Molecular mechanisms of toxicity of important food-borne phytotoxins

Biomacromolecule-based nanocarrier strategies to deliver plant-derived bioactive components for cancer treatment: A recent review

The quest for safe chemotherapy has attracted researchers to explore anticancer potential of herbal medicines. Owing to upsurging evidence of herbal drug's beneficial effects, hopes are restored for augmenting survival rates in cancer patients. However, phytoconstituents confronted severe limitations in terms of poor absorption, low-stability, and low bioavailability. Along with toxicity issues associated with phytoconstituents, quality control and limited regulatory guidance also hinder the prevalence of herbal medicines for cancer therapy. Attempts are underway to exploit nanocarriers to circumvent the limitations of existing and new herbal drugs, where biological macromolecules (e.g., chitosan, hyaluronic acid, etc.) are established highly effective in fabricating nanocarriers and cancer targeting. Among the discussed nanocarriers, liposomes and micelles possess properties to cargo hydro- and lipophilic herbal constituents with surface modification for targeted delivery. Majorly, PEG, transferrin and folate are utilized for surface modification to improve bioavailability, circulation time and targetability. The dendrimer and carbon nanotubes responded in high-loading efficiency of phytoconstituent; whereas, SLN and nanoemulsions are suited carriers for lipophilic extracts. This review emphasized unveiling the latent potential of herbal drugs along with discussing on extended benefits of nanocarriers-based delivery of phytoconstituents for safe cancer therapy owing to enhanced clinical and preclinical outcomes without compromising safety.

Base Excision DNA Repair in Plants: Arabidopsis and Beyond

Base excision DNA repair (BER) is a key pathway safeguarding the genome of all living organisms from damage caused by both intrinsic and environmental factors. Most present knowledge about BER comes from studies of human cells, E. coli, and yeast. Plants may be under an even heavier DNA damage threat from abiotic stress, reactive oxygen species leaking from the photosynthetic system, and reactive secondary metabolites. In general, BER in plant species is similar to that in humans and model organisms, but several important details are specific to plants. Here, we review the current state of knowledge about BER in plants, with special attention paid to its unique features, such as the existence of active epigenetic demethylation based on the BER machinery, the unexplained diversity of alkylation damage repair enzymes, and the differences in the processing of abasic sites that appear either spontaneously or are generated as BER intermediates. Understanding the biochemistry of plant DNA repair, especially in species other than the Arabidopsis model, is important for future efforts to develop new crop varieties.

Plant Toxic Proteins: Their Biological Activities, Mechanism of Action and Removal Strategies

Plants evolve to synthesize various natural metabolites to protect themselves against threats, such as insects, predators, microorganisms, and environmental conditions (such as temperature, pH, humidity, salt, and drought). Plant-derived toxic proteins are often secondary metabolites generated by plants. These proteins, including ribosome-inactivating proteins, lectins, protease inhibitors, α-amylase inhibitors, canatoxin-like proteins and ureases, arcelins, antimicrobial peptides, and pore-forming toxins, are found in different plant parts, such as the roots, tubers, stems, fruits, buds, and foliage. Several investigations have been conducted to explore the potential applications of these plant proteins by analyzing their toxic effects and modes of action. In biomedical applications, such as crop protection, drug development, cancer therapy, and genetic engineering, toxic plant proteins have been utilized as potentially useful instruments due to their biological activities. However, these noxious metabolites can be detrimental to human health and cause problems when consumed in high amounts. This review focuses on different plant toxic proteins, their biological activities, and their mechanisms of action. Furthermore, possible usage and removal strategies for these proteins are discussed.

Bioassay of oxidative properties and toxic side effects of apple juice

Introduction. Apple juice owes its beneficial properties to various biologically active compounds, e.g. antioxidants. Therefore, food science needs effective methods that would cover all the mechanisms of their effect on human metabolism. However, fruit juice production raises certain safety issues that are associated not only with production risks, but also with some natural components in the raw material. The Allium cepa test seems to be an effective solution to the problem. This plant bioassay has a good correlation tested on mammalian cell cultures. Study objects and methods. Onion roots (A. cepa) were treated with aqueous solutions of juices and sorbic acid to assess their antioxidant profile. The toxic effects on root tissues were described according to biomass growth, malondialdehyde (MDA) concentration, and proliferative and cytogenetic disorders. Results and discussion. The study revealed the optimal conditions for the A. cepa assay of the antioxidant properties of apple juice. The antioxidant activity was at its highest when the juice was diluted with water 1:9 and the onion roots were treated with sorbic acid. The lipid oxidation of the A. cepa roots decreased by 43%. A comparative analysis of three different juice brands showed that the difference in their antioxidant profiles was ≤ 3%. As for toxic side effects, the chromosome aberrations increased by six times in all samples. Conclusion. The research offers a new in vivo method for determining the antioxidant profile of apple juice. Three juice brands proved to have irreversible cytotoxic and genotoxic effects.

Structure, Spectroscopic Investigation, Molecular Docking and In vitro Cytotoxicity Studies on 4,7-dihydroxycoumarin: A Breast Cancer Drug

Coumarin derivatives are broadly used as anti-inflammatory, antioxidants, anticancer, and antiviral drugs in recent years. In particular, hydroxy coumarins have great importance because of their various biological and pharmacological purposes. The quantum chemical studies of 4,7-dihydroxycoumarin (DHC) have been performed using the cc-pVTZ level of basis set. The DHC molecular structure has been optimized and the computed frequency assignments have been correlated well with the experimental results. The experimental [Formula: see text]C NMR shifts of DHC have been compared with the computed [Formula: see text]C NMR in the dimethyl sulfoxide (DMSO) solution using the Gauge-invariant atomic orbital (GIAO) method. The electron delocalization within the DHC is shown by highest occupied molecular orbitals (HOMO)-lowest unoccupied molecular orbitals (LUMO) energy analysis, and the resulting small energy gap value reveal the molecule’s bioactive characteristics. The natural bond orbital (NBO) analysis approves the bioactive property of the DHC molecule. The DHC compound has a cytotoxic impact on the MCF-7 breast cancer cell line, according to in vitro cytotoxicity studies. The docking study approves that the DHC works as a new inhibitor of breast cancer targeted proteins such as epidermal growth factor receptor (EGFR), estrogen receptor (ER), and progesterone receptor (PR). Thus, this work covers the approach for the evolution of new drugs against breast cancer.

Comparative study of the genotoxic activity of Artemisia vulgaris L. and Artemisia alba Turra extracts in vitro

In this study, the genotoxic activity of acetone and aqueous extracts of two species of genus Artemisia (Artemisia vulgaris L. and Artemisia alba Turra), and possible role of their polyphenolic composition in the observed activities were investigated. Polyphenolic contents were evaluated by high-performance liquid chromatography (HPLC-PDA), while the genotoxic activity was tested using cytokinesis block micronucleus (CBMN) assay on human peripheral blood lymphocytes (PBLs) in vitro. HPLC-PDA showed that both A. alba extracts were richer in polyphenolic contents than A. vulgaris extracts. The acetone A. alba extract was the richest of polyphenolic content where we detected six phenolic acids and two flavonoids. CBMN assay showed that aqueous extract of A. vulgaris significantly increased micronucleus (MN) frequency in the PBLs treated with all tested concentrations (10, 50, 100, and 250 µg/mL), while A. alba did not significantly affect the mean MN frequency. Further, both acetone extracts were genotoxic in all tested concentrations, except the lowest tested (10 µg/mL) of A. alba. All tested extracts affected the nuclear division index (NDI) except the aqueous A. alba extract (p < 0.05). Based on our results, we can conclude that both acetone and aqueous A. vulgaris extracts and A. alba acetone extract were genotoxic in PBLs in vitro. A. alba aqueous extract was not genotoxic and cytotoxic in tested concentrations. We suggest that the aqueous extract of A. alba can be used in treatment, which has been confirmed by traditional medicine, but with a high dose of caution and not in high concentrations.

In vitro biochemical characterization and genotoxicity assessment of Sapindus saponaria seed extract

ETHNOPHARMACOLOGICAL RELEVANCE

Sapindus saponaria, also popularly known as soapberry, has been used in folk medicinal values because of its therapeutic properties and several compounds in its composition, which represent a target in potential for drug discovery. However, few data about its potential toxicity has been reported.

AIM OF THE STUDY

Plant proteins can perform essential roles in survival, acting as defense mechanism, as well functioning as important molecular reserves for its natural metabolism. The aim of the current study was to investigate the in vitro toxicity profile of protein extract of S. saponaria and detect protein potentially involved in biological effects such as collagen hydrolysis and inhibition of viral proteases.

MATERIALS AND METHODS

Protein extract of soapberry seeds was investigated for its cytotoxic and genotoxic action using the Ames test. The protein extract was also subjected to a partial purification process of a protease and a protease inhibitor by gel chromatography filtration techniques and the partially isolated proteins were characterized biochemically.

RESULTS

Seed proteins extract of S. saponaria was evaluated until 100 μg/mL concentration, presenting cytotoxicity and mutagenicity in bacterial model mostly when exposed to exogenous metabolic system and causing cytotoxic and genotoxic effects in HepG2 cells. The purification and partial characterization of a serine protease (43 kDa) and a cysteine protease inhibitor (32.8 kDa) from protein extract of S. Saponaria, corroborate the idea of ​​the biological use of the plant as an insecticide and larvicide. Although it shows cytotoxic, mutagenic and genotoxic effects.

CONCLUSION

The overall results of the present study provide supportive data on the potential use of proteins produced in S. saponaria seeds as pharmacological and biotechnological agents that can be further explored for the development of new drugs.

African Herbal Medicines: Adverse Effects and Cytotoxic Potentials with Different Therapeutic Applications

The African continent is naturally endowed with various plant species with nutritional and medicinal benefits. About 80% of the people in developing countries rely on folk medicines to treat different diseases because of indigenous knowledge, availability, and cost-effectiveness. Extensive research studies have been conducted on the medicinal uses of African plants, however, the therapeutic potentials of some of these plants has remained unexploited. Over the years, several studies have revealed that some of these African floras are promising candidates for the development of novel drugs. Despite the plethora of studies on medicinal plant research in Africa, there is still little scientific data supporting the folkloric claims of these plants. Besides, safety in the use of folk medicines has been a major public health concern over the year. Therefore, it has become mandatory that relevant authority should take measures in safeguarding the populace on the use of herbal mixtures. Thus, the present review extracted relevant information from different scientific databases and highlighted some problems associated with folk medicines, adverse effects on reproductive systems, issue about safety due to the toxicity of some plants and their toxicity effects with potential therapeutic benefits are discussed.

Analytical Separation of Carcinogenic and Genotoxic Alkenylbenzenes in Foods and Related Products (2010-2020)

Alkenylbenzenes are potentially toxic (genotoxic and carcinogenic) compounds present in plants such as basil, tarragon, anise star and lemongrass. These plants are found in various edible consumer products, e.g., popularly used to flavour food. Thus, there are concerns about the possible health consequences upon increased exposure to alkenylbenzenes especially due to food intake. It is therefore important to constantly monitor the amounts of alkenylbenzenes in our food chain. A major challenge in the determination of alkenylbenzenes in foods is the complexity of the sample matrices and the typically low amounts of alkenylbenzenes present. This review will therefore discuss the background and importance of analytical separation methods from papers reported from 2010 to 2020 for the determination of alkenylbenzenes in foods and related products. The separation techniques commonly used were gas and liquid chromatography (LC). The sample preparation techniques used in conjunction with the separation techniques were various variants of extraction (solvent extraction, liquid-liquid extraction, liquid-phase microextraction, solid phase extraction) and distillation (steam and hydro-). Detection was by flame ionisation and mass spectrometry (MS) in gas chromatography (GC) while in liquid chromatography was mainly by spectrophotometry.

Amygdalin: Toxicity, Anticancer Activity and Analytical Procedures for Its Determination in Plant Seeds

Amygdalin (d-Mandelonitrile 6-O-β-d-glucosido-β-d-glucoside) is a natural cyanogenic glycoside occurring in the seeds of some edible plants, such as bitter almonds and peaches. It is a medically interesting but controversial compound as it has anticancer activity on one hand and can be toxic via enzymatic degradation and production of hydrogen cyanide on the other hand. Despite numerous contributions on cancer cell lines, the clinical evidence for the anticancer activity of amygdalin is not fully confirmed. Moreover, high dose exposures to amygdalin can produce cyanide toxicity. The aim of this review is to present the current state of knowledge on the sources, toxicity and anticancer properties of amygdalin, and analytical methods for its determination in plant seeds.

A Snapshot on Food Allergies: A Case Study on Edible Flowers

This perspective study addresses the main causes of adverse reactions to foods in humans, by taking into account the main allergic reactions that may occur as a result of food ingestion, as well the main allergens present in food and how their allergenicity change as a result of food preparation. In addition, European legislation on food labeling and novel foods was taken into account. The case study of this perspective is on the potential allergenicity of edible flowers as well as evidence of phytochemistry and toxic compounds and the risk associated with their ingestion. Regarding edible flowers, a key issue to address is if they are safe to consume or not. In the framework of the project “Innovative activities for the development of the cross-border supply chain of the edible flower” (ANTEA), we considered 62 different species and varieties of edible flowers. The results obtained by consulting two databases on allergens, COMPRISE and Allergen Nomenclature, marked two alerts for two species of edible flowers selected in the project. Moreover, based on edible flower consumption, about ten grams per serving, and on their protein content, we can also state that the risk of allergic reactions due to edible flower ingestion is very low.

Toxicity of apple juice and its components in the model plant system

Introduction. In view of the ongoing research into the negative effects of fruit juice on human health, we aimed to study the subchronic toxicity of apple juice, a model mixture based on its components, and ethanol on biomass growth, cellular oxidative enzymes, and chromosomal abnormalities in Allium cepa roots. Study objects and methods. Our objects of study included clarified apple juice and its components such as fructose, glucose, sucrose, D-sorbitol, and malic acid. After treating Allium cepa roots with apple juice and a model mixture in different concentrations, we analyzed their toxic effects on biomass growth, malondialdehyde levels, as well as the nature and frequency of proliferative and cytogenetic disorders in the plant tissues. Results and discussion. The incubation in an aqueous solution of apple juice at a concentration of 1:5 inhibited the growth in root mass by 50% compared to the control (water). The mitotic index of cells decreased with higher concentrations of juice, reaching zero at a 1:5 dilution. The fructose and model solutions in the same concentrations appeared less toxic in relation to cell mitosis and root mass growth. Although malondialdehyde levels increased in the onion roots treated with juice and model solutions, they were twice as low as in the control due to the juice’s antioxidant activity. Adding 1% ethanol to the 1:2 diluted juice abolished the effect of acute toxicity on root growth and reduced malondialdehyde levels by 30%. Conclusion. The study revealed a complex of interdependent biomarkers of apple juice responsible for its subchronic toxicity in Allium cepa roots. These data can be used to create biological response models based on the approaches of systems biology and bioinformatics.

Differentiation between wild and artificial cultivated Stephaniae tetrandrae radix using chromatographic and flow-injection mass spectrometric fingerprints with the aid of principal component analysis

High-performance liquid chromatographic (HPLC) and flow-injection mass spectrometric (FIMS) fingerprinting profiles were used to differentiate between wild and artificial cultivated Stephaniae tetrandrae Radix samples. HPLC and FIMS fingerprints of 15 wild S. tetrandrae Radix samples and 12 artificial cultivated S. tetrandrae Radix samples were obtained and analyzed with the aid of principal component analysis (PCA). PCA of the fingerprints showed that the chemical differences between wild and artificial cultivated S. tetrandrae Radix samples could be differentiated by either HPLC or FIMS fingerprints. The HPLC fingerprints provided more chemical information but required longer analytical time compared with FIMS fingerprints. This study indicated that the wild samples contained higher concentrations of almost all of the major compounds than the cultivated samples. Three characteristic compounds which were responsible for the differences between the samples were tentatively identified with the aid of MS data. Furthermore, these three compounds, tetrandrine (TET), fangchinoline (FAN), and cyclanoline (CYC), were quantified. The HPLC and FIMS fingerprints combined with PCA could be used for quality assessment of wild and artificial cultivated S. tetrandrae Radix samples.

Extracting and Analyzing Pyrrolizidine Alkaloids in Medicinal Plants: A Review

Pyrrolizidine alkaloids (PAs) are distributed in plant families of Asteraceae, Boraginaceae, and Fabaceae and serve in the chemical defense mechanism against herbivores. However, they became a matter of concern due to their toxicity associated with the high risk of intake within herbal preparations, e.g., phytopharmaceutical formulations, medicinal teas, or other plant-derived drug products. In 1992, the German Federal Ministry of Health established the first limits of PA content for fourteen medicinal plants. Because of the toxic effects of PAs, the Federal Institute of Risk Assessment (BfR) established more stringent limits in 2011, whereby a daily intake <0.007 µg/kg body weight was recommended and valid until 2018. A threefold higher limit was then advised by BfR. To address consumer safety, there is the need for more efficient extraction procedures along with robust, selective, and sensitive analytical methods to address these concerns. With the increased prevalence of, e.g., phytopharmaceutical formulations, this timely review comprehensively focuses on the most relevant extraction and analysis strategies for each of those fourteen plant genera. While a variety of extraction procedures has been reported, differences in PA content of up to 1110 ppm (0.11% (w/w)) were obtained dependent on the nature of the solvent and the applied extraction technique. It is evident that the efficient extraction of PAs requires further improvements or at least standardization of the extraction conditions. Comparing the various analytical techniques applied regarding selectivity and sensitivity, LC-MS methods appear most suited. This review shows that both standardized extraction and sensitive determination of PAs is required for achieving appropriate safety levels concerning public health in future.

Detection of Nutmeg Abuse by Gas Chromatography-Mass Spectrometric Screening of Urine

High doses of nutmeg (seeds from Myristica fragrans Houtt.) can be abused as a psychoactive drug due to phenylpropene ingredients. During controlled abstinence, e.g., in forensic psychiatric clinics, nutmeg abuse has to be distinguished from an ingestion of other spices having phenylpropene ingredients (e.g., black pepper or garden lovage) or unintentional low-dose nutmeg intake. The aim of this study was to develop an evaluation model for the estimation of time point and amount of nutmeg abuse and differentiation from ingestion of other spices or low doses of nutmeg based on the gas chromatographic-mass spectrometric (GC-MS) analysis of urine samples. A total of 3 volunteers ingested 1.5 g of freshly ground nutmeg. No symptoms were reported. Urine samples were collected for up to 3 days. In addition, 18 blank samples from volunteers with regular diet and 2 authentic samples from forensic psychiatry patients with supposed nutmeg abuse were analyzed. All samples were analyzed by GC-MS in full scan mode. Metabolites of the nutmeg ingredients safrole, myristicin and elemicin were identified via a library search. For semi-quantitative estimations, the area ratios of the analytes to the internal standard (MDMA-d5) were normalized to the creatinine concentration. Up to 8 different metabolites were detected for at least 18 hours after intake of 1.5 g of nutmeg. In the two authentic samples, the normalized area ratios of those metabolites were 0.5-14 times the maximum reached in the intake study. Two additional metabolites could be detected in authentic samples. Probably due to ingestion of other spices, 5 of the 8 metabolites after intake of 1.5 g of nutmeg were detected in blank urine samples as well. The intake of high doses of nutmeg can be differentiated from the ingestion of other spices or low doses of nutmeg via standard GC-MS analysis of urine and application of the proposed evaluation model.

Application of ion chromatography with pulsed amperometric detection for the determination of trace cyanide in biological samples, including breast milk

Cyanide (CN) is the biomarker of exposure to the components of tobacco smoke, although its presence in biological samples is also due to the consumption of products containing cyanogenic glycosides. In this work, we determine the concentration of the free cyanide in urine, saliva and breast milk matrices, using ion chromatography with pulsed amperometric detection (IC-PAD). IC-PAD is an emerging method, with only few documented applications in urine and saliva, and the presented determination in breast milk is its first published report for any method. The biological samples, which were obtained from women staying in a maternity ward, showed cyanide concentrations spanning 1.82-98.47 μg L^-1. Under the optimized chromatographic conditions, the IC-PAD system exhibited satisfactory repeatability (R < 3%, n = 3) and good linearity in the range of 1-100 μg L^-1. Thus, it proved to be an effective tool for monitoring trace cyanide concentration in a series of human body fluid matrices, including breast milk. This last matrix is especially important due to the possible effect on infant health related to the mothers' smoking habits.

Natural occurrence of genotoxic and carcinogenic alkenylbenzenes in Indonesian jamu and evaluation of consumer risks

The consumer risks of jamu, Indonesian traditional herbal medicines, was assessed focussing on the presence of alkenylbenzene containing botanical ingredients. Twenty-three out of 25 samples contained alkenylbenzenes at levels ranging from 3.8 to 440 μg/kg, with methyleugenol being the most frequently encountered alkenylbenzene. The estimated daily intake (EDI) resulting from jamu consumption was estimated to amount to 0.2-171 μg/kg bw/day for individual alkenylbenzenes, to 0.9-203 μg/kg bw/day when adding up all alkenylbenzenes detected, and to 0.9-551 μg/kg bw/day when expressed in methyleugenol equivalents using interim relative potency (REP) factors. The margin of exposure (MOE) values obtained were generally <10,000 indicating a priority for risk management when assuming daily consumption during a lifetime. Using Haber's rule it was estimated that two weeks consumption of these jamu only once would not raise a concern (MOE >10,000). However, when considering use for two weeks every year during a lifetime, 5 samples still raise a concern. It is concluded that the consumption of alkenylbenzene containing jamu can be of concern especially when consumed on a daily basis for longer periods of time on a regular basis.

Biotransformation and bioactivation reactions - 2016 literature highlights

We are pleased to present a second annual issue highlighting a previous year's literature on biotransformation and bioactivation. Each contributor to this issue worked independently to review the articles published in 2016 and proposed three to four articles, which he or she believed would be of interest to the broader research community. In each synopsis, the contributing author summarized the procedures, analyses and conclusions as described in the original manuscripts. In the commentary sections, our authors offer feedback and highlight aspects of the work that may not be apparent from an initial reading of the article. To be fair, one should still read the original article to gain a more complete understanding of the work conducted. Most of the articles included in this review were published in Drug Metabolism and Disposition or Chemical Research in Toxicology, but attempts were made to seek articles in 25 other journals. Importantly, these articles are not intended to represent a consensus of the best papers of the year, as we did not want to make any arbitrary standards for this purpose, but rather they were chosen by each author for their notable findings and descriptions of novel metabolic pathways or biotransformations. I am pleased that Drs. Rietjens and Dalvie have again contributed to this annual review. We would like to welcome Grover P Miller as an author for this year's issue, and we thank Tom Baillie for his contributions to last year's edition. We have intentionally maintained a balance of authors such that two come from an academic setting and two come from industry. Finally, please drop us a note if you find this review helpful. We would be pleased to hear your opinions of our commentary, and we extend an invitation to anyone who would like to contribute to a future edition of this review. This article is dedicated to Professor Thomas Baillie for his exceptional contributions to the field of drug metabolism.

A Review of Bioinsecticidal Activity of Solanaceae Alkaloids

Only a small percentage of insect species are pests. However, pest species cause significant losses in agricultural and forest crops, and many are vectors of diseases. Currently, many scientists are focused on developing new tools to control insect populations, including secondary plant metabolites, e.g., alkaloids, glycoalkaloids, terpenoids, organic acids and alcohols, which show promise for use in plant protection. These compounds can affect insects at all levels of biological organization, but their action generally disturbs cellular and physiological processes, e.g., by altering redox balance, hormonal regulation, neuronal signalization or reproduction in exposed individuals. Secondary plant metabolites cause toxic effects that can be observed at both lethal and sublethal levels, but the most important effect is repellence. Plants from the Solanaceae family, which contains numerous economically and ecologically important species, produce various substances that affect insects belonging to most orders, particularly herbivorous insects and other pests. Many compounds possess insecticidal properties, but they are also classified as molluscides, acaricides, nematocides, fungicides and bactericides. In this paper, we present data on the sublethal and lethal toxicity caused by pure metabolites and crude extracts obtained from Solanaceae plants. Pure substances as well as water and/or alcohol extracts cause lethal and sublethal effects in insects, which is important from the economical point of view. We discuss the results of our study and their relevance to plant protection and management.

Adverse effects of plant food supplements and botanical preparations: a systematic review with critical evaluation of causality

AIMS

The objective of this review was to collect available data on the following: (i) adverse effects observed in humans from the intake of plant food supplements or botanical preparations; (ii) the misidentification of poisonous plants; and (iii) interactions between plant food supplements/botanicals and conventional drugs or nutrients.

METHODS

PubMed/MEDLINE and Embase were searched from database inception to June 2014, using the terms 'adverse effect/s', 'poisoning/s', 'plant food supplement/s', 'misidentification/s' and 'interaction/s' in combination with the relevant plant name. All papers were critically evaluated according to the World Health Organization Guidelines for causality assessment.

RESULTS

Data were obtained for 66 plants that are common ingredients of plant food supplements; of the 492 papers selected, 402 (81.7%) dealt with adverse effects directly associated with the botanical and 89 (18.1%) concerned interactions with conventional drugs. Only one case was associated with misidentification. Adverse effects were reported for 39 of the 66 botanical substances searched. Of the total references, 86.6% were associated with 14 plants, including Glycine max/soybean (19.3%), Glycyrrhiza glabra/liquorice (12.2%), Camellia sinensis/green tea ( 8.7%) and Ginkgo biloba/gingko (8.5%).

CONCLUSIONS

Considering the length of time examined and the number of plants included in the review, it is remarkable that: (i) the adverse effects due to botanical ingredients were relatively infrequent, if assessed for causality; and (ii) the number of severe clinical reactions was very limited, but some fatal cases have been described. Data presented in this review were assessed for quality in order to make the results maximally useful for clinicians in identifying or excluding deleterious effects of botanicals.

Fumigant Toxicity of Phenylpropanoids Identified in Asarum sieboldii Aerial Parts to Lycoriella ingenua (Diptera: Sciaridae) and Coboldia fuscipes (Diptera: Scatopsidae)

Lycoriella ingenua (Dufour) (Diptera: Sciaridae) and Coboldia fuscipes (Meigen) (Diptera: Scatopsidae) are two of the most economically important insect pests of cultivated mushrooms. The toxicities to the fly larvae of the three phenylpropanoids (methyleugenol, myristicin, and safrole) from aerial parts of Asarum sieboldii Miquel (Aristolochiaceae) were compared with those of the currently available carbamate insecticide benfuracarb. In a contact+fumigant mortality bioassay with L. ingenua and C. fuscipes larvae, methyleugenol (1.46 and 2.33 µg/cm2) was the most toxic compound, followed by safrole (2.03 and 2.59 µg/cm2) and myristicin (3.59 and 4.96 µg/cm2), based on 24-h LC50 values. The phenylpropanoids were less toxic than benfuracarb (LC50, 0.75 and 0.55 µg/cm2). In vapor-phase mortality tests with the larvae, the phenylpropanoids were consistently more toxic in closed versus open containers, indicating that the effect of the compounds was largely a result of vapor action. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on A. sieboldii plant-derived products as potential fumigants for the control of mushroom fly populations in mushroom houses and mushroom compost.

Evaluation of toxic, cytotoxic, mutagenic, and antimutagenic activities of natural and technical cashew nut shell liquids using the Allium cepa and Artemia salina bioassays

The cashew nut releases a substance that is known as cashew nut shell liquid (CNSL). There are both natural (iCNSL) and technical (tCNSL) cashew nut shell liquids. This study used an Artemia salina bioassay to evaluate the toxic effects of iCNSL and tCNSL cashew nut shell liquids. It also evaluated the toxicity, cytotoxicity, and mutagenicity of CNSL and its effects on the damage induced by copper sulfate (CuSO4·5H2O) on the meristems' root of Allium cepa. Effects of the damage induced by CuSO4·5H2O were evaluated before (pre-), during (co-), and after (post-) treatments. The iCNSL contained 94.5% anacardic acid, and the tCNSL contained 91.3% cardanol. The liquids were toxic to A. salina. Toxicity, cytotoxicity, and mutagenicity were observed with iCNSL compared with the negative control. Similarly, iCNSL failed to inhibit the toxicity and cytotoxicity of CuSO4·5H2O. The tCNSL was not toxic, cytotoxic, or mutagenic in any of the concentrations. However, the lowest iCNSL concentrations and all of the tCNSL concentrations had preventive, antimutagenic, and reparative effects on micronuclei and on chromosomal aberrations in the A. cepa. Therefore, protective, modulating, and reparative effects may be observed in the A. cepa, depending on the concentration and type of CNSL used.

The growing use of herbal medicines: issues relating to adverse reactions and challenges in monitoring safety

The use of herbal medicinal products and supplements has increased tremendously over the past three decades with not less than 80% of people worldwide relying on them for some part of primary healthcare. Although therapies involving these agents have shown promising potential with the efficacy of a good number of herbal products clearly established, many of them remain untested and their use are either poorly monitored or not even monitored at all. The consequence of this is an inadequate knowledge of their mode of action, potential adverse reactions, contraindications, and interactions with existing orthodox pharmaceuticals and functional foods to promote both safe and rational use of these agents. Since safety continues to be a major issue with the use of herbal remedies, it becomes imperative, therefore, that relevant regulatory authorities put in place appropriate measures to protect public health by ensuring that all herbal medicines are safe and of suitable quality. This review discusses toxicity-related issues and major safety concerns arising from the use of herbal medicinal products and also highlights some important challenges associated with effective monitoring of their safety.

Vietnamese traditional medicine from a pharmacist's perspective

Traditional medicine plays an important role in the healthcare system of Vietnam. Vietnamese traditional medicine (VTM) is underpinned by the oriental philosophy and theory of healing. VTM is largely influenced by traditional Chinese medicine, but differs to a certain extent. VTM is largely not evidence-based from a clinical perspective but subclinical research data from the past decades support the traditional use of many herbal VTM drugs. For safe use, knowledge of the occurrence of adverse reactions and herb-drug interactions is necessary. The Vietnamese government supports further development of VTM in a scientific way and integration of VTM with Western medicine. This article first gives an overview of the general aspects of VTM (historical perspective, regulatory aspects, comparison with traditional Chinese medicine, philosophical background, the Vietnamese market situation, quality assurance and formulations), and subsequently focuses on its safe and effective use in Vietnamese clinical pharmacy and medical practice.

Brunfelsia australis (Yesterday, Today, and Tomorrow tree) and Solanum poisoning in a dog

A 2.5 yr old female beagle presented for acute abdominal pain and vomiting after consuming limited offerings of green potato skins. Progressive complications associated with suspected ingestion of a higher potency toxin followed within 5 hr. Subsequent investigations revealed a significant ingestion of an Australian shrub commonly called a "Yesterday, Today, and Tomorrow" tree (Brunfelsia australis). The toxic principle for this emerging toxicity is referred to as "strychnine-like" and is potentially lethal with gastrointestinal, central nervous system, and cardiac pathology. This plant is currently being aggressively promoted by United States nurserymen for its dramatic tri-colored blooms and drought resistance.

Structural determinant of chemical reactivity and potential health effects of quinones from natural products

Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization of an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relatively higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ∼1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules.

Herbal medicines: can we do without pharmacologist?

The increase of herbal medicine use led many scientists to contribute to the research in this field. Also a few pharmacologists, after an initial phase of correct criticisms, today recognize the possibility of investigating the scientific value of medicinal products composed essentially of vegetable extracts. However, it is logical to pose the questions: (i) is there a role for the pharmacologist in herbal medicine (or phytotherapy)? (ii) can we do without pharmacologists’? First, two worlds—drug researchers (pharmacologists) and herbal medicines—yesterday appearing in opposition, are today closer and it is not unusual to read scientific works describing herbal extracts in journals traditionally dedicated to the study of synthetic drugs. Second, clinical application of herbal medicines is evaluable through the methods of modern clinical pharmacology. Efficacy and safety of medicinal plants represent naturally the object of interest for the pharmacologist and it is surely this aspect which gives the most important information on herbal medicine use. Many plants have been studied and results published showing, one time good or another poor, efficacy. Safety aspects of some of the most frequently used plants are now well known. For example, today we learn to use hypericum and we do not give it to patients taking other drugs because the interactions of hypericum with them. Contraindications of other plants, often represented by interactions with drugs, are finally known (Ginkgo biloba and drugs acting on blood coagulation). In conclusion, antagonistic behavior of pharmacologists versus herbal medicines is not useful. On the contrary, modern phytotherapy needs the contribution of researchers usually trained to evaluate efficacy and safety of medicinals.

Evolution of detoxifying systems: the role of environment and population history in shaping genetic diversity at human CYP2D6 locus

OBJECTIVE

The transition from food collection to food production (FP) modified the nature of selective pressures, and several studies illustrate that genetic adaptation to new lifestyle has occurred in humans since the agricultural revolution. Here we test the hypothesis that high levels of genetic variation at CYP2D6, a locus coding for a detoxifying enzyme of the cytochrome P450 complex, reflect this change.

METHODS

We compared DNA sequences and predicted the levels of enzyme activity across 10 African, Asian and European populations, six of which currently rely on hunting and gathering (HG) while four on food production (FP).

RESULTS AND CONCLUSION

HG and FP showed similar levels of CYP2D6 diversity, but displayed different substitution patterns at coding DNA sites possibly related to selective differences. Comparison with variation at presumably neutral independent loci confirmed this finding, despite the confounding effects of population history, resulting in higher overall variation in Africans than in Eurasians. The differences between HG and FP populations suggest that new lifestyle and dietary habits acquired in the transition to agriculture affected the variation pattern at CYP2D6, leading to an increase in FP populations of the frequency of alleles that are associated with a slower rate of metabolism. These alleles reached a balanced co-existence with other important and previously selected variants. We suggest that the pronounced substrate-dependent activity of most of these enzymes expanded the spectrum of the metabolic response.

Role of VltAB, an ABC transporter complex, in viologen tolerance in Streptococcus mutans

Streptococcus mutans, a Gram-positive organism, is the primary causative agent in the formation of dental caries in humans. To persist in the oral cavity, S. mutans must be able to tolerate rapid environmental fluctuations and exposure to various toxic chemicals. However, the mechanisms underlying the ability of this cariogenic pathogen to survive and proliferate under harsh environmental conditions remain largely unknown. Here, we wanted to understand the mechanisms by which S. mutans withstands exposure to methyl viologen (MV), a quaternary ammonium compound (QAC) that generates superoxide radicals in the cell. To elucidate the essential genes for MV tolerance, screening of ∼3,500 mutants generated by ISS1 mutagenesis, revealed 15 MV-sensitive mutants. Among them, five and four independent insertions had occurred in SMU.905 and SMU.906 genes, respectively. These two genes are appeared to be organized in an operon and encode a putative ABC transporter complex; we designated the genes as vltA and vltB, for viologen transporter. To verify our results, vltA was deleted by using an antibiotic resistance marker; the mutant was just as sensitive to MV as the ISS1 insertion mutants. Furthermore, vltA and vltB mutants were also sensitive to other viologen compounds such as benzyl and ethyl viologens. Complementation assays were also carried out to confirm the role of VltA and VltB in viologen tolerance. Sensitivity to various drugs, including a wide range of QACs, was evaluated. It appears that a functional VltA is also required for full resistance toward acriflavin, ethidium bromide, and safranin; all are well-known QACs. These results indicate that VltA/B constitute a heterodimeric multidrug efflux pump of the ABC family. BLAST-P analysis suggests that homologs of VltA/B are widely present in streptococci, enterococci, and other important Gram-positive pathogens.

Comparative Nephrotoxicity of Aristolochic Acid and Tetrandrine In Vitro and In Vivo

Aristolochic acid (AA) and tetrandrine (TET) are the major bioactive components in Chinese herbs used for weight loss. The nephropathy caused by the 2 Chinese herbs has not been simultaneously investigated. The aim of this study was to examine the potential nephrotoxicity of AA and TET using Madin-Darby canine kidney (MDCK) cells and mice. The results showed that TET was more potent than AA in inhibiting MDCK cell growth via inducing apoptosis, as determined by annexin-V staining, 4’, 6’-diamino-2-phenylindole (DAPI) staining, DNA fragmentation, and caspase 3 activity. Mice treated with AA (10 mg/kg) by intraperitoneal administration for 3 months showed nephrotoxicity, elevated blood urea nitrogen, and increased renal tubular injuries. In contrast, mice treated with 50 mg/kg of TET in the same time period had moderate hydropic degeneration of the distal tubules in the kidneys. These results suggest that TET is more cytotoxic than AA in MDCK cells but shows less nephrotoxic than AA in mice.

Biological reactive intermediates (BRIs) formed from botanical dietary supplements

The use of botanical dietary supplements is increasingly popular, due to their natural origin and the perceived assumption that they are safer than prescription drugs. While most botanical dietary supplements can be considered safe, a few contain compounds, which can be converted to biological reactive intermediates (BRIs) causing toxicity. For example, sassafras oil contains safrole, which can be converted to a reactive carbocation forming genotoxic DNA adducts. Alternatively, some botanical dietary supplements contain stable BRIs such as simple Michael acceptors that react with chemosensor proteins such as Keap1 resulting in induction of protective detoxification enzymes. Examples include curcumin from turmeric, xanthohumol from hops, and Z-ligustilide from dang gui. Quinones (sassafras, kava, black cohosh), quinone methides (sassafras), and epoxides (pennyroyal oil) represent BRIs of intermediate reactivity, which could generate both genotoxic and/or chemopreventive effects. The biological targets of BRIs formed from botanical dietary supplements and their resulting toxic and/or chemopreventive effects are closely linked to the reactivity of BRIs as well as dose and time of exposure.

In-vitro mutagenic potential and effect on permeability of co-administered drugs across Caco-2 cell monolayers of Rubus idaeus and its fortified fractions

This study investigated the mutagenic, anti-mutagenic and cytotoxic effects of acetone extract of raspberry, Rubus idaeus L. (v. Ottawa) Rosaceae, and the isolated and characterized ellagitannin and anthocyanin fractions thereof, suitable for food applications. The studied raspberry extract and fractions did not show any mutagenic effects determined in the miniaturized Ames test and were not cytotoxic to Caco-2 cells at the used concentrations. However, the anti-mutagenic properties were changed (i.e. decreased mutagenicity of 2-nitrofluorene in strain TA98, and slightly increased mutagenicity of 2-aminoanthracene in strain TA100) with metabolic activation. Further, their influence on the permeability of co-administered common drugs (ketoprofen, paracetamol, metoprolol and verapamil) across Caco-2 monolayers was evaluated. The apical-to-basolateral permeability of highly permeable verapamil was mostly affected (decreased) during co-administration of the raspberry extract or the ellagitannin fraction. Ketoprofen permeability was decreased by the ellagitannin fraction. Consumption of food rich in phytochemicals, as demonstrated here with chemically characterized raspberry extract and fractions, with well-absorbing drugs would seem to affect the permeability of some of these drugs depending on the components. Thus their effects on the absorption of drugs in-vivo cannot be excluded.

Cytological and biochemical effects of St. John's Wort supplement (a complex mixture of St. John's Wort, Rosemary and Spirulina) on somatic and germ cells of Swiss Albino mice

Commercially available St. John’s wort supplement (SJWS) composed of an herbal mixture of St. John’s Wort (SJW), Rosemary (RM) and Spirulina (SP) is used as a dietary supplement for the treatment of psychiatric disorders. Although the minor ingredients, (RM and SP) are proven antioxidants, their quantity is quite insignificant as compared to the SJW, which is the major ingredient. Most of the toxic effects of SJWS are attributed to the main constituents of SJW which differ due to the influence of light (hypericin) and variations in temperature above freezing point (hyperforin). However, there are no reports on toxicity of SJWS maintained at room temperature in pharmacies and supermarkets. In view of the folkloric importance, immense (prescribed or unprescribed) use and a paucity of literature on SJWS, it was found worthwhile to (1) determine the genotoxic effects of SJWS in somatic and germ cells of mice and (2) investigate the role of biochemical changes, as a possible mechanism. The protocol included the oral treatment of mice with different doses (380, 760 and 1520 mg/kg/day) of SJWS for 7 days. The following experiments were conducted: (i) cytological studies on micronucleus test, (ii) cytogenetic analysis for meiotic chromosomes, (iii) cytological analysis of spermatozoa abnormalities, (iv) quantification of proteins and nucleic acids in hepatic and testicular cells and (v) estimation of malondialdehyde (MDA) and nonprotein sulfhydryl (NP-SH) in hepatic and testicular cells. The treatment increased the frequency of micronuclei in polychromatic erythrocytes (PCE) in the femora. It caused aberrations in chromosomes of testes and induced spermatozoa abnormalities. These changes might be attributed to the epigenetic mechanisms as revealed by an increase in concentrations of MDA and depletion of nucleic acids and NP-SH levels in both hepatic and testicular cells observed in the present study. Since, the samples of SJWS used were not drawn from extremities of light and temperature; the observed effect might not be related to the main constituents of SJW. However, these changes might be ascribed to the combined effect of terpenes, tannins, quercetin and flavonoids present in SJW.

Toxicity of kava kava

Kava is a traditional beverage of various Pacific Basin countries. Kava has been introduced into the mainstream U.S. market principally as an anti-anxiety preparation. The effects of the long-term consumption of kava have not been documented adequately. Preliminary studies suggest possible serious organ system effects. The potential carcinogenicity of kava and its principal constituents are unknown. As such, kava extract was nominated for the chronic tumorigenicity bioassay conducted by the National Toxicology Program (NTP). At present toxicological evaluation of kava extract is being conducted by the NTP. The present review focuses on the recent findings on kava toxicity and the mechanisms by which kava induces hepatotoxicity.

Enforcement of the ban on aristolochic acids in Chinese traditional herbal preparations on the Dutch market

In traditional Chinese medicine several Aristolochia species are used. Aristolochia spp. contain a mixture of aristolochic acids (AAs), mainly AA I and AA II which are nephrotoxicants and carcinogens. After AA-related nephropathy (AAN) and urothelial cancer were described in female patients in Belgium following intake of AA-contaminated herbal preparations, herbs with AAs were prohibited worldwide. Confusing nomenclature can cause AA contamination of certain Chinese traditional herbal preparations (THPs). Here we report the results of investigations by the Dutch Food and Consumer Product Safety Authority (VWA) into the presence of AAs in THPs sampled on the Dutch market using a liquid-chromatography--mass spectrometry method. Between 2002 and 2006 we sampled 190 Chinese THPs using recent information on Chinese THPs potentially containing AAs. AA I was found in 25 samples up to a concentration of 1,676 mg/kg. AA II was also found in 13 of these samples up to 444 mg/kg. All 25 positive samples including Mu Tong, Fang Ji, Tian Xian Teng and Xi Xin were part of a group of 68 THPs identified as possibly containing AAs. In a worst-case scenario, use of a sample of Mu Tong with the highest AA content over a 7-day period would result in the same intake levels of AAs which significantly raised the cancer risk in the Belgian AAN cases. Our results show that contaminated THPs still can be found on the market following worldwide publicity. Therefore, it can be concluded that testing of possibly AA-contaminated THPs is still essential.