plant extracts with active cytotoxic effects, but only 77 of these compounds (41%) have demonstrated cytoxicity. Seventeen of these active principles have not been reported in other plant species. However, only 5 compounds have been evaluated in vivo, and 3 of them could be considered as active. CONCLUSION: Clearly, this review indicates that it is time to increase the number of experimental studies and to begin to conduct clinical trials with those Mexican plants and its active compounds selected by in vitro and in vivo activities. Also, the mechanisms of action by which plant extracts and their active compounds exert anti-cancer effects remain to be studied.

Honokiol and magnolol production by in vitro micropropagated plants of Magnolia dealbata, an endangered endemic Mexican species.

An efficient protocol for the in vitro propagation of Magnolia dealbata Zucc., an important medicinal plant that is the source of the anxiolytic and anticancer compounds honokiol and magnolol, was established. This plant is wild-crafted, and conservationists have expressed concerns with regard to the sustainability of production. In the present work, two factors were found to be of importance for the regeneration of M. dealbata and the production of honokiol and magnolol. These factors were the type of explants and the combination and concentration of plant-growth regulators. Green, compact, nodular organogenic callus was obtained from leaf explants in a medium fortified with Murashige and Skoog salts and supplemented with 1.5 mg/L 2,4-dicholorophenoxyacetic acid and 1.5 mg/L kinetin. Shoots multiplication from callus cultures was achieved in the Murashige and Skoog (MS) medium with 1.5 mg/L thidiazuron (TDZ). Phenol secretion was controlled by the addition of 250 mg/L of activated charcoal. For rooting, shoots were transferred to MS medium supplemented with several auxins. After root induction, the plants were hardened in earthen pots containing sand, soil, and vermiculite. The contents of honokiol (HK) and magnolol (MG) were determined in different plant materials by high-performance liquid chromatography-diode-array detection techniques. This analysis revealed that the honokiol and magnolol content in aerial and underground parts of micropropagated M. dealbata were higher than that observed in wild plants (both 6 months old). Our results suggest that conservation of M. dealbata is possible by means of in vitro multiplication of leaf-derived callus. The usefulness of M. dealbata regeneration and production of HK and MG may be attributed to the proper selection of explant sourcing and identification of the correct growth medium to support adequate growth. This careful selection of explants and growth medium leads to a very useful source of plant material for pharmacological and phytomedicinal screening applications and, above all, would safeguard this plant species from the threat of extinction.

Production of honokiol and magnolol in suspension cultures of Magnolia dealbata Zucc.

Honokiol and magnolol, important anxiolytic and anti-cancer agents, have been produced in cell-suspension cultures of the endangered Mexican plant Magnolia dealbata Zucc. In vitro cultures of the plant were established, and the accumulation of honokiol and magnolol in callus and cell-suspension cultures was measured. Leaf samples were the best explants for callus establishment and metabolite production, and Murashige and Skoog medium supplemented with 1 mg/L 2, 4-dichlorophenoxyacetic acid and 1 mg/L kinetin yielded 2.3 mg/g of honokiol and 5.9 mg/g of magnolol. Bacterial and fungal contamination was inhibited with a multiple-step tissue sterilization procedure. Oxidation was inhibited with 1 g/L activated charcoal. Cell-suspension batch cultures derived from friable callus obtained from leaves of this species were grown for 30 days in shaker flasks containing Murashige and Skoog medium. Throughout the growth cycle, honokiol and magnolol levels, fresh and dry weight, and sucrose uptake were determined. The effects of carbon source concentration on biomass accumulation and the synthesis of bioactive compounds were studied. By using 3 mL of inocula supplemented with 3% (w/v) sucrose, maximum yields of honokiol (8.1 mg/g) and magnolol (13.4 mg/g) were obtained after 25 days. These yields were 300% and 382%, respectively, of the yields of honokiol and magnolol obtained from field-grown plants.