Xysmalobium undulatum (uzara) - review of an antidiarrhoeal traditional medicine

Uzara (Xysmalobium undulatum) - An underutilized anti-diarrhoeic and spasmolytic herbal remedy

ETHNOPHARMACOLOGICAL RELEVANCE

Uzara, Xysmalobium undulatum (L.) W.T.Aiton, a herbal medicine for diarrhoea and smooth-muscle cramps is little-known outside Germany, where it has had a market presence for ∼110 years. The early introduction of this Southern African medicinal plant into Europe and the US was entrepreneurially driven, similar to buchu (Agathosma spp.) and Umckaloabo (Pelargonium sidoides DC.). Much of its history of commercialization, from its origin, identity and supply chain to its composition and clinical evidence of efficacy and safety, has been poorly studied and/or scantly published.

AIM OF THE STUDY

The aim of this review is to uncover enough data to create a coherent timeline, many of which are published here for the first time, and to evaluate all published data, mostly historical and/or elusive, to corroborate Uzara's status as a safe and efficacious botanical medicine.

MATERIALS AND METHODS

Multiple searches were conducted in the PubMed, Scopus, Web of Science, Science Direct, and Google Scholar databases with the following keywords: all scientific and common plant names combined with taxonomy, nomenclature, ethnobotany, traditional use, ecology, cultivation, sustainability, economy, trade, CITES, chemistry, biochemistry, compounds, pre-clinical, pharmacology, clinical, RCT, safety, toxicology, veterinary, review for the period of 1600-2022. Reference sections of selected publications were searched manually. Additionally, product registration databases of national competent health authorities in Europe were consulted for products, license holders and formulations.

RESULTS

The authors find an underutilized potential of uzara as anti-diarrhoeic (with or without underlying infection) and spasmolytic remedy. A by-product of this review is a largely inclusive bibliography of publications on uzara.

CONCLUSIONS

Further clinical research supporting antidiarrhoeal and spasmolytic efficacy would be desirable.

Calotropis procera accumulates Uzarigenin and Calotropagenin in response to environmental lighting and drought

Calotropis procera (C. procera) was evaluated as a pharmaceutically useful plant and for its therapeutic effects in the most significant studies. Uzarigenin and Calotropagenin are significant components of this plant that have pharmacological effects on certain systems, including the digestive, immunological, and focal, and peripheral sensory systems. In this study, pathway genes are extracted from high throughput data acc.no. SRR1554320. Seven critical enzymes are involved in studying the effects of sunlight on the formation of Uzaragenin and Calotropagenin in C. procera before and after irrigation. Molecular identification and NCBI submission of six enzyme genes were successful; HSD (acc.no. OQ091761) for 3β-hydroxystroid dehydrogenase, OR (acc.no. OQ091762) for 5beta-pregnan oxidoreductase, MO (acc.no. OQ091763) for Pregnan monooxygenase, HOX (acc.no. OQ091764) for Steroid hydroxylase, MAT (acc.no. OQ091765) for Melonyletransferase, UHOX (acc.no. OQ091766) for Uzarigenin hydroxylase. During dawn after irrigation, the Uzargenin pathway showed the highest activity, however midday after irrigation was the lowest. The most period that showed high activity for the Uzargenin pathway was dawn after irrigation, however, midday after irrigation was the lowest. This data is confirmed by chromatography analysis (UPLC) to calculate the accumulation of Uzarigenin and Calotropagenin in different periods.

A Novel Cardenolide Glycoside Isolated from Xysmalobium undulatum Reduces Levels of the Alzheimer's Disease-Associated β-Amyloid Peptides Aβ42 In Vitro

Elevated levels of the amylo β-proteins (Aβ), particularly Aβ42, are associated with a high risk of Alzheimer’s disease (AD). The Aβ proteins are produced from cellular processing of the amyloid precursor proteins (APPs). To identify natural products that block the formation of Aβ-proteins from APPs, we previously screened a library of plant extracts and identified Xysmalobium undulaum (Apocynaceae) as a potential plant for further research. Here, we provide a report on the isolation and identification of the active principles from the plant species using a bioassay-guided fractionation. Fractions and resulting pure compounds from the purification process of the extract of X. undulatum were screened in vitro against APPs transfected HeLa cell lines. Three compounds, acetylated glycosydated crotoxogenin (1), xysmalogenin-3, β-d-glucopyranoside (2), and crotoxigenin 3-O-glucopyranoside (3), were subsequently isolated and their structures elucidated using NMR and mass spectrometry. Compound 1, a novel cardenolide, and 2 significantly decreased the Aβ42 levels in a dose-dependent manner while compound 3 was inactive. In silico investigations identified the AD’s β-secretase enzyme, BACE1, as a potential target for these compounds with the glycoside moiety being of significance in binding to the enzyme active site. Our study provides the first report of a novel cardenolide and the potential of cardenolides as chemical scaffolds for developing AD treatment drugs.

Anticancer Potential of Sutherlandia frutescens and Xysmalobium undulatum in LS180 Colorectal Cancer Mini-Tumors

Colorectal cancer remains to be one of the leading causes of death worldwide, with millions of patients diagnosed each year. Although chemotherapeutic drugs are routinely used to treat cancer, these treatments have severe side effects. As a result, the use of herbal medicines has gained increasing popularity as a treatment for cancer. In this study, two South African medicinal plants widely used to treat various diseases, Sutherlandia frutescens and Xysmalobium undulatum, were evaluated for potential activity against colorectal cancer. This potential activity for the treatment of colorectal cancer was assessed relative to the known chemotherapeutic drug, paclitaxel. The cytotoxic activity was considered in an advanced three-dimensional (3D) sodium alginate encapsulated LS180 colorectal cancer functional spheroid model, cultured in clinostat-based rotating bioreactors. The LS180 cell mini-tumors were treated for 96 h with two concentrations of each of the crude aqueous extracts or paclitaxel. S. frutescens extract markedly decreased the soluble protein content, while decreasing ATP and AK per protein content to below detectable limits after only 24 h exposure. X. undulatum extract also decreased the soluble protein content, cell viability, and glucose consumption. The results suggested that the two phytomedicines have potential to become a source of new treatments against colorectal cancer.

Identification of potential SARS-CoV-2 inhibitors from South African medicinal plant extracts using molecular modelling approaches

The coronavirus is a group of viruses found in animals as well as humans and have been detected since the 1960s. However, a newly identified form, SARS-CoV-2, has triggered a recent pandemic of respiratory disease now called COVID-19. There is currently no specific antiviral drug for the treatment of this pandemic, with most treatment strategies focused on symptomatic management and supportive therapy. As such, several drug discovery efforts are ongoing for potent treatment agents, with medicinal plants gradually gaining prominence. Approximately 80% of the South African population use traditional medicines to meet their primary health care needs. The current study aimed to identify potential COVID-19 therapeutic agents from a list of 29 bioactive compounds isolated from commonly used South African medicinal plants using molecular docking and molecular dynamics. Molecular docking identified arabic acid from Acacia senegal and L-canavanine found in Sutherlandia frutescens as a potential inhibitor of SARS-CoV-2 3C-like main protease. Similarly, hypoxoside isolated from Hypoxis hemerocallidea and uzarin from Xysmalobium undulatum, were identified as a potential inhibitor of SARS-CoV-2 receptor binding domain and SARS-CoV-2 RNA-dependent polymerase. These four bioactive compounds exhibited favourable binding orientations characterized by strong molecular interactions within respective inhibitors binding pockets of the target enzymes. Molecular dynamics simulations revealed that the binding of the identified inhibitors are characterized by structural perturbations which favour the inhibitory potency of these bioactive compounds. Additionally, in silico pharmacokinetic assessment of the compounds demonstrated favourable anti-SARS-CoV-2 properties. Although not conclusive, further experimental exploration of these compounds could serve as a starting point for the discovery of novel SARS-CoV-2 therapeutic.

A review on antimicrobial botanicals, phytochemicals and natural resistance modifying agents from Apocynaceae family: Possible therapeutic approaches against multidrug resistance in pathogenic microorganisms

Accelerated emergence of drug- resistant pathogenic microbes, their unbeatable virulence and a gradual loss of efficacy of currently used antimicrobial agents over the last decade, have expanded the scope of herbal medicine to combat this emerging challenge to have a wide spectrum of activity to develop effective medicines with lesser untoward side effects. Plant-based natural products should be of utmost interest to today's pharmaceutical industries since they are a primary source of new chemical entities directed at new drug targets. Apocynaceae or 'Dogbane' family has attained a global reputation as a source of some life-saving plant-derived products and novel compounds. Members of this family have also been extensively investigated against several nosocomial pathogenic microbes through in vitro and in vivo experimental settings. Several plant-derived components obtained from members of this family have also exhibited remarkable microbial growth inhibitory properties. Popular and widely accepted international databases such as PubMed, Science Direct, ResearchGate, Scopus, Google Scholar, JSTOR and more were searched using the various search strings such as Apocynaceae, antimicrobials, multidrug resistance, resistance modifying agents and pathogenic microorganisms were used in various combinations to retrieve several citations related to the topic. The current review encompasses recent developments in experimental studies and phytochemical analyses which correlates with antimicrobial efficacy of selected Apocynaceous plants along with synergistic mechanism and structural details. The present review recognizes and leverages the importance of Apocynaceae plants, which could be of significant interest in the development of more effective and less toxic antimicrobial drugs which may surmount multidrug resistance. Three different paradigm models harnessing clinical antimicrobial resistance (AMR) including the plant family Apocynaceae, Gram-positive and Gram-negative bacterial species have been broadly discussed in this review. In a nutshell, the present review represents a comprehensive account on the antimicrobials and resistance modifying agents obtained from the members of the plant family Apocynaceae and derived phytochemicals. It also gives an insight into the underlying mode of action of these phytochemicals against an array of pathogenic bacteria, their mechanism of antibiosis, plant parts from which the phytochemicals were isolated or the extracts was prepared with a critical discussion on the botanically-derived antibiotics as a template for antimicrobial drug development.

A sub-chronic Xysmalobium undulatum hepatotoxicity investigation in HepG2/C3A spheroid cultures compared to an in vivo model

ETHNOPHARMACOLOGY RELEVANCE

Traditional herbal medicines are utilized by 27 million South Africans. Xysmalobium undulatum (Uzara) is one of the most widely used traditional medicinal plants in Southern Africa. A false belief in the safety of herbal medicine may result in liver injury. Herb-induced liver injury (HILI) range from asymptomatic elevation of liver enzymes, to cirrhosis and in certain instances even acute liver failure. Various in vitro and in vivo models are available for the pre-clinical assessment of drug and herbal hepatotoxicity. However, more reliable and readily available in vitro models are needed, which are capable of bridging the gap between existing models and real human exposure. Three-dimensional (3D) spheroid cultures offer higher physiological relevance, overcoming many of the shortcomings of traditional two-dimensional cell cultures.

AIMS OF THIS STUDY

This study investigated the hepatotoxic and anti-prolific effects of the crude X. undulatum aqueous extract during a sub-chronic study (21 days), in both a 3D HepG2/C3A spheroid model and the Sprague Dawley rat model.

METHODS

HepG2/C3A spheroids were treated with a known hepatotoxin, valproic acid, and crude X. undulatum aqueous extract for 21 days with continuous evaluation of cell viability and proliferation. This was done by evaluating cell spheroid growth, intracellular adenosine triphosphate (ATP) levels and extracellular adenylate kinase (AK). Sprague Dawley rats were treated with the same compounds over 21 days, with evaluation of in vivo toxicity effects on serum chemistry.

RESULTS

The results from the in vitro study clearly indicated hepatotoxic effects and possible liver damage following treatment with valproic acid, with associated growth inhibition, loss of cell viability and increased cytotoxicity as indicated by reduced intracellular ATP levels and increased AK levels. These results were supported by the increased in vivo levels of AST, ALT and LDH following treatment of the Sprague Dawley rats with valproic acid, indicative of hepatic cellular damage that may result in hepatotoxicity. The in vitro 3D spheroid model was also able to predict the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. Similarly, the results obtained from the in vivo Sprague Dawley model indicated moderate hepatotoxic potential.

CONCLUSION

The data from both the 3D spheroid model and the Sprague Dawley model were able to indicate the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. The results obtained from this study also confirmed the ability of the 3D spheroid model to effectively and reliably predict the long-term outcomes of possible hepatotoxicity.

Medicinal plants with acetylcholinesterase inhibitory activity

Alzheimer's disease, a progressive neurodegenerative disease, is characterised by hypofunction of acetylcholine (ACh) neurotransmitter in the distinct region of brain. Acetylcholinesterase (AChE) is an enzyme that metabolises the ACh at synaptic cleft resulting in Alzheimer's disease. Medicinal plants have been used to treat numerous ailments and improve human health from ancient time. A traditional system of medicine is long recognised for its effective management of neurological disorders. The present review confers the scope of some common medicinal plants with a special focus on AChE-mediated central nervous system complications especially Alzheimer's disease. Literature suggests that medicinal plants reduce neuronal dysfunctions by reducing AChE activity in different brain regions. In some instances, activation of AChE activity by medicinal plants also showed therapeutic potential. In conclusion, medicinal plants have a wide scope and possess therapeutic potential to efficiently manage neurological disorders associated with AChE dysregulation.

MEDICINAL HERBS USED BY HIV-POSITIVE PEOPLE IN LESOTHO

BACKGROUND

The use of medicinal herbs whose efficacy and toxicities are not known by HIV-positive people in Lesotho is a threat to the effectiveness of antiretroviral treatment. This study explored some medicinal herbs used by HIV-positive people in Lesotho and the reasons for their use.

METHODS

This was a cross sectional study based on a questionnaire distributed to purposively-sampled HIV-positive people in Leribe and Maseru districts of Lesotho. The participants' socio-demographic and clinical variables were summarized using frequency tables in Stata version 13 statistical software. Data variables for medicinal herbs used, frequency of use, uses by the participants and in the literature, parts of plants used and the method of preparation were also explored.

RESULTS

Out of 400 questionnaires distributed to the participants, 389 were returned with data acceptable for analysis. Ages of the participants ranged from 18 to 75 years (Mean=43 + 11.6). Out of the 272 (69.9%) participants who conceded that they had used medicinal herbs at least once, 30 (7.7%) participants used medicinal herbs frequently while 242 (62.2 %) rarely used the herbs. At least 20 plant species belonging to 16 families were reportedly used by the participants. Asteraceae was the most common plant family reportedly used by the participants. Allium sativum and Dicoma anomala, reportedly used by 21.0% and 14.3% respectively, were the most commonly used medicinal herbs in this population. In addition, boosting the immune system and treating gastrointestinal ailments, apparently cited by 32% and 28% participants respectively, were the most commonly reported reasons for using medicinal herbs.

CONCLUSION

A considerable proportion (69.9%) of HIV-positive people use medicinal herbs in this population, and 7.7% use them frequently. At least 20 plant species belonging to 16 families were reportedly used by the participants. HIV counselling protocols in Lesotho should emphasize the dangers of using medicinal herbs whose safety and compatibility with antiretroviral drugs is not known. The efficacy and toxicity profiles of the medicinal plants identified in this study need to be investigated. Furthermore, the effects of these plants on antiretroviral treatment outcomes including herb-drug interactions need to be explored.

Antidiabetic Medicinal Plants Used by the Basotho Tribe of Eastern Free State: A Review

Diabetes mellitus (DM) belongs to the group of five leading important diseases causing death globally and remains a major health problem in Africa. A number of factors such as poverty, poor eating habit, and hormonal imbalance are responsible for the occurrence of the disease. It poses a major health challenge in Africa continent today and the prevalence continues to increase at an alarming rate. Various treatment options particularly the usage of herbs have been effective against diabetes because they have no adverse effects. Interestingly, South Africa, especially the Basotho tribe, is blessed with numerous medicinal plants whose usage in the treatment of DM has been effective since the conventional drugs are expensive and often unaffordable. The present study attempted to update the various scientific evidence on the twenty-three (23) plants originating from different parts of the world but widely used by the Sotho people in the management of DM. Asteraceae topped the list of sixteen (16) plant families and remained the most investigated according to this review. Although limited information was obtained on the antidiabetic activities of these plants, it is however anticipated that government parastatals and scientific communities will pay more attention to these plants in future research.

Medicinal plants: An invaluable, dwindling resource in sub-Saharan Africa

ETHNOPHARMACOLOGICAL RELEVANCE

The use of plant species for different therapeutic/medicinal purposes is well-entrenched in sub-Saharan Africa.

AIM OF THE REVIEW

To provide a critical and updated review of the enormous medicinal plant heritage in sub-Saharan Africa with regards to the abundance, importance, conservation status and potential means to help sustain their availability for future generations.

METHODS

A comprehensive literature search involving different online databases, books and theses were conducted in order to obtain, collate and synthesize available information on various fundamental aspects pertaining to African medicinal plants.

RESULTS

African biodiversity hotspots are endowed with a high level of endemic species with a significant portion possessing medicinal value. Apart from the extensive ethnobotanical uses of medicinal plants found in Africa, scientific validation of their biological potential such as antimicrobial, antioxidant, anti-inflammatory and anti-diabetic properties have been recognized. Together with the demand arising from their biological efficacies, other anthropogenic factors are exerting conservation strains of the wild population of these medicinal plants. Even though researchers have acknowledged the importance and value of conserving these medicinal plants, several challenges have hampered these efforts on the Continent as a whole.

CONCLUSIONS

The rich flora occurring in sub-Saharan Africa suggests enormous potential for discovery of new chemical entity with therapeutic value. However, concerted efforts focused on documenting the conservation status of African medicinal plants are pertinent. Application of different biotechnological techniques is needed to sustain these valuable botanical entities, especially to meet increasing pharmaceutical demand. Most importantly, increased public enlightenment and awareness may help eradicate the prejudice against cultivation of medicinal plants.

Xysmalobium undulatum (Uzara) research- how everything began

ETHNOPHARMACOLOGICAL RELEVANCE

Xysmalobium undulatum (Uzara) is a traditionally used medicinal plant from South Africa. It found its way into European research in the early 20th century and is widely used as a remedy against diarrhoea. The purpose of this study was to explore the circumstances of knowledge transfer and early research into phytochemistry and therapeutic potential of Xysmalobium undulatum.

RESULTS

The drug was brought to Europe through a former soldier, Wilhelm Heinrich Adolph Hopf (1887-1929). Some details about his life are provided here the first time, as well as some aspects of early research on the drug, which has mainly been done at the University of Marburg, Germany.