Elicitation of Medicinal Plants In Vivo—Is It a Realistic Tool? The Effect of Methyl Jasmonate and Salicylic Acid on Lamiaceae Species

Salicylic acid (SA) and methyl jasmonate (MeJa) are prominent phytohormones that are involved in stress reactions. Both compounds may influence the biosynthesis of secondary compounds; however, scientific experiments in vivo are rare and contradictive. This paper reports on a study on the elicitation of volatiles and total phenolics (TPC) by MeJa and SA. The subjects were four Lamiaceae species studied in open field conditions in Budapest (Hungary). According to the results, both elicitors provoked specific responses in each plant species depending on the dosage applied and the parameter studied; 2 mM of SA stimulated essential oil (EO) accumulation in marjoram and peppermint, while in hyssop 0.1 mM was optimal. MeJa proved to be effective only in marjoram and in basil. In marjoram, cis-sabinene hydrate was decreased and in hyssop, isopinocamphone was increased by both dosages of SA. In peppermint, pulegone content was reduced by 2 mM SA, but no significant change of the major components of basil EO was detected. SA was successful in increasing TPC and antioxidant activity (AC) in three of the experimental species, but not in hyssop. In marjoram, only 0.1 mM induced TPC and eventually AC, while in peppermint and basil both dosages of SA were effective. Optimalisation of the treatments is suggested in further in vivo experiments.

Detection of Senecionine in Dietary Sources by Single-Use Electrochemical Sensor

Pyrrolizidine alkaloids (PAs) are produced by plants as secondary compounds that are the most widely distributed natural toxins. There have been many cases of human toxicity caused by consumption of toxic plant species, as herbal teas and grain or grain products contaminated with PA-containing seeds have been reported. Companies that produce dried spices and tea leaves should examine the PA level in their products. For the first time in the literature, a simple and inexpensive electrochemical assay based on a single-use sensor was introduced for quantitative determination of senecionine (SEN) in the most frequently contaminated food sources. SEN was immobilized on a pencil graphite electrode surface by the passive adsorption technique. Differential pulse voltammetry (DPV) was used to evaluate the oxidation signal of SEN, which was observed to be around +0.95 V. The oxidation signal was specific to the SEN in the sample, and the current value was proportional to its concentration. The selectivity of our assay was also tested in the presence of other similar PAs such as intermedine, lycopsamine, and heliotrine. The detection limit is calculated by developed assay and found to be 5.45 µg/mL, which is an acceptable concentration value of SEN occurring at toxic levels for consumers. As an application of the developed sensor in food products, the electrochemical detection of SEN was successfully performed in flour and herbal tea products.

Homo medicus: The transition to meat eating, increased pathogen pressure, and the constitutive and inducible use of pharmacological plants in Homo

The human lineage entered a more carnivorous niche 2.6 mya. A range of evidence indicates this increased zoonotic pathogen pressure. This evidence includes increased zoonotic infections modern hunter-gatherers and bushmeat hunters relative to others living in the same environments, exceptionally low stomach pH compared to other primates, human-specific downregulation in ANTXR2 that would have protected against increased exposure to zoonotic anthrax, exceptional human immune responses to LPS compared to other primates, and other divergent immune genes. These all point to change, and likely intensification, in the disease environment of Homo compared to earlier hominins and other apes. At the same time, the brain, an organ in which inflammatory immune responses are highly constrained, begins to increase, eventually tripling in size. We propose that the combination of increased zoonotic pathogen pressure and the challenges of defending a large brain and body from pathogens across what would eventually become the longest lifespan of any mammal, selected for intensification of the self-medication strategies already in place in apes and other primates, resulting in a variety of plant-based pathogen defenses. In support, there is evidence of medicinal plant use by hominins in the middle Paleolithic, and all cultures today have sophisticated, plant-based medical systems, incorporate plant components high in secondary compounds (spices) into food, and regularly consume psychoactive substances that are harmful to helminths and other pathogens in the CNS and other tissues. The computational challenges of discovering effective plant-based treatments, and the economic challenges of benefiting from costly-to- acquire medical knowledge that would be more often useful to others than oneself, were selection pressures for increased cognitive abilities and unique exchange relationships in Homo. In the story of human evolution, which has long featured hunters, shamans and healers had an equal role to play.

Phytochemical Analysis and Biological Activity of Three Stachys Species (Lamiaceae) from Romania

Three species of Stachys genus (S. byzantina, S. officinalis, S. sylvatica) were investigated in the present study in terms of aromatic profile and total polyphenol content, as well as antibacterial activity and antioxidant capacity. Gas chromatography coupled with flame ionization detection (GC/FID) was used for exploration of the herbal alcoholic extracts. Using statistical analysis, volatile organic compounds (VOCs) and total phenolic chemical fingerprints were compared in order to describe differences and identify putative signature traits of the three Stachys species. The results showed that the analyzed Stachys extracts have a total polyphenol content being between 197 ± 0.27 mg GAE/g for S. sylvatica and 232 ± 43 mg GAE/g for S. officinalis. The antioxidant activity was between 444 ± 58 mM Trolox/g (S. sylvatica) and 602 ± 75 mM Trolox/g (S. officinalis). The volatile compounds identified were mostly sesquiterpenes, followed by monoterpenes and secondary compounds. The most abundant in all three species was germacrene D (21.9% 28–25.2%). The multivariate analysis demonstrated the potential of using plant tissue VOC profiles to discriminate between different Stachy species, with a total of 31 VOCs being identified from all three species. Although there were strong similarities among the three species’ VOC profiles, distinctions can be made using chemometric analysis. The microbiological results showed an antimicrobial capacity of all three extracts, especially on Gram-positive bacteria. In addition to increasing consumers’ understanding regarding the health benefits of these Stachy species, this investigation contributes to defining and preserving a precious genetic and cultural-historical biodiversity.

Ecdysteroids

Ecdysteroid: member of a class of polyhydroxylated steroids found in invertebrate animals (zooecdysteroids; moulting hormones), plants (phytoecdysteroids) and fungi (mycoecdysteroids). Over 500 structural analogues are currently known. Biosynthetically, they derive from C27-, C28- or C29-sterols. The most frequently encountered analogue (in arthropods and plants) is 20-hydroxyecdysone (2β,3β,14α, 20R,22R,25-hexahydroxycholest-7-en-6-one). In arthropods, ecdysteroids occur universally and regulate development by inducing moulting and reproduction, where their action is mediated by high-affinity binding to an intracellular member of the class of nuclear receptor (NR) proteins (ecdysteroid receptor; EcR) dimerised with a second NR (USP/RxR). This receptor complex binds to specific DNA promoter sites and regulates gene expression. In plants, ecdysteroids are a class of secondary compounds, occurring in varying amounts in certain species, but not all in others. Phytoecdysteroids are believed to contribute to the reduction of invertebrate predation by acting as feeding deterrents or endocrine disruptors. Ecdysteroids also possess a wide range of positive pharmacological effects in mammals, where the mode of action involves moderate-affinity binding to plasma-membrane-bound receptors and not interaction with the classical NRs for vertebrate steroid hormones.

The Modulatory Influence of Plant-Derived Compounds on Human Keratinocyte Function

The plant kingdom is a rich source of secondary metabolites with numerous properties, including the potential to modify keratinocyte biology. Keratinocytes are important epithelial cells that play a protective role against various chemical, physical and biological stimuli, and participate in reactive oxygen scavenging and inflammation and wound healing processes. The epidermal cell response may be modulated by phytochemicals via changes in signal transduction pathways. Plant extracts and single secondary compounds can possess a high antioxidant capacity and may suppress reactive oxygen species release, inhibit pro-apoptotic proteins and apoptosis and activate antioxidant enzymes in keratinocytes. Moreover, selected plant extracts and single compounds also exhibit anti-inflammatory properties and exposure may result in limited production of adhesion molecules, pro-inflammatory cytokines and chemokines in keratinocytes. In addition, plant extracts and single compounds may promote keratinocyte motility and proliferation via the regulation of growth factor production and enhance wound healing. While such plant compounds may modulate keratinocyte functions, further in vitro and in vivo studies are needed on their mechanisms of action, and more specific toxicity and clinical studies are needed to ensure their effectiveness and safety for use on human skin.

Compostos secundàrios de anona na proteçâo de plantas contra pests / Secondary compounds of anona in plant protection against pests

En tiempos remotos las culturas antiguas utilizaron los compuestos secundarios de las plantas para el manejo de las plagas de los cultivos. Actualmente surge la necesidad de rescatar estos conocimientos como una alternativa al uso de plaguicidas sintéticos. Las anonáceas presentan principios activos que causan repelencia, disuasión de la alimentación, disuasión de la oviposición y reguladores de crecimiento en los insectos, esta actividad se debe principalmente a la presencia de las acetogeninas. En este sentido, se aplicaron concentraciones de 0.000001, 0.00001, 0.0001, 0.001, 0.01, 0.1 y 1.0% con cuatro repeticiones de extractos crudos de anona amarilla Annona lutescens extraídos con metanol, etanol, diclorometano y hexano, para determinar su efecto repelente en adultos de mosca Trialeurodes vaporariorum comparados con los testigo químico y absoluto. La unidad de muestreo consistió en introducir 20 adultos en un vaso transparente de 1 L, conteniendo una hoja de tomate tratada con el extracto y dosis respectiva colocado en un frasco gotero de 10 mL con agua de la llave, los datos de moscas posadas se tomaron a las 3, 6, 12, 24, 48 y 72 h y por diferencia se calculó los no posados, obteniendo como resultado que las siete concentraciones de los cuatro extractos crudos de anona causaron de 75.7 a 93.0% de repelencia de los adultos de mosca blanca de las 3 a las 72 h después de la aplicación. Por otro lado, desde el inicio hasta el final de las observaciones los extractos crudos de anona causaron mayor repelencia que el producto químico. Esto hace sugerir el uso del extracto de anona en el manejo de adultos de mosca blanca.

Transcription Factors in Alkaloid Engineering

Plants produce a large variety of low-molecular-weight and specialized secondary compounds. Among them, nitrogen-containing alkaloids are the most biologically active and are often used in the pharmaceutical industry. Although alkaloid chemistry has been intensively investigated, characterization of alkaloid biosynthesis, including biosynthetic enzyme genes and their regulation, especially the transcription factors involved, has been relatively delayed, since only a limited number of plant species produce these specific types of alkaloids in a tissue/cell-specific or developmental-specific manner. Recent advances in molecular biology technologies, such as RNA sequencing, co-expression analysis of transcripts and metabolites, and functional characterization of genes using recombinant technology and cutting-edge technology for metabolite identification, have enabled a more detailed characterization of alkaloid pathways. Thus, transcriptional regulation of alkaloid biosynthesis by transcription factors, such as basic helix–loop–helix (bHLH), APETALA2/ethylene-responsive factor (AP2/ERF), and WRKY, is well elucidated. In addition, jasmonate signaling, an important cue in alkaloid biosynthesis, and its cascade, interaction of transcription factors, and post-transcriptional regulation are also characterized and show cell/tissue-specific or developmental regulation. Furthermore, current sequencing technology provides more information on the genome structure of alkaloid-producing plants with large and complex genomes, for genome-wide characterization. Based on the latest information, we discuss the application of transcription factors in alkaloid engineering.

Epigenomic Insight of Lingonberry: Health Promoting Trait Under Micropropagation

Epigenetic variation plays a role in developmental gene regulation and responses to the environment. An efficient interaction of zeatin induced cytosine methylation and secondary compounds has been displayed for the first time in tissue-culture shoots of lingonberry (Vaccinium vitis-idaea) in vitro, in vivo and its cutting-cultivar Erntedank. Through MSAP assay, we observed highest methylated sites in leaf regenerants (LC1) from all primer combinations (108 bands), with their highest variation in secondary metabolites. We measured that four tissue-culture plants showed higher methylation bands than cutting propagated donor plants (ED) which exhibited 79 bands of methylation, which is comparatively low. On the other hand, we observed the highest total phenolic content in node culture-derived greenhouse grown plants, NC3 but leaf culture-derived greenhouse grown plants, LC1 represented low phenolic content. Our study showed more methylation in micropropagated plants (NC1, NC2, NC3, LC1) than those derived from cutting propagated ED plants, where methylation was not present. On the contrary, we observed higher secondary metabolites in ED plants but comparatively less in micropropagated shoots (NC1, NC2) and plants (NC3, LC1). Our study displayed that higher methylation sites observed in micropropagated plants possessed less amount of secondary metabolites.

Carbohydrates and Secondary Compounds of Alpine Tundra Shrubs in Relation to Experimental Warming

Background: It is critical to understand the sensitivity, response direction and magnitude of carbohydrates and secondary compounds to warming for predicting the structure and function of the tundra ecosystem towards future climate change. Results: Open-top chambers (OTCs) were used to passively increase air and soil temperatures on Changbai Mountain alpine tundra. After seven years’ continuous warming, the vegetation coverage, nonstructural carbohydrates (soluble sugars and starch) and secondary compounds (total phenols, flavonoids and triterpenes) of leaves and roots in three dominant dwarf shrubs, Dryas octopetala var. asiatica, Rhododendron confertissimum and Vaccinium uliginosum, were investigated during the growing season. Warming did not significantly affect the concentrations of carbohydrates but decreased total phenols for the three species. Carbohydrates and secondary compounds showed significantly seasonal pattern and species-specific variation. No significant trade-off between carbohydrates and secondary compounds was observed. Warming significantly increased the coverage of Dr. octopetala var. asiatica, did not change it for V. uliginosum and decreased it for Rh. confertissimum. Rh. confertissimum had significantly lower carbohydrates and higher secondary compounds investment than the other two species. Enhanced dominance and competitiveness of Dr. octopetala var. asiatica was companied by increased trend in carbohydrate concentrations and decreased ratio of secondary compounds to total carbon in the warming OTCs. Conclusions: We, therefore, predict that Dr. octopetala var. asiatica will continue to maintain dominant status, but the competition ability of V. uliginosum could gradually decrease with warming, leading to changes in species composition and community structure of the Changbai tundra ecosystem under future climate warming.