Cognitive Enhancement and Neuroprotective Abilities of Plants

Extensive research suggests that a number of plant-derived chemicals and traditional Oriental herbal remedies possess cognition-enhancing properties. Widely used current treatments for dementia include extracts of Ginkgo biloba and several alkaloidal, and therefore toxic, plant-derived cholinergic agents. Several non-toxic, European herbal species have pan-cultural traditions as treatments for cognitive deficits, including those associated with aging. Acute administration has also been found to reliably improve mnemonic performance in healthy young and elderly cohorts, whilst a chronic regime has been shown to attenuate cognitive declines in sufferers from Alzheimer's disease. The present chapter looks at the ethnobotanical and pharmacological importance of various plants cognitive enhancing and other neuroprotective abilities.

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.

Sempervirine Inhibits Proliferation and Promotes Apoptosis by Regulating Wnt/β-Catenin Pathway in Human Hepatocellular Carcinoma

Gelsemium elegans (G. elegans) Benth., recognized as a toxic plant, has been used as traditional Chinese medicine for the treatment of neuropathic pain and cancer for many years. In the present study, we aim to obtain the anti-tumor effects of alkaloids of G. elegans and their active components in hepatocellular carcinoma (HCC) and the potential mechanism was also further investigated. We demonstrated that sempervirine induced HCC cells apoptosis and the apoptosis was associated with cell cycle arrest during the G1 phase, up-regulation of p53 and down-regulation of cyclin D1, cyclin B1 and CDK2. Furthermore, sempervirine inhibited HCC tumor growth and enhances the anti-tumor effect of sorafenib in vivo. In addition, inactivation of Wnt/β-catenin pathway was found to be involved in sempervirine-induced HCC proliferation. The present study demonstrated that alkaloids of G. elegans were a valuable source of active compounds with anti-tumor activity. Our findings justified that the active compound sempervirine inhibited proliferation and induced apoptosis in HCC by regulating Wnt/β-catenin pathway.

Impact of Shodhana on Semecarpus anacardium Nuts

Semecarpus anacardium is classified in Ayurveda under the category of toxic plants. However, this toxic plant is reported to possess anti-inflammatory activity, anti-arthritic effect, antioxidant activity, antimicrobial activity, anti- carcinogenic activity, hypoglycemic activity, cardioprotective, hepatoprotective, neuroprotective, and hypolipidemic activity etc. All these activities are attributed to its various constituents like phenolic compounds, flavonoids, carbohydrates, alkaloids, steroids, etc. In Ayurveda, a series of pharmaceutical procedures which converts a poisonous drug into a safe and therapeutically effective medicine is termed as Shodhana. Shodhana improves the yield, decreases the phenolic and flavonoid content; and converts toxic urushiol into nontoxic anacardol derivative thereby reducing toxicity of nuts of Semecarpus anacardium. There are reports of alteration in pharmacology and phytochemistry of nuts of Semecarpus anacardium due to Shodhana.

Physiologically based kinetic modelling predicts the in vivo relative potency of riddelliine N-oxide compared to riddelliine in rat to be dose dependent

Pyrrolizidine alkaloids (PAs) are toxic plant constituents occurring often in their N-oxide form. This raises the question on the relative potency (REP) values of PA-N-oxides compared to the corresponding parent PAs. The present study aims to quantify the in vivo REP value of riddelliine N-oxide compared to riddelliine using physiologically based kinetic (PBK) modelling, taking into account that the toxicity of riddelliine N-oxide depends on its conversion to riddelliine by intestinal microbiota and in the liver. The models predicted a lower Cmax and higher Tmax for the blood concentration of riddelliine upon oral administration of riddelliine N-oxide compared to the Cmax and Tmax predicted for an equimolar oral dose of riddelliine. Comparison of the area under the riddelliine concentration–time curve (AUCRID) obtained upon dosing either the N-oxide or riddelliine itself revealed a ratio of 0.67, which reflects the in vivo REP for riddelliine N-oxide compared to riddelliine, and appeared to closely match the REP value derived from available in vivo data. The models also predicted that the REP value will decrease with increasing dose level, because of saturation of riddelliine N-oxide reduction by the intestinal microbiota and of riddelliine clearance by the liver. It is concluded that PBK modeling provides a way to define in vivo REP values of PA-N-oxides as compared to their parent PAs, without a need for animal experiments.

Plasmodium metabolite HMBPP stimulates feeding of main mosquito vectors on blood and artificial toxic sources

Recent data show that parasites manipulate the physiology of mosquitoes and human hosts to increase the probability of transmission. Here, we investigate phagostimulant activity of Plasmodium-metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), in the primary vectors of multiple human diseases, Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Aedes aegypti, and Culex pipiens/Culex torrentium complex species. The addition of 10 µM HMBPP to blood meals significantly increased feeding in all the species investigated. Moreover, HMBPP also exhibited a phagostimulant property in plant-based-artificial-feeding-solution made of beetroot juice adjusted to neutral pH similar to that of blood. The addition of AlbuMAXTM as a lipid/protein source significantly improved the feeding rate of An. gambiae s.l. females providing optimised plant-based-artificial-feeding-solution for delivery toxins to control vector populations. Among natural and synthetic toxins tested, only fipronil sulfone did not reduce feeding. Overall, the toxic-plant-based-artificial-feeding-solution showed potential as an effector in environmentally friendly vector-control strategies.

Management of the soil-borne fungal pathogen – Verticillium dahliae Kleb. causing vascular wilt diseases

Vascular wilt diseases caused by Verticillium dahliae Kleb. are difficult to control and lead to increasing losses of many crops worldwide. It can cause disease on not only horticultural crops but also many economically important crops such vegetables, legumes, forest trees, woody and herbaceous plants. Reasons of this situation are various: (i) the specialization of crop production resulted in the accumulation of the pathogen in the soil, especially monoculture production; (ii) the lack of an efficient and safe soil fumigation method; (iii) the production in large amounts of survival structures—microslerotia and melanized hyphae that are resistant to chemical and biological degradation.Due to the lack of effective synthetic agents for eradication of V. dahliae from soil, considerable interest in this paper has been focused on biological control, especially the selection of microorganisms with mycoparasitic activity towards V. dahliae microsclerotia, that can decrease their number in soil. The main attention is paid on the Trichoderma fungi, non pathogenic Fusarium spp., Talaromyces flavus and bacteria Bacillus spp., Pseudomonas spp. and Streptomyces spp. that are discussed in this review. In this work the suppressive effect of organic amendments against this soil-borne pathogen is also mentioned. In addition biofumigation using toxic plant materials, which is an approach to the soil-borne pathogen management could be an effective method to control diseases caused by V. dahliae.

In Vitro Metabolism of Humantenine in Liver Microsomes from Human, Pig, Goat and Rat

Background: Gelsemium elegans Benth（G. elegans） is a well-known toxic plant. Alkaloids are main active components of G. elegans. Currently, the metabolism of several alkaloids, such as gelsenicine, koumine, and gelsemine, has been widely studied. However, as one of the most important alkaloids in G. elegans, the metabolism of humantenine has not been studied yet. Methods: In order to elaborate on the in vitro metabolism of humantenine, a comparative analysis of its metabolic profile in human, pig, goat and rat liver microsomes was carried out using high-performance chromatography/quadrupole time-of-flight mass spectrometry (HPLC/QqTOF-MS) for the first time. Results: Totally, ten metabolites of humantenine were identified in liver microsomes from human (HLMs), pig (PLMs), goat (GLMs) and rat (RLMs) based on the accurate MS/MS spectra. Five metabolic pathways of humantenine, including demethylation, dehydrogenation, oxidation, dehydrogenation and oxidation, and demethylation and oxidation, were proposed in this study. There were qualitative and quantitative species differences in the metabolism of humantenine among the four species. Conclusions: The in vitro metabolism of humantenine in HLMs, PLMs, GLMs and RLMs was studied by a sensitive and specific detection method based on HPLC/QqTOF-MS. The results indicated that there were species-related differences in the metabolism of humantenine. This work might be of great significance for the further research and explanation of species differences in terms of toxicological effects of G. elegans.

Spontaneous outbreak of Pascalia glauca poisoning in sheep in Argentina

Pascalia glauca is a native weed and one of the most common hepatotoxic plant affecting cattle in Argentina. Although experimental P. glauca poisoning have been reported in sheep, no spontaneous cases have been reported in this species. This work describes an outbreak of intoxication after spontaneous consumption of P. glauca, affecting 20% (6/30) sheep of a commercial flock. Affected sheep were ataxic, depressive, with mucous nasal discharge, cough and abdominal breathing. During post mortem examination, liver was swollen and a diffuse enhancement of the reticular pattern (“nutmeg liver”) was visible. Histopathological examination reveals severe and extensive acute diffuse centrilobular hepatic necrosis with hemorrhage. The presence of the toxic plant, the clinical and pathological findings allows us to confirm the etiology of this outbreak.

A REVIEW ON TOXICITY OF GUNJA (ABRUS PRECATORIUS)

Gunja (Abrus precatorius Linn.) is a toxic plant which is described in various Samhita and other Ayurvedic texts. In Sushruta Samhita Vishaja dravyas are classified into Sthavara, Jangama and Kritima Visha. Gunja is mentioned in Sthavara Visha. In Sthavara Visha it is mentioned under Moolaja Adhisthan, which is one of the ten Adhisthan of Sthavara Visha. According to Rasa Tarangani Sthavara Visha are further divided into Mahavisha and Upavisha. Gunja is mentioned in Upavisha which is less potent toxic than Mahavisha. All parts of the plant are toxic, but the most toxic part is the seed which contains the active principle abrin. According to the modern concept, it is an irritant organic poison. In the Ayurvedic concept, if toxic plants are used after Shodhana process, they are useful in various types of diseases. The main aim of this study is to collect all the information related to Gunja and its toxicity. Keywords: Gunja, Visha, Toxicity, Abrin, Shodhana