Chemical Characterization of Plant Extracts and Evaluation of their Nematicidal and Phytotoxic Potential.

Nacobbus aberrans ranks among the "top ten" plant-parasitic nematodes of phytosanitary importance. It causes significant losses in commercial interest crops in America and is a potential risk in the European Union. The nematicidal and phytotoxic activities of seven plant extracts against N. aberrans and Solanum lycopersicum were evaluated in vitro, respectively. The chemical nature of three nematicidal extracts (EC50,48h ≤ 113 µg mL-1) was studied through NMR analysis. Plant extracts showed nematicidal activity on second-stage juveniles (J2): (≥87%) at 1000 µg mL-1 after 72 h, and their EC50 values were 71.4-468.1 and 31.5-299.8 µg mL-1 after 24 and 48 h, respectively. Extracts with the best nematicidal potential (EC50,48h < 113 µg mL-1) were those from Adenophyllum aurantium, Alloispermum integrifolium, and Tournefortia densiflora, which inhibited L. esculentum seed growth by 100% at 20 µg mL-1. Stigmasterol (1), ß-sitosterol (2), and α-terthienyl (3) were identified from A. aurantium, while 1, 2, lutein (4), centaurin (5), patuletin-7-ß-O-glucoside (6), pendulin (7), and penduletin (8) were identified from A. integrifolium. From T. densiflora extract, allantoin (9), 9-O-angeloyl-retronecine (10), and its N-oxide (11) were identified. The present research is the first to report the effect of T. densiflora, A. integrifolium, and A. aurantium against N. aberrans and chemically characterized nematicidal extracts that may provide alternative sources of botanical nematicides.

EVALUATION OF ANTICANCER POTENTIAL OF EIGHT VEGETAL SPECIES FROM THE STATE OF OAXACA.

BACKGROUND: Eight plant species from Oaxaca, some of them used in traditional medicine, were subjected to screening of several biological activities to provide data regarding their anticancer potential, although no scientific information is available about their pharmacological effects. MATERIALS AND METHODS: Methanol extracts from stems or roots of the eight plants were tested for antioxidant activity by the DPPH- method. Antimicrobial activity was determined using the agar diffusion method and the minimal inhibitory concentration (MIC) was obtained by broth dilution method. Antitopoisomerase activity was assessed using mutant strains of Saccharomyces cerevisiae JN362a, JN394, JN394t-1, JN394t2.4 and JN394t2-5. The mutagenic activity was evaluated using the Ames test (Salmonella typhimurium TA1535). RESULTS: No extract showed significant antioxidant activity. The best antimicrobial activity was observed for Salpianthus arenarius (MIC 56.25 µg/mL) and Lantana achyranthifolia (MIC 78.12 µg/mL) against Staphylococcus aureus. Extracts of Acalypha cuspidata, Alloispermum integrifolium and L. achyranthifolia stems showed antitopoisomerase II activity with JN394t-1 growth of -30.88±0.0%, -38.11±4.95%, and -70.97±12.02% respectively. Galium mexicanum stem extract showed antitopoisomerase I activity with growth of 35.31±6.36% on the same mutant strain. All plant extracts were non-mutagenic. Fractionation of A. cuspidata extract led to identification of two subfractions with antitopoisomerase I and II activity at 154µg/mL (Positive controls 50 and 100µg/mL). CONCLUSION: Methanol extracts of A. cuspidata, A. integrifolium, G. mexicanum, and L. achyranthifolia stems showed antitopoisomerase and non-mutagenic activities, and consequently could be promising as a source of anticancer drugs.

Inhibitory effect of Camellia sinensis, Ilex paraguariensis and Ardisia compressa tea extracts on the proliferation of human head and neck squamous carcinoma cells.

In vitro cell proliferation, cell cycle arrest and induction of apoptosis were investigated, using three human head and neck squamous cell carcinoma (HNSCC) cell lines (OSCC-3, SCC-61, and SQ-20B). Aqueous extracts of Camellia sinensis, Ilex paraguariensis, and Ardisia compressa were tested and (-) epigallocatechin-3-gallate (EGCG) was used for comparison. For EGCG the IC50 values were between 80 and 166 µM and for the extracts among 75 and 505 µM eq. (+) catechin, with C. sinensis demonstrating dominant cytotoxicity. There was not a correlation between antioxidant capacity and cytotoxicity. Flow cytometry analysis revealed similarities in response for EGCG and C. sinensis. The A. compressa extract altered DNA distribution (P < 0.05) and was the most effective in induction of apoptosis via caspases (P < 0.05). Not all HNSCC cells tested responded to the same preventive agents. The fact that A. compressa inhibits HNSCC cell proliferation makes this aqueous extract a potential source of chemopreventive agents.

Impact of caffeine and coffee on our health.

Coffee is the most frequently consumed caffeine-containing beverage. The caffeine in coffee is a bioactive compound with stimulatory effects on the central nervous system and a positive effect on long-term memory. Although coffee consumption has been historically linked to adverse health effects, new research indicates that coffee consumption may be beneficial. Here we discuss the impact of coffee and caffeine on health and bring attention to the changing caffeine landscape that includes new caffeine-containing energy drinks and supplements, often targeting children and adolescents.

Ardisia: health-promoting properties and toxicity of phytochemicals and extracts.

Ardisia species (Myrsinaceae) are found throughout tropical and subtropical regions of the world. Traditional medicinal uses attributed to Ardisia include alleviation of liver cancer, swelling, rheumatism, earache, cough, fever, diarrhea, broken bones, dysmenorrhea, respiratory tract infections, traumatic injuries, inflammation, pain, snake and insect bites, birth complications and to improve general blood circulation, among others. Ardisia species are rich in polyphenols, triterpenoid saponins, isocoumarins, quinones and alkylphenols. A summary of the uses, potential health benefits, adverse reactions and important bioactive phytochemicals isolated from the Ardisia species is presented. Future research needs to include more toxicological studies, more comprehensive chemical characterization of extracts, bioavailability, extract standardization, investigation of possible herb-drug interactions, plant improvement with regards to bioactivity and composition, and additional human and animal studies to confirm the health-promoting properties claimed for Ardisia species. The information presented here exemplifies the potential of Ardisia species as a source of chemotherapeutic, chemo-modulating and/or chemopreventive agents.

Bioactive saponins from Microsechium helleri and Sicyos bulbosus.

Eleven oleanane-type saponins (1-11) have been isolated from Microsechium helleri and Sicyos bulbosus roots and were evaluated for their antifeedant, nematicidal and phytotoxic activities. Saponins {3-O-ß-D-glucopyranosyl (1→3)-ß-D-glucopyranosyl-2ß,3ß,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-[ß-D-xylopyranosyl-(1→3)]-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside} (1), and {3-O-ß-D-glucopyranosyl-2ß,3ß,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-[ß-D-xylopyranosyl-(1→3)]-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside} (2) were also isolated from M. helleri roots together with the two known compounds 3 and 4. Seven known structurally related saponins (5-11) were isolated from S. bulbosus roots. The structures of these compounds were established as bayogenin and polygalacic glycosides using one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds 7, 10, bayogenin (12) and polygalacic acid (13) showed significant (p<0.05) postingestive effects on Spodoptera littoralis larvae, compounds 5-11 and 12 showed variable nematicidal effects on Meloydogyne javanica and all tested saponins had variable phytotoxic effects on several plant species (Lycopersicum esculentum, Lolium perenne and Lactuca sativa). These are promising results in the search for natural pesticides from the Cucurbitaceae family.

Comparative in vitro bioactivities of tea extracts from six species of Ardisia and their effect on growth inhibition of HepG2 cells.

AIM OF THE STUDY: Ardisia species, notably A. compressa, are used in some regions of the world as food or in traditional medicine for prevention and treatment of certain health conditions including liver disease. We investigated the chemical composition and relative anticancer potential of six Ardisia species [A. japonica (AJ), A. escallonioides (AES), A. mamillata (AM), A. compressa (AC), A. crenata (ACR), and A. elliptica (AE)]. MATERIALS AND METHODS: Antioxidant capacity, DNA human topoisomerase II catalytic inhibition, and cytotoxicity on human liver cancer cells (HepG2) were determined in vitro in tea extracts of the 6 Ardisia species evaluated. Selected pure phenolic compounds present in Ardisia species were also evaluated. RESULTS: AC showed the highest topoisomerase II catalytic inhibition (IC(50)=12 microg/ml) and cytotoxicity (IC(50)=117 microg/ml) against HepG2 cells, followed by ACR and AJ. Total polyphenols ranged from 21 to 72 mg equivalents of gallic acid (GA)/g solid extract (SE). LC-MS analysis revealed the presence of GA, quercetin derivatives, ardisenone, ardisiaquinone, ardisianone, bergenin, norbergenin, and embelin. However, neither total polyphenol concentration nor antioxidant capacity correlated with anticancer capacity. Significant HepG2 cytotoxicity was also achieved by bergenin (IC(50)=18 microM) and embelin (IC(50)=120 microM). AC, bergenin, embelin, and quercetin showed a tendency to accumulate cells in the G1 phase and reduced G2/M leading to apoptosis. CONCLUSIONS: Although the mechanism is not entirely clear, AC, ACR, and AJ are the Ardisia species with the greatest anticancer potential against liver cancer cells in vitro and deserve further investigation.

Bioactive components of tea: cancer, inflammation and behavior.

Tea is one of the most widely consumed beverages worldwide. Several studies have suggested that catechins and theaflavins found in tea may reduce the risk of various types of cancers. Major advances have been made to understand the molecular events leading to cancer prevention; however, the evidence is not conclusive. Evidence from pre-clinical and clinical studies also suggests that persistent inflammation can progress to cancer. Several possible mechanisms of action may explain the cancer preventive aspects of tea components specifically anti-inflammatory effects. In regards to brain health, green tea catechins have been recognized as multifunctional compounds for neuroprotection with beneficial effects on vascular function and mental performance. Theanine, a unique amino acid in tea, enhances cognition in humans and has neuroprotective effects. Human interventional studies with well characterized tea products are needed.

Effect of yerba mate (Ilex paraguariensis) tea on topoisomerase inhibition and oral carcinoma cell proliferation.

Tea flavonoids have antitopoisomerase activity and can inhibit cell proliferation. The objectives of this study were to determine the phenolic content of yerba mate tea products (MT) (Ilex paraguariensis) and evaluate their capacity to inhibit topoisomerase I (Topo I) and II (Topo II) activities and oral carcinoma cell proliferation. Total polyphenols of aqueous extracts of dried MT leaves were measured by the Folin-Ciocalteau assay, using chlorogenic (CH) and gallic (GA) acids as standards. Topoisomerase inhibition was determined by a clone-forming assay, which uses yeast (Saccharomyces cerevisiae) strains as a model. Controls included dimethyl sulfoxide (1.66%); camptothecin (50 microg/mL), a Topo I inhibitor; and amsacrine (100 microg/mL), a Topo II inhibitor. Cytotoxicity studies were conducted using a nontumorigenic human keratinocyte cell line HaCaT and two human squamous cancer cell lines (SCC-61 and OSCC-3). MT was found to be a rich source of phenolic compounds. Total polyphenol content of various commercially available traditional MT products ranged from 236 to 490 mg equiv of CH/g of dry leaves. Such levels were significantly different among products depending on their origin (P < 0.001). Higher anti-topoisomerase II activity was observed against JN394t(2-4) strain for Nobleza Gaucha MT (IC50 = 0.43 microg equiv of CH) in comparison to GA (IC50 = 112 mM) and CH (IC50 > 1500 mM). MT showed catalytic anti-topoisomerase activity against Topo II but not against Topo I. In addititon, MT exhibited dose-dependent cytotoxicity against all squamous cell lines tested. In comparison to premalignant cell line HaCaT [28 microg equiv of (+)-catechin mL(-1)], the cell line SCC-61 [21 microg equiv of (+)-catechin mL(-1)] was the most sensitive to MT, resulting in 50% inhibition of net cell growth. It is concluded that MT is rich in phenolic constituents and can also inhibit oral cancer proliferation. The effect on cancer cell proliferation may be mediated via inhibition of topoisomerase II. The lack of correlation between polyphenol content and the inhibition of topoisomerases suggests that the effect of MT on topoisomerase inhibition may be due to other still unidentified biologically active phytochemicals constituents.

In vitro chemopreventive activity of Camellia sinensis, Ilex paraguariensis and Ardisia compressa tea extracts and selected polyphenols.

Several herbal teas contain bioactive compounds that have been associated with a lower risk of chronic diseases including cancer. The aim of this study was to evaluate the chemopreventive activity of tea aqueous extracts and selected constituent pure polyphenols using a battery of in vitro marker systems relevant for the prevention of cancer. The effects of (-) epigallocatechin gallate (EGCG), quercetin (Q), gallic acid (GA), green tea (GT, Camellia sinensis), ardisia tea (AT, Ardisia compressa) and mate tea (MT, Ilex paraguariensis) extracts were tested. Cytotoxicity, TPA-induced ornithine decarboxylase (ODC) and quinone reductase (QR) activities were evaluated in vitro using HepG2 cells. The topoisomerase inhibitory activity was also tested, using the Saccharomyces cerevisiae yeast system. Results suggest that MT, AT and GT are cytotoxic to the HepG2 cells, with MT demonstrating dominant cytotoxicity. EGCG showed greater cytotoxicity than Q and GA against HepG2 cells. The greatest inhibition (82%) of TPA-induced ODC activity was shown by Q, with 25 microM (IC50 = 11.90 microM). Topoisomerase II, but not topoisomerase I, was the cellular target of MT, AT, EGCG, Q and GA, which acted mainly as true catalytic inhibitors. The cytotoxic activity and the inhibition of topoisomerase II may contribute to the overall chemopreventive activity of AT and MT extracts. Ardisia and mate teas may thus share a public health potential as chemopreventive agents.

Vitamin C protects against in vitro cytotoxicity of cypermethrin in rat hepatocytes.

The objective of this study was to investigate the effect of ascorbic acid (AA) on the in vitro cytotoxicity of cypermethrin (CM), and on glutathione (GSH) metabolism in rat hepatocytes. In vitro cell viability, lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) leakage were measured, as indicators of hepatic damage, at 1, 15 and 30 min of exposure to CM. Glutathione and the activities of glutathione-S-transferase (GST) and gamma glutamyl transpeptidase (gamma-GT) were also measured. CM hepatotoxicity increased in a time and dose-dependent manner. In the presence of 30 microM CM, ALT and AST also increased 49 and 130% (P < 0.05), respectively, indicating metabolic hepatocyte damage. AA (1 mM) was capable to preserve 100% of cell integrity and modulated ALT and AST. Furthermore, CM induced a 27% reduction in the endogenous antioxidant GSH, and increased 203% GST and 283% gamma-GT (P < 0.05), indicating an oxidative insult. The presence of AA showed chemopreventive capacity against CM, recovering 60% of GSH and a 54% decrease in gamma-GT activity. These results suggest that AA in a 1:33 (CM:AA) ratio can modulate up to 90% of the damage caused to the cells by CM. It also demonstrates that AA can act as a primary antioxidant and hepatoprotector in rat hepatocytes.

Comparative study of the antioxidant effect of ardisin and epigallocatechin gallate in rat hepatocytes exposed to benomyl and 1-nitropyrene.

The objective of this study was to compare the antioxidant effect of ardisin and epigallocatechin 3-O-gallate (EGCG) in hepatocytes exposed to either benomyl or 1-nitropyrene (1-NP). Rat hepatocytes were incubated in a serum-free medium with non-cytotoxic concentrations of either ardisin (0.27 microg/ml) or EGCG (3 microg/ml), and with either benomyl (35 microg/ml) or 1-NP (0.25 microg/ml). The level of malondialdehyde (MDA) as a marker of lipid peroxidation was determined, as well as the content of glutathione (GSH) and the activities of glutathione peroxidase (GPx) and glutathione reductase (GR). In comparison to the control, the concentration of GSH improved 282% (P<0.05) and 260% (P<0.05) after the cells were pre-incubated with ardisin or EGCG and then exposed to benomyl, respectively. The activity of GPx decreased 55% with ardisin (P<0.05) and 51% with EGCG (P<0.05), and MDA decreased 7% and 23% (P<0.05) with the same treatments. The concentration of GSH also improved when the cells were incubated with either EGCG (49%, P<0.05) or ardisin (83%, P<0.05) simultaneously with 1-NP, relative to 1-NP alone. Moreover, ardisin decreased MDA formation by 65% (p<0.05), and enhanced the activity of GR by 137% (P<0.05). These results suggest that ardisin is a better suppressor of lipid peroxidation induced by benomyl and 1-NP than EGCG. It is concluded that ardisin and EGCG are potent antioxidants that can afford protection against free radical mediated diseases.

Topoisomerase I and II enzyme inhibitory aqueous extract of Ardisia compressa and ardisin protect against benomyl oxidation of hepatocytes.

Tea preparations of Ardisia compressa (AC) have been used in folk medicine against liver disorders. The objective of this study was to evaluate the in vitro topoisomerase I and II enzyme inhibition and the antioxidant effect of an aqueous extract from dry leaves of AC and a pure component (ardisin) purified from AC on benomyl (Be)-induced cytotoxicity in primary culture rat hepatocytes. Lipid peroxidation (malondialdehyde), antioxidant enzyme activities of glutathione reductase, glutathione peroxidase, and superoxide dismutase, and glutathione levels were studied. Topoisomerase I and II enzyme inhibition was used to guide purification of ardisin, which was purified using TLC, MPLC, and preparative and analytical HPLC methods. Benomyl increased malondialdehyde (58% change in comparison to the control) and glutathione peroxidase (10%), producing a significant consumption of endogenous antioxidant glutathione (65%, P < 0.05). A 94% hepatocyte protection was observed when cells were first exposed to ardisin (0.27 microg/mL), followed by Be (35 microg/mL). Cell protection by the tea extract of AC (AE) was greater than that by (-)-epigallocatechin 3-gallate (EGCG). Ardisin showed a clear inhibition of topoisomerases I and II catalytic activity in Saccharomyces cerevisiae mutant cells JN 394, JN394t(-)(1), and JN394t-(2)(-)(5). The potency of ardisin was superior to that of AE and EGCG as an antioxidant, protecting rat hepatocytes when exposed to Be. On the basis of the effective concentrations of equivalents to [+]catechin found in the present study, it can be estimated that, in order to gain antioxidative protection, a person would need to ingest approximately 1 L of AC tea per day, with a total content of 10.8 g of plant material.

Leaf extract from Ardisia compressa protects against 1-nitropyrene-induced cytotoxicity and its antioxidant defense disruption in cultured rat hepatocytes.

Herbal tea preparations of Ardisia compressa (AC) have been used in folk medicine against liver disorders. The objective of this study was to evaluate the in vitro protective effect of an aqueous extract of dry leaves of AC on 1-nitropyrene (1-NP) induced cytotoxicity on rat hepatocytes. Lipid peroxidation (malondialdehyde), antioxidant enzyme activities (glutathione reductase, glutathione peroxidase, superoxide dismutase) and glutathione levels were studied. After 2 h of incubation, 0.25 microg/ml of 1-NP had an approximately 50% cytotoxic effect on hepatocytes. This environmental toxicant also increased malondialdehyde (77%), and glutathione peroxidase (46%), producing a significant consumption of endogenous antioxidant glutathione. (-)Epigallocatechin 3-gallato (EGCG) and AC decreased the viability of hepatocytes after 2 h of incubation at concentrations above 3 microg/ml and 2.52 microg, equivalents of (+)catechin/ml, respectively. A 100% hepatocyte protection was observed when cells were first exposed to AC (2.52 microg, equivalents of (+)catechin/ml), and then followed by 1-NP (0.25 microg/ml). Cells incubated with AC, either simultaneously or before treatment with 1-NP, were protected 75 and 84%, respectively. Cell protection of AC was superior to EGCG. Addition of AC to 1-NP (1:10) modulated superoxide dismutase and glutathione reductase activities (P<0.005), as well as the cellular level of GSH. The results indicate that AC has an antioxidant protective effect on rat hepatocytes when exposed to 1-NP.