Toxic pyrrolizidine alkaloids provide a warning sign to overuse of the ethnomedicine Arnebia benthamii

Medicinal plants traditionally used in health care practices by inhabitants of Paddar region of Jammu and Kashmir, India

ETHNOPHARMACOLOGICAL RELEVANCE

The present study is the first quantitative assessment of ethno-medicinal plants of Paddar region of Jammu and Kashmir.

AIM OF THE STUDY

The study aimed to document the relative importance of medicinal plants used in human ailments by the villagers in the Paddar region of Jammu and Kashmir, India.

MATERIAL AND METHODS

Data were collected from 132 informants (72 male and 60 female) through semi structured interviews and group discussions. Use report (UR) and Informant consensus factor (ICF) were employed to quantitatively examine the data.

RESULTS

The inhabitants of Paddar reported the use of 98 plants species of 55 families to treat 63 ailments. Rosaceae (10 spp.) was the most frequently used family in the study area. Herbs were dominantly (66 spp., 50%) utilized in herbal preparation and leaves the mostly used plant parts (25%). The highest informant consensus factor (ICF = 0.96) was obtained for parasitic problems. Important new uses for species stated by informants to treat human diseases were; Viburnum grandiflorum Wall. ex DC., Sium latijugum C.B.Clarke, Corylus jacquemontii Decne., Capsella bursa-pastoris (L.) Medik., Cannabis sativa L., Taraxacum campylodes G.E.Haglund, Euphorbia helioscopia L., Juglans regia L., Cotoneaster acuminatus Lindl., Ficus palmata Forssk., Plantago lanceolata L., and Eleusine coracana (L.) Gaertn.

CONCLUSIONS

The current study contributes towards the preservation of indigenous plants' based knowledge. Although the therapeutic value of most of the preferred medicinal plants has already been validated, some medicinal plants lack proper scientific validation. We recommend further phytochemical investigations and pharmacological validations of Viburnum grandiflorum, C. jacquemontii, F. palmata, Viola pilosa, Cotoneaster acuminatus, Eleucine coracana, Sium latijugum, Aquilegia pubiflora, Euphorbia helioscopia, Plantago lanceolata and Pinus gerardiana.

Regulatory role of oxidative stress in retrorsine - Induced apoptosis and autophagy in primary rat hepatocytes

Pyrrolizidine alkaloids (PAs) are a group of naturally occurring alkaloids widely present in plants. PAs are highly hepatotoxic and have been documented to cause many incidents of human and animal poisoning. Retrorsine (RTS) is a pyrrolizidine alkaloid (PA) derived from the Compositae Senecio, which has been shown to cause hepatotoxicity. Human liver poisoning occurs through the consumption of RTS-contaminated food, and animals can also be poisoned by ingesting RTS-containing toxic plants. The mechanism of RTS-induced liver toxicity is not fully understood. In this study, we demonstrated that RTS-induced oxidative stress plays a pivotal role in RTS-induced liver toxicity involving apoptosis and autophagy. The results showed that RTS treatment in the cultured Primary rat hepatocytes caused cytotoxicity and release of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a time- and dose-dependent manner. Our study showed that treatment of RTS induced ROS and MDA (malondialdehyde, a lipid peroxidation marker) in the hepatocytes, and reduced antioxidant capacity (GSH content, SOD activity), suggesting RTS treatment caused oxidative stress response in the hepatocytes. Furthermore, we found that RTS induced apoptosis and autophagy in the hepatocytes, and RTS-induced apoptosis and autophagy could be alleviated by ROS scavenger N-acetylcysteine (NAC) and the MAPK pathway inhibitors suggesting ROS/MAPK signaling pathway plays a role in RTS induced apoptosis and autophagy. Collectively, this study reveals the regulatory mechanism of oxidative stress in RTS-induced apoptosis and autophagy in the hepatocytes, providing important insights of molecular mechanisms of hepatotoxicity induced by RTS and related pyrrolizidine alkaloids in liver. This mechanism provides a basis for the prevention and treatment of PA poisoning in humans and animals.

Wound Healing Properties of Natural Products: Mechanisms of Action

A wound is the loss of the normal integrity, structure, and functions of the skin due to a physical, chemical, or mechanical agent. Wound repair consists of an orderly and complex process divided into four phases: coagulation, inflammation, proliferation, and remodeling. The potential of natural products in the treatment of wounds has been reported in numerous studies, emphasizing those with antioxidant, anti-inflammatory, and antimicrobial properties, e.g., alkaloids, saponins, terpenes, essential oils, and polyphenols from different plant sources, since these compounds can interact in the various stages of the wound healing process. This review addresses the most current in vitro and in vivo studies on the wound healing potential of natural products, as well as the main mechanisms involved in this activity. We observed sufficient evidence of the activity of these compounds in the treatment of wounds; however, we also found that there is no consensus on the effective concentrations in which the natural products exert this activity. For this reason, it is important to work on establishing optimal treatment doses, as well as an appropriate route of administration. In addition, more research should be carried out to discover the possible side effects and the behavior of natural products in clinical trials.

Sub-acute toxicity study on hydromethanolic leaves extract of Combretum hypopilinum (Combretaceae) Diels in Wistar rats

The plant Combretum hypopilinum Diels (Combretaceae) has been utilized in Nigeria and other African nations to treat many diseases including liver, inflammatory, gastrointestinal, respiratory, infectious diseases, epilepsy and many more. Pharmacological investigations have shown that the plant possesses anti-infective, antidiarrhoeal, hepatoprotective, anti-inflammatory, anticancer, sedative, antioxidant, and antiepileptic potentials. However, information on its toxicity profile is unavailable despite the plant's therapeutic potential. As such, this work aimed to determine the acute and sub-acute oral toxic effects of the hydromethanolic leaves extract of C. hypopilinum. The preliminary phytochemical evaluation was carried out based on standard procedures. The acute toxicity evaluation was conducted by oral administration of the extract at the dose of 5000 mg/kg based on the guideline of the Organization of Economic Co-operation and Development (OECD) 423. To investigate the sub-acute toxicity effects, the extract was administered orally to the animals daily for 28-consecutive days at the doses of 250, 500, and 1000 mg/kg. Mortality, body weight and relative organ weight were observed. The hepatic, renal, haematological, and lipid profile parameters were investigated. The liver, kidney, heart, lung, small intestine, and stomach were checked for any histopathological alterations. The results of the phytochemical investigation showed cardiac glycosides, tannins, steroids, flavonoids, alkaloids, saponins, and triterpenes. Based on the acute toxicity investigation outcome, no death and signs of toxic effects were observed. The result showed that the oral median lethal dose (LD50) of the extract was more than the 5000 mg/kg. The extract remarkably reduced the weekly body weight of the animals at 500 mg/kg in the first and second weeks. It also significantly decreased the relative kidney weight, alkaline phosphatase, glucose, potassium, and low-density lipoprotein. There was a remarkable elevation in the percentage of eosinophils, basophils, monocytes, and granulocyte. There were histopathological abnormalities on the kidney, lung, stomach, and small intestine. The extract is relatively safe on acute exposure but moderately toxic at higher doses on sub-acute administration, particularly to the kidney.

Ethnopharmacological Survey, Mineral and Chemical Content, In Vitro Antioxidant, and Antibacterial Activities of Aqueous and Organic Extracts of Chamaerops humilis L. var. argentea Andre Leaves

Introduction. The present study is carried out for the first time on Chamaerops humilis L. var. argentea Andre from the region of Taza using an ethnopharmacological survey, an experimental study of the mineralogical and chemical compositions, and evaluations of the antioxidant and antibacterial activities. Methods. After conducting the ethnopharmacological survey, a mineralogical and phytochemical study involving the preparation of aqueous and organic extracts was done. Essential oils were also extracted by hydrodistillation. Subsequently, qualitative and quantitative chemical analyses were performed. In vitro evaluation of antioxidant activities was performed by five tests (H2O2, DPPH, ABTS, FRAP, and RP) and antibacterial activities by the disc method and determination of MIC and MBC. A principal component analysis (PCA) was performed to visualize the different correlations. Results. The different parts of the plant are used for the treatment of digestive disorders, cardiovascular diseases, and diabetes. In addition, the leaves are rich in mineral compounds, catechic tannins, flavonoids, and sterols. However, they have some traces of essential oils. The quantitative analysis revealed that the ethanolic macerated had a higher content of total polyphenols ( $100.27\pm 1.95\text{mg}$ EAG/g E) and catechic tannins ( $52.11\pm 1.02\text{mg}$ EC/g E). This extract had a strong antioxidant capacity (H2O2 ( $37.34\pm 0.55\%$ ), DPPH ( $\text{I}{\text{C}}_{50}=31.18\pm 0.66\mu \text{g}/\text{ml}$ ), ABTS ( $108.28\pm 1.29\text{mg}$ E AA/g E), FRAP ( $148.85\pm 0.43\text{mg}$ E T/g E), and RP ( $10.86\pm 0.01\text{mg}$ E AA/g E). The same extract had a bactericidal effect against Staphylococcus aureus. Principal component analysis (PCA) showed that antioxidant activity was highly correlated with the chemical composition of C. humilis leaves; a high correlation was recorded between the total polyphenol content and ABTS ( $r=0.9779$ ), FRAP ( $r=0.9644$ ), DPPH ( $r=0.9418$ ), and PR ( $r=0.9271$ ) tests. In addition, cathectic tannins were highly correlated with the tests of DPPH ( $r=0.9753$ ) and ABTS ( $r=0.8843$ ). Flavonoids were similarly correlated with DPPH ( $r=0.8897$ ) and ABTS ( $r=0.7599$ ) tests. Conclusion. These results could justify the traditional use of the leaves of Chamaerops humilis in the region of Taza for the treatment of some diseases.

Bioactive chemical constituents, in vitro anti-proliferative activity and in vivo toxicity of the extract of Curcuma singularis Gagnep rhizomes

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma singularis Gagnep is a Vietnamese medicinal plant which has been commonly used as a medicinal remedy in traditional and folk medicines for improving health as well as for treating some diseases, like rheumatoid arthritis, kidney failure. However, pharmacological effects, including anti-cancer activity and the safety of this plant has not been fully investigated.

AIM OF THE STUDY

This study aimed to investigate the in vitro anti-growth activity of an extract derived from Curcuma singularis rhizome extract (CSE) against cell lines as well as determine its phytochemical composition. The other goal of our study was to assess the safety of CSE in rats.

MATERIALS AND METHODS

The main constituents in the extract were identified and quantitatively analyzed. The in vitro cytotoxicity of CSE was evaluated in several cancer and normal cell lines. The apoptotic activity of CSE and the expression of the apoptosis-related genes were investigated in AGS cells to clarify the underlying molecular mechanisms. The in vivo toxicity of CSE was assessed via acute and subacute oral studies on Sprague-Dawley rats, respectively according to the guidelines 425 and 407 of the Organization for Economic Cooperation and Development (OECD). The drug-related toxicity signs, mortality, body and organ weights were recoreded during the experimental period. In addition, the selected hematological and biochemical parameters, and histological alterations were determined at the end of the subacute toxicity test.

RESULTS

Germacrone, ar-turmerone, and curcumol were three sesquiterpene components found in the extract. CSE showed cytotoxic effects in different cancer cells, but had minimal effects on normal cells. Apoptosis in AGS cells was caused by CSE in a concentration-dependent pattern through increase of Bax/Bcl-2 ratio, and release of cytochrome c, which leads to activation of caspase-3/-7, caspase-9, as well as cleavage of PARP. In the acute toxicity test, no signs of toxicity and no mortality were recorded in rats at both doses of 1000 and 5000 mg/kg. In the subacute toxicity study, CSE showed no drug-related adverse effects on water and food consumption, body and organ weights. CSE at a dose of 1000 mg/kg slightly increased WBC and platelet values in female rats, while it increased WBC values in male rats in all tested doses. The decrease of total cholesterol and triglyceride levels were found in female rats treated CSE at doses of 250 or 500 mg/kg. In addition, the increase of serum ALT and AST levels in rats treated at the dose of 1000 mg/kg were noted. No significant changes in histopathological structures of kidneys, spleen, heart and lungs, except liver tissue with minor modifications was found.

CONCLUSIONS

Our findings indicated that CSE exhibited in vitro anti-proliferative effects on AGS cells by mainly activating the caspase-dependent mitochondrial apoptotic pathway. CSE also showed in vivo toxicity signals at the dose of 1000 mg/kg with proven minor hepatic injuries, which should be avoided the high dose for prolonged use. Curcuma singularis rhizomes may be used as a chemotherapeutic agent for the treatment of gastric cancer with in vitro anti-cancer investigation and in vivo biological safety evaluation.

Evaluation of in vitro cytotoxicity and in vivo potential toxicity of the extract from in vitro cultivated Anoectochilus roxburghii Lindl

Anoectochilus roxburghii Lind. (A. roxburghii) has promising anti-oxidant, hyperglycemic, hepatoprotective, and immunomodulatory activities as well as anti-tumor effects. However, the pharmacological actions of in vitro cultured plants remain to be determined. Therefore, the objective of the study was to assess in vitro cytotoxicity and in vivo potential toxicity of an extract derived from in vitro cultivated A. roxburghii, termed as iARE. The total flavonoid content and predominant flavonoid compounds of extract were identified and quantitatively analyzed. The in vitro cytotoxicity of iARE was examined using several cancer and normal cell lines. The apoptotic activity and expression of apoptosis-associated genes were also examined in MCF7 cells to determine the underlying mechanisms related to anti-proliferative effects. In vivo potential toxicity of iARE was assessed following acute and subchronic oral administration in Sprague Dawley rats. Quercetin, kaempferol, and isorhamnetin were three flavonoid components identified in iARE. The extract exerted cytotoxic effects on various cancer cells but not normal fibroblasts. Apoptosis in MCF7 cells was induced by iARE in a concentration-dependent manner associated with increased Bax/Bcl-2 ratio and reduced mitochondrial membrane potential ΔΨm, leading to release of cytochrome c, activation of caspase-3/7 and caspase-9, and cleavage of PARP. In the acute oral toxicity study, no mortality or toxicological signs were observed in rats at 1000 or 5000 mg/kg. In a subchronic oral toxicity study, iARE at a dosage of up to 1000 mg/kg produced no mortality or treatment-related adverse effects on general behavior, food intake, body weight, relative organ weights. No apparent marked changes in the histopathology of the liver and kidney were detected. Data demonstrated that iARE induced in vitro cytotoxic effects in cancer cells are associated with lackof invivo toxicity. Thus, iARE was suggested to be considered as apotential therapeutic candidate for cancer treatment.

CHOP Regulates Endoplasmic Reticulum Stress-Mediated Hepatoxicity Induced by Monocrotaline

Monocrotaline (MCT), a pyrrolizidine alkaloid, is the major toxin in Crotalaria, which causes cell apoptosis in humans and animals. It has been reported that the liver is a vulnerable target of MCT. However, the exact molecular mechanism of the interaction between endoplasmic reticulum (ER) stress and liver injury induced by MCT is still unclear. In this study, the cytotoxicity of MCT on primary rat hepatocytes was analyzed by a CCK-8 assay and Annexin V-FITC/PI assay. Protein expression was detected by western blotting and immunofluorescence staining. As a result, MCT significantly decreased the cell viability and mediated the apoptosis of primary rat hepatocytes. Meanwhile, MCT could also induce ER stress in hepatocytes, indicated by the expression of ER stress-related proteins, including GRP78, p-IRE1α, ATF6, p-eIF2α, ATF4, and CHOP. Pretreatment with 4-PBA, an inhibitor of ER stress, or knockdown of CHOP by siRNA could partly enhance cell viability and relieve the apoptosis. Our findings indicate that ER stress is involved in the hepatotoxicity induced by MCT, and CHOP plays an important role in this process.

The Failures of Ethnobotany and Phytomedicine in Delivering Novel Treatments for Snakebite Envenomation

Snakebite envenomation (SBE) is a high-priority, neglected tropical disease. This devastating occupational health hazard disproportionately affects rural farming communities in tropical countries. This is exacerbated by the distribution and densities of venomous snakes, incidence of encounters, and limited access to advanced healthcare, including antivenom. Before the development of antivenom, desperation and spiritual beliefs led patients to experiment with a wide range of traditional treatments. Many of these treatments still survive today, particularly in regions where access to healthcare is limited. Plants are a major source of bioactive molecules, including several lifesaving medications that are widely used to this day. However, much of the research into the use of traditional plant treatments for SBE are limited to preliminary analysis or have focused on techniques used to confirm antibody efficacy that are not suitable for non-antibody-containing treatments. Modern drugs are developed through a robust pharmaceutical drug discovery and development process, which applies as much to SBE as it does to any other disease. This review discusses specifically why research into ethnobotanical practices has failed to identify or develop a novel treatment for SBE and proposes specific approaches that should be considered in this area of research in the future.

Acute and subchronic oral toxicity assessments of Combretum micranthum (Combretaceae) in Wistar rats

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Acute and subchronic oral toxicity assessments of Combretum micranthum leaves extract were evaluated in Wistar rats of both sexes.

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In acute oral toxicity assessment, LD50 of Combretum micranthum leaves extract is greater than 5000 mg/kg.

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In subchronic oral toxicity assessment at doses of 500 and 1000 mg/kg/day for 28 days, No significant changes in food consumption, body weight gain, organ weights and in biochemical parameters.

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The level of PLT increased in female rats in the sub-chronic study but the immune system was not affected.

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No treatment related pathology was identified during histopathology.

Background

Combretum micranthum (CM) (Combretaceae) is widely used in traditional medicine throughout West Africa for the treatment of diabetes, hypertension, inflammation, malaria and liver ailments. In our recent research we demonstrated that CM has nephroprotective potentials in diabetes mellitus, hypertension and renal disorders. However, to the best of our knowledge, no systematic study concerning its toxicity profile has been reported.

Aim of the study

The study carried out to evaluates the potential toxicity of the hydroalcoholic extract from leaves of the CM, through the method of acute and sub-chronic oral administration in rats.

Materials and methods

During the acute toxicity study, male and female rats were orally administrated with CM extract at single doses of 5000 mg/kg (n = 5/group/sex). Abnormal behaviour, toxic symptoms, weight, and death were observed for 14 consecutive days to assess the acute toxicity. For sub-chronic toxicity study, the extract was administered orally at doses of 500 and 1000 mg/kg (n = 5/group/sex) daily to Wistar rats for 28 days. The general behaviour and body weight of the rats was observed daily. A biochemical, haematological, macroscopical and histopathological examinations of several organs were conducted at the end of the treatment period. The CM extract was subjected to Fourier transform infrared spectrophotometric examination in order to detect the presence or absence of cyanide toxic compounds.

Results

The absence of absorbance peaks between the 2220−2260 cm⁻¹ region of FT-IR spectrum of CM, indicating the absence of cyanide groups. This suggested that the CM extract may not contain toxic substances. During the acute toxicity test, no mortality or adverse effects were noted at the dose of 5000 mg/kg. In the subchronic study, the CM extract induced no mortality or treatment-related adverse effects with regard to body weight, general behaviour, relative organ weights, hematological, and biochemical parameters. Histopathological examination of vital organs showed normal architecture suggesting no morphological alterations.

Conclusion

The present study revealed that oral administration of CM extract for 28 days, at dosage up to 1000 mg/kg did not induce toxicological damage in rats. From acute toxicity study, the median lethal dose (LD₅₀) of the extract was estimated to be more than 5000 mg/kg.

Development of UPLC-Q-TOF-MS Coupled with Cation-exchange Solid-phase Extraction Method for the Determination of Ten Pyrrolizidine Alkaloids in Herbal Medicines

Pyrrolizidine alkaloids are secondary metabolites of plants and can cause significant hepatotoxicity in humans. In this study, a fast and simple method was developed to determine ten pyrrolizidine alkaloids (PAs) in six types of herbal medicines using ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS). An efficient solid-phase extraction procedure was carried out by using strong cation-exchange cartridges and the parameters were optimized. The established analytical method was validated and the results showed that the method presented satisfactory accuracy and precision. The established method was successfully applied for the determination of PAs in six herbal plants, including Senecionis Scandentis Hebra, Arnebiae Radix, Asteris Radix Et Rhizoma, Farfarae Flos, Senecionis Cannabifolii Herba and Emilia sonchifolia. PAs were found in all of these herbal plant samples. Eight types of related commercial herbal drugs were also detected, six of them were detected with different amounts of PAs. This work not only provided a powerful technical platform for both qualitative and quantitative analysis of PAs in herbal medicines, but also obtained information concerning PAs in these herbal samples, which could provide reference to the government regulatory authorities and non-governmental organizations.

Pyrrolizidine Alkaloids: Chemistry, Pharmacology, Toxicology and Food Safety

Pyrrolizidine alkaloids (PA) are widely distributed in plants throughout the world, frequently in species relevant for human consumption. Apart from the toxicity that these molecules can cause in humans and livestock, PA are also known for their wide range of pharmacological properties, which can be exploited in drug discovery programs. In this work we review the current body of knowledge regarding the chemistry, toxicology, pharmacology and food safety of PA.