Acute toxicity studies of the South African medicinal plant Galenia africana

Chemical characterisation and appraisal of antidiabetic potential of Terminalia citrina extract in streptozotocin induced hyperglycaemia in Wistar rats

The current research was aimed to evaluate the antidiabetic activity of Terminalia citrina methanolic extract (TCME) by streptozotocin-induced diabetes in male Wistar rats. TCME exhibited better in-vitro antioxidant and alpha-amylase inhibitory activity as compared to other tested extracts. TCME at 250, 500, and 750 mg/kg showed notable (p < .05) antidiabetic potential by lowering fasting blood glucose level, restoring lipid level, serum amylase, HbA1c, kidney, and liver function tests as coevidenced from histological findings of the liver, pancreas, and kidney. TCME remarkably reinstated the antioxidant enzymatic activities (CAT: 0.181 ± 0.011 IU/mg protein, SOD: 21.45 ± 1.53 IU/mg protein) and reduced lipid peroxidation level (40.60 ± 2.41 µM/mg protein) in the liver and kidney tissue of diabetic rats at 750 mg/kg dose. The acute and subacute oral toxicity study of TCME exhibited no clinical toxicity signs and mortality. Its GC-MS spectrum unveiled the existence of 10-octadecenoic acid and other compounds which might have contributed to antidiabetic potential.

Current Trends in Toxicity Assessment of Herbal Medicines: A Narrative Review

Even in modern times, the popularity level of medicinal plants and herbal medicines in therapy is still high. The World Health Organization estimates that 80% of the population in developing countries uses these types of remedies. Even though herbal medicine products are usually perceived as low risk, their potential health risks should be carefully assessed. Several factors can cause the toxicity of herbal medicine products: plant components or metabolites with a toxic potential, adulteration, environmental pollutants (heavy metals, pesticides), or contamination of microorganisms (toxigenic fungi). Their correct evaluation is essential for the patient’s safety. The toxicity assessment of herbal medicine combines in vitro and in vivo methods, but in the past decades, several new techniques emerged besides conventional methods. The use of omics has become a valuable research tool for prediction and toxicity evaluation, while DNA sequencing can be used successfully to detect contaminants and adulteration. The use of invertebrate models (Danio renio or Galleria mellonella) became popular due to the ethical issues associated with vertebrate models. The aim of the present article is to provide an overview of the current trends and methods used to investigate the toxic potential of herbal medicinal products and the challenges in this research field.

Medicinal plants utilized in the management of epilepsy in Ethiopia: ethnobotany, pharmacology and phytochemistry

Epilepsy is a common central nervous system (CNS) disorder that affects 50 million people worldwide. Patients with status epilepticus (SE) suffer from devastating comorbidities and a high incidence of mortalities. Antiepileptic drugs (AEDs) are the mainstream treatment options for the symptomatic relief of epilepsy. The incidence of refractory epilepsy and the dose-dependent neurotoxicity of AEDs such as fatigue, cognitive impairment, dizziness, attention-deficit behavior, and other side effects are the major bottlenecks in epilepsy treatment. In low- and middle-income countries (LMICs), epilepsy patients failed to adhere to the AEDs regimens and consider other options such as complementary and alternative medicines (CAMs) to relieve pain due to status epilepticus (SE). Plant-based CAMs are widely employed for the treatment of epilepsy across the globe including Ethiopia. The current review documented around 96 plant species (PS) that are often used for the treatment of epilepsy in Ethiopia. It also described the in vivo anticonvulsant activities and toxicity profiles of the antiepileptic medicinal plants (MPs). Moreover, the phytochemical constituents of MPs with profound anticonvulsant effects were also assessed. The result reiterated that a lot has to be done to show the association between herbal-based epilepsy treatment and in vivo pharmacological activities of MPs regarding their mechanism of action (MOA), toxicity profiles, and bioactive constituents so that they can advance into the clinics and serve as a treatment option for epilepsy.

Effect of methanol root extract of Eriosema psoraleoides on biochemical and haematological parameters and cyclooxygenase levels in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Eriosema psoraleoides is a remedial plant utilised traditionally in the African continent. It is said to possess a wide range of pharmacological activity. In a previous study, the analgesic and anti-inflammatory activity of its methanol root extract have been scientifically demonstrated. The growing use of medicinal plants by people from low-income countries and the plethora of adverse effects accompanying this increasing use has demonstrated the need for comprehensive toxicological evaluation of these plants which have shown therapeutic activity. However, in the capsule that is Nigeria, these studies are seldom done even though locals continue to patronize these plants for their health benefits.

AIM OF THE STUDY

To establish the repeated dose toxicity profile of the methanol root extract of Eriosema psoraleoides (EPE) in rats and also to investigate a possible mechanism for its analgesic and anti-inflammatory activity.

MATERIALS AND METHODS

Male Wistar rats were utilised for the test. All animals used for the test were healthy. The oral repeated dose study was carried out for 28 days with animals being given the following doses daily; 250, 500 and 1000 mg/kg orally. The Wistar rats were euthanized afterwards and blood samples were taken. The samples were subjected to serum biochemistry in tandem with haematological testing. After acute induction of inflammation with 1% carrageenan in normal saline, sera samples were obtained from the animals: serum cyclooxygenase 1 and 2 levels (COX 1 and COX 2) were assayed using Enzyme-Linked Immunosorbent Assay kits. Data were analysed utilising the appropriate software and tests.

RESULTS

Oral Repeated dose administration of EPE for 28 days didn't produce any lethality in any animal throughout the duration of the test. Repeated dose administration of EPE showed a significant (p < 0.05) decrease in the serum levels of Alanine Aminotransferase as well as Aspartate Aminotransferase at 250 and 1000 mg/kg dose levels. Total protein and albumin were also significantly (p < 0.01) decreased. A statistically significant (p < 0.05) decrease in serum urea level was also observed compared to the normal saline group (1 ml/kg). Sodium levels also showed a decrease with a statistically significant level only in the group treated with the extract at a dose of 1000 mg/kg (p < 0.05). Haematological parameters were not significantly affected by EPE. The extract demonstrated an ability to down-regulate serum concentration of both COX 1 and 2, though not to a statistically significant level.

CONCLUSION

The results of this study suggest that prolonged use of EPE might potentially adversely affect vital organs in the body and EPE may potentially act through its downregulation of COX 1 and 2.

Evaluation of Dermal Toxicity and Wound Healing Activity of Cnestis ferruginea Vahl ex DC

Cnestisferruginea is a tropical plant, which is traditionally used in the treatment and management of various conditions including skin infections and wounds. The aim of this study was to investigate the dermal toxicity and wound healing potential of C. ferruginea. Ten millimeter full-thickness mucosal wounds were created on the dorsal midportion of the Sprague Dawley rats. Wounds were treated with 10, 5, and 2.5% w/w aqueous creams, prepared from the methanol extract of the root bark of C. ferruginea (CFM). The wound tissues were harvested on day 21 for histology studies. Compared with the untreated group, 10, 5, and 2.5% w/w CFM-treated wounds significantly reduced the wound size over the study period ( $P<0.0001$ ). Tissue histology revealed a healed wound with well-regenerated collagen and skin appendages with no pus cells. A skin irritation test was conducted on CFM, as well as the dermal toxicity of CFM was determined in the repeated dose and acute dermal toxicity bioassays. These tests revealed that CFM showed no toxic effect on the skin and showed that CFM was not a skin irritant. C. ferruginea exhibited wound healing activity, which gives credence to its folkloric use.

Green Synthesis of Metallic Nanoparticles Using Some Selected Medicinal Plants from Southern Africa and Their Biological Applications

The application of metallic nanoparticles (MNPs), especially that of silver, gold, cobalt, and zinc as antimicrobial, anticancer, drug delivery, contrast, and bioimaging agents has transformed the field of medicine. Their functions, which are attributed to their physicochemical properties, have gained prominence in various technological fields. Although MNPs can be produced via rigorous physical and chemical techniques, in recent years, a biological approach utilizing natural materials has been developed. With the increasing enthusiasm for safe and efficient nanomaterials, the biological method incorporating microorganisms and plants is preferred over physical and chemical methods of nanoparticle synthesis. Of these bio-entities, plants have received great attention owing to their capability to reduce and stabilize MNPs in a single one-pot protocol. South Africa is home to ~10% of the world's plant species, making it a major contributor to the world's ecological scenery. Despite the documented contribution of South African plants, particularly in herbal medicine, very few of these plants have been explored for the synthesis of the noble MNPs. This paper provides a review of some important South African medicinal plants that have been utilized for the synthesis of MNPs. The enhanced biological properties of the biogenic MNPs attest to their relevance in medicine. In this endeavour, more of the African plant biodiversity must be explored for the synthesis of MNPs and be validated for their potential to be translated into future nanomedicine.

Phytochemical and Safety Evaluations of Zingiber ottensii Valeton Essential Oil in Zebrafish Embryos and Rats

Zingiber ottensii Valeton (ZO) exhibits pharmacological activity and has long been used in traditional medicine. However, reports about its safety profiles are limited. The present study aimed to evaluate the phytochemical profile and the toxic effects of ZO essential oil on the development of zebrafish and acute oral toxicity in rats. The essential oil was isolated from ZO rhizomes, and phytochemicals were analyzed using a gas chromatography-mass spectrometer (GC-MS). The embryotoxic and teratogenic effects of ZO essential oil were evaluated in zebrafish embryos and larvae and the acute oral toxicity was determined in rats. GC-MS results showed the essential oil contained zerumbone as a major phytoconstituent (24.73%). The zebrafish embryotoxicity of ZO essential oil appeared to be concentration- and time-dependent manner, with a moderate LC₅₀ (1.003 µg/mL). Teratogenicity in zebrafish embryos also included morphological defects, decreased hatchability, and reduced heart rate. In rats, ZO essential oil (2000 mg/kg, p.o.) resulted in no mortality or significant toxicities. These findings suggest that ZO has embryotoxic and teratogenic effects in zebrafish embryos but does not result in death or acute oral toxicity in rats. Further long-term toxicity studies are needed to confirm the safety of products developed from ZO essential oil.

Acute oral toxicity of a novel functional drink based on Ilex guayusa, Vernonanthura patens, and cocoa husk

A novel functional drink with nutraceutical properties was formulated from the aqueous extracts of Ilex guayusa, and Vernonanthura patens leaves, and cocoa husks. This juice contains various bioactive compounds, such as phenolic compounds and methylxanthines, with antioxidant and stimulant properties of pharmacological interest. However, it is known whether herbal extracts' interaction may have adverse toxic effects on human health. To evaluate this functional drink's innocuity, we estimated the acute oral toxicity (AOT) in experimental mice. This paper presents the AOT evaluation of two formulations of a functional drink (pre-formulation and microencapsulation) at a single dose of 2000 mg/kg of body weight (b.w.). No signs of adverse toxicity and mortality were observed after a single oral dose of 2000 mg/kg b.w. Likewise, no significant body and organ weight changes, food and water consumption behavior, and no histopathological changes were observed in the main organs evaluated. In conclusion, this functional drink can be categorized as low toxicity " according to the Globally Harmonized Classification System (GHS), making it a potential beverage with high nutritional and pharmacological value.

In Vitro Comparison of the Anti-Proliferative Effects of Galenia africana on Human Skin Cell Lines

Malignant melanoma is the major cause of skin cancer-related deaths. Surgery in combination with radiotherapy, immunotherapy or chemotherapy is used to eradicate cancer cells, however, this treatment option is limited by the tolerance of the surrounding healthy tissue. The extracts from Galenia africana have been shown to possess anti-cancer flavonoid compounds and can be a safer and cost-effective alternative treatment. The study aimed to compare the anti-proliferative effects of G. africana on human skin cells (HaCaT) and human malignant melanoma cells (A375). The cells were exposed to various concentrations of the G. africana extract at different times. In vitro assays were employed to determine cell viability and cytotoxicity. Hoechst 33342 staining was performed to observe the nuclear changes, including apoptosis. G. africana significantly reduced the cell viability of the A375 cells in a dose and time-dependent manner, while having no effect on the HaCaT cells. The A375 cells displayed nuclear condensation, brightly stained nuclei and nuclear fragmentation indicative of apoptosis. This suggests a clinical rationale for the use of G. africana as a potential anti-melanoma agent offering efficacy and low toxicity. This study provides new insights for future work on investigating the utilization of G. africana in malignant melanoma treatment.

Phytochemical analysis of ionic liquid-Graviola (Annona muricata) fruit extract and its acute toxicity on zebrafish early-life stages

Annona muricata, commonly known as soursop and Graviola, is a member of the Annonaceae family. Some of its phytochemicals were reported to have a neurotoxicity effect causing neurodegenerative diseases. However, different parts of this tree have been used for ages in traditional medicine due to their biological activities, such as anti-inflammatory, antimicrobial, antioxidant and anticancer effects. This study aimed to qualitatively screen the crude ionic liquid-Graviola fruit extract (IL-GFE) phytochemical composition, assess its acute toxicity and determine the lethal concentrations using zebrafish (Danio rerio) embryos. IL-GFE contains acetogenins, alkaloids, phenols, terpenoids, tannins and flavonoids. Acute toxicity effects of IL-GFE on zebrafish embryos were observed from 24 to 120 hours of post fertilisation (hpf). The survival rate, LC50, sublethal endpoints and effect of IL-GFE on the heart rate of zebrafish larvae were assessed. Results showed that the lethal concentration (LC50) of the crude IL-GFE was 173.45 μg/mL. Interestingly, no significant changes on the morphology of the treated zebrafish were observed at a concentration of 125 μg/mL. However, the heart rate of zebrafish larvae at 96 hpf was significantly decreased by 33.76% after treated with crude IL-GFE at 125 µg/mL (119.00 ± 4.72 beats/min) as compared to the untreated group (179.67 ± 4.66 beats/min). This preliminary finding showed that crude ionic liquid-Graviola fruit extract and its phytoconstituents might have the potential to be developed as a food supplement or herbal product. However, further tests need to be conducted to evaluate its medicinal properties and adverse effects on organisms of higher orders.

Cytotoxic and antimicrobial potential of different leaves extracts of R. fruticosus used traditionally to treat diabetes

•

Rubus fruticosus is an indigenous plant used traditionally in Oman to treat different disorders.

•

Antimicrobial activity of crude extracts and isolated fractions of the selected plant was determined by diffusion method.

•

Cytotoxic activity of crude extracts and isolated fractions of the selected plant was determined by brine shrimp method.

•

Hydro alcoholic extract showed the highest activity and it could be used as folk medicine to treat diseases.

Medicinal plant as herbal medicine is widely used to cure infectious diseases. Rubus fruticosus L (R. fruticosus) has been studied for its antimicrobial and cytotoxic activities. Different polarity leave extracts were prepared by using hexane, chloroform, ethyl acetate and hydro alcoholic solvents. Agar diffusion method has been used to assess the antibacterial activity against two gram-positive Enterococcus faecalis and Staphylococcus aureus and two gram-negative Escherichia coli and Haemophilus influenza bacterial strains. Cytotoxic activity was carried out against brine shrimp using the nauplii method (BSL). The results so obtained for various experiments demonstrates the total number of extracts produces moderate to strong antibacterial activity against the gram (+ and -). The best activity was discovered within hydro alcoholic upon all concentrations, whereas the inhibition zone exists within the range of 6−11 mm. In addition to that, the cytotoxic activity test confirms that hydro alcoholic extracts the maximum toxicity for values LC₅₀ (4.68–6.96 μg/ml), where the LC₅₀ values for all extracts be located within the range of 4.68–6.96 μg/ml. Finally, the plant itself and its derived extracts have been used as a folk medicine to treat serious infectious diseases.

Design, synthesis and evaluation of quinolinone derivatives containing dithiocarbamate moiety as multifunctional AChE inhibitors for the treatment of Alzheimer's disease

A series of novel quinolinone derivatives bearing dithiocarbamate moiety were designed and synthesised as multifunctional AChE inhibitors for the treatment of AD. Most of these compounds exhibited strong and clearly selective inhibition to eeAChE. Among them, compound 4c was identified as the most potent inhibitor to both eeAChE and hAChE (IC₅₀ = 0.22 μM for eeAChE; IC₅₀ = 0.16 μM for hAChE), and it was also the best inhibitor to AChE-induced Aβ aggregation (29.02% at 100 μM) and an efficient inhibitor to self-induced Aβ aggregation (30.67% at 25 μM). Kinetic and molecular modelling studies indicated that compound 4c was a mixed-type inhibitor, which could interact simultaneously with the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of AChE. In addition, 4c had good ability to cross the BBB, showed no toxicity on SH-SY5Y neuroblastoma cells and was well tolerated in mice at doses up to 2500 mg/kg (po).

Oral toxicity of arjunolic acid on hematological, biochemical and histopathological investigations in female Sprague Dawley rats

Background

Arjunolic acid (AA) is a potent phytochemical with wider pharmacological activities. Despite potential medicinal properties on various in vitro and in vivo studies, there is still a dearth of scientific data related to its safety profile and toxicological parameters. The current study aimed to investigate acute toxicity of AA in normal female Sprague Dawley rats.

Methods

In this study, AA was administered orally at an individual dose of 300 and 2000 mg/kg body weight to group 1 and 2 respectively, while group 3 served as normal control. All the animals were observed for 2 weeks to determine any behavioral and physical changes. On day 15, blood was collected for hematological and biochemical investigation, later animals from all the three groups were euthanized to harvest and store essential organs for histopathological analysis. Four different staining techniques; hematoxylin and eosin, Masson trichrome, Periodic acid Schiff and Oil O Red were used to investigate any alterations in different tissues through microscopical observation.

Results

The results of the study showed no morbidity and mortality at two different dosage of AA treatment. Daily food & water intake, body weight, relative organ weight, hematological and biochemical parameters were detected to be normal with no severe alteration seen through microscopical investigation in the structure of harvested tissues. Our findings support the safety profile of AA, which was well tolerated at higher dose. Thus, an in-detail study on the subacute disease model is warranted.

Toxicity study on Clinacanthus nutans leaf hexane fraction using Danio rerio embryos

•

The C. nutans n-hexane fraction is harmful with the LC₅₀ of 75.49 μg/mL.

•

The mortality rate increased as the fraction concentration increased.

•

Morphological defects such as less pigmentation, dented tail, oedema malformed yolk sac was detected at the median lethal concentration.

•

GC–MS analysis revealed the presence of sterols, fatty acids and some of its derivatives in the n-hexane fraction.

Clinacanthus nutans, an herbal shrub belonging to the Acanthaceae family, is traditionally used as a functional food to treat various ailments in Malaysia and Indonesia. Although the polar fraction of this plant shows non-toxic effect, the toxicity of the non-polar extract is not reported so far. The present study aimed to assess the toxic effect and determine the lethal concentration of this non-polar fraction using zebrafish embryos. The n-hexane fraction was partitioned from the crude extract of C. nutans obtained using 80% methanolic solution. After spawning of the adult male and female zebrafish, the eggs were collected, transferred into a 96-well plate and incubated with the n-hexane fraction at concentrations of 15.63 μg/ml, 31.25 μg/ml, 62.5 μg/ml, 125 μg/ml, 250 μg/ml and 500 μg/ml in 2% DMSO. The survival and sublethal endpoint were assessed, the mortality and hatchability rates were calculated based on microscopic observation, while the heartbeat rate was measured using DanioScope software. The median lethal concentration (LC₅₀) of the C. nutans n-hexane fraction, which was determined using probit analysis, was calculated to be 75.49 μg/mL, which is harmful. Moreover, gas chromatography-mass spectrometry (GC–MS) analysis revealed the presence of palmitic acid, phytol, hexadecanoic acid, 1-monopalmitin, stigmast-5-ene, pentadecanoic acid, heptadecanoic acid, 1-linolenoylglycerol and stigmasterol in the n-hexane fraction.

Chemical profile and in vivo toxicity evaluation of unripe Citrus aurantifolia essential oil

Citrus aurantifolia (Christm.) Swingle (syn. C. MEDICA var. ACIDA Brandis) (family: Rutaceae) essential oil is one of the cheapest oils found in local markets. Although, it is generally accepted as non-toxic to vital organs and cells, majority of people are cynical about it usage. Herein, the present study reports the chemical composition and in vivo oral toxicity study of unripe C. aurantifolia essential oil found in Ghana. The toxicity of C. aurantifolia essential oil extract was investigated via oral administration using two methods: The acute toxicity single dose study (SDS) and the repeated dose method. The oil exhibited no acute toxicity but in the sub-chronic studies, the effects was dose and time-dependent. Chemical profile investigation of the oil showed 9 constituent of phytochemicals (Germacrene isomers (61.2%), Pineen (14%), Linalool dimmer (2.9%), Bornane (11%), Citral (2.9%), Anethole (1.5%), Anisole (1.1%), Safrole (0.3%) and Demitol (0.6%)). Histopathological studies revealed conditions such as necrosis, edema and inflammatory reaction in the liver, spleen and kidneys. Marginal upsurge of biochemical parameters above normal and elevated levels of lymphocytes (35.20-46.40 g/dL) demonstrated mild toxicity among the 100 mg/kg and 500 mg/kg dose groups at the sub-chronic stage. Low levels of hemoglobin (13.60 to 12.70 g/dL), MCV (34.20-24.0 fL), MCH (40.20-36.40 g/dL) along with high levels of liver enzymes confirmed the mild toxicity of the oil at sub-chronic stage. These results demonstrate that, despite consideration of lime essential oil as safe, it can have mild hematotoxic, nephrotoxic and hepatotoxic effects.