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Medicinal plants in tropical medicine. 1. Medicinal plants against protozoal diseases.

The active principles obtained from some of the traditional medicinal plants which are used worldwide for the treatment of protozoal diseases are reviewed. Among the active molecules considered from recent literature are bisbenzylisoquinoline, protoberberine and indole alkaloids, sesquiterpenes, quassinoids and limonoids. This review indicates that there are many antiprotozoal natural products already known which require further scientific investigation. There is a strong possibility that other antiprotozoal compounds with novel chemical structures and potentially novel modes of action will be discovered in plants.

Humans↗

PubMed1982

Electro-blot radioimmunoassay of virus-infected plant sap - a powerful new technique for detecting plant viruses.

A new technique for detecting viruses in plant sap is described. It consists of sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the infected plant sap, electrophoretic transfer of protein bands to activated paper by the Electro-Blot technique, the subsequent probing of the viral coat protein band by specific antiserum (prepared against intact virus), and detection of immune complex with 125 I-labelled protein A. The technique successfully detected tobacco mosaic virus at a sap dilution of 1 : 10,000, four strains of sugarcane mosaic virus (a potyvirus) in their perennial hosts infected for about 4 years, and five different isolated of potato leaf roll virus (a luteovirus). The latter virus occurs in extremely low concentration and is difficult to detect by the other known methods.

Electrophoresis, Polyacrylamide Gel↗

PubMed1992

The mannose-specific plant lectins from Cymbidium hybrid and Epipactis helleborine and the (N-acetylglucosamine)n-specific plant lectin from Urtica dioica are potent and selective inhibitors of human immunodeficiency virus and cytomegalovirus replication in vitro.

A series of four mannose(Man)-, three N-acetylglucosamine (GlcNAc)n-, ten N-acetylgalactosamine/galactose(GalNAc/Gal)-, one 5-acetylneuraminic acid (alpha-2,3-Gal/GalNAc)- and one 5-acetylneuroaminic acid(alpha-2,6-Gal/Gal-NAc)-specific plant agglutinins were evaluated for their antiviral activity in vitro. the mannose-specific lectins from the orchid species Cymbidium hybrid (CA), Epipactis helleborine (EHA) and Listera ovata (LOA) were highly inhibitory to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in MT-4, and showed a marked anti-human cytomegalovirus (CMV), respiratory syncytial virus (RSV) and influenza A virus activity in HEL, HeLa and MDCK cells, respectively. The 50% effective concentration (EC50) of CA and EHA for HIV ranged from 0.04 to 0.08 micrograms/ml, that is about 3 orders of magnitude below their toxicity threshold (50% inhibitory concentration for MT-4 cell growth: 54 to 60 micrograms/ml). Also, the (GlcNAc)n-specific lectin from Urtica dioica (UDA) was inhibitory to HIV-1-, HIV-2-, CMV-, RSV- and influenza A virus-induced cytopathicity at an EC50 ranging from 0.3 to 9 micrograms/ml. The GalNAc/Gal-, alpha-2,3-Gal/GalNAc- or alpha-2,6-Gal/GalNAc-specific lectins were not inhibitory to HIV or CMV at non-toxic concentrations. CA, EHA and UDA proved to be potent inhibitors of syncytium formation between persistently HIV-1- and HIV-2-infected HUT-78 cells and CD4+ Molt/4 (clone 8) cells (EC50: 0.2-2 micrograms/ml). Unlike dextran sulfate, the plant lectins CA, EHA and UDA did not interfere with HIV-1 adsorption to MT-4 cells and RSV- and influenza A virus adsorption to HeLa and MDCK cells, respectively. They presumably interact at the level of virion fusion with the target cell.

Acetylglucosamine↗

PubMed1993

Plants used in Guatemala for the treatment of gastrointestinal disorders. 3. Confirmation of activity against enterobacteria of 16 plants.

Ethnobotanical surveys and literature review identified 408 plants used in Guatemala for the treatment of gastrointestinal disorders. The screening of 84 showed that 34 inhibit one or more enterobacteria; 16 of these were selected for further investigation. Extracts were obtained with three solvents of different polarity (n-hexane, acetone and alcohol) and the in vitro activity was demonstrated against enteropathogenic Escherichia coli, Salmonella enteritidis and Shigella flexneri. The activity of nine ethanolic extracts against enterobacteria, particularly Acalypha guatemalensis, Diphysa robinioides, Lippia dulcis, Psidium guajava and Spondias purpurea was confirmed. The plants with antibacterial activity are discussed.

Diarrhea↗

PubMed2006

Caged gene-inducer spatially and temporally controls gene expression and plant development in transgenic Arabidopsis plant.

Two new types of caged gene-inducers, caged 17beta-estradiol and caged dexamethazone, were synthesized. Caged gene-inducers were applied to transgenic Arabidopsis plants carrying a steroid hormone-inducible transactivation system. Light uncaged caged gene-inducers and controlled spatial and temporal expression of transgene in the transgenic plant. Furthermore, caged gene-inducers enabled the control of root development by light.

Arabidopsis↗

PubMed2005

Characterization of a novel plant growth-promoting bacteria strain Delftia tsuruhatensis HR4 both as a diazotroph and a potential biocontrol agent against various plant pathogens.

A novel, plant growth-promoting bacterium Delftia tsuruhatensis, strain HR4, was isolated from the rhizoplane of rice (Oryza sativa L., cv. Yueguang) in North China. In vitro antagonistic assay showed this strain could suppress the growth of various plant pathogens effectively, especially the three main rice pathogens (Xanthomonas oryzae pv. oryzae, Rhizoctonia solani and Pyricularia oryzae Cavara). Treated with strain HR4 culture, rice blast, rice bacterial blight and rice sheath blight for cv. Yuefu and cv. Nonghu 6 were evidently controlled in the greenhouse. Strain HR4 also showed a high nitrogen-fixing activity in N-free Döbereiner culture medium. The acetylene reduction activity and 15N2-fixing activity (N2FA) were 13.06 C2H4 nmolml(-1) h(-1) and 2.052 15Na.e.%, respectively. The nif gene was located in the chromosome of this strain. Based on phenotypic, physiological, biochemical and phylogenetic studies, strain HR4 could be classified as a member of D. tsuruhatensis. However, comparisons of characteristics with other known species of the genus Delftia suggested that strain HR4 was a novel dizotrophic PGPB strain.

Antibiosis↗

PubMed2002

Concentration of caesium-137, cobalt-60 and potassium-40 in some wild and edible plants around the nuclear power plant in Bulgaria.

The activities of 137Cs, 60Co and 40K were determined in samples of wild (Taraxacum officinale, Plantago lanceolata and Populus nigra 'Italica') and edible (vegetable, corn, fruit) plants as well as soil collected from the 30 km safety zone of the Bulgarian NPP "Kozloduy" and comparisons with earlier measurements and analyses of samples from other regions and with literature values were performed. The derived transfer factors for 137Cs and 40K from soil to plants ranged between 0.002 and 0.009 for 137Cs, and between 0.09 and 0.35 for 40K. The individual effective dose (calculated from the present results and data on the activity of other foodstuffs and from information about dietary habits) comprises 4.5% of the annual dose limit.

Bulgaria↗

PubMed1998

Plants used in Guatemala for the treatment of protozoal infections: II. Activity of extracts and fractions of five Guatemalan plants against Trypanosoma cruzi.

The activities of crude plant extracts of five plants popularly used in Guatemala against bacterial and protozoal infections and some of their fractions have been evaluated against the trypomastigote and epimastigote forms of Trypanosoma cruzi in vitro. The most active fraction of Neurolaena lobata has also been screened in vivo. Main in vitro activities against trypomastigotes have been observed for the hexane and ethanol extracts of N. lobata (Asteraceae). Both extracts were also active against epimastigotes, whereas all other extracts tested had no effect on epimastigotes. For the hexane extracts of Petiveria alliacea (Phytolaccaceae) and Tridax procumbens (Asteraceae) a marked inhibition of trypomastigotes has been found. Also the ethanol extracts of Byrsonima crassifolia (Malpighiaceae) leafs and Gliricidia sepium (Papilionaceae) bark showed some trypanocidal activity. Fraction 2 of the ethanol extract of N. lobata was highly active against T. cruzi as well in vitro as in vivo. The chloroforme fraction of P. alliacea showed a high inhibition of trypomastigotes in vitro. Also three fractions of the active extract of B. crassifolia inhibited T. cruzi trypomastigotes. No fraction of G. sepium bark extract showed a marked trypanocidal activity.

Animals↗

PubMed1998

Plants used in Guatemala for the treatment of protozoal infections. I. Screening of activity to bacteria, fungi and American trypanosomes of 13 native plants.

Extracts were prepared from 13 native plants used for the treatment of protozoal infections. Activity against bacteria and fungi was demonstrated by dilution procedures; Trypanosoma cruzi was evaluated in vitro against epimastigote and trypomastigotes and in vivo against trypomastigotes. In active extracts, toxicity was evaluated by Artemia salina nauplii, oral acute toxicity (1-5 g/kg) and oral and intraperitoneal subacute toxicity in mice (500 mg/kg). From the plants screened, six showed activity (< or = 2 mg/ml) against bacteria, three against yeasts, five against Microsporum gypseum and five against T. cruzi in vitro and/or in vivo. In vitro and in vivo activity was demonstrated by Neurolaena lobata and Solanum americanum; in vitro or in vivo activity was shown by Acalypha guatemalensis, Petiveria alliacea and Tridax procumbens. Toxicity studies showed that extracts from S. americanum are toxic to A. salina (aqueous, 160 ppm). None showed acute or oral toxicity to mice; S. americanum showed intraperitoneal subacute toxicity.

Animals↗

PubMed1999

Evaluation of the antioxidant activity of environmental plants: activity of the leaf extracts from seashore plants.

The antioxidant activity of the methanolic extracts of the leaves of 39 plant species was examined. These leaves were collected from the plants growing on subtropical seashores. The activity was evaluated by three kinds of assay methods, which included the DPPH radical scavenging assay, linoleic acid oxidation assay, and oxidative cell death assay. Two extracts from Excoecaria agallocha and Terminalia catappa showed remarkably potent activity in all assay systems. The HPLC analysis of the extracts indicated the presence of the same antioxidant and isolation work for the compound identified ellagic acid. The isolated ellagic acid showed strong antioxidant activity in the assay systems used.

Antioxidants↗

PubMed1998

A plant transformation vector with a minimal T-DNA II. Irregular integration patterns of the T-DNA in the plant genome.

A minimal T-DNA binary vector was used for Agrobacterium-mediated transfer of a chimeric T4 lysozyme gene located next to the left border, and transgenic potato plants which expressed T4 lysozyme protein were identified and further analysed. Frequent rearrangements of T4 lysozyme transgenes were detected. A vector derivative containing two matrix associated regions (MARs) flanking its multiple cloning site was constructed. In transgenic potato plants, reduced variability in gene expression due to position effects was detected. When either the donor vector contained MAR sequences, or when vector pPCV701 which contains a pBR322 fragment next to the left border were used, only relatively few rearrangements were observed. However, when the T4 lysozyme gene was driven by a CaMV 35S promoter modified by multiplied enhancer region carrying either 2 or 4 elements, frequent rearrangements were again obtained.

Blotting, Southern↗

PubMed2003

Interactions between plant RING-H2 and plant-specific NAC (NAM/ATAF1/2/CUC2) proteins: RING-H2 molecular specificity and cellular localization.

Numerous, highly conserved RING-H2 domains are found in the model plant Arabidopsis thaliana (thale cress). To characterize potential RING-H2 protein interactions, the small RING-H2 protein RHA2a was used as bait in a yeast two-hybrid screen. RHA2a interacted with one of the plant-specific NAC [NAM ('no apical meristem'), ATAF1/2, CUC2 ('cup-shaped cotyledons 2')] transcription factors, here named ANAC (abscisic acid-responsive NAC). The core RING-H2 domain was sufficient for the interaction. The ability of 11 structurally diverse RING-H2 domains to interact with ANAC was then examined. Robust interaction was detected for three of the domains, suggesting multi-specificity for the interaction. The domains that interacted with ANAC contain a glutamic acid residue in a position corresponding to a proline in many RING-H2 domains. Conversion of this glutamic acid residue into proline in RHA2a decreased its ability to interact with ANAC, most likely by changing the interaction surface. This suggested that a short, divergent region in RING-H2 domains modulate interaction specificity. ANAC contains a degenerate bipartite nuclear localization signal (NLS), while RHG1a, also identified as an ANAC interaction partner, contains a basic NLS. Both signals localized beta-glucuronidase reporter fusions to the nucleus. N-terminally truncated RHA2a also directed nuclear localization, apparently dependent on basic amino acids in the RING-H2 domain. Nuclear co-localization of the RING-H2 proteins and ANAC may enable their interaction in vivo to regulate the activity of the ANAC transcription factor.

Amino Acid Sequence↗

PubMed2004

Replication of plant RNA virus genomes in a cell-free extract of evacuolated plant protoplasts.

The replication of eukaryotic positive-strand RNA virus genomes occurs through a complex process involving multiple viral and host proteins and intracellular membranes. Here we report a cell-free system that reproduces this process in vitro. This system uses a membrane-containing extract of uninfected plant protoplasts from which the vacuoles had been removed by Percoll gradient centrifugation. We demonstrate that the system supported translation, negative-strand RNA synthesis, genomic RNA replication, and subgenomic RNA transcription of tomato mosaic virus and two other plant positive-strand RNA viruses. The RNA synthesis, which depended on translation of the genomic RNA, produced virus-related RNA species similar to those that are generated in vivo. This system will aid in the elucidation of the mechanisms of genome replication in these viruses.

Animals↗

PubMed1988

Plant small nuclear RNAs. V. U4 RNA is present in broad bean plants in the form of sequence variants and is base-paired with U6 RNA.

U4 RNA, which is known to play an indispensable role in pre-mRNA splicing, is present in plant nuclei, has a canonical m3 2,2,7 G cap at its 5' end and is associated with U6 RNA in snRNP particles. It occurs in broad bean in the form of a number of sequence variants. Two of these were sequenced: U4A RNA is 154 and U4B RNA is 152 nucleotides long. Sequence similarity of broad bean U4B RNA is 94 per cent to broad bean U4A RNA, 65 per cent to rat U4A RNA, 61 per cent to Drosophila U4A RNA and 50 per cent to snR14, the U4 RNA equivalent of the yeast Saccharomyces cerevisiae. Sequence conservation is much more pronounced in the 5' half of the molecule than in its 3' half. The secondary structure of both variants of broad bean U4 RNA perfectly fits with that of all other U4 RNAs sequenced so far. Nucleotide changes between broad bean U4A and U4B RNAs are restricted to molecular regions that affect the thermodynamic stability of these molecules. A model is proposed for the base pairing interaction of broad bean U4 RNA with broad bean U6 RNA. This is the first report on the structure of a plant U4 RNA.

Animals↗

PubMed1997

Heat generation and dissipation in plants: can the alternative oxidative phosphorylation pathway serve a thermoregulatory role in plant tissues other than specialized organs?

A number of hypothetical physiological roles have been proposed for the cyanide-insensitive alternative pathway in plants (Palmer, 1976; Laties, 1982; Meeuse, 1984; Purvis and Shewfelt, 1994; Wagner and Krab, 1995). The calorimetric observations of Raskin and co-workers (Ordentlich et al., 1991; Nevo et al., 1992; Moynihan et al., 1995) are significant contributions showing an interesting metabolic, chilling-induced response of the alternative pathway activity and differences in the low-temperature response among species adapted to different climates. Since different oxidative pathways do not have large differences in enthalpy, and observed heat rate increases are insufficient to cause significant temperature increases of physiological importance in nonthermogenic plants, other explanations must be developed for the relationship between the partitioning of electron flow and physiological conditions such as low temperature. The induction and engagement of the alternative respiratory pathway is involved in metabolic stasis, maintaining proper balance between carbon flow, ATP-ADP ratio, and electron flow during fluctuating or extreme temperature conditions. The alternative oxidase is engaged when ATP requirements are adequately met, as discussed by Palmer (1976), Meeuse (1983), Lambers (1985), and Wagner and Krab (1995). The expression and kinetic activity of the alternative oxidase are regulated by concentrations of key metabolites (Day and Wiskich, 1995; Siedow and Umbach, 1995; Wagner and Krab, 1995; Day et al., 1996). Dynamic partitioning of electron flow between Cyt oxidase and the alternative oxidase depends on the kinetic behavior of the two oxidases and the substrate dehydrogenases (Day and Wiskich, 1995; Siedow and Umbach, 1995; Wagner and Krab, 1995; Day et al., 1996). Furthermore, Moynihan et al. (1995) found that Episces cupreata Hook, adapted to the tropics, has very little alternative oxidase activity compared with wheat (Nevo et al., 1992), adapted to a large range of temperature climates. This results is consistent with the general relation between the apparent alternative oxidase activity and the climate of origin of the species.

Hot Temperature↗

PubMed1991

Conserved amino acid sequences among plant proteins sorted to protein bodies and plant vacuoles. Can they play a role in protein sorting?

Amino acid sequence comparisons were made between the soybean alpha subunit of beta-conglycinin and 34 members of different plant protein families targeted to seed protein bodies or vacuoles. A number of short conserved amino acid sequences were identified in seed storage proteins, plant protease inhibitors and lectins, and the probable functions of these sequences are discussed. For proteins of known tertiary structure, these sequences map to the surface of the respective molecules. It is postulated that these regions produce a common secondary structure which could interact with other molecules involved in the sorting process. One of these regions, region A, is similar to the yeast carboxypeptidase Y (CPY) vacuolar targeting signal, and is present in both storage proteins and lectins. Computer modeling based upon the tertiary structure of concanavalin A (ConA) was used to generate models representing the structure of two highly related lectins from Dolichos biflorus, one of which is targeted to protein bodies and the other secreted. A different glycosylation pattern together with amino acid sequences upstream of the identified conserved amino acid sequences are predicted to modulate the presentation of the sorting domains in the lectins and be the determinant in the sorting of these lectins.

Amino Acid Sequence↗

PubMed2002

Trypanocidal constituents in plants 1. Evaluation of some Mexican plants for their trypanocidal activity and active constituents in Guaco, roots of Aristolochia taliscana.

Crude extracts of Mexican medicinal plants were screened for trypanocidal activity against Trypanosoma cruzi, which is the etiological agent for Chagas' disease, one of the most serious protozoan diseases in Latin America. There were 43 kinds of methanolic and other organic extracts from 39 plants which were examined by the preliminary screening test to see immobilization of epimastigotes of T. cruzi in vitro. Eighteen of them showed activity at the concentration of 2 mg/ml after incubation for 2 h, while 13 showed activity at the concentration of 1 mg/ml after incubation for 48 h. Among them, the MeOH extract of roots of Aristolochia taliscana (Aristolochiaceae), locally known as "Guaco," immobilized all the epimastigotes even at lower concentration of 0.5 mg/ml (48 h). In order to identify principal compounds for this activity, the MeOH extract of Guaco was subjected to bioassay-guided fractionation. From the active fractions, four neolignans, eupomatenoid-7 (1), licarin A (2), eupomatenoid-1 (5) and licarin B (6), and two lignans, austrobailignan-7 (3) and fragransin E1 (4) were isolated. Compounds 1-4 immobilized all the epimastigotes at the minimum concentration of 25-75 microg/ml after incubation for 48 h, while compounds 5 and 6 were inactive. Corresponding concentration of gossypol, berberine chloride and harmine was 280 microg/ml, 300 microg/ml and >500 microg/ml, respectively.

Animals↗

PubMed2000

Coumarin-related compounds as plant growth inhibitors from two rutaceous plants in Thailand.

Chemical investigation of naturally occurring plant growth inhibitors from Rutaceous plants in Thailand led us to identify five 7-methoxycoumarins and one 5,7-dimethoxycoumarin from Murraya paniculata, and six furanocoumarins from Citrus aurantifolia. Of these compounds, murranganon senecioate (1) is a new natural compound found in M. paniculata. Minumicrolin (6) was found to be highly active against the 2nd leaf sheath elongation of rice seedlings.

Coumarins↗