Toxicity studies of medicinal plants used in sub-Saharan Africa

Pharmacological mechanisms involved in the diuretic activity of the ethanol-soluble fraction of Baccharis milleflora (Less.) DC. - An ethnopharmacological investigation

ETHNOPHARMACOLOGICAL RELEVANCE

Baccharis milleflora (Less.) DC. is a plant native to Brazil that is frequently used in traditional medicine as a diuretic and antihypertensive. However, even though it is traditionally used for these purposes, its diuretic and hypotensive effects have not been fully elucidated.

AIM

Investigate the cardiorenal effects of the ethanol-soluble fraction (ESBM) of Baccharis milleflora in normotensive rats.

MATERIALS AND METHODS

Cladodes of B. milleflora were analyzed using light and scanning electron microscopy to provide anatomical data to support quality control. Subsequently, the ESBM was obtained and analyzed using LC-DAD-MS, and its components were annotated. The acute toxicity of ESBM was assessed in female Wistar rats. The acute and prolonged diuretic and hypotensive effects were then studied in Wistar rats. Finally, we assessed the mechanisms responsible for the diuretic effects of ESBM, including the activity of renal Na+/K+/ATPase, angiotensin-converting enzyme, and erythrocyte carbonic anhydrase. Additionally, we also investigated the involvement of bradykinin, prostaglandins, and nitric oxide.

RESULTS

From LC-DAD-MS data, thirty-three metabolites were identified from ESBM, including chlorogenic acids, glycosylated phenolic derivatives, C-glycosylated flavones, and O-glycosylated flavonols. No signs of acute toxicity were observed in female rats. The findings showed that ESBM had significant diuretic and natriuretic effects, as well as a potassium-sparing effect. The treatment with ESBM was able to significantly decrease serum levels of creatinine and malondialdehyde, and also significantly increase levels of nitrite, an indirect marker of nitric oxide bioavailability. Furthermore, pre-treatment with L-NAME abolished all diuretic effects induced by ESBM.

CONCLUSION

This study presented important morpho-anatomical and phytochemical data that support the quality control of Baccharis milleflora. The ESBM exhibited a significant diuretic and natriuretic effect following acute and seven-days repeated treatment in Wistar rats, without affecting renal potassium elimination. These effects appear to be dependent on the activation of the nitric oxide-cyclic GMP pathway. This study suggests the potential use of B. milleflora preparations in clinical situations where a diuretic effect is needed.

Chemical profiling, anticonvulsant and anxiolytic effects of the smoke constituents isolated from Leonotis leonurus (L.) R.Br

ETHNOPHARMACOLOGICAL RELEVANCE

The use of medicinal plants for central nervous system (CNS)-related ailments, such as epilepsy and anxiety, is prevalent in South Africa. Plants from the Lamiaceae family are commonly used for their therapeutic benefits. Leonotis leonurus (L.) R.Br. has been reported in ethnobotanical literature to have anticonvulsant and anxiolytic effects through the inhalation of pyrolysis products obtained by combustion of the aerial parts.

AIM AND OBJECTIVES

To explore the chemical profiles and CNS activity of the smoke extract and isolated constituents of L. leonurus in zebrafish larvae, through anticonvulsive and anxiolytic activity assays.

MATERIALS AND METHODS

The smoke extract of L. leonurus was obtained through the combustion of the aerial parts of the plant using a custom-built smoke recovery apparatus. The chemical profile of the smoke constituents was determined using Ultra-Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Targeted compounds were subjected to preparative High-Performance Liquid Chromatography for separation before structure elucidation using Nuclear Magnetic Resonance (NMR). The maximum tolerated concentrations, as well as the anxiolytic activity of the smoke extract were determined in five days post fertilisation zebrafish larvae. Reverse-thigmotaxis and locomotor activity of larvae in the light/dark transition assay were used to determine anxiolytic activity. Zebrafish larvae at six days post fertilisation (dpf) were subjected to several concentrations of the smoke constituents of L. leonurus. The baseline locomotor activity of the larvae was tracked for 30 min, prior to addition of pentylenetetrazole (PTZ) to induce seizure-like behaviour in the larvae, after which the locomotor activity of the larvae was once again tracked for an additional 30 min.

RESULTS

The UPLC-MS profiles of the smoke extract revealed the presence of two main compounds, leoleorin A and leoleorin B, which were targeted and isolated. Upon subjection to NMR spectroscopy for structure elucidation, the compounds were confirmed to be labdane diterpenoids. Both leoleorin A and leoleorin B, and the smoke extract displayed suppression of the PTZ induced seizure-like behaviour in zebrafish larvae. Under light and dark conditions, the smoke extract and compounds displayed potential anxiolytic activity at different concentrations.

CONCLUSION

Our results suggest that the smoke constituents of L. leonurus may exert anticonvulsant and anxiolytic effects which align with the traditional indications and the mode of administration.

Acute exposure of zebrafish (Danio rerio) adults to psychotria carthagenensis leaf extracts: chemical profile, lack of genotoxicity and histological changes

Psychotria carthagenensis is a shrubby plant, often consumed by traditional populations in religious rituals. Previous studies have shown that this plant's infusion can inhibit the activity of Acetylcholinesterase (AChE) in rats. Despite the therapeutic potential, there is a lack of research regarding its possible toxicological and genotoxic effects. Hence, this study aimed to analyze the chemical profile of the ethanol extract from P. carthagenensis leaves by LC-DAD-MS and assess its possible toxicity and genotoxicity in zebrafish (Danio rerio). Adult zebrafish (N = 9/group) were exposed at different concentrations and the LC50 was calculated. Frequencies of micronucleus (MN) and nuclear abnormalities (NA) were estimated for genotoxic effects, and degree of tissue changes (DTC) was used to assess the liver and gill histopathology. From the LC-DAD-MS analyses, the identified compounds included N-fructosyl valine, ethyl hexoside, 5-O-E-caffeoylquinic acid, N-feruloylagmatime, roseoside, di-O-deoxyhexoyl-hexosyl quercetin, loiolide, and oleamide. The calculated values of LC50 did not vary significantly during the time of exposure. At the concentrations of 1.25, 2.5, 3.75, 5, 7.5, 10 and 15 mg/L, there was no genotoxicity, and only low to moderate toxicity for the tissues was observed, despite mortality of 100% at doses of 20-100 mg/L of P. carthagenensis ethanolic leaf extract. There were changes in cytoplasm of hepatocytes at 1.25 mg/L, and karyorrhexis, karyolysis and megalocytosis at 10 mg/L. In the gills, the alterations were primary lamellar hyperplasia in all concentrations, and at 10 mg/L, secondary lamellar edema and vascular hyperemia were common. Additionally, the chemical composition of P. carthagenensis was expanded.

Harnessing medicinal plant compounds for the control of Campylobacter in foods: a comprehensive review

Campylobacter is a major foodborne and zoonotic pathogen, causing severe human infections and imposing a substantial economic burden on global public health. The ongoing spread and emergence of multidrug-resistant (MDR) strains across various fields exacerbate therapeutic challenges, raising the incidence of diseases and fatalities. Medicinal plants, renowned for their abundance in secondary metabolites, exhibit proven efficacy in inhibiting various foodborne and zoonotic pathogens, presenting sustainable alternatives to ensure food safety. This review aims to synthesize recent insights from peer-reviewed journals on the epidemiology and antimicrobial resistance of Campylobacter species, elucidate the in vitro antibacterial activity of medicinal plant compounds against Campylobacter by delineating underlying mechanisms, and explore the application of these compounds in controlling Campylobacter in food. Additionally, we discuss recent advancements and future prospects of employing medicinal plant compounds in food products to mitigate foodborne pathogens, particularly Campylobacter. In conclusion, we argue that medicinal plant compounds can be used as effective and sustainable sources for developing new antimicrobial alternatives to counteract the dissemination of MDR Campylobacter strains.

Acute and subacute toxicological evaluation of the ethanol leaf extract of Morus mesozygia stapf. (Moraceae) in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally, the Morus mesozygia tree leaf has been used to manage maladies such as peptic ulcer, hyperglycemia, dermatitis, rheumatism, stomach-ache, arthritis, cough, malignancies, and malaria in parts of Africa.

AIM OF THE STUDY

The study aimed to evaluate the potential of ethanol leaf extract of Morus mesozygia (EEMm) to induce toxicity by employing both acute and sub-acute oral toxicity experimental models.

MATERIAL AND METHODS

The extract's cytotoxicity was studied using brine shrimps (Artemia salina) lethality assay (BSLA), while in the acute toxicity test, male and female mice were administered a single oral dose of EEMm (2000 mg/kg). Male and female Wistar rats received repeated doses of 100 or 500 mg/kg EEMm orally for 28 days in the sub-acute toxicity experiment. The phytochemical analysis of EEMm was done using the HPLC.

RESULTS

The BSLA revealed a moderate cytotoxic potential of the extract, with an LC50 of 567.13 ± 0.27 μg/mL. All the animals survived the acute toxicity test, with no significant changes in the relative organ weights, suggesting that LD50 is greater than 2000 mg/kg. The animal weights did not vary significantly in the sub-acute toxicity test neither were the alterations in biochemical and hematological tests pronounced, although the histoarchitectures of the kidney, liver and spleen indicated slight anomalies in the evaluated animals. The HPLC analysis revealed the presence of quercetin, ferulic acid, rutin, caffeic acid, morin and gallic acid.

CONCLUSIONS

Ethanol leaf extract of Morus mesozygia demonstrated a safe toxicity profile in rodents, supporting its broad folkloric use in African ethnomedicine.

Safety assessment of crude aqueous methanol extract of Annona senegalensis stem bark: acute and sub-chronic toxicity studies

Annona senegalensis Pers., (wild custard apple), is a shrub used traditionally to treat respiratory and skin diseases. Previous studies have demonstrated its anti-malaria, anti-snake envenomation and anti-cancer activities. However, its toxicological profile remains limited, particularly in male and female animals. This study aims to evaluate the safety of crude aqueous methanol extract of Annona senegalensis stem bark (AMEAS) through acute and sub-chronic toxicity studies. The stem bark of A. senegalensis was collected, air-dried, pulverized, and extracted using 70% methanol. Phytochemical screening, elemental analysis, and acute toxicity evaluation were carried out on AMEAS. Sub-chronic toxicity study was conducted on Wistar rats of both sexes at different doses administered orally for 28 days. Elemental analysis revealed the presence of heavy metals and essential mineral elements with the highest contents being calcium (59.88%) and potassium (25.39%). Acute toxicity testing showed no mortality up to 5000 mg/kg, suggesting an LD50 greater than 5000 mg/kg. In the sub-chronic toxicity study, no mortality or significant harmful effects were observed. The blood glucose decreased from 13.68 mMol/L at 250 mg/kg to 10.71 mMol/L at 1000 mg/kg, much lower than the distilled water group (17.06 mMol/L). In conclusion, the extract appeared to be well-tolerated, with no obvious adverse effects. AMEAS is rich in Calcium (Ca) and potassium (K). It has been shown to have LD50 greater than 5000 mg/kg and is assumed to be safe. On repeated use, AMEAS may cause hypoglycemia and weight loss which may be useful in managing diabetes and obesity respectively.

Compounds isolation from Syzygium cumini leaf extract against the Vibrio species in shrimp through bioassay-guided fractionation

This study was conducted to isolate and identify the bioactive compounds from the ethanolic extract of Syzygium cumini leaf against Vibrio species through a bioassay-guided fractionation. The ethanol extract was exposed to silica gel chromatography followed by reversed phase HPLC to isolate the most effective fraction against V. parahaemolyticus. Using further UHPLC-orbitrap-ion trap mass spectrometry, five compounds were isolated with broad-spectrum potency against a range of Vibrio species viz. V. parahaemolyticus, V. alginolyticus, V. harveyi, V. vulnificus and V. anguillarum. The IC50 values for the compounds ranged from 8 to 48 µg/mL against the most sensitive species V. vulnificus and 58 to >400 µg/mL against V. alginolyticus. The results of the toxicity tests demonstrated that the compounds were not harmful for shrimp. The study's findings indicate that S. cumini leaf extract may contain bioactive molecules that are able to be substituted for antibiotics to treat vibriosis in shrimp farming.

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.

Toxicological effects of acute and repeated doses (180 days) of fruits from Malpighia emarginata (acerola) in rodents

Malpighia emarginata has a high amount of vitamin C with pharmacological or food preservation potential. However, despite its wide use and application possibilities its toxicity in repeated doses and for a long time (6 months) has not yet been studied. In this context, this study aimed to evaluate the acute toxicity and repeated doses from fruits of this plant. The extract was produced with the pulp (EMe) of the lyophilized fruit and submitted to chromatographic and spectroscopic analysis (HPLC and ESI-IT-MSn). In the acute test, the EMe was administered orally and parenterally to rodents (mice and rats) for 14 days, at a dose of 2000 mg/kg. Subsequently, the repeated dose toxicity test was administered orally for 180 days at doses of 50, 300 or 1000 mg/kg. The HPLC assay revealed a high concentration of vitamin C (16.3%), and spectroscopic analyses pointed to the presence of five other polyphenolic compounds. In the acute test, the plant extract showed no apparent toxicity or lethality in rodents. The LD50 was estimated to be greater than 2000 mg/kg and falls into category 5 (low toxicity). In the repeated dose assay, there was no evidence of toxicity, and no differences were observed in water intake, food, weight development, or behavior of the animals in relation to the vehicle group (water). However, hematological and biochemical evaluations pointed out some nonconformities in the levels of cholesterol, leukocytes, and neutrophils of the male rats, but overall, these results did not reveal significant toxicity. Therefore, the Level of Unobserved Adverse Effects (NOAEL) was 1000 mg/kg. Together, the results suggest that the extract obtained from the fruits of M. emarginata does not present representative toxicity in rodents.

Pharmacognostic characterization, wound healing and toxicity assessment of the stem bark of Xylia evansii Hutch (Leguminosae)

Xylia evansii is widely used in traditional medicine to stop bleeding gums and treat wounds. This study was undertaken to assess the wound healing activity and toxicity profile of the stem bark methanol extract of X. evansii (XES). Wound healing activity was determined by the dermal excision model in rats. The free radical scavenging capacity, antioxidant activity, total phenolic and flavonoid contents were evaluated by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, total antioxidant capacity (TAC), aluminum chloride colorimetric and Folin Ciocalteu methods respectively. Acute and sub-acute oral toxicity assessment was performed following the Organization for Economic Co-operation and Development guidelines. Significant (p < 0.05) dose-dependent wound healing effect, similar to that of 1 % silver sulphadiazine was elicit by the 10, 15 and 20 %w/w XES ointments. The highest effect was demonstrated by XES 20 %w/w which resulted in 98.3 % wound surface closure by day 9 of treatment (p < 0.0001). The total phenolic and flavonoid contents were determined to be 381.2 ± 12.57 mg/g gallic acid equivalent (GAE) and 460 ± 29.07 mg/g quercetin equivalent respectively. XES exhibited remarkable free radical scavenging effect (IC50 = 68.13 ± 1.87 μg/mL) and had a total antioxidant capacity of 279.2 ± 32.08 mg/g GAE. The LD50 of XES was estimated to be > 5000 mg/kg. In sub-acute toxicity, 28 days treatment with XES (250, 500, 1000 mg/kg body weight) did not result in any significant (p > 0.05) change in the body weight or weight of the heart, lung, spleen, liver and kidneys. The haematological and biochemical profiles of XES-treated rats were not significantly (p > 0.05) affected after 4-weeks treatment with XES, except for platelet count which increased significantly (p < 0.0001) in a non-dose-dependent manner. Histopathological examination did not reveal any toxic effect to liver cells, however at 1000 mg/kg XES, slight abnormalities were identified in the glomeruli. Microscopy of the powdered stem bark displayed calcium oxalate crystals, pitted vessels and lignified fibres. Tannins, flavonoids, coumarins, saponins, triterpenes and alkaloids were identified in the bark. This is the first report on the wound healing potential and safety profile of X. evansii, giving scientific credence to its use in traditional medicine.

Safety Assessment and Hepatic-Renal Protection of Cajanus cajan (L.) Millsp. Root and Its Soy Isoflavone Contents

Cajanus cajan (L.) Millsp., also known as pigeon pea, has roots that have exhibited much pharmacological potential. The present study was conducted to assess the safe dose of the ethanolic extract of C. cajan roots (EECR95) and to analyze the main soy isoflavones contents. In vitro, we investigated the mutagenicity and cytotoxic effect of EECR95 on Salmonella typhimurium-TA98 and TA100 (by Ames tests) and RAW 264.7, L-929, and HGF-1 cell lines (by MTT tests) for 24 h of incubation. We found no mutagenic or cytotoxic effects of EECR95. After administration of 0.2 or 1.0 g/kg bw of EECR95 to both male and female Wistar rats for 90 days, there were no significant adverse effects on the behaviors (body weight, water intake, and food intake), organ/tissue weights, or immunohistochemical staining, and the urine and hematological examinations of the rats were within normal ranges. EECR95 potentially decreases renal function markers in serum (serum uric acid, BUN, CRE, and GLU) or liver function markers (cholesterol, triglyceride, and glutamic-pyruvate-transaminase (GPT)). We also found that EECR95 contained five soy isoflavones (genistein, biochanin A, daidzein, genistin, and cajanol), which may be related to its hepatorenal protection. Based on the high dose (1.0 g/kg bw) of EECR95, a safe daily intake of EECR95 for human adults is estimated to be 972 mg/60 kg person/day.

The African cherry: A review of the botany, traditional uses, phytochemistry, and biological activities of Prunus africana (Hook.f.) Kalkman

ETHNOPHARMACOLOGICAL RELEVANCE

Prunus africana (Hook.f.) Kalkman (Rosaceae), commonly known as "Pygeum" or "African cherry", occurs in mainland montane forests scattered across sub-Saharan Africa, Madagascar, and some surrounding islands. Traditionally, decoctions of the stem-bark are taken orally for the treatment of a wide variety of conditions, such as benign prostatic hyperplasia (BPH), stomach ache, chest pain, malaria, heart conditions, and gonorrhoea, as well as urinary and kidney diseases. The timber is used to make axe handles and for other household needs. The dense wood is also sawn for timber.

AIM

The fragmented information available on the ethnobotany, phytochemistry, and biological activities of the medicinally important P. africana was collated, organised, and analysed in this review, to highlight knowledge voids that can be addressed through future research.

MATERIALS AND METHODS

A bibliometric analysis of research output on P. africana was conducted on literature retrieved, using the Scopus® database. The trend in the publications over time was assessed and a network analysis of collaborations between countries and authors was carried out. Furthermore, a detailed review of the literature over the period 1971 to 2021, acquired through Scopus, ScienceDirect, SciFinder, Pubmed, Scirp, DOAJ and Google Scholar, was conducted. All relevant abstracts, full-text articles and various book chapters on the botanical and ethnopharmacological aspects of P. africana, written in English and German, were consulted.

RESULTS

A total of 455 documents published from 1971 to 2021, were retrieved using the Scopus search. Analysis of the data showed that the majority of these documents were original research articles, followed by reviews and lastly a miscellaneous group comprising conference papers, book chapters, short surveys, editorials and letters. Data were analysed for annual output and areas of intense research focus, and countries with high research output, productive institutions and authors, and collaborative networks were identified. Prunus africana is reported to exhibit anti-inflammatory, analgesic, antimicrobial, anti-oxidant, antiviral, antimutagenic, anti-asthmatic, anti-androgenic, antiproliferative and apoptotic activities amongst others. Phytosterols and other secondary metabolites such as phenols, triterpenes, fatty acids, and linear alcohols have been the focus of phytochemical investigations. The biological activity has largely been ascribed to the phytosterols (mainly 3-β-sitosterol, 3-β-sitostenone, and 3-β-sitosterol-glucoside), which inhibit the production of prostaglandins in the prostate, thereby suppressing the inflammatory symptoms associated with BPH and chronic prostatitis.

CONCLUSIONS

Many of the ethnobotanical assertions for the biological activity of P. africana have been confirmed through in vitro and in vivo studies. However, a disparity exists between the biological activity of the whole extract and that of single compounds isolated from the extract, which were reported to be less effective. This finding suggests that a different approach to biological activity studies should be encouraged that takes all secondary metabolites present into consideration. A robust technique, such as multivariate biochemometric data analysis, which allows for a holistic intervention to study the biological activity of a species is suggested. Furthermore, there is a need to develop rapid and efficient quality control methods for both raw materials and products to replace the time-consuming and laborious methods currently in use.

Acute and sub-acute toxicity evaluation of Merremia tridentata (L.) stem extract on mice

The acute and sub-acute toxicity studies were performed in male and female Swiss albino mice as per the guidelines mentioned in OECD. The oral administration of M. tridentata stem extract (MSE) showed no treatment-related mortality and body weight change in mice up to the single dose of 30,000 mg/kg body weight in the acute toxicity study and up to a dose of 30,000 mg/kg/day body weight in the sub-acute toxicity study. Moreover, the clinical signs, body weight, gross pathology, organ weight, hematology (except for platelet count), biochemical analysis, and histopathology did not show significant variation at a medium dose of 15,000 mg/kg/day body weight compared to the control group. However, toxicological signs in behavior, very mild interstitial nephritis, as well as significant variation in platelet count and total protein parameters were observed at a dose of 30,000 mg/kg/day in the 28-day oral toxicity study. Thus, the no-observed-adverse-effect level was determined at a dose of 15,000 mg/kg/day body weight. Based on study results, it is concluded that MSE showed LD₅₀ of greater than 5000 mg/kg/day body weight. Hence, this could be a potential candidature as a future safe pharmaceutical product.

Anthelmintic Agents from African Medicinal Plants: Review and Prospects

Soil-transmitted helminthiasis affects more than 1.5 billion people globally and largely remains a sanitary problem in Africa. These infections place a huge economic burden on poor countries and affect livestock production, causing substantial economic losses and poor animal health. The emergence of anthelmintic resistance, especially in livestock, and the potential for its widespread in humans create a need for the development of alternative therapies. Medicinal plants play a significant role in the management of parasitic diseases in humans and livestock, especially in Africa. This report reviews anthelmintic studies that have been conducted on medicinal plants growing in Africa and published within the past two decades. A search was made in various electronic databases, and only full articles in English were included in the review. Reports show that aqueous and hydroalcoholic extracts and polar fractions obtained from these crude extracts form the predominant (80%) form of the extracts studied. Medicinal plants, extracts, and compounds with different chemical groups have been studied for their anthelmintic potential. Polyphenols and terpenoids are the most reported groups. More than 64% of the studies employed in vitro assays against parasitic and nonparasitic nematode models. Egg hatch inhibition, larval migration inhibition, and paralysis are the common parameters assessed in vitro. About 72% of in vivo models involved small ruminants, 15% rodents, and 5% chicken. Egg and worm burden are the main factors assessed in vivo. There were no reports on interventions in humans cited within the period under consideration. Also, few reports have investigated the potential of combining plant extracts with common anthelmintic drugs. This review reveals the huge potential of African medicinal plants as sources of anthelmintic agents and the dire need for in-depth clinical studies of extracts, fractions, and compounds from African plants as anthelmintic agents in livestock, companion animals, and humans.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents

OBJECTIVES

Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study.

METHODS

Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods.

RESULTS

The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible.

CONCLUSIONS

The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.

The Fight against Infection and Pain: Devil’s Claw (Harpagophytum procumbens) a Rich Source of Anti-Inflammatory Activity: 2011–2022

Harpagophytum procumbens subsp. procumbens (Burch.) DC. ex Meisn. (Sesame seed Family—Pedaliaceae) is a popular medicinal plant known as Devil’s claw. It is predominantly distributed widely over southern Africa. Its impressive reputation is embedded in its traditional uses as an indigenous herbal plant for the treatment of menstrual problems, bitter tonic, inflammation febrifuge, syphilis or even loss of appetite. A number of bioactive compounds such as terpenoids, iridoid glycosides, glycosides, and acetylated phenolic compounds have been isolated. Harpagoside and harpagide, iridoid glycosides bioactive compounds have been reported in countless phytochemical studies as potential anti-inflammatory agents as well as pain relievers. In-depth studies have associated chronic inflammation with various diseases, such as Alzheimer’s disease, obesity, rheumatoid arthritis, type 2 diabetes, cancer, and cardiovascular and pulmonary diseases. In addition, 60% of chronic disorder fatalities are due to chronic inflammatory diseases worldwide. Inflammation and pain-related disorders have attracted significant attention as leading causes of global health challenges. Articles published from 2011 to the present were obtained and reviewed in-depth to determine valuable data findings as well as knowledge gaps. Various globally recognized scientific search engines/databases including Scopus, PubMed, Google Scholar, Web of Science, and ScienceDirect were utilized to collect information and deliver evidence. Based on the literature results, there was a dramatic decrease in the number of studies conducted on the anti-inflammatory and analgesic activity of Devil’s claw, thereby presenting a potential research gap. It is also evident that currently in vivo clinical studies are needed to validate the prior massive in vitro studies, therefore delivering an ideal anti-inflammatory and analgesic agent in the form of H. procumbens products.

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services.

Assessment of Larval Toxicity and the Teratogenic Effect of Three Medicinal Plants Used in the Traditional Treatment of Urinary Tract Infections in Benin

Objective

Mangifera indica Linn, Bridelia ferruginea Benth, and Alstonia boonei De Wild are three plants commonly used in the traditional treatment of urinary tract infections in Benin. This study sets out to assess the cytotoxic and teratogenic effects of extracts of these plants on Artemia salina larvae and hen embryos.

Methods and Results

The aqueous and ethanolic extracts were obtained by maceration of the powders in solvents. Larval cytotoxicity was performed on Artemia salina larvae. The teratogenic effect of these plants was evaluated on chick embryos at 100 mg/kg and 300 mg/kg. The extracts were injected on the 7th and 14th days of incubation. The quality of the hatched chicks was evaluated by the Tona score followed by the hematological and the biochemical parameter assays. The extracts did not show cytotoxicity on the larvae. The eggs treated with plant extracts at 300 mg/kg significantly lowered the hatchability rate, except for the Mangifera indica Linn. The chicks obtained were all at the very good quality. Then, no significant variation was observed between hematological parameters except white blood cells. For the biochemical parameters, only ASAT showed some significant variations for a few extracts. It would be important to assess the genotoxicity of the plant extracts to determine more broader toxicity. These data justify the use of these medicinal plants in traditional Beninese medicine and constitute in fact a source of production of anti-infectious drugs.

Anti-seizure activity of African medicinal plants: The identification of bioactive alkaloids from the stem bark of Rauvolfia caffra using an in vivo zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Epilepsy is one of the major chronic diseases that does not have a cure to date. Adverse drug reactions have been reported from the use of available anti-epileptic drugs (AEDs) which are also effective in only two-thirds of the patients. Accordingly, the identification of scaffolds with promising anti-seizure activity remains an important first step towards the development of new anti-epileptic therapies, with improved efficacy and reduced adverse effects. Herbal medicines are widely used in developing countries, including in the treatment of epilepsy but with little scientific evidence to validate this use. In the search for new epilepsy treatment options, the zebrafish has emerged as a chemoconvulsant-based model for epilepsy, mainly because of the many advantages that zebrafish larvae offer making them highly suitable for high-throughput drug screening.

AIM OF THE STUDY

In this study, 20 medicinal plants traditionally used in South Africa to treat epilepsy were screened for anti-epileptic activity using a zebrafish larvae model.

MATERIALS AND METHODS

Toxicity triaging was conducted on 120 crude extracts, 44 fractions and three isolated compounds to determine the maximum tolerated concentration (MTC) of each extract, fraction or compound. MTC values were used to guide the concentration range selection in bioactivity studies. The effectiveness of crude extracts, fractions and isolated compounds from Rauvolfia caffra Sond. in suppression of pentylenetetrazole (PTZ) induced seizure-like behaviour in a 6-dpf zebrafish larvae model was measured using the PTZ assay.

RESULTS

Following a preliminary toxicity triage and bioactivity screen of crude extracts from 20 African plants used traditionally for the treatment and management of epilepsy, the methanolic extract of Rauvolfia caffra Sond. was identified as the most promising at suppressing PTZ induced seizure-like behaviour in a zebrafish larvae model. Subsequent bioactivity-guided fractionation and spectroscopic structural elucidation resulted in the isolation and identification of two tryptoline derivatives; a previously unreported alkaloid to which we assigned the trivial name rauverine H (1) and the known alkaloid pleiocarpamine (2). Pleiocarpamine was found to reduce PTZ-induced seizures in a dose-dependent manner.

CONCLUSIONS

Accordingly, pleiocarpamine represents a promising scaffold for the development of new anti-seizure therapeutic compounds. Furthermore, the results of this study provide preliminary evidence to support the traditional use of Rauvolfia caffra Sond. in the treatment and management of epilepsy. These findings warrant further studies on the anti-epileptic potential of Rauvolfia caffra Sond. using other models.

Phytochemicals and Amino Acids Profiles of Selected sub-Saharan African Medicinal Plants' Parts Used for Cardiovascular Diseases' Treatment

For years, the focus on the lipid-atherosclerosis relationship has limited the consideration of the possible contribution of other key dietary components, such as amino acids (AAs), to cardiovascular disease (CVD) development. Notwithstanding, the potential of plant-based diets, some AAs and phytochemicals to reduce CVDs' risk has been reported. Therefore, in this study, the phytochemical and AA profiles of different medicinal plants' (MPs) parts used for CVDs' treatment in sub-Saharan Africa were investigated. Fourier-transform infrared analysis confirmed the presence of hydroxyl, amino and other bioactive compounds' functional groups in the samples. In most of them, glutamic and aspartic acids were the most abundant AAs, while lysine was the most limiting. P. biglobosa leaf, had the richest total branched-chain AAs (BCAAs) level, followed by A. cepa bulb. However, A. cepa bulb had the highest total AAs content and an encouraging nutraceutical use for adults based on its amino acid score. Principal component analysis revealed no sharp distinction between the AAs composition of MPs that have found food applications and those only used medicinally. Overall, the presence of medicinally important phytochemicals and AAs levels in the selected MPs' parts support their use for CVDs treatment as they might not add to the AAs (e.g., the BCAAs) burden in the human body.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents

OBJECTIVES

Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study.

METHODS

Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods.

RESULTS

The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible.

CONCLUSIONS

The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.

A Review of Plant-Based Therapies for the Treatment of Urinary Tract Infections in Traditional Southern African Medicine

Urinary tract infections (UTIs) are amongst the most common bacterial infections globally, with ∼11% of the world's population contracting at least one infection annually. Several South African plants are used in traditional healing systems to treat UTIs, yet the therapeutic potential of these plants against bacteria that cause UTI remains poorly explored. This study documents southern African plant species used traditionally to treat UTIs. An extensive literature review was undertaken to document the southern African plant species that are used in traditional South African medicine to treat UTIs, thereby highlighting gaps in the current research that require further study. One hundred and fifty-three southern African plant species that are used to treat UTIs were identified. Eighty-five southern African plants were identified as having noteworthy inhibitory activity against the major UTI-causing bacteria. Few of those studies screened against all of the bacterial causes of UTIs, and none of those studies examined the mechanism of action of the plant preparations. Furthermore, many of those studies did not test the toxicity of the plant extracts, so an evaluation of the safety for therapeutic usage was lacking. Substantial further research is to determine their potential for therapeutic use.

A Review of the Toxicity and Phytochemistry of Medicinal Plant Species Used by Herbalists in Treating People Living With HIV/AIDS in Uganda

Introduction: Despite concerns about toxicity, potentially harmful effects and herb-drug interactions, the use of herbal medicines remains widely practiced by people living with HIV/AIDS (PLHIV) in Uganda. Objective: The objective of the paper was to comprehensively review the literature on the toxicity and chemical composition of commonly used medicinal plant species in treating PLHIV in Uganda. Methods: We reviewed relevant articles and books published over the last sixty years on ethnobotany, antiviral/anti-HIV activity, toxicity, phytochemistry of Vachellia hockii, Albizia coriaria, Bridelia micrantha, Cryptolepis sanguinolenta, Erythrina abyssinica, Gardenia ternifolia, Gymnosporia senegalensis, Psorospermum febrifugium, Securidaca longipendunculata, Warburgia ugandensis and Zanthoxylum chalybeum and their synonyms. We searched PubMed, Web of Science, Scopus, Science Direct and Google Scholar. Discussion: Most of the plant species reviewed apart from P. febrifugium, S. longipedunculata and C. sanguinolenta lacked detailed phytochemical analyses as well as the quantification and characterization of their constituents. Crude plant extracts were the most commonly used. However, purified/single component extracts from different plant parts were also used in some studies. The U87 human glioblastoma was the most commonly used cell line. Water, ethanol, methanol and DMSO were the commonest solvents used. In some instances, isolated purified compounds/extracts such as Cryptolepine and Psorospermin were used. Conclusion: Cytotoxicity varied with cell type, solvent and extract type used making it difficult for direct comparison of the plant species. Five of the eleven plant species namely, A. coriaria, C. sanguinolenta, G. ternifolia, P. febrifugium and Z. chalybeum had no cytotoxicity studies in animal models. For the remaining six plant species, the crude aqueous and ethanol extracts were mainly used in acute oral toxicity studies in mice. Herbalists reported only A. coriaria and W. ugandensis to cause toxic side effects in humans. However, selective cytotoxic plant extracts can potentially be beneficial as anticancer or anti-tumour drugs.

Phytochemical composition and in vitro safety evaluation of Ziziphora clinopodioides Lam. ethanolic extract: Cytotoxicity, genotoxicity and mutagenicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

The application of the herb Ziziphora clinopodioides Lam. in folk medicine and as a food additive has been recommended due to its many claimed bioactivities. Regardless of the plant benefits, its safety considerations are largely unknown.

AIM OF THE STUDY

The aim of the present research was to determine the chemical compositions and cytotoxicity, genotoxicity, and mutagenicity potentials of the ethanolic extract of Ziziphora clinopdioides Lam. (EEZC).

MATERIALS AND METHODS

GC-MS and LC-MS analysis were used for chemical composition determination. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and trypan blue exclusion dye assays were used for cytotoxicity and the Comet assay was employed for genotoxicity assessment on human blood lymphocytes. Also, the Ames Salmonella/microsome test was carried out for the evaluation of mutagenicity.

RESULTS

Pulegone was the main component of the n-hexane fraction. Different phenolic acids and flavonoids were detected by LC-MS. The cytotoxicity study indicated a conspicuous decline in human lymphocyte viability ranging from 52% to 100% as showed by the MTT assay and 67% up to 100% by the trypan blue assay, at 1 and 10 mg/mL, respectively. The Comet assay results revealed a dose dependent genotoxicity, in so much as 90% and 98% of the cells were screened as damaged at concentrations of 5 and 10 mg/mL, respectively. An incidence rate of 8% and 13% of grade 4 damage was observed at 5 and 10 mg/mL, respectively. Additionally, the DNA damage index (DI) was elevated dose-dependently by a rising concentration of the extract, wherein the DI at 10 mg/mL concentration was 2.22, which was 22 times greater than that of negative control, and even more than positive control. The Ames test exhibited no signs of mutagenicity for neither Salmonella typhimurium TA98 nor TA100 strains, accompanied or unaccompanied by S9 metabolic activation.

CONCLUSION

Results indicated a dose-dependent cytotoxicity and genotoxicity potential of the EEZC on human lymphocytes, suggesting that this plant should be used with caution by consumers, even in the food and pharmaceutical industries. Since the plant usage in daily life continues to increase due to its ever growing phytotherapical and phytonutritional properties, it may pose a health risk by its high concentration's uptake. Although no mutagenicity of this extract was observed in this study, further research is recommended to clarify the mutagenic risks of this herb.

Safety assessment of oral administration of ethanol extract of Justicia carnea leaf in healthy wistar rats: hematology, antioxidative and histology studies

Background

Consumption of medicinal plants has diverse therapeutic benefits and could also have toxic effect. Justicia carnea is a medicinal plant that is used conventionally as blood tonic from time immemorial in Nigeria. The aim of this study is to evaluate the safety of ethanol extract of J. carnea leaf assessing the hematology indices, organ antioxidant system and histology in healthy male wistar rats.

Methods

Powdered sample was extracted using absolute ethanol and concentrated to obtain a slurry paste of J. carnea ethanol extracts. Acute toxicity was determined in two phases using Lorke method. In subacute study, rats were randomized into six groups of five rats per group: Group 1 (control) received distilled water, group 2, 3, 4, 5, 6 received 50, 100, 500, 800 and 1200 mg/kg body weight of J. carnea ethanol extract once daily using oral gavage. At the end of 14th day of administration, rats were allowed to fast overnight, sacrificed to collect samples for biochemical analysis and histopathological examination.

Results

The LD50 of extract was greater than 5000 mg/kg body weight. Higher doses (> 500 mg/kg) of extract significantly (p < 0.05) increased RBC, hemoglobin and platelet compared to the control. Liver superoxide dismutase (SOD) activity was significantly (p < 0.05) increased at 1200 mg/kg while other tested doses caused no detrimental effect on glutathione, catalase, SOD and malondialdehyde level in liver and kidney. Histopathological examination of liver and kidney showed mild to severe pathological lesion in a dose dependent manner.

Conclusions

The results of this study suggests that ethanol extract of J. carnea leaf is relatively safe, could be beneficial in alleviating hematology related abnormalities without causing adverse effects on endogenous antioxidant system. However, caution should be taken as higher dose at 1200 mg/kg could cause noticeable tissue injury.

Phytochemical characterization, genotoxicity, cytotoxicity, and antimicrobial activity of Gautheria procumbens essential oil

This study investigated the chemical constituents of Gaultheria procumbens essential oil and is the first to relate cytogenotoxicity with oxidative metabolism and antimicrobial activity. Chromatographic analysis of the essential oil showed methyl salicylate (99.96%) and linalool (0.04%) as the major compounds. The essential oil showed no signs of cytogenotoxicity at different concentrations (1.82 to 58.34 mg mL^-1). Furthermore, G. procumbens essential oil and methyl salicylate were used to evaluate the minimal inhibitory concentrations (MIC) and minimal microbicidal concentrations (MMC). The results showed efficacy against several microorganisms, including Aeromonas caviae, Candida albicans, and Mycobacterium fortuitum with MIC values ranging from 1.82 to 3.64 mg mL^-1 and MMC values ranging from 3.64 to 12.67 mg mL^-1, which were confirmed by time-kill kinetics. Based on our results, the essential oil is a promising alternative to developing future formulations to treat infections caused by microorganisms.

Poisonous medicinal plants used in the popular pharmacopoeia of the Rif, northern Morocco

Popular herbal medicine has served as a unique health provider for human beings for thousands of years. In the present study, we document the toxic plants used as medicines in the Rif, intending to assess the knowledge of indigenous people on the toxicity of the natural products used. Ethnobotanical survey was conducted in the Rif, northern Morocco between June 2016 and June 2018 using semi-structured questionnaires and focus groups. An investigation of the scientific literature was conducted to sustain or verify the claimed toxicological information. A total of 84 species of plants belonging to 67 genera and 30 families were reported as being used in the prevention and treatment of diseases. The families reported to be most representatives of these kinds of plants are Asteraceae and Fabaceae (7 species). However, the highly toxic plant prescribed was Rosmarinus officinalis L. Leaf was the most commonly used plant part, and the majority of herbal remedies were prepared from a decoction (40.6%). The results of this investigation showed that the local people in the Rif are still dependent on herbal medicine. These species used for remedial purposes are noted to have a potential toxic impact associated with their irrational consumption. Therefore, we recommend that attention should be observed when using them as medicinal sources.

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

•

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.

Acute and sub-acute toxicity evaluation of the root extract of Rheum turkestanicum Janisch

Despite the widespread use of Rheum turkestanicum in herbal medicine, no study has yet examined its in vivo toxicity. The aim of this study is to evaluate the acute and sub-acute toxicity of hydroalcoholic extract of R. turkestanicum root. In acute toxicity experiment, female and male mice (n = 5/group/sex) were orally administrated with the extract at single doses of 300, 2000 and 3000 mg/kg and observed for 14 days. In the sub-acute study, the extract was orally administered daily at doses of 100 and 400 mg/kg to male rats (n = 8) for 4 weeks. During the acute toxicity test, there were no deaths or any signs of toxicity observed after administration of the R. turkestanicum extract at 300 mg/kg, which was the no-observed-adverse-effect level (NOAEL). The extract at a dose of 3000 mg/kg led to the death of one female and one male mouse (LD₅₀ > 3000 mg/kg). In sub-acute toxicity experiment, the extract induced no mortality or significant changes in body weight, general behaviors, hematological parameters, serum biochemical factors (related to the kidney and liver function), and histopathology of the heart, liver, kidney, and brain up to the highest dose tested of 400 mg/kg (NOAEL). High-performance liquid chromatography-mass spectrometry revealed the presence of phenolic compounds, flavonoids, alkanes, and anthraquinones in the extract. In conclusion, short-term use of R. turkestanicum root does not appear to produce significant toxicity up to a dose of 400 mg/kg.

Pharmacological properties of Rheum turkestanicum Janisch

Medicinal herbs have been increasingly used worldwide for diseases prevention and treatment. Rheum turkestanicum Janisch. is a perennial shrub of the Polygonaceae family. Genus Rheum includes more than 60 species growing around the world which are used in foods and traditional medicines. R. turkestanicum is believed to be able to improve different kinds of disorders including diabetes, hypertension, jaundice and cancer. In recent years, this medicinal plant has been a subject of many experimental studies to document its health-beneficial properties. These studies have revealed antidiabetic, anticancer, nephroprotective, cardioprotective, and hepatoprotective properties of R. turkestanicum. The presence of flavonoids (e.g. epicatechin and quercetin) and anthraquinones (e.g. chrysophanol, physcion, and emodin) in R. turkestanicum justifies its health-beneficial effects. Nevertheless, possible therapeutic applications and safety of this plant still need to be elucidated in further clinical studies.

Curative effects of Distemonanthus benthamianus Baillon. Trunk-bark extracts on enteropathogenic Escherichia coli 31-induced diarrhea in rats

Background Distemonanthus benthamianus is used in the Western part of Cameroon to treat diarrheal episodes and infections. This study assessed its trunk-bark extracts activity against enteropathogenic Escherichia coli 31 (EPEC 31)-induced diarrhea in rats. Methods Aqueous and methanolic extracts were analyzed through high-performance liquid chromatography (HPLC). In vitro minimum inhibitory and bactericidal concentrations (MICs/MBCs) were evaluated on Enterococcus faecalis (ATCC 10,541), E. coli (ATCC 6539), Klebsiella pneumoniae (ATCC 13,883), Salmonella typhi (ATCC 6539) strains and on Proteus mirabilis, Pseudomonas aeruginosa (PA 01) and Shigella flexneri isolates using the microdilution method. Diarrhea was induced by inoculating rats with EPEC 31 (1.5 × 108 CFU/mL; p.o). Serum transaminases level assay and enzyme-linked immunosorbent assay (ELISA) for cytokines determination were performed. Hematoxylin-eosin (H-E) staining was used for intestinal tissue analysis. Results HPLC fingerprints of extracts showed presence of gallic acid and other unidentified compounds. The lowest MIC of 256 µg/mL was obtained with methanolic extract. At 100 mg/kg, both extracts significantly (p<0.001) inhibited diarrhea, with the methanolic extract being the most active. In addition, the methanolic extract significantly (p<0.001) increased the relative mass of the liver compared to negative control (Tween-DMSO 8%). The aqueous extract (100 mg/kg) significantly (p<0.01) increased alanine aminotransferase (ALT) serum concentration; while the methanolic extract (100 mg/kg) exhibited similar effect over aspartate aminotransferase (AST). At 50 and 100 mg/kg, the methanolic extract significantly (p<0.05 and p<0.01) decreased the Interleukin-1β (IL-1β) serum level, compared to negative control (Tween-DMSO 8%). Serum level of tumor necrosis factor alpha (TNF-α) significantly (p<0.001) decreased with 100 mg/kg of aqueous extract and all doses of methanolic extract. Inhibition of inflammatory cells tissue infiltration and epithelial regeneration was highly noticed in the ileum and colon of extracts-treated rats than in ciprofloxacin-treated animals. Conclusion These findings suggest that D. benthamianus trunk-bark extracts displayed therapeutic effects against infectious diarrhea in rats.

Toxicity studies of Acacia nilotica (L.): A review of the published scientific literature

Introduction: Acacia nilotica is a valuable plant with medicinal properties that increasinglyincites the curiosity of many researchers. Its pharmacological properties are reported in manystudies, but the fact remains that the plant can be just as toxic as any modern pharmaceuticaldrug. It is very important to dispose sufficient knowledge on what are reported concerning itstoxicity profile. This review is aimed to provide comprehensive summary (all-in-one) of whathave been reported about the toxicity of A. nilotica and to determine the necessity or not toconduct more toxicological studies in a further step toward rationalizing its medicinal use.Methods: Scientific information about the toxicity and or safety of A. nilotica reported elsewherewere reviewed. Search engines such as Google, Bing and Baidu and databases of scientificjournals such as PubMed, Scopus, CAS, CABI, HINARI and AJOL were used to retrieve studiesfrom 1999 to 2017.Results: Few studies have reported the toxicity potential of A. nilotica and most with very limitedinformation. Three of them have reported serious deleterious toxic effects of certain parts of theplant on major organ systems such as kidney and liver. Stem bark as part of A. nilotica appearedto be the most cited to cause observable clinical signs of toxicity and organs lesions.Conclusion: Overall, this review provided comprehensive information on what is known aboutthe toxicity of A. nilotica and showed the necessity to conduct more advanced long-term-basedtoxicological studies.

Propensity of Tagetes erecta L., a Medicinal Plant Commonly Used in Diabetes Management, to Accumulate Perfluoroalkyl Substances

It has been extensively demonstrated that plants accumulate organic substances emanating from various sources, including soil and water. This fact suggests the potentiality of contamination of certain vital bioresources, such as medicinal plants, by persistent contaminants, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutane sulfonate (PFBS). Hence, in this study, the propensity of Tagetes erecta L. (a commonly used medicinal plant) to accumulate PFOA, PFOS, and PFBS was determined using liquid chromatography/tandem mass spectrometry (LC⁻MS/MS-8030). From the results, PFOA, PFOS, and PFBS were detected in all the plant samples and concentration levels were found to be 94.83 ng/g, 5.03 ng/g, and 1.44 ng/g, respectively, with bioconcentration factor (BCF) ranges of 1.30 to 2.57, 13.67 to 72.33, and 0.16 to 0.31, respectively. Little evidence exists on the bioaccumulative susceptibility of medicinal plants to these persistent organic pollutants (POPs). These results suggest that these medicinal plants (in particular, Tagetes erecta L., used for the management of diabetes) are also potential conduits of PFOA, PFOS, and PFBS into humans.

Evaluation of the glycemic effect of Ceratonia siliqua pods (Carob) on a streptozotocin-nicotinamide induced diabetic rat model

Background

Ceratonia siliqua pods (carob) have been nominated to control the high blood glucose of diabetics. In Yemen, however, its antihyperglycemic activity has not been yet assessed. Thus, this study evaluated the in vitro inhibitory effect of the methanolic extract of carob pods against α-amylase and α-glucosidase and the in vivo glycemic effect of such extract in streptozotocin-nicotinamide induced diabetic rats.

Methods

2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant power assay (FRAP) were applied to evaluate the antioxidant activity of carob. In vitro cytotoxicity of carob was conducted on human hepatocytes (WRL68) and rat pancreatic β-cells (RIN-5F). Acute oral toxicity of carob was conducted on a total of 18 male and 18 female Sprague-Dawley (SD) rats, which were subdivided into three groups (n = 6), namely: high and low dose carob-treated (CS5000 and CS2000, respectively) as well as the normal control (NC) receiving a single oral dose of 5,000 mg kg^-1 carob, 2,000 mg kg^-1 carob and 5 mL kg^-1 distilled water for 14 days, respectively. Alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, total bilirubin, creatinine and urea were assessed. Livers and kidneys were harvested for histopathology. In vitro inhibitory effect against α-amylase and α-glucosidase was evaluated. In vivo glycemic activity was conducted on 24 male SD rats which were previously intraperitoneally injected with 55 mg kg^-1 streptozotocin (STZ) followed by 210 mg kg^-1nicotinamide to induce type 2 diabetes mellitus. An extra non-injected group (n = 6) was added as a normal control (NC). The injected-rats were divided into four groups (n = 6), namely: diabetic control (D0), 5 mg kg^-1glibenclamide-treated diabetic (GD), 500 mg kg^-1 carob-treated diabetic (CS500) and 1,000 mg kg^-1 carob-treated diabetic (CS1000). All groups received a single oral daily dose of their treatment for 4 weeks. Body weight, fasting blood glucose (FBG), oral glucose tolerance test, biochemistry, insulin and hemostatic model assessment were assessed. Pancreases was harvested for histopathology.

Results

Carob demonstrated a FRAP value of 3191.67 ± 54.34 µmoL Fe⁺⁺ and IC₅₀ of DPPH of 11.23 ± 0.47 µg mL^-1. In vitro, carob was non-toxic on hepatocytes and pancreatic β-cells. In acute oral toxicity, liver and kidney functions and their histological sections showed no abnormalities. Carob exerted an in vitro inhibitory effect against α-amylase and α-glucosidase with IC₅₀ of 92.99 ± 0.22 and 97.13 ± 4.11 µg mL^-1, respectively. In diabetic induced rats, FBG of CS1000 was significantly less than diabetic control. Histological pancreatic sections of CS1000 showed less destruction of β-cells than CS500 and diabetic control.

Conclusion

Carob pod did not cause acute systemic toxicity and showed in vitro antioxidant effects. On the other hand, inhibiting α-amylase and α-glucosidase was evident. Interestingly, a high dose of carob exhibits an in vivo antihyperglycemic activity and warrants further in-depth study to identify the potential carob extract composition.

Acute and chronic toxicity of a polyherbal preparation - Jueyin granules

Background

The potential toxicity of Chinese herbal medicine has attracted more attention in recent years. Jueyin granules (JYG), a polyherbal formula, have been proven to be an effective agent for treating psoriasis in both animal models and clinical research. However, little is known about the possible acute and chronic toxicity of JYG. The objective of this study was to investigate the safety of JYG in ICR mice and Wistar rats.

Methods

To examine the acute toxicity of JYG, ICR mice were randomly divided into an experimental group and a control group, each comprising 20 mice (10 male and 10 female). The experimental group was fed JYG solution at a dose of 21.5 g/kg, equivalent to 143 times the clinical human dosage, for 14 days, whereas control animals were fed distilled water. In the chronic toxicity test, Wistar rats were divided into four groups, each comprising 40 rats (20 male and 20 female). For 6 months, the experimental animals were given JYG at a dose of 7.5, 3.75 and 1.875 g/kg, whereas control animals were given distilled water. The animals’ body weight, food and water consumptions were monitored weekly. In addition, their biochemical and hematological parameters, histopathology, and body and organ weights were all measured at specific observation time points.

Results

According to the results of the acute toxicity test, no mortality was found and no abnormal pathological changes in major organs were observed in mice treated with JYG. In the chronic toxicity test, JYG did not cause significant abnormalities in the physiological parameters or pathological changes in the major organs of the rats.

Conclusion

The results indicated that JYG at the given doses did not induce any harmful effects in animals. Thus, it is reasonable to conclude that JYG is safe at the studied dosage levels and causes no acute or chronic toxicity in animal models.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2211-z) contains supplementary material, which is available to authorized users.

The role of pollutants in type 2 diabetes mellitus (T2DM) and their prospective impact on phytomedicinal treatment strategies

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes and it is characterized by high blood sugar and abnormal sera lipid levels. Although the specific reasons for the development of these abnormalities are still not well understood, traditionally, genetic and lifestyle behavior have been reported as the leading causes of this disease. In the last three decades, the number of diabetic patients has drastically increased worldwide, with current statistics suggesting the number is to double in the next two decades. To combat this incurable ailment, orthodox medicines, to which economically disadvantaged patients have minimal access to, have been used. Thus, a considerable amalgamation of medicinal plants has recently been proven to possess therapeutic capabilities to manage T2DM, and this has prompted studies primarily focusing on the healing aspect of these plants, and ultimately, their commercialization. Hence, this review aims to highlight the potential threat of pollutants, i.e., polyfluoroalkyl compounds (PFCs), endocrine disrupting chemicals (EDCs) and heavy metals, to medicinal plants, and their prospective impact on the phytomedicinal therapy strategies for T2DM. It is further suggested that auxiliary research be undertaken to better comprehend the factors that influence the uptake of these compounds by these plants. This should include a comprehensive risk assessment of phytomedicinal products destined for the treatment of T2DM. Regulations that control the use of PFC-precursors in certain developing countries are also long overdue.

Human Plant Exposures Reported to a Regional (Southwestern) Poison Control Center Over 8 Years

BACKGROUND

There is little published data about human plant exposures reported to US poison control centers (PCCs).

METHODS

A retrospective chart review of all reported plant exposures to a single regional PCC between January 1, 2003 and December 31, 2010 was done to understand better the characteristics of plant exposure cases. Specific generic plant codes were used to identify cases. Recorded variables included patient demographics, plant involved, exposure variables, symptoms, management site, treatments, and outcome. Univariate and multivariate regression was used to identify outcome predictors.

RESULTS

A total of 6492 charts met inclusion criteria. The average age was 16.6 years (2 months-94 years); 52.4% were male. The most common exposure reason was unintentional (98%), and the majority (92.4%) occurred at the patient's home. Ingestions (58.3%) and dermal exposures (34.3%) accounted for most cases. Cactus (27.5%), oleander (12.5%), Lantana (5.7%), and Bougainvillea (3.8%) were most commonly involved. Symptoms developed in 47.1% of patients, and were more likely to occur following Datura (66.7%), and Morning Glory or Milkweed (25% each) exposures. Almost 94% of patients were managed onsite (home) and only 5.2% involved evaluation in a health care facility (HCF). Only 37 (0.6%) patients required hospital admission, and 2.9% of cases resulted in more than minimal effects. Exposures resulting in more than minimal clinical effects were predicted by several variables: abnormal vital signs (OR = 35.62), abnormal labs (OR = 14.87), and management at a HCF (OR = 7.37). Hospital admissions were increased for patients already at a HCF (OR = 54.01), abnormal vital signs (OR = 23.28), and intentional exposures (OR = 14.7).

CONCLUSION

Plant exposures reported to our poison control center were typically unintentional ingestions occurring at home. Most patients were managed onsite and few developed significant symptoms.

Medicinal plants of Guinea-Bissau: Therapeutic applications, ethnic diversity and knowledge transfer

ETHNOPHARMACOLOGICAL RELEVANCE

The rich flora of Guinea-Bissau, and the widespread use of medicinal plants for the treatment of various diseases, constitutes an important local healthcare resource with significant potential for research and development of phytomedicines. The goal of this study is to prepare a comprehensive documentation of Guinea-Bissau's medicinal plants, including their distribution, local vernacular names and their therapeutic and other applications, based upon local notions of disease and illness.

MATERIALS AND METHODS

Ethnobotanical data was collected by means of field research in Guinea-Bissau, study of herbarium specimens, and a comprehensive review of published works. Relevant data were included from open interviews conducted with healers and from observations in the field during the last two decades.

RESULTS

A total of 218 medicinal plants were documented, belonging to 63 families, of which 195 are native. Over half of these species are found in all regions of the country. The medicinal plants are used to treat 18 major diseases categories; the greatest number of species are used to treat intestinal disorders (67 species). More than thirty ethnic groups were identified within the Guinea-Bissau population; 40% of the medicinal plants have been recorded in the country's principal ethnic languages (i.e. Fula and Balanta).

CONCLUSIONS

This multi-disciplinary, country-wide study identifies a great diversity of plants used by indigenous communities as medicinal, which constitute an important common reservoir of botanical species and therapeutic knowledge. The regional overlap of many indigenous species, the consensual nature of disease groups based upon local perceptions of health conditions, and the relevance of local vernacular including Guinean Creole are key factors specific to the country which enhance the potential for the circulation and transmission of ethno-botanical and therapeutic knowledge.