A broad review of commercially important southern African medicinal plants

Antitumor Activity of Warbugia ugandensis: Methanolic Extracts and Gene Regulation in Colorectal Cancer

A promising approach to accelerating the development of innovative anti-cancer therapies involves the evaluation of natural plant compounds. In this study, we focused on examining the effects of Warbugia ugandensis (W. ugandensis) methanolic root and stem infusions on the activity of five target genes-COX-2, CASPS-9, Bcl-xL, Bcl2, and 5-LOX-using colorectal cancer (CRC) cell lines (Caco-2). The plant extracts were prepared for testing by dissolving them in dimethyl sulfoxide (DMSO) after undergoing a step-by-step extraction process. Caco-2 cells were then treated with different concentrations of the extracts, and RNA was extracted and purified for analysis. Our results demonstrated a dose-dependent relationship between the phytoconstituents of W. ugandensis and the overexpression of CASP9, along with the downregulation of COX-2, 5-LOX, Bcl-xL, and Bcl2 genes. This suggests that W. ugandensis acts as a potent natural inhibitor of CRC progression. Given the potential clinical benefits, we propose the use of W. ugandensis methanolic root and stem extracts as promising organic inhibitors for CRC tumorigenesis, with more in vitro studies warranted to validate and expand on our findings. Additionally, we recommend further studies to identify and characterize the specific metabolites in W. ugandensis that contribute to the modulation of pathways responsible for inhibiting CRC growth.

In pursuit of natural occurring chiral dienes {(R/S)-carvone} as bidentate ligands for coordination to rhodium(I)

Bis-rhodium-mu-chlorido dinuclear complexes with natural occurring limonene-type enantiomeric diene nucleophiles, (S)- and (R)-carvone [SCar and RCar], are presented and their single crystal structures reported. Utilizing the diolefinic bonds of the carvones, mu-[RhI(SCar)Cl]2 (IA/B) and mu-[RhI(RCar)Cl]2 (IIA/B) were obtained in ca. 80% yields in clean reactions with reactant RhCl3(H2O)x. The "structured" chiral nanomaterials (IA/B and IIA/B > 1.1 nm) crystallize as two independent, dinuclear chiral molecules Syn-mu-[RhI(SCar)Cl]2 (IA), Anti-mu-[RhI(SCar)Cl]2 (IB), and Syn-mu-[RhI(RCar)Cl]2 (IIA, Anti-mu-[RhI(RCar)Cl]2 (IIB), respectively (based on the relative orientation of the carvone ring, oxo and methyl groups). Principal differences between the IA/IIA vs IB/IIB complexes in the solid state include the relative orientation of the two carvones, inducing a significant distortion in the µ 2-Rh2Cl2 core, with the dihedral angles of 49.7(1)°/49.73(6)° in IA/IIA (Syn-mu geometry), versus 23.8(1)°/24.00(6)° in IB/IIB (Anti-mu geometry), respectively. The presence of the two structurally independent complexes in the solid state is also inferred from 1H NMR spectra.

Therapeutic importance of Kigelia africana subsp. africana: an alternative medicine

AIM

To summarise a detailed up-to-date review of the traditional uses, phytoconstituents, and pharmacological activities of various parts of Kigelia africana.

MATERIALS AND METHODS

Google Scholar, PubMed, PubChem, Elsevier, King Draw, indianbiodiversity.org.

RESULT

The phytochemical analysis of Kigelia africana subsp. africana has revealed the presence of approximately 145 compounds extracted from different parts of the plant. These bioactive extracts of the plant possess anti-inflammatory, antioxidant, antimicrobial, antidiabetic, antineoplastic, and anti-urolithic activities. Due to its anti-inflammatory, antioxidant, and immune-booster properties, Kigelia can prove to be an essential source of drugs for treating various disorders.

CONCLUSION

Knowledge of the phytoconstituents, non-medicinal and medicinal traditional uses, pharmacological activities, and products obtained from Kigelia is described in this review with the hope that the updated findings will promote research on its biological pathways.

An updated inventory of medicinal and ritual plants of southern Africa

ETHNOPHARMACOLOGICAL RELEVANCE

For the first time in two decades, a comprehensive, up-to-date overview of the medicinal and ritual plants of southern Africa is presented. This data is analysed and compared with a previous survey done in 2002.

STUDY AIM

The main aim is to update the checklist of medicinal and ritual plants of southern Africa and to determine the number of new records since 2002. We also provide a high-level perspective on the selection of medicinal and ritual plant species in southern Africa, a taxonomic analysis of the new checklist as well as a chronological perspective on the citation of medicinal and ritual species before and after 2002.

MATERIALS AND METHODS

The most recently published medicinal and ritual plants checklist for southern Africa was reviewed and updated. A wide range of ethnobotanical literature, including books, field guides and electronic journals, was used. All calculations were done by using formulas and functions in Microsoft Excel and R Studio.

RESULTS

4120 medicinal and ritual taxa and 3784 medicinal and ritual species have been recorded. Compared with the 2002 checklist, there are 1239 new taxa (1228 new species). A strong correlation between available taxa and selected medicinal taxa exists on order level, which corresponds with the results of an analysis done in 2008. The top 10 species-rich medicinal plant families of southern Africa are Asteraceae, Fabaceae, Apocynaceae, Euphorbiaceae, Asphodelaceae, Malvaceae, Lamiaceae, Poaceae, Rutaceae and Rubiaceae. Different patterns of plant family representation can be seen across certain cultural healing systems of southern Africa. The species popularity (number of citations) of Hypoxis hemerocallidea Fisch. & C.A.Mey. Has increased substantially after 2002. Other medicinal and ritual plant species have been consistently researched, such as Artemisia afra Jacq. ex Willd., Carpobrotus edulis (L.) L.Bolus, Aloe ferox Mill., Leonotis leonurus (L.) R.Br. and Gunnera perpensa L.

CONCLUSIONS

The numerous new medicinal and ritual plant records that have been reported in the last two decades provide evidence of an incompletely documented ethnobotanical heritage that urgently requires documentation. Patterns of taxonomic diversity on family level indicate distinctive differences between cultural healing systems. Signs of the adaptability and dynamics of traditional healing systems in southern Africa can be seen in the changes in the citation of species over time.

Biosystematic studies of genus Withania Pauquy in Egypt

Withania (Solanaceae, Solanoideae) is a widespread genus. Comparative macro-, micro-morphological, anatomical, and molecular features of this genus in Egypt were examined using light and scanning electron microscopy to reassess the conflicted taxonomic relationships between the two studied species. The most significant morphological differences that have been found were: the shape of the lamina, apex, anther, and stigma, and the ratio of calyx tube/lobe; anatomical examination of taxonomic interest are as follows: number of vascular bundles, presence of ears and distribution of accessory vascular bundles in petiole and shape of spongy cells, and number of lower parenchyma in the midrib region of the leaf; trichomes of both species showed no significant differences; pollen, and seed characters are of taxonomic significance in differentiation and characterization between them. Protein profiling revealed that W. somnifera has only conserved proteins, while W. obtusifolia possessed both conserved and additional proteins in their SDS-PAGE banding patterns. Eleven starts codon-targeted (ScoT) primers were applied and produced 96 amplicons with an average of 70.83% polymorphism/primer. W. obtusifolia generated more polymorphic bands and maintained monomorphic ones. SDS-PAGE disclosed that both Withania species were 50% related. While Scot-Dendrogram revealed that both Withania species were poorly related. So, protein and molecular analyses showed considerable genetic variations between these two species.

Evaluation of cytotoxic effect of siphonochilone from African ginger: an in vitro analysis

Plants provide a wide array of compounds that can be explored for potential anticancer properties. Siphonochilone, a furanoterpene that represents one of the main components of the African plant Siphonochilus aethiopicus, shows numerous health benefits. However, to date, its antiproliferative properties have not been tested. The aim of this study was to analyze the cytotoxic effects of siphonochilone on a panel of cancer cell lines and its underlying mechanism of action. Our results demonstrated that siphonochilone exhibited significant cytotoxic effects on pancreatic, breast, lung, colon, and liver cancer cell lines showing a IC50 ranging from 22 to 124 μM at 72 h of treatment and highlighting its cytotoxic effect against MCF7 and PANC1 breast and pancreas cancer cell lines (22.03 and 39.03 μM, respectively). Cell death in these tumor lines was mediated by apoptosis by the mitochondrial pathway, as evidenced by siphonochilone-induced depolarization of the mitochondrial membrane potential. In addition, siphonochilone treatment involves the generation of reactive oxygen species that may contribute to apoptosis induction. In this work, we described for the first time the cytotoxic properties of siphonochilone and provided data about the molecular processes of cell death. Although future studies will be necessary, our results support the interest in this molecule in relation to their clinical application in cancer, and especially in breast and pancreatic cancer.

Procedures to evaluate potential of plants as natural food preservatives: Phytochemical characterization, novel extraction technology, and safety evaluation-A comprehensive review

There is increasing demand for natural food preservative in food manufacturing industry as it is the key to meet consumers' preferences toward healthier food choice. Plant is listed among the most important resources of bioactive components to be utilized as the green and natural food preservatives. There are more than 10,000 kinds of bioactive components in plants that possess antioxidant and antimicrobial properties. Artemisia with potential antimicrobial and antioxidant attributes, as well as functional and medicinal properties, is one of the most important plant species. The manuscript presents a comprehensive review of the potential of the Artemisia species as natural food preservatives. The current challenges and ways forward in using Artemisia EOs and extracts as food preservatives are also discussed. This topic is timely and important considering the natural preservatives used to replace chemical ingredients, sustaining quality, healthy properties, and shelf life of food products as well as efficient and novel extraction techniques.

Antimicrobial activity of Southern African medicinal plants on Helicobacter pylori and Lactobacillus species

ETHNOPHARMACOLOGICAL RELEVANCE

Numerous medicinal plants have been used traditionally in South Africa for gastric ulcer treatment. Helicobacter pylori is known for causing inflammation and the onset of gastric ulcers. While several studies explored medicinal plants against H. pylori, investigation of medicinal plants used for gastric ulcers has been neglected, as well as the effects these plants would have on bacteria occurring naturally in the gut microbiome.

AIM OF THE STUDY

This study aimed to investigate Southern African medicinal plants used traditionally for treating gastric ulcers against H. pylori , as well as the effects that these plants have when combined with Lactobacillus species and tested against H. pylori.

METHODOLOGY

Based on evidence from the ethnobotanical literature, 21 plants were collected. Their antimicrobial activity was assessed against five clinical H. pylori strains, and in combination with each of three Lactobacillus species, using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) broth microdilution assays. Toxicity was assessed using the brine shrimp lethality assay.

RESULTS

Noteworthy activity was observed against at least one H. pylori strain for 12 plant species. The lowest mean MICs were from organic extracts of Carissa edulis Vahl (0.18 mg/mL) and Chironia baccifera L. (0.20 mg/mL), and aqueous extracts of Sansevieria hyacinthoides (L.) Druce (0.26 mg/mL) and Dodonaea viscosa Jacq. (0.30 mg/mL). Aqueous extracts of the investigated plants were combined with Lactobacillus species, and the majority of combinations showed increased antimicrobial activity compared with the extracts alone. Combinations of Lactobacillus rhamnosus with 18 of the 21 aqueous plant extracts showed at least a two-fold decrease in the mean MBC against all H. pylori strains tested. Lactobacillus acidophilus combined with either Protea repens L., Carpobrotus edulis (L.) L. Bolus or Warburgia salutaris (Bertol.f.) Chiov. aqueous extracts had the best anti-H. pylori activity (mean MBCs of 0.10 mg/mL for each combination). Only four organic and one aqueous extract(s) were considered toxic.

CONCLUSION

These results highlight the potential of medicinal plants to inhibit H. pylori growth and their role in traditional treatments for the management of ulcers. The results also indicate that aqueous extracts of these plants do not hinder the growth of bacteria that occur naturally in the gut microbiome and play a role in maintaining gut health, as well as show the potential benefit of including Lactobacillus species as potentiators of H. pylori activity.

Isolation and Antitumoral Effect of a New Siphonochilone Derivative from African Ginger

A new eusdesmane sesquiterpenoid, characterized as 3,5,8a-trimethyl-8-oxo-4,4a,5,6,7,8,8a,9-octahydronaphtho[2,3-b]furan-5-yl acetate (1), has been isolated from the rhizomes of the South African variety of wild ginger (Siphonochilus aethiopicus (Schweinf) B. L. Burtt). The compound was obtained by silica gel column chromatography. Its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass-spectrometric (MS) analyses, including 1D-, 2D-NMR, and HR-LCMS. We also investigated the cytotoxic effect of 1 on a panel of cancer cell lines, human breast, pancreas, lung, colon, and central nervous system cancer lines. The data are not encouraging since its antitumor effect is poor. Nonetheless, the discovery of new molecules may provide a source of new compounds with important biological effects applicable to the field of medicine.

Inhibition of pro-inflammatory cytokines by selected southern African medicinal plants in LPS-stimulated RAW 264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Bark is frequently used in southern African traditional medicine to treat inflammation, yet it remains to be rigorously examined for its immunological and anti-inflammatory activity.

AIM OF THE STUDY

Barks obtained from ten important and popular southern Africa plants were evaluated for their anti-inflammatory and immunomodulatory properties against the secretion of some pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) as well as chemokines (monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2) in murine RAW 264.7 macrophages.

MATERIALS AND METHODS

The inhibitory effects of aqueous and ethanol extracts were determined using cytokine multiplex-bead assays in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 cells.

RESULTS

Overall, the ethanol extracts were more potent cytokine inhibitors compared to the aqueous extracts. The LPS-stimulated cells treated with the ethanol extracts of Erythrina lysistemon Hutch., Pterocelastrus rostratus Walp. Syzygium cordatum Hochst. ex Krauss and Warburgia salutaris (G. Bertol.) Chiov., demonstrated significant (p < 0.005) inhibition up to 85% of IL-1β, IL-6, and TNF-α secretion compared to the LPS control. Additionally, P. rostratus and S. cordatum aqueous bark extracts substantially decreased the secretion of all the tested cytokines and chemokines. Chemical investigation of the S. cordatum extract resulted in the identification of four ellagic acid derivatives: ellagic acid 4-O-α-rhamnopyranoside (1), ellagic acid 4-O-α-4″-acetylrhamnopyranoside (2), 3-O-methylellagic acid 4'-O-α-3″-O-acetylrhamnopyranoside (3) and 3-O-methylellagic acid 4'-O-α-4″-O-acetylrhamnopyranoside (4), along with mixtures of ellagic acid 4-O-α-2″-acetylrhamnopyranoside (5), ellagic acid 4-O-α-3″-acetylrhamnopyranoside (6) and ellagic acid (7). Their structures were confirmed by mass spectrometry, NMR spectroscopy, and comparison with data from literature.

CONCLUSION

The cytokine inhibition properties of most of the medicinal plants screened herein are reported for the first time. Our results provide insights into the mechanism of action by which the selected southern African medicinal plants regulate inflammation.

Bioactivity of Eriocephalus africanus essential oil against concanavalin A-induced hepatitis via suppressing immune cell infiltration, inhibiting TNF-α/NF-κB and IFN-γ/STAT1 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Eriocephalus africanus infusion is used as a diuretic and a diaphoretic and is also used in the treatment of gastrointestinal disorders and gynaecological conditions, inflammation and dermal disorders, asthma, coughs, fevers, and painful ailments. The plant has been used traditionally as a medication to cure inflammation and skin problems.

AIM OF THE STUDY

Studying E. africanus essential oil (EAEO) as a potential hepatoprotective measure against concanavalin (Con) A-induced hepatitis in mice and investigating its underlying mechanism.

MATERIALS AND METHODS

Hydro-distilled oil of the fresh plant aerial shoots is subjected to GC/MS analysis. Autoimmune hepatitis (AIH) was induced in mice by intravenous injection of Con A (15 mg/kg). EAEO was administered orally before Con A injection to test its hepatoprotective activity.

RESULTS

GC/MS analysis revealed the presence of 22 compounds representing 99.43% of the oil components. The monoterpene artemisia ketone (41.02%) and the sesquiterpene juniper camphor (14.17%) are the major components. The in vivo study showed that the oil suppressed Con A-induced neutrophil and CD4+T cell infiltration into the liver, restored hepatic redox balance, inhibited Con A-induced elevation of tumor necrosis factor-alpha (TNF-α), interleukin (IL-6), and interferon-gamma (IFN-γ) hepatic levels which were correlated with its ability to suppress nuclear factor kappa B (NF-κB) and Signal Transducer and Activator of Transcription (STAT1) activation in the liver.

CONCLUSION

EAEO showed hepatoprotective potential against Con A-induced hepatitis in mice collectively through selective anti-oxidant, anti-inflammatory, and anti-necrotic effects.

Challenges in natural product-based drug discovery assisted with in silico-based methods

The application of traditional medicine by humans for the treatment of ailments as well as improving the quality of life far outdates recorded history. To date, a significant percentage of humans, especially those living in developing/underprivileged communities still rely on traditional medicine for primary healthcare needs. In silico-based methods have been shown to play a pivotal role in modern pharmaceutical drug discovery processes. The application of these methods in identifying natural product (NP)-based hits has been successful. This is very much observed in many research set-ups that use rationally in silico-based methods in combination with experimental validation techniques. The combination has rendered the use of in silico-based approaches even more popular and successful in the investigation of NPs. However, identifying and proposing novel NP-based hits for experimental validation comes with several challenges such as the availability of compounds by suppliers, the huge task of separating pure compounds from complex mixtures, the quantity of samples available from the natural source to be tested, not to mention the potential ecological impact if the natural source is exhausted. Because most peer-reviewed publications are biased towards "positive results", these challenges are generally not discussed in publications. In this review, we highlight and discuss these challenges. The idea is to give interested scientists in this field of research an idea of what they can come across or should be expecting as well as prompting them on how to avoid or fix these issues.

Regulatory activities of Warbugia ugandensis ethanolic extracts on colorectal cancer-specific genome expression dose-dependently

The evaluation of natural biomass sources is a promising strategy in accelerating the development of novel anti-cancer medications. Our study aimed to evaluate the activity of W. ugandensis ethanolic roots and stems extracts on the expression of five targeted genes (COX-2, CASPS-9, Bcl-xL, Bcl2 and 5-LOX) in colorectal cancer (CRC) cell lines (Caco-2). Plant extracts were obtained using serial exhaustive extraction and dissolved in Dimethyl sulfoxide appropriately for bioassay. Caco-2 cell lines were passaged, treated with plant extracts at varying concentrations and their RNA's isolated for evaluation. Our unique study reports on W. ugandensis as efficient natural inhibitors of CRC growth, by directly linking its phytoconstituents to; downregulation of COX-2, 5-LOX, Bcl-xL, Bcl2 and upregulation of CASPS9 genes dose-dependently. We present W. ugandensis ethanolic roots and stems extracts as promising natural inhibitors for CRC carcinogenesis and recommend in vivo and subsequent clinical trials, with substantial clinical effects postulated. We further suggest studies on identification and characterization of the specific metabolites in W. ugandensis involved in the modulatory mechanisms, resulting to inhibition of CRC growth and possible metastases.

Phytochemical Composition and Antibacterial Activity of Barleria albostellata C.B. Clarke Leaf and Stem Extracts

Barleria albostellata (Acanthaceae) is a shrub located in South Africa and is relatively understudied. However, plants within this genus are well known for their medicinal and ethnopharmacological properties. This study aimed to characterise the phytochemical compounds and antibacterial efficacies of B. albostellata. Phytochemical analysis, fluorescence microscopy and gas chromatography-mass spectrometry (GC-MS) analysis were performed to determine the composition of compounds that may be of medicinal importance. Crude leaf and stem extracts (hexane, chloroform and methanol) were subjected to an antibacterial analysis against several pathogenic microorganisms. The qualitative phytochemical screening of leaf and stem extracts revealed the presence various compounds. Fluorescence microscopy qualitatively assessed the leaf and stem powdered material, which displayed various colours under bright and UV light. GC-MS chromatograms represents 10-108 peaks of various compounds detected in the leaf and stem crude extracts. Major pharmacologically active compounds found in the extracts were alpha-amyrin, flavone, phenol, phytol, phytol acetate, squalene and stigmasterol. Crude extracts positively inhibited Gram-positive and Gram-negative bacteria. Significance was established at p < 0.05 for all concentrations and treatments. These results indicate that the leaves and stems of B. albostellata are rich in bioactive compounds, which could be a potential source of antibacterial agents for treating various diseases linked to the pathogenic bacteria studied. Future discoveries from this plant could advance the use of indigenous traditional medicine and provide novel drug leads.

Comparing the effects of essential oils and methanolic extracts on the inhibition of Aspergillus flavus and Aspergillus parasiticus growth and production of aflatoxins

The antifungal and antiaflatoxigenic effects of four distinct plant species against Aspergillus flavus and Aspergillus parasiticus were investigated. Essential oils and methanolic extracts were prepared from aerial parts of Lippia javanica, Ocimum gratissimum, Satureja punctata, and stem barks of Toddalia asiatica by hydro-distillation and maceration, respectively. The poisoned food method was used to confirm the antifungal activity of essential oils and methanolic extracts from four different plant species against Aspergillus flavus and Aspergillus parasiticus, and high-performance liquid chromatography was used to quantify the antiaflatoxigenic activity. The essential oils of Satureja punctata and Lippia javanica showed the highest antiaflatoxigenic activity against the fungi strains tested at concentrations of 1.25, 2.5, and 5 µL/mL, followed by Ocimum gratissimum essential oil while Toddalia asiatica essential oil exerted moderate antiaflatoxigenic activity. Meanwhile, the methanolic extracts showed a wide spectrum of low to high antifungal and antiaflatoxigenic activities at concentrations of 125, 250, and 500 µg/mL against A. flavus and A. parasiticus. This study has indicated that the essential oils of Satureja punctate, Lippia javanica, and Ocimum gratissimum had substantial antifungal and antiaflatoxigenic activities compared to their methanolic extracts, while Toddalia asiatica methanolic extract had a moderate antifungal activity compared to its essential oil.

Plants of Commercial Importance in Lesotho: Ethnobotanical and Pharmacological Insights

Several plants have been processed in Lesotho to manufacture various commercial prodcts, ranging from cosmetics and beverages (juice, tea) to traditional herbal mixtures and crafts. Even though plants of commercial importance have been documented in different regions and countries, this is not the case in Lesotho. Therefore, the aim of the study is to record plant species commonly used in the country for development of commercial products. A physical survey was undertaken in different places in the Maseru District of Lesotho between January 2019 and October 2021, taking a record of existing commercial products and identifying plants used in their development. A total of 15 plants of commercial importance in the country are recorded in the current study, namely Agave americana, Aloe ferox, Artemisia afra, Cannabis sativa, Helichrysum odoratissimum, Hemannia depressa, Hypoxis hemerocallidea, Leudeboria cooperi, Mentha spp., Merxmuellera spp., Pelargonium sidoides, Opuntia ficus-indica, Rosa rubiginosa and Urtica urens. Most of the plants are used for production of commercial products in the country, whereas some are exported as raw materials, mainly to countries such as Germany, South Africa, Australia and America. The latter are C. sativa, Merxmuellera spp., P. sidoides and R. rubiginosa. Profiling of the plants provides important information about their commercial potential. However, conservation of the plants is encouraged to ensure their sustainable utilisation.

Probing the bioactive compounds of Kigelia africana as novel inhibitors of TNF-α converting enzyme using HPLC/GCMS analysis, FTIR and molecular modelling

Tumor Necrosis Factor Alpha Converting Enzyme (TACE) mediates inflammatory disorder and contributes to the pathophysiology of a variety of illnesses, such as chronic inflammation and cancer. This study identified metabolites in solvent extracts of Kigelia africana as putative TACE inhibitors due to the plant's known anti-inflammatory properties. HPLC-MS/GCMS analysis was used to characterize tentative phytochemicals from K. africana. The identified metabolites (n = 123) were docked with TACE to reveal the lead compounds. Binding free energy, ADMET prediction, molecular dynamics simulation at 100 ns, and DFT calculation were further conducted. The results revealed that K. africana contains sterol, phenols, alkaloids, terpenes and flavonoids. The FTIR shows that the extracts had peaks that correspond to the presence of different functional groups. The quantum polarized ligand docking (QPLD) analysis identified compound (n = 3) with binding affinity higher than standard compound IK-682. The hits also had modest ADMET profiles, interacted with essential residues within TACE binding pockets, and formed stable complexes with the protein. The 100 ns MD simulation shows that the compounds formed fairly stable interactions and complex with the protein as evidenced through RMSF, RMSD and MM-GBA results. The HOMO/LUMO, global descriptive molecular electrostatic potential Fukui function aid in the identification of the compounds' atomic sites prone to electrophilic/neutrophilic attacks, and non-covalent interactions. This study suggests that K. africana's bioactive compounds are capable of mitigating inflammation by inhibiting TACE.Communicated by Ramaswamy H. Sarma.

An Inventory of South African Medicinal Plants Used in the Management of Sexually Transmitted and Related Opportunistic Infections: An Appraisal and Some Scientific Evidence (1990-2020)

The current work is aimed at generating the first inventory of South African medicinal plants used in the treatment of sexually transmitted and related opportunistic infections associated with HIV-AIDS. This is important in assisting researchers to access a list of plant species to evaluate for potential phytocompounds, as this area of research is greatly lagging in South Africa. A total of 335 medicinal plants from 103 families have been documented in the current work. The most represented families are Fabaceae (11.64%) and Asteraceae (6.27%). Herbs constitute 36.53%, trees 32.34%, shrubs 29.04%, climbers 1.80% and parasites 0.30%. It is worrying that on the plant parts used, the roots constitute 47.18%, while leaves and stem bark yield 16.62 and 15.01%, respectively. Catharanthus roseus exhibited the highest number of citations (19), while Peltophorum africanum had 14 and both Carica papaya and Vachelia karoo had 12. In the mode of administration of the reported medicinal plant species, most of the plants are boiled and taken orally (48.22%), while other plant species are used as mouth washes (3.25%). Although there is reasonable in vitro activity of some of the plant species, validating the relevance of use, there is still a need to explore the mode of action of such plant species; isolated compounds and possible derivatives thereof are of paramount importance and need to be explored as well. Furthermore, toxicological aspects of such plant species need to be explored.

Network Pharmacology- and Molecular Dynamics Simulation-Based Bioprospection of Aspalathus linearis for Type-2 Diabetes Care

The medicinal herb Aspalathus linearis (rooibos) is globally recognized in type-2 diabetes mellitus (T2DM) treatment due to its known and distinctive compounds. This work utilized network pharmacology (NP) coupled with molecular dynamics simulation in gaining new insight into the anti-diabetic molecular mechanism of action of rooibos teas. It looked at the interactions between rooibos constituents with various relevant protein receptors and signaling routes associated with T2DM progression. The initial analysis revealed 197 intersecting gene targets and 13 bioactive rooibos constituents linked to T2DM. The interactions between proteins and compounds to the target matrix were generated with the Cystoscope platform and STRING database. These analyses revealed intersecting nodes active in T2DM and hypoxia-inducible factor 1 (HIF-1) as an integral receptors target. In addition, KEGG analysis identified 11 other pathways besides the hub HIF-1 signaling route which may also be targeted in T2DM progression. In final molecular docking and dynamics simulation analysis, a significant binding affinity was confirmed for key compound-protein matrices. As such, the identified rooibos moieties could serve as putative drug candidates for T2DM control and therapy. This study shows rooibos constituents' interaction with T2DM-linked signaling pathways and target receptors and proposes vitexin, esculin and isovitexin as well as apigenin and kaempferol as respective pharmacologically active rooibos compounds for the modulation of EGFR and IGF1R in the HIF-1 signaling pathway to maintain normal homeostasis and function of the pancreas and pancreatic β-cells in diabetics.

Bioprospecting of Essential Oil-Bearing Plants: Rapid Screening of Volatile Organic Compounds Using Headspace Bubble-in-Drop Single-Drop Microextraction for Gas Chromatography Analysis

Essential oils are vital constituents of oil-bearing plants. However, their screening still demands harvesting of the plant for laboratory analysis. We report herein a simple, rapid and robust headspace bubble-in-drop microextraction screening technique (BID-SPME) requiring only small amounts of plant material. The optimised method uses 0.5 g of the crushed plant leaves sample obtained in a 2 mL capped chromatography vial, heated to 55 °C and sampled with 2 µL heptadecane in a Hamilton gastight syringe equilibrated for 15 min exposed to the headspace volume. The method was applied to three plants, Pinus radiata, Tagetes minuta and Artemisia afra, which are known for their essential oil content. The method was able to extract at least 80% of the oil constituents in such abundance that they could be easily annotated using the gas chromatography-mass spectrometry (GC-MS) mass spectral libraries. The major volatile organic compounds (VOCs) detected included tagetone, terpinen-4-ol, ocimenone, caryophyllene, dihydrotagetone, terpinolene and artemisia ketone, just to mention a few, at different concentrations in different plants. Importantly, these annotated VOCs were also reported in other studies in the same and even different plants, extracted using normal steam distillation and importantly those reported in the literature for different extraction techniques.

A Review of the Green Synthesis of ZnO Nanoparticles Utilising Southern African Indigenous Medicinal Plants

Metal oxide nanoparticles (NPs), such as zinc oxide (ZnO), have been researched extensively for applications in biotechnology, photovoltaics, photocatalysis, sensors, cosmetics, and pharmaceuticals due to their unique properties at the nanoscale. ZnO NPs have been fabricated using conventional physical and chemical processes, but these techniques are limited due to the use of hazardous chemicals that are bad for the environment and high energy consumption. Plant-mediated synthesis of ZnO NPs has piqued the interest of researchers owing to secondary metabolites found in plants that can reduce Zn precursors and stabilise ZnO NPs. Thus, plant-mediated synthesis of ZnO NPs has become one of the alternative green synthesis routes for the fabrication of ZnO NPs. This is attributable to its environmental friendliness, simplicity, and the potential for industrial-scale expansion. Southern Africa is home to a large and diverse indigenous medicinal plant population. However, the use of these indigenous medicinal plants for the preparation of ZnO NPs is understudied. This review looks at the indigenous medicinal plants of southern Africa that have been used to synthesise ZnO NPs for a variety of applications. In conclusion, there is a need for more exploration of southern African indigenous plants for green synthesis of ZnO NPs.

NADES Compounds Identified in Hypoxis hemerocallidea Corms during Dormancy

Soaking Hypoxis hemerocallidea corms in distilled water improved the propagation and development of cormlets, suggesting the potential leaching-out of inhibitory chemical compounds. To investigate the presence of inhibitory compounds, nuclear magnetic resonance (NMR) spectral data of the leachate from dormant H. hemerocallidea corms were obtained using a 600 MHz ¹H-NMR spectrometer. The ¹H-NMR analysis led to the identification of choline, succinate, propylene glycol, and lactose, as inhibitory compounds. These four chemical compounds are part of the “Natural Deep Eutectic Solvents” (NADES) that protect plant cells during stress periods, each of which has the potential to inhibit bud growth and development. These compounds are supposedly leached out of the corms during the first rain under natural conditions, possibly accompanied by changes in the ratios of dormancy-breaking phytohormones and inhibitory compounds, to release bud dormancy. The identified chemical compounds heralded a novel frontier in the vegetative propagation of H. hemerocallidea as a medicinal plant, and for its enhanced sustainable uses.

Antidiabetic Medicinal Plants Used in the Eastern Cape Province of South Africa: An Updated Review

Oral antidiabetic drugs are usually costly and are associated with several adverse side effects. This has led to the use of medicinal plants that are considered to have multiple therapeutic targets and are readily accessible. In the Eastern Cape province of South Africa, the number of people using medicinal plants for the management of diabetes has been climbing steadily over the past two decades due to their cultural acceptability, accessibility, affordability, efficacy, and safety claims. In this study, a review of antidiabetic medicinal plants used in the Eastern Cape province of South Africa was conducted. A comprehensive literature survey was thoroughly reviewed using several scientific databases, ethnobotanical books, theses and dissertations. About forty-eight (48) plant species were identified as being used to treat diabetes by the people of Eastern Cape province. Among the plant species, only eight (8) species have not been scientifically evaluated for their antidiabetic activities and twenty antidiabetic compounds were isolated from these medicinal plants. This review has confirmed the use and potential of the antidiabetic medicinal plants in the Eastern Cape province and identified several promising species for further scientific investigation.

Exploring the plant-derived bioactive substances as antidiabetic agent: An extensive review

Diabetes mellitus (DM) is a metabolic syndrome. Diabetes has become more common in recent years. Chemically generated drugs are used to lessen the effects of DM and its following repercussions due to unpleasant side effects such as weight gain, gastrointestinal issues, and heart failure. On the other hand, medicinal plants could be a good source of anti-diabetic medications. This article aims to determine any plant matrix's positive potential. Food restriction, physical activity, and the use of antidiabetic plant-derived chemicals are all being promoted as effective ways to manage diabetes because they are less expensive and have fewer or no side effects. This review focuses on antidiabetic plants, along with their bioactive constituent, chemically characterization, and plant-based diets for diabetes management. There is minimal scientific data about the mechanism of action of the plant-based product has been found. The purpose of this article is to highlight anti-diabetic plants and plant-derived bioactive compounds that have anti-diabetic properties. It also provides researchers with data that may be used to build future strategies, such as identifying promising bioactive molecules to make diabetes management easier.

Benzoylcyclopropane Derivatives from Hypoxis hemerocallidea Corms

Two monobenzoylcyclopropane (hypoxhemerol A (1: ) and hypoxhemeroloside G (2: )) and three dibenzoylcyclopropane (hypoxhemerol B (3: ), hypoxhemeroloside H (4: ), and hypoxhemeroloside I (5: )) derivatives were isolated from the hydro-alcoholic extract of Hypoxis hemerocallidea corms. This is the first instance where benzoylcyclopropane analogs were isolated from any natural source. Structure elucidation was mainly based on 1D- and 2D-NMR and HRESIMS data. The absolute configuration (2R, 4R) of 1: was determined via NOESY NMR and experimental and calculated ECD data analyses. Compounds 1: -5: and 11 recently reported metabolites (hypoxoside, obtuside A, interjectin, acuminoside, curcapicycloside, and hypoxhemerolosides A - F) were screened for in vitro antimicrobial activity against various bacterial and fungal strains. Curcapicycloside and acuminoside exhibited antibacterial activity against Escherichia coli with 78 and 79% inhibition at 20 µg/mL, respectively. Hypoxhemeroloside A showed mild antifungal activity against Cryptococcus neoformans with 63% inhibition at 20 µg/mL.

Ethnobotany and Toxicity Status of Medicinal Plants with Cosmeceutical Relevance from Eastern Cape, South Africa

The indigenous people of the Eastern Cape residing within the richest plant biodiversity in the world, including Africa’s floral ‘gold mine’, have a long history of plant use for skincare. However, such rich flora comes with numerous plants that have the potential to cause harm to humans through their usage. Therefore, the study was aimed at documenting the toxicity status of important medicinal plants used by the indigenous people from the Eastern Cape for skincare and supported by literature for cosmeceutical relevance. A list of plants used for skincare was produced following an ethnobotanical survey. In addition, data on the level of toxicity and cosmeceutical relevance of plants listed from the survey were collected from literature resources. The study listed a total of 38 plants from 25 plant families, the majority being represented by the Asphodelaceae and Asteraceae, both at 13.2%. The most preferred plant parts were the leaves (60.4%) indicating sustainable harvesting practices by the community. The literature reports validated 70% of the medicinal plants surveyed for skincare were nontoxic. Most of the plants can be incorporated in the formulation of products intended for skincare due to their low toxicity and high cosmeceutical relevance.

A review of the traditional use of southern African medicinal plants for the treatment of inflammation and inflammatory pain

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammation is a serious global concern due to its debilitating symptoms, resulting in considerable suffering and lost productivity. Chronic and auto-immune inflammatory diseases are of particular concern. Several pharmaceutical therapies are already available. However, the use of non-steroidal anti-inflammatory drugs (NSAID's) is accompanied by harmful and toxic side effects. Hence, the search for safer alternative therapeutics with limited side effects is imperative. The use of medicinal plants is common practice amongst the southern African population and may provide targets for drug development.

AIM OF THE STUDY

This study aims to review and document the medicinal uses and pharmacological properties of southern African medicinal plants used for inflammation and pain-related ailments.

MATERIAL AND METHODS

An extensive literature review was undertaken to identify southern African plants used traditionally to treat inflammation. A variety of ethnobotanical books and grey literature, as well as ScienceDirect, Google Scholar and Scopus search engines were used as sources of information.

RESULTS

This review identified 555 medicinal plants from 118 families which were traditionally used in southern Africa to treat inflammation and pain. Fabaceae was the most prominent family with 63 species, followed by Asteraceae (54 species) and Apocynaceae (33 species). The top category of ailments indicated include non-specific inflammation with 150 species, followed by inflammatory pain (148 species), headache (114 species) and toothache (114 species).

CONCLUSION

Despite a large number of southern African medicinal plants used to treat inflammation and pain, relatively few have been screened for their anti-inflammatory properties. Furthermore, biologically active plant extracts have been tested against relatively few inflammatory markers and considerable further work is required.

Neglected and Underutilised Crops: A Systematic Review of Their Potential as Food and Herbal Medicinal Crops in South Africa

The African continent harbours many native species with nutraceutical and pharmaceutical potential. This study reviewed underutilised crops in South Africa to determine their potential as food and herbal medicinal crops. Over 5,000 species have been identified and earmarked for their medical attributes in formal and informal setups. Researchers, plant breeders and policymakers have mostly ignored the development potential of these crops. Consequently, their value chains are poorly developed. In South Africa, there is a wide range of neglected and underutilised crops, which were historically popular and used by communities; however, over the years, they have lost their status within farming systems and been relegated to the status of neglected and underutilised. Recently, driven by the need to transition to more sustainable and resilient food systems, there has been renewed interest in their potential as food and herbal medicinal crops to establish new value chains that include vulnerable groups. They are now gaining global attention, and their conservation and sustainable utilisation are now being prioritized. The review confirmed that several of these crops possess nutraceutical and pharmaceutical properties, highlighting their potential for development as food and herbal medicines. However, current production levels are too low to meet the requirements for industrial development; research and development should focus on all aspects of their value chain, from crop improvement to utilisation. A transdisciplinary approach involving a wide range of actors is needed to develop the identified neglected and underutilised crops' potential as food and herbal medicinal crops and support the development of new and inclusive value chains.

Traditional Medicine Utilisation Among Pregnant Women in Sub-saharan African Countries: A Systematic Review of Literature

Traditional medicine has the potential to boost the health and economies of many SSA countries, especially if regulatory mechanisms are deployed to govern their protection and utilisation. There is lack of knowledge regarding traditional medicines and their impact on pregnancy. This paper reviews the literature on traditional medicine utilisation among pregnant women in Sub-Saharan African countries. The paper, determined the proportion of pregnant women utilising traditional medicines in Sub-Saharan Africa, identified the different types of traditional medicine used during antenatal care and reasons for Use in Sub-Saharan Africa and also identified challenges that are faced by women who use traditional medicine in antenatal care. A systematic exploratory review was conducted guided by the PRISMA framework. The databases that were searched included Google Scholar, PubMed, Cochrane, HINARI and the World Health Organization. Forty-one literature sources were eligible and included in the review process. Reported traditional medicine utilisation ranged between 12 and 93% among pregnant women in Sub-Saharan Africa. Different types of traditional medicines have been utilised in Sub-Saharan Africa for different purposes. Safety and poor management of usage were reported to be some of the challenges associated with traditional medicine. There is a need to determine chemical components and mode of action of these herbs as some could be beneficial, whilst others harmful, leading to severe pregnancy complications.

Alien woody plants are more versatile than native, but both share similar therapeutic redundancy in South Africa

Understanding why alien plant species are incorporated into the medicinal flora in several local communities is central to invasion biology and ethnobiology. Theories suggest that alien plants are incorporated in local pharmacopoeias because they are more versatile or contribute unique secondary chemistry which make them less therapeutically redundant, or simply because they are locally more abundant than native species. However, a lack of a comprehensive test of these hypotheses limits our understanding of the dynamics of plants knowledge, use and potential implications for invasion. Here, we tested the predictions of several of these hypotheses using a unique dataset on the woody medicinal flora of southern Africa. We found that the size of a plant family predicts the number of medicinal plants in that family, a support for the non-random hypothesis of medicinal plant selection. However, we found no support for the diversification hypothesis: i) both alien and native plants were used in the treatment of similar diseases; ii) significantly more native species than alien contribute to disease treatments particularly of parasitic infections and obstetric-gynecological diseases, and iii) alien and native species share similar therapeutic redundancy. However, we found support for the versatility hypothesis, i.e., alien plants were more versatile than natives. These findings imply that, although alien plant species are not therapeutically unique, they do provide more uses than native plants (versatility), thus suggesting that they may not have been introduced primarily for therapeutic reasons. We call for similar studies to be carried out on alien herbaceous plants for a broader understanding of the integration of alien plants into the pharmacopoeias of the receiving communities.

Anti-Acne Vulgaris Potential of the Ethanolic Extract of Mesua ferrea L. Flowers

Acne vulgaris is a common chronic inflammatory skin disease. In the present study, we reported the anti-acne vulgaris effect of the Mesua ferrea (M. ferrea) flower extract. The extract was evaluated for three anti-acne-causing bacteria properties including Cutibacterium acnes (C. acnes), Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus). The results indicated that the M. ferrea flower extract could be considered as the bactericidal agent against S. epidermidis and S. aureus with MIC values of 0.78 and 6.25 mg mL−1 and MBC values of 1.56 and 12.50 mg mL−1 and the bacteriostatic agent against C. acnes with MIC and MBC values of 3.12 and 25.00 mg mL−1, respectively. The extract at a concentration of 25 µg mL−1 also presented potent anti-inflammatory activity with a significant decrease of nitric oxide (NO) and tumor necrosis factor (TNF)-α productions in RAW 264.7 macrophage cells stimulated by LPS. In addition, the extract showed moderate to weak anti-oxidative capacities against DPPH, ABTS, FRAP and NO assays and also showed weak anti-tyrosinase activity. M. ferrea flower extract may serve as the alternative natural anti-acne formulations.

Unravelling the Anticancer Mechanisms of Traditional Herbal Medicines with Metabolomics

Metabolite profiling of cancer cells presents many opportunities for anticancer drug discovery. The Chinese, Indian, and African flora, in particular, offers a diverse source of anticancer therapeutics as documented in traditional folklores. In-depth scientific information relating to mechanisms of action, quality control, and safety profile will promote their extensive usage in cancer therapy. Metabolomics may be a more holistic strategy to gain valuable insights into the anticancer mechanisms of action of plants but this has remained largely unexplored. This review, therefore, presents the available metabolomics studies on the anticancer effects of herbal medicines commonly used in Africa and Asia. In addition, we present some scientifically understudied ‘candidate plants’ for cancer metabolomics studies and highlight the relevance of metabolomics in addressing other challenges facing the drug development of anticancer herbs. Finally, we discussed the challenges of using metabolomics to uncover the underlying mechanisms of potential anticancer herbs and the progress made in this regard.

The effect of incorporating herbal (Lippia javanica) infusion on the phenolic, physicochemical, and sensorial properties of fruit wine

The use of medicinal herbs in food processing to improve food quality and human health is growing in sub-Saharan Africa. Herbal infusions have perceived medicinal benefits. This study investigated the effect of incorporating L. javanica extract on the phenolic, physicochemical, and sensory properties of a Uapaca kirkiana fruit-based wine. The fruit and L. javanica were analyzed for proximate, pH, total soluble sugars (TSS), total sugar, titratable acidity, phenolics, and antioxidant activity (AOA). The prepared substrate was fermented at optimized fermentation temperature of 23°C, pH of 3.4, inoculum concentration of 9.5% (v/v) (Saccharomyces cerevisiae), and L. javanica extract concentration of 10% (v/v). The produced wine had a pH, total sugar, TSS, total acidity, and vitamin C content of 3.1 ± 0.2, 3.0 ± 0.1 g/L, 4.8 ± 0.1%, 5.9 ± 0.01 g/L, and 4.4 ± 0.1 mg/100 g, respectively. The wine had 12.2 ± 2.1 mg GAE/g, 0.06 ± 0.01 mg/g, and 1.8 ± 1.1 mg CE/g total phenols, tannins, and flavonoids, respectively. The alcohol, free sulfur dioxide (SO2), AOA, and color values of the produced wine were 10.2 ± 0.1 alcohol by volume (ABV)%, 58.1 ± 1.2 mg/L, 73.1 ± 0.1 EC50 mg/L, and 40.4 ± 2.1% yellow, respectively. The flavor, color, and overall acceptance of the produced wine were rated as "good" and were significantly different (p < .05) from control wine. The addition of L. javanica extracts enhanced total phenol, color, and sensory properties of the wine. The utilization of U. kirkiana fruit by incorporating L. javanica infusion can reduce postharvest losses and improve nutrition and health.

The transition to agricultural cultivation of neo-crops may fail to account for wild genetic diversity patterns: insights from the Cape Floristic Region

Aim

The global increase in the cultivation of native wild plants has raised concerns regarding potential risks associated with translocating genetic lineages beyond their natural range. This study aimed to investigate whether agricultural cultivation of neo-crops (a) accounts for the levels of genetic diversity present in wild populations, and whether (b) cultivated populations are genetically divergent from wild populations and thus pose a potential threat to wild genetic diversity.

Location

The Cape Floristic Region (CFR), located along the southern Cape of South Africa.

Methods

High Resolution Melt analysis (HRM) coupled with Sanger sequencing was used to screen three non-coding chloroplast DNA loci in Cyclopia Vent. (Fabaceae), a CFR endemic neo-crop cultivated for the production of a herbal infusion referred to as Honeybush tea. Wild and cultivated populations for three of three widely cultivated Honeybush species (C. intermedia, C. longifolia, and C. subternata) were screened. Genetic diversity and differentiation were measured and compared between wild and cultivated groups.

Results

Across all asseccions, a total of 17 haplotypes were detected, four of which were shared between wild and cultivated populations, while the remaining 13 were only detected in wild populations. Genetic diversity and differentiation was significantly higher in wild populations than in cultivated populations.

Conclusions

If no guidelines exist to facilitate the introduction of native wild plant taxa to a cultivated setting, wild genetic diversity patterns are likely to be compromised by cultivated populations. In the case presented here, cultivation represents a genetic bottleneck, failing to account for rare haplotypes, and may have disrupted species boundaries by initiating interspecific hybridization. More empirical work is required to evaluate the extent to which neo-crop cultivation poses a risk to wild genetic resources in the CFR and globally.

Traditional Foods and Sustainable Rural Development: Exploiting the Case of the Comoros Tea as a Potential Source of Bioactive Compounds

Although modern medicine is available in many developing countries, such as the Comoros Islands, the primary health-care needs of the local population are based on traditional foods and beverages derived from natural resources and medicinal plants for cultural and historical reasons. Aphloia theiformis (Vahl) Benn. (‘Mfandrabo’), Cinnamomum verum J.Presl (‘Mani yamdrara’), Ocimum gratissimum L. (‘Roulé’), Plectranthus amboinicus (Lour.) Spreng. (‘Ynadombwe’), Cymbopogon nardus (L.) Rendle (‘Sandze monach’) and Ocimum americanum L. (‘Kandza’) are six wild plants that are largely utilised to treat many diseases. The leaves of these plants are used in the traditional Comorian tea (aqueous infusion). This study aimed to identify and quantify the main health-promoting compounds in the traditional formulation of Comorian tea by HPLC profiling together with a preliminary assessment of antioxidant capacity to confirm the traditional use of these plants by the local population. The single plants were also studied. The Comoros tea presented a total polyphenolic content (TPC) of 4511.50 ± 74.41 mgGAE/100 g DW, a value higher than the TPCs of the different plants included in the Comorian tea. Moreover, the Comorian tea showed an antioxidant capacity (AOC) of 578.65 ± 6.48 mmol Fe2+/Kg DW, a value higher if compared to all the AOC values obtained in the single plants. The polyphenolic fraction (771.37 ± 35.76 mg/100 g DW) and organic acids (981.40 ± 38.38 mg/100 g DW) were the most important phytochemical classes in the Comorian tea (40.68% and 51.75% of the total phytocomplex, respectively), followed by the monoterpenes (5.88%) and vitamin C (1.67%), while carotenoids were detected in trace (0.02%). The Comorian tea could be important in meeting the high demand in the Comoros Islands and other developing countries for cost-effective and natural health-promoting foods and/or beverages to be produced by agri-food industries and used by the local population. This study may promote traditional foods in rural communities in the Comoros Islands and contribute to sustainable rural development and a commercial valorisation of these plants for health-promoting and food applications.

The COVID-19 Treatment Landscape: A South African Perspective on a Race Against Time

The pandemic caused by SARS-CoV-2 has infected more than 94 million people worldwide (as of 17 January 2020). Severe disease is believed to be secondary to the cytokine release syndrome (CRS or "cytokine storm") which causes local tissue damage as well as multi-organ dysfunction and thrombotic complications. Due to the high mortality rates in patients receiving invasive ventilation, practice has changed from "early-intubation" for acute respiratory distress syndrome (ARDS) to a trial of non-invasive ventilation (NIV) or high flow nasal cannula (HFNC) oxygen. Reports indicating the benefit of NIV and HFNC have been encouraging and have led to more than 20,000 such devices being manufactured and ready for roll-out in South Africa (SA) as of July 2020. The need to identify drugs with clear clinical benefits has led to an array of clinical trials, most of which are repurposing drugs for COVID-19. The treatment landscape reflects the need to target both the virus and its effects such as the CRS and thrombotic complications. Conflicting results have the potential to confuse the implementation of coordinated treatment strategies and guidelines. The purpose of this review is to address pertinent areas in the current literature on the available medical treatment options for COVID-19. Remdesivir, tocilizumab, and dexamethasone are some of the treatment options that have shown the most promise, but further randomized trials are required to particularly address timing and dosages to confidently create standardized protocols. For the SA population, two healthcare sectors exist. In the private sector, patients with medical insurance may have greater access to a wider range of treatment options than those in the public sector. The latter serves >80% of the population, and resource constraints require the identification of drugs with the most cost-effective use for the greatest number of affected patients.

Ethnomedicinal uses, biological activities, phytochemistry and conservation of African ginger (Siphonochilus aethiopicus): A commercially important and endangered medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE

In sub-Saharan Africa, African ginger (Siphonochilus aethiopicus) is used for treating common illnesses including colds, coughs, inflammation and related symptoms. The available literature survey on this plant provided scarce anecdotal information, particularly in western and eastern Africa, with a few reports on its bioactivity. In addition, the indigenous knowledge and conservation strategies of this economically important and critically endangered species are currently fragmented.

AIM OF THE REVIEW

This review entails a critical appraisal of existing literature on the ethnomedicinal uses, biological activities, phytochemicals, research opportunities and prospects for the sustainable use of S. aethiopicus.

MATERIALS AND METHODS

This review was conducted using a comprehensive literature search on the ethnomedicinal uses, biological activities and phytochemistry of S. aethiopicus throughout its distributional range. The conservation status and associated bio-economy potential of African ginger were also assessed. We searched different online databases (e.g. Google Scholar, ScienceDirect, PubMed and Scopus) for peer-reviewed journals, conference outputs, international, regional and national organizational reports, published books and theses.

RESULTS

We established that S. aethiopicus is used to treat a wide variety of ailments such as respiratory problems (including cough, influenza), pain, inflammation and malaria. Extracts of African ginger are used as an ingredient in some commercialised products for nutraceutical, cosmeceutical and pharmaceutical purposes. The rhizome extract demonstrated anti-asthmatic, anti-inflammatory, and antiplasmodial activities, which led to the development of a patented novel extract for treating asthma and allergies. Phytochemical analysis of leaf, root and rhizome extracts of African ginger revealed the presence of flavonoids, phenolic acids, volatile and essential oils as the major constituents. These phytochemicals are known to possess bioactivities such as antimicrobial and anti-inflammatory activities. Particularly, the bioactive compounds, siphonochilone and eucalyptol, found in the roots and rhizomes have demonstrated potential to be used in remedies for treating asthma and allergic reactions. Furthermore, extracts of S. aethiopicus contained natural anti-inflammatory mediators with potential to combat and manage chronic inflammation. This plant is classified on the Red List of South African Plants as a critically endangered plant. Its high risk of extinction due to its unsustainable harvesting and exploitation necessitates its rapid propagation and cultivation to meet its increasing demand.

CONCLUSIONS

The review highlights the therapeutic potential of S. aethiopicus and rational prioritization of this plant species with the potential for isolating new bioactive compounds. In the light of the use of this plant extract in traditional medicine and many commercial products, there is a heightened need to explore the mechanism(s) of action of the identified extracts and bioactive compounds in order to fully understand their pharmacokinetics and probably elucidate the pathways of their activities.

Potential role of neglected and underutilized plant species in improving women's empowerment and nutrition in areas of sub-Saharan Africa

In the context of the nutrition transition, women in sub-Sahara Africa are a critical target group from a nutrition standpoint, and they experience significant discrimination in food production. Food-based, women-centered strategies are recommended to address nutrient gaps, and to educate and empower women. In this context, local natural resources, such as neglected and underutilized plant species (NUS), may contribute to adding nutritional value, enriching diet diversity, and ensuring nutrition security. The aim of the current narrative review is to investigate the nutritional status of the sub-Saharan African population and the potential role of local agriculture strategies in improving food production and diet diversity and in expanding income-generating activities for women. The nutritional properties of the most important regional NUS are also discussed.

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.

Critical review of the Withania somnifera (L.) Dunal: ethnobotany, pharmacological efficacy, and commercialization significance in Africa

BACKGROUND

Withania somnifera (L.) Dunal (W. somnifera) is a herb commonly known by its English name as Winter Cherry. Africa is indigenous to many medicinal plants and natural products. However, there is inadequate documentation of medicinal plants, including W. somnifera, in Africa. There is, therefore, a need for a comprehensive compilation of research outcomes of this reviewed plant as used in traditional medicine in different regions of Africa.

METHODOLOGY

Scientific articles and publications were scooped and sourced from high-impact factor journals and filtered with relevant keywords on W. somnifera. Scientific databases, including GBIF, PubMed, NCBI, Google Scholar, Research Gate, Science Direct, SciFinder, and Web of Science, were accessed to identify the most influential articles and recent breakthroughs published on the contexts of ethnography, ethnomedicinal uses, phytochemistry, pharmacology, and commercialization of W. somnifera.

RESULTS

This critical review covers the W. somnifera ethnography, phytochemistry, and ethnomedicinal usage to demonstrate the use of the plant in Africa and elsewhere to prevent or alleviate several pathophysiological conditions, including cardiovascular, neurodegenerative, reproductive impotence, as well as other chronic diseases.

CONCLUSION

W. somnifera is reportedly safe for administration in ethnomedicine as several research outcomes confirmed its safety status. The significance of commercializing this plant in Africa for drug development is herein thoroughly covered to provide the much-needed highlights towards its cultivations economic benefit to Africa.

Assessment of essential and non-essential elements in selected traditional medicines from India, Ghana and China

Traditional medicine (TM) also known as folk medicine consists of medical knowledge systems that were developed over generations in various countries before the era of modern medicine. Over the last few years, there has been a shift in universal trend from modern medicine to TM because it is believed that these medicines are non-toxic to humans, have little to no side-effects, are readily available and affordable. The purpose of this study was to investigate the essential and non-essential elemental concentrations of ayurvedic medicines (AM), Ghanaian traditional medicines (GTM) and Chinese traditional medicines (CTM). The results indicate that the mean elemental concentrations in TM varied greatly. The mean concentrations of copper and mercury in AM, GTM and CTM ranged from 4 to 45 mg/kg and 0.01 to 2 mg/kg, respectively. Multivariate statistical analyses applied to recognise inter-element associations indicated that at 0.05 significant level, there was a positive correlation between elements suggesting they may have originated from the same source. The study concludes by highlighting the need for monitoring of the elemental concentrations in commonly consumed traditional medicines regularly to detect contamination in these medicines since the occurrence of metals in these medicines above or below legally permissible limits can be harmful to consumers.

Sceletium for Managing Anxiety, Depression and Cognitive Impairment: A Traditional Herbal Medicine in Modern-Day Regulatory Systems

Modern-day regulatory systems governing conditions for how health products enter national markets constitute a barrier of access for traditional herbal medicines on an international level. Regulatory intentions are focused on ensuring that consumers are being provided with safe, efficacious and high-quality products that, however, collaterally limit opportunities for traditional herbal medicinal products, especially those that do not already have a long-standing tradition of use established in the respective national marketplaces. This case study investigates and compares how a Southern African herbal medicine with great potential as an anxiolytic and mild antidepressant - Mesembryanthemum tortuosum L. [syn. Sceletium tortuosum (L.) N.E.Br.] aerial parts - fares internationally in today's regulatory environments. It is argued that inadvertent regulatory favoritism combined with the lack of means for adequate protection of intellectual property may obstruct innovation by creating an almost insurmountable economical hurdle for successful product development and introduction of botanicals from developing countries into most of the world's health product markets.

Essential Oil Variation within Warburgia salutaris-A Coveted Ethnomedicinal Aromatic Tree

Warburgia salutaris, known as 'Pepper bark', is an ethnomedicinally important tree found in the southern regions of Africa. A total of 75 fresh leaf specimens of W. salutaris (n=40 wild and 35 cultivated) were collected from the Limpopo (wild) and KwaZulu-Natal provinces (cultivated), two distinct locations in South Africa. In this study, the leaf essential oils obtained by hydrodistillation were characterized using gas chromatography coupled to mass spectrometry/flame ionization detection (GC/MS/FID). More than 15 compounds, accounting for 90-99 % of the total oil composition were identified. The analysis revealed that myrcene (0.6-65.3 %), (E)-β-ocimene (nd-56.9 %), (Z)-β-ocimene (nd-19.1 %), α-pinene (nd-19.1 %) and limonene (nd-11.7 %) are major constituents of W. salutaris essential oils. Chemometric analysis revealed two major chemotypes within the essential oils with a modeled variation of approximately 60 %. Linalool and germacrene D were revealed as markers associated with the wild-harvested oils, while cultivated oils were distinguished by higher levels of limonene and α-humulene. The intra-population variation indicated two chemically distinct chemotypes from three different populations, however, the season of harvest did not have a direct influence on the chemical profiles of the essential oils.

Chemotypic variation of non-volatile constituents of Artemisia afra (African wormwood) from South Africa

Artemisia afra (African wormwood) is a popular medicinal plant of southern Africa and is an excellent candidate for commercialisation. This current study was aimed at exploring the phytochemistry and chemical variation of non-volatile compounds within wild populations of A. afra, and developing chromatographic quality control protocols for raw materials based on the identification of marker compounds. Chromatographic data, from samples representing 12 distinct populations, were obtained using liquid chromatography-mass spectrometry. An untargeted chemometric approach revealed three clusters. Marker compounds for each cluster, revealed through discriminant analysis, were isolated and identified using NMR spectroscopy, as acacetin (1) (Group 1), chrysoeriol (2) (Group 2), and 3,5-di-O-caffeoylquinic acid (3) and scopoletin (4) (Group 3). In addition, (3) and rutin (5), (both reported for the first time from A. afra), and (1), (2), (4) and 4-caffeoylquinic acid (6) were established as reliable markers for species identification, since they were abundant in most samples. Quantitative analysis using a validated method established (4) as the dominant compound in the samples (1080-19,600 μg/g dry weight (d.w.)), followed by (5) (49.5-2490 μg/g d.w.). A high performance thin layer chromatography (HPTLC) method was developed. The Rf values and colours of the bands corresponding to the marker compounds were recorded so that these compounds could be easily identified for quality control purposes. Multivariate analysis of the data using the rTLC online application confirmed the presence of different chemical groupings within the samples. It was deduced that quantitative, rather than qualitative differences, characterised the samples. Future research should focus on comparing the efficacy of the various chemical clusters in multi-target biological assays aligned to the traditional use of the plant.

Yield and Metabolite Production of Pelargonium sidoides DC. in Response to Irrigation and Nitrogen Management

Competition for water between agricultural and non-agricultural economic sectors hampers agricultural production, especially in water-scarce regions. Understanding crop responses in terms of yield and quality to irrigation is an important factor in designing appropriate irrigation management for optimal crop production and quality. Pelargonium sidoides DC., often harvested from the wild, is in high demand in the informal market and for commercial formulations. Agricultural production of high-quality materials through cultivation can help reduce pressure on its wild populations. This study aimed at determining the effects of water and nitrogen on P. sidoides yield and metabolite production. The irrigation treatments applied were 30%, 50%, and 70% of an allowable depletion level (ADL), while the nitrogen (N) levels were 0 (control), 50, 100, and 150 kg ha⁻¹. The 30% ADL resulted in a significantly higher biomass and root yield. Nitrogen at 50 and 100 kg ha⁻¹ resulted in a significantly higher biomass yield, compared to the N control. An increase in sugars and citrate cycle components was observed for the well-watered 30% ADL treatment, whereas water-stressed (50% and 70% ADL) treatments increased alanine, aspartate, and glutamate metabolism, increasing levels of asparagine, 4-aminobutyrate, and arginine. The treatments had no significant effect on the root content of esculin, scopoletin, and umckalin. Water stress induced metabolite synthesis to mitigate the stress condition, whereas under no water stress primary metabolites were synthesized. Moreover, cultivation of P. sidoides as a conservation strategy can increase yield without affecting its bioactivity, while providing sustenance for the rural communities.

Diversity and Conservation through Cultivation of Hypoxis in Africa—A Case Study of Hypoxis hemerocallidea

Africa has the largest diversity of the genus Hypoxis, accounting for 61% of the current globally accepted taxa within the genus, including some endemic species. Using Hypoxis hemerocallidea as a case study, this review addresses the conservation concerns arising from the unsustainable, wild harvesting of a number of Hypoxis species. Hypoxis hemerocallidea is one of the wild-harvested, economically important, indigenous medicinal plants of southern Africa, with potential in natural product and drug development. There are several products made from the species, including capsules, tinctures, tonics and creams that are available in the market. The use of H. hemerocallidea as a “cure-all” medicine puts an important harvesting pressure on the species. Unsustainable harvesting causes a continuing decline of its populations and it is therefore of high priority for conservation, including a strong case to cultivate the species. Reviewing the current knowledge and gaps on cultivation of H. hemerocallidea, we suggest the creation of a platform for linking all the stakeholders in the industry.

Medicinal Plants Used in Traditional Management of Cancer in Uganda: A Review of Ethnobotanical Surveys, Phytochemistry, and Anticancer Studies

The burden of neoplastic diseases is a significant global health challenge accounting for thousands of deaths. In Uganda, about 32,617 cancer cases were reported in 2018, accompanied by 21,829 deaths. In a view to identify some potential anticancer plant candidates for possible drug development, the current study was designed to compile the inventory of plants with reported anticancer activity used in rural Uganda and the evidences supporting their use in cancer therapy. An electronic survey in multidisciplinary databases revealed that 29 plant species belonging to 28 genera distributed among 24 families have been reported to be used in the management of cancer in Uganda. Anticancer plants were majorly from the families Bignoniaceae (7%), Caricaceae (7%), Fabaceae (7%), Moraceae (7%), and Rutaceae (7%). Most species occur in the wild (52%), though some are cultivated (48%). The growth habit of the plants is as trees (55%) or herbs (45%). Anticancer extracts are usually prepared from leaves (29%), bark (24%), roots (21%), and fruits (13%) through decoctions (53%), as food spices (23%) or pounded to produce ointments that are applied topically (10%). Prunus africana (Hook.f.) Kalkman, Opuntia species, Albizia coriaria (Welw. ex Oliver), Daucus carota L., Cyperus alatus (Nees) F. Muell., Markhamia lutea (Benth.) K. Schum., and Oxalis corniculata L. were the most frequently encountered species. As per global reports, Allium sativum L., Annona muricata L., Carica papaya L., Moringa oleifera Lam., Opuntia species, Prunus africana (Hook.f.) Kalkman, and Catharanthus roseus (L.) G. Don. are the most studied species, with the latter having vincristine and vinblastine anticancer drugs developed from it. Prostate, cervical, breast, and skin cancers are the top traditionally treated malignancies. There is a need to isolate and evaluate the anticancer potential of the bioactive compounds in the unstudied claimed plants, such as Cyperus alatus (Nees) F. Muell., Ficus dawei Hutch., Ficus natalensis Hochst., and Lovoa trichilioides Harms, and elucidate their mechanism of anticancer activity.