Antioxidant and acetylcholinesterase inhibitory activity of selected southern African medicinal plants

Alzheimer's disease (AD) is the most common type of dementia in the aging population. Enhancement of acetylcholine levels in the brain is one means of treating the disease. However, the drugs presently used in the management of the disease have various drawbacks. New treatments are required and in this study, extracts of Salvia tiliifolia Vahl. (whole plant), Chamaecrista mimosoides L. Greene (roots), Buddleja salviifolia (L.) Lam. (whole plant) and Schotia brachypetala Sond. (root and bark) were evaluated to determine their polyphenolic content, antioxidant and acetylcholinesterase inhibitory (AChEI) activity. The DPPH and ABTS assays were used to determine antioxidant activity and Ellman colorimetric method to quantify AChEI activity. Although all four plants showed activity in both assays, the organic extracts of C. mimosoides root was found to contain the highest AChEI activity (IC₅₀ = 0.03 ± 0.08 mg/ml) and B. salviifolia whole plant had the highest antioxidant activity (ABTS; IC₅₀ = 0.14 ± 0.08 mg/ml and DPPH; IC₅₀ = 0.23 ± 0.01 mg/ml). The results suggest that the tested plant species may provide a substantial source of secondary metabolites, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of AD.     

Acetylcholinesterase‐Inhibitory Activities of the Extracts from Sponges Collected in Mauritius Waters

Patients diagnosed with Alzheimer's disease (AD) show a characteristic neurochemical deficit of acetylcholine, especially in the basal forebrains. The use of acetylcholinesterase (AChE) inhibitors to retard the hydrolysis of acetylcholine has been suggested as a promising strategy for AD treatment. In this study, we evaluated the acetylcholinesterase inhibitory (AChEI) activities of 134 extracts obtained from 45 species of marine sponges. Thin‐layer chromatography (TLC) and microplate assays reveal potent acetylcholinsterase inhibitory activities of two AcOEt extracts from the sponges Pericharax heteroraphis and Amphimedon navalis Pulitzer‐Finali . We further investigated the inhibitory kinetics of the extracts and found them to display mixed competitive/noncompetitive inhibition and associated their inhibitory activity partly to terpenoids. Acetylcholinesterase inhibitors from marine organisms have been rarely studied, and this study demonstrated the potential of marine sponges as a source of pharmaceutical leads against neurodegenerative diseases.     

Velnacrine thiaanalogues as potential agents for treating Alzheimer's disease

The only therapeutic drugs for combating dementia disease are acetylcholine esterase inhibitors (AChEI). However, the use of tacrine, the first AChEI to be launched as an Alzheimer's disease (AD) drug, has been limited by serious side effects. Therefore, efforts to search for more potent and selective inhibitors of AChE still remain highly significant in the therapeutic treatment of AD. In this work we modified the cyclohexyl ring of velnacrine, a less toxic analogue of tacrine, by synthesizing a series of thiopyranoquinolines in which the C-3 methylene unit was replaced by a sulphur atom. The anti-AChE data show that the activity was maintained with the bioisosteric substitution carried out. The introduction of a chlorine atom at different positions of the aromatic ring resulted in an array of different activities. In an attempt to understand the different behaviours displayed by the chlorine-substituted derivatives, a molecular docking study was performed.     

Phenolic Composition,Anti‐Inflammatory,Antioxidant, and Antimicrobial Activities of Alchemilla mollis (Buser) Rothm.

The current study was designed to evaluate the antioxidant, anti‐inflammatory and antimicrobial activities of Alchemilla mollis (Buser ) Rothm . (Rosaceae) aerial parts extracts. Chemical composition was analyzed by spectrophotometric and chromatographic (HPLC) techniques. The antioxidant properties assessed included DPPH^· and ABTS^·+ radical scavenging, β‐carotene‐linoleic acid co‐oxidation assay. Antimicrobial activity was evaluated with disc diffusion and micro dilution method. In order to evaluate toxicity of the extracts, with the sulforhodamine B colorimetric assay L929 cell line (mouse fibroblast) was used. The anti‐inflammatory activities of the potent antioxidant extracts (methanol, 70% methanol, and water extracts) were determined by measuring the inhibitory effects on NO production and pro‐inflammatory cytokine TNF‐α levels in lipopolysaccharide stimulated RAW 264.7 cells. 70% methanol and water extracts which were found to be rich in phenolic compounds (184.79 and 172.60 mg GAE/g extract) showed higher antioxidant activity. Luteolin‐7‐O‐glucoside was the main compound in the extracts. Ethyl acetate and 70% methanol extracts showed higher antibacterial activity against Staphylococcus aureus and Salmonella enteritidis with MIC value of 125 μg/ml. 70% methanol extract potentially inhibited the NO and TNF‐α production (18.43 μm and 1556.22 pg/ml, respectively, 6 h).     

Analyzing the Impact of Ramalina digitellata,R. fastigiata,R. fraxinea,and R. polymorpha's Usnic Acid Concentration on Antioxidant,DNA-Protective,Antimicrobial, and Cytotoxic Properties

The present study is focused on the antimicrobial, antioxidant, cytotoxic, and DNA protective effects of methanol extract obtained from R. digitellata, R. fastigiata, R. fraxinea, and R. polymorpha species that are distributed in Turkey. The highest total phenol content was determined in R. digitellata (144.6 mgGAE/g_extract), and the highest total amount of flavonoids was found in R. fastigiata (20.40 mgGAE/g_extract). The content of usnic acid was determined by High-Performance Liquid Chromatography (HPLC) and the highest amount was found in R. digitellata. DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS [2,2’-azinobis(3-ethylbenzathiazoline-6-sulfonic acid)] radical scavenging methods were used for antioxidant activity. R. fraxinea showed the highest DPPH⋅ and ABTS⁺⋅ scavenging activity. In addition, the DNA protective effect was investigated using pBR322 plasmid DNA, and; all studied species were found to have DNA protective effects. The antibacterial activity was investigated using the disc diffusion method, and the R. digitellata methanol extract showed the best results with a 12.35 mm zone on Proteus mirabilis. On the human lung cancer (A549) and breast cancer (MDA-MB-231) cell lines, cytotoxic activity was assessed using an MTT assay. All lichen extracts were found to have a significant cytotoxic effect on both cancer cell lines at 1000 μg/mL concentration. These results suggest that Ramalina species may be potential candidates for developing new phytopharmaceuticals and functional components.     

In vitro evaluation of the efficacy of plant and callus extracts of Cardiospermum halicacabum L. on important phytopathogenic fungi

The aqueous and different solvent extracts viz., petroleum ether, chloroform, methanol and ethanol extracts of leaf and leaf derived callus of Cardiospermum halicacabum L. (Sapindaceae) at different concentrations were screened in vitro for antifungal activity by the poisoned food technique against a wide array of seed-borne phytopathogenic fungi. The test organisms include Aspergillus flavus, A. niger, Curvularia lunata, Drechslera halodes, Fusarium moniliforme, F. solani, and F. oxysporum, which are frequently associated with sorghum [Sorghum bicolor (L.) Moench], maize (Zea mays L.) and paddy (Oryza sativa L.) seeds. Aqueous leaf extracts of C. halicacabum showed significant inhibition was observed at 50% concentration particularly in Aspergillus species. With regard to the comparative efficiency of leaf and leaf derived callus extracts, aqueous leaf extract was found to be more effective than callus extract. Among the different solvent extracts, it was observed that at 3000 ppm concentration methanol extract of C. halicacabum leaf recorded the highest degree of activity and percentage inhibition was more, but in petroleum ether and chloroform extracts did not show any significant activity. C. halicacabum leaf derived callus at 3000 ppm methanol extract showed significant antifungal activity on Fusarium species. Leaf of C. halicacabum aqueous and methanol extract showed significant antifungal activity against all the tested fungi. C. halicacabum has significant medicinal value, hence the results of the present investigation indicate that it could be exploited in the management of seed-borne pathogenic fungi.     

Composition and biological activities of different extracts of Salvia jurisicii,a rare and endemic Macedonian species

This is the first report on the phenolic composition and biological activities of endemic species Salvia jurisicii Ko?anin (Lamiaceae) originating from Macedonia. Aerial parts of S. jurisicii were extracted with dichloromethane, ethyl acetate, methanol, ethanol and water. All extracts were tested spectrophotometrically for total phenolic and flavonoid contents, while their phenolic composition was analyzed using HPLC-DAD. The antioxidant activity of extracts was studied using 2,2-dyphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ferric reducing ability of plasma and ß-carotene bleaching assays. Being the most frequently used solvents for extraction of bioactive ingredients from medicinal plants, water and ethanol extracts were chosen for further testing of antimicrobial, cytotoxic and antineurodegenerative activities. More polar solvent extracts showed higher total phenolic content and lower flavonoid content. Ethanol and methanol extracts, followed by water extract exhibited the strongest antioxidant activity. Extracts showed antimicrobial activity against certain bacteria and micromycetes. The cytotoxicity assay showed slight toxicity to HCT-116 cell line. In the antineurodegenerative assays, the extracts performed lower inhibition of acetylcholinesterase and tyrosinase than standards. According to the results of this study, it can be inferred that more polar extracts of S. jurisicii were quantitatively richer in total phenolics, showing stronger antioxidant activity. Ethanol extract showed stronger biological activities comparing to water extract.     

Inhibitory Effects of Some Spice and Herb Extracts Against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii

Seventeen spice and medicinal plant extracts (methanol and chloroform) were assayed for their antimicrobial activity against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii. In general, all of the tested extracts were able, to a different extent, to inhibit the growth of the selected Arcobacter species. Cinnamon, bearberry, chamomile, sage and rosemary extracts showed strong antimicrobial activity toward arcobacter strains tested. Overall, the methanol extracts showed better activity than the chloroform extracts (P < 0.05); however, enhanced antibacterial activity of chloroform extracts of cinnamon and rosemary has been observed in comparison with their methanol counterparts. The inhibitory dose of the most active extracts (the diameter of zone of inhibition ≥ 20 mm) was determined using the disc-diffusion method as well.     

Phenolic acids reduce the genotoxicity of acridine orange and ofloxacin inSalmonella typhimurium

Naturally occurring plant phenolics,p-coumaric acid (PA), caffeic acid (CA), ferulic acid (FA) and gentisic acid (GA) (25–100 nmol/L) had protective effects on acridine orange (AO; 216 μmol/L)- and ofloxacin (3 μmol/L)-induced genotoxicity inSalmonella typhimurium. FA, GA and CA exhibited a significant concentration-dependent protective effect against the genotoxicity of AO and ofloxacin, with the exception of PA, which at all concentrations tested abolished the AO and ofloxacin genotoxicity. UV spectrophotometric measurements showed the interaction of PA, FA, GA and CA with AO but not with ofloxacin; this interaction is obviously responsible for the reduction of AO-inducedS. typhimurium mutagenicity. In the case of ofloxacin the antimutagenic effect of PA, FA, GA and CA is assumed to be a result of their ability to scavenge reactive oxygen species (ROS) produced by ofloxacin.     

Lignicolous fungi from northern Serbia as natural sources of antioxidants

As a result of an interest in natural derived metabolites, lignicolous fungi have taken on great importance in biochemical investigations. In the present study, antioxidative screening analyses have included in vitro testing of different extracts (aqueous, methanol, chloroform) of four fungal species using three different assays: Fe²⁺/ascorbate-induced lipid peroxidation by TBA assay, the neutralisation of OH· radicals and the radical scavenging capacity with the DPPHk]assay. TLC analysis confirmed the existance of phenolics in the extracts, but also indicates the presence of some other compounds. The obtained results indicate that MeOH extracts manifested a degree of activity higher than that of CHCl₃ extracts. With respect to antioxidative activity, the extracts can be ranged in the following declining order: G. lucidum, G. applanatum, M. giganteus and F. velutipes. These results suggest that analyzed fungi are of potential interest as sources of strong natural antioxidants that could be used in the food industries and nutrition.     

Antioxidant and antimicrobial activity of some lichen species

The aim of the research is to explore the overall in vitro antioxidant activity, total phenol content, reduction power and antimicrobial activity of the methanol extracts of the lichens Cetraria pinastri, Cladonia digitata, Cladonia fimbriata, Fulgensia fulgens, Ochrolechia parella and Parmelia crinita. The methanol extract of the Cetraria pinastri showed a strong antioxidant activity, whereas the extracts of the species Fulgenesi fulgens, Cladonia fimbriata and Parmelia crinita showed the moderate one and the extract of the species Ochrolechia parella and Cladonia digitata the weak one. The methanol extract of the lichen Cetraria pinastri had the biggest total phenol content (32.9 mg/g of the dry extract). A certain correlation was established between the antioxidant activity and the total phenol content for the researched lichen extracts. The work also explores the antimicrobial activity of the methanol extracts of the mentioned species of lichens against six bacterial and eleven fungi species by the disc-diffusion method and by establishing the minimum inhibitory concentration (MIC). The methanol extracts of the lichens Cetraria pinastri and Parmelia crinita showed the strongest both antibacterial and antifungal activity against most of the tested microorganisms. These researches suggest that the lichens Cetraria prunastri can be used as new sources of the natural antioxidants and the substances with antimicrobial features.     

Synthesis and in vitro evaluation of N-alkyl-7-methoxytacrine hydrochlorides as potential cholinesterase inhibitors in Alzheimer disease

All approved drugs for Alzheimer disease (AD) in clinical practice ameliorate the symptoms of the disease. Among them, acetylcholinesterase inhibitors (AChEIs) are used to increase the cholinergic activity. Among new AChEI, tacrine compounds were found to be more toxic compared to 7-MEOTA (9-amino-7-methoxy-1,2,3,4-tetrahydroacridine). In this Letter, series of 7-MEOTA analogues (N-alkyl-7-methoxytacrine) were synthesized. Their inhibitory ability was evaluated on recombinant human acetylcholinesterase (AChE) and plasmatic human butyrylcholinesterase (BChE). Three novel compounds showed promising results towards hAChE better to THA or 7-MEOTA. Three compounds resulted as potent inhibitors of hBChE. The SAR findings highlighted the C₆–C₇ N-alkyl chains for cholinesterase inhibition.     

Antioxidant and antimicrobial properties of the lichens <Emphasis Type="Italic">Anaptychya ciliaris,Nephroma parile,Ochrolechia tartarea</Emphasis> and <Emphasis Type="Italic">Parmelia centrifuga</Emphasis>

The aim of this study was to characterize the antioxidant and antimicrobial activity of the methanol extracts of: Anaptychya ciliaris, Nephroma parile, Ochrolechia tartarea and Parmelia centrifuga. The methanol extract of the P. centrifuga showed a strong antioxidant activity, in comparison to the extracts from A. ciliaris, O. tartarea and N. parile which were relatively weaker. Furthermore, the methanol extract of the lichen P. centrifuga was shown to contain the highest total phenol content (54.19 mg/g of the dry extract). Interestingly, a statistically significant positive relationship between the antioxidant activity and the total phenol content was observed. The minimum inhibitory concentration (MIC) against six bacterial and eleven fungi was established for the methanol extracts from each of species of lichens. The methanol extracts of the lichens P. centrifuga and O. tartarea showed the strongest both antibacterial and antifungal activity. Taken together, the results from this study suggest that the lichens P. centrifuga and O. tartarea may be used as a natural source of antioxidants in addition to providing certain antimicrobial features.     

The Impact of Fungal Extracts on Leaf Litter on the Food Preference of Gammarus roeselii

We investigated the effect of methanol and methanol/methylene chloride extracts of the oomycete Pythium sp. JN 1‐b and of the fungi Ascomycete sp. PVSo8, Fusarium sporotrichoides, and Cylindrocarpon sp. 94‐2057 on the food preference of Gammarus roeselii. The preference for leaf discs coated with these extracts compared to uncoated leaf discs was tested in food‐choice assays. Methanol extracts of all strains repelled G. roeselii, and the effect of the extract concentration on relative consumption was strain specific. The repellent effect of these extracts, especially of extracts of Cylindrocarpon sp., decreased when the fungi were grown on leaf extract medium as opposed to synthetic medium containing sucrose. None of the methanol/methylene chloride extracts affected the food preference of the gammarid. We conclude that biologically active compounds were extracted from fungi and an oomycete were soluble in methanol but not in methanol/methylene chloride. Only repellent activity was observed with the extracts, and relative ratios of repellents and attractants might determine the consumption of fungi by G. roeselii. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Antibacterial activity of some salt marsh halophytes and mangrove plants against methicillin resistant Staphylococcus aureus

The antibacterial activity of aqueous and methanol extracts of leaves/shoots of five salt marsh halophytes and six mangroves was studied against methicillin resistant, clinical isolates of Staphylococcus aureus. There was a clear comparability between the salt marsh halophytes and mangroves in their antibacterial action. The mangrove plants possessed higher antibacterial potency than the salt marsh halophytes. The highest activity was recorded with the methanol extract of Excoecaria agallocha followed by the methanol extracts of Aegiceras corniculatum, Lumnitzera racemosa and Ceriops decandra. The minimum inhibitory concentration (MIC) values ranged from 0.125 to 4 mg/mL and 1 to 16 mg/mL for methanol and aqueous extracts, respectively. Further separation of active principle from the potent mangrove plant will be useful for the control of drug resistant strains of S. aureus.     

Glassworts as Possible Anticancer Agents Against Human Colorectal Adenocarcinoma Cells with Their Nutritive,Antioxidant and Phytochemical Profiles

In this study, the possible uses of glassworts as potential food ingredients and their antiproliferative activity against colorectal adenocarcinoma cells together with their antioxidant and phytochemical profiles were investigated for the first time. MeOH extracts of five different taxa collected from different localities were screened for their antioxidant capacities by DPPH (IC₅₀ 2.91 – 5.49 mg/ml) and ABTS (24.4 – 38.5 μmol TE/g extract) assays. Salicornia freitagii exhibited the highest DPPH radical scavenging activity. LC/MS/MS analysis displayed that vanillic acid and p‐coumaric acid were two main phenolic compounds in the extract. Salicornia freitagii extracts also exhibited high antiproliferative activity against HT‐29 (IC₅₀ 1.67 mg/ml) and Caco‐2 (IC₅₀ 3.03 mg/ml) cells for 72 h. Mineral analysis indicated that all the species with different proportions of elemental components contained high amount of cations. These results indicate that investigated glassworts, with their high phenolic and mineral contents and also notable antioxidant and cytotoxic properties, may be utilized as a promising source of therapeutics.     

Aldehyde oxidases of Drosophila: Contributions of several enzymes to observed activity patterns

At least four enzymes contribute to histochemically, electrophoretically, or spectrophotometrically detectable aldehyde oxidase (AO) activity in Drosophila melanogaster. The one we designate AO-1 contributes the majority of activity measured in extracts of whole flies. Pyridoxal oxidase (PO) is also a broad range AO. It is prominent only in midgut and Malpighian tubules, where it apparently accounts for a substantial fraction of total AO activity. The tissue distributions of these enzymes are clearly disparate despite close linkage of their structural loci and parallel dependence on the mal, lxd, and cin loci. A similarly related enzyme, xanthine dehydrogenase (XDH), is detected as an AO only in electrophoretic gels. A fourth broad range AO, not dependent on mal, lxd, and cin, is confined to the ejaculatory bulb. A similar array of AO isozymes is present in phylogenetically distant Drosophila species.This work was supported by NIH Grant 2 RO1 HD 10723.     

Effect of fasting on hypogean (<Emphasis Type="Italic">Niphargus stygius</Emphasis>) and epigean (<Emphasis Type="Italic">Gammarus fossarum</Emphasis>) amphipods: a laboratory study

Two amphipods, the hypogean Niphargus stygius and epigean Gammarus fossarum, were analyzed for fatty acid (FA) composition, electron transport system (ETS) activity and respiration (R) during a laboratory fasting experiment. In agreement with ETS and R measurements (and the ETS/R ratio), the hypogean N. stygius utilized FA more slowly than the epigean G. fossarum. Inter-specific differences in the utilization of certain FA during fasting were also revealed. While N. stygius tended to preserve all of its FA during the experimental fasting period, G. fossarum showed a tendency to utilize MUFA (monounsaturated FA) and SAFA (saturated FA) and preferentially retain PUFA (polyunsaturated FA). The significant correlations between ETS activity and composition of specific FA during fasting can be linked to R. During the fasting, both ETS activity and respiration rate of G. fossarum decreased, however, ETS/R ratio increased. In contrast, N. stygius did not show significant changes in these parameters. This is the first report, which connects ETS activity with changes in concentrations of specific FA during fasting. Such evolutionary adaptations of hypogean species enables them to better survive chronically low and/or discontinuous food supplies compared to epigean species, which live in environments where food shortages are much less frequent.     

Amentoflavone Stimulates Mitochondrial Dysfunction and Induces Apoptotic Cell Death in <Emphasis Type="Italic">Candida albicans</Emphasis>

Amentoflavone was isolated from an ethyl acetate extract of the whole plant of Selaginella tamariscina. It is a traditional herb for the therapy of chronic trachitis and exhibits some anti-tumor activity. Previously, we confirmed the antifungal effects of amentoflavone. The objective of this study was to investigate the antifungal mechanism(s) of amentoflavone, such as mitochondria-mediated apoptotic cell death. The cells that were treated with amentoflavone exhibited a series of cellular changes that were consistent with apoptosis: externalization of phosphatidylserine, DNA and nuclear fragmentation, accumulation of intracellular reactive oxygen species (ROS) and hydroxyl radicals, and activation of metacaspase. In addition, diagnostic markers of apoptosis, including the reduction of mitochondrial inner-membrane potential and the release of cytochrome c from mitochondria, were observed. These phenomena are important changes in mitochondria-mediated apoptosis. Furthermore, the effect of thiourea as hydroxyl radical scavenger on amentoflavone-induced apoptosis was evaluated. A hydroxyl radical is a more active ROS species. Mitochondrial dysfunction was inhibited, which was indicated by decreased levels of intracellular hydroxyl radicals. Taken together, our results present the first evidence that amentoflavone induces apoptosis in C. albicans cells and is associated with the mitochondrial dysfunction. Besides, amentoflavone-induced hydroxyl radicals may play a significant role in mitochondria-mediated apoptosis.     

石榴果皮提取物抑菌活性研究

以12种常见的食品污染菌为供试菌,采用平板打孔法对10个品种石榴果皮的9种溶剂提取物进行抑菌效果研究,并对甲醇提取物的化学成分进行了初步分析。结果表明,甲醇提取物抑菌活性最强;石榴果皮提取物对供试菌种中的细菌的抑制效果最强,对革兰氏阳性菌的抑制效果强于对革兰氏阴性细菌的抑制效果,对酵母菌的抑制效果较弱,对霉菌几乎没有抑制作用。在供试的10个石榴品种中,‘峄城软籽’石榴果皮甲醇提取物的抑菌活性最高。化学成分系统预试结果表明,石榴果皮甲醇提取物中含有黄酮及其苷类物质、生物碱、酚类、鞣质类等成分。