In vitro profiling and functional assessments of the anti-diabetic capacity of phenolic-rich extracts of Bulbine natalensis and Bulbine frutescens.

AIMS: Bulbine natalensis (BN) and Bulbine frutescens (BF) are recommended in South African traditional medicine to treat diabetes, but their modes of action are unknown. This study assessed the phenolic acid profiles, mineral composition and in vitro functional effects of BN and BF to better understand their glucose-lowering capabilities. METHODS: Phenolic acid and mineral composition of BN and BF methanolic extracts were determined by HPLC and inductively coupled plasma optical emission spectroscopy respectively. Antioxidant capacity was assessed by potassium ferricyanide reducing power and 2,2-diphenyl-2-picrylhydrazyl radical scavenging assays, and inhibition of alpha-amylase, alpha-glucosidase, pancreatic lipase and DPP4 was evaluated by standard enzyme assays. The effects of BN and BF extracts on insulin secretion were investigated using static incubations of isolated mouse islets and molecular docking analysis was used to identify interactions of BN and BF with partners that could mediate stimulatory effects on insulin secretion. RESULTS: Methanolic extracts of BN and BF contained high concentrations of protocatechuic and gallic acids, and high levels of Zn, Mn and Cr. The extracts inhibited alpha-glucosidase, alpha-amylase, pancreatic lipase and DPP4 activities, and they also inhibited free radical generation. Both extracts significantly potentiated glucose-stimulated insulin secretion without significantly affecting basal insulin secretion or islet cell viability. Protocatechuic acid, the most abundant phenolic acid in the extracts, showed high affinity for PKA, PKC, DPP4 and CaMK II in the docking analysis. CONCLUSIONS: BN and BF have multiple beneficial effects on glucoregulatory pathways and they, or their derivatives, could be developed to treat type 2 diabetes.

Phenolics Profiling of Carpobrotus edulis (L.) N.E.Br. and Insights into Molecular Dynamics of Their Significance in Type 2 Diabetes Therapy and Its Retinopathy Complication.

Adverse effects associated with synthetic drugs in diabetes therapy has prompted the search for novel natural lead compounds with little or no side effects. Effects of phenolic compounds from Carpobrotus edulis on carbohydrate-metabolizing enzymes through in vitro and in silico methods were assessed. Based on the half-maximal inhibitory concentrations (IC50), the phenolic extract of the plant had significant (p < 0.05) in vitro inhibitory effect on the specific activity of alpha-amylase (0.51 mg/mL), alpha-glucosidase (0.062 mg/mL) and aldose reductase (0.75 mg/mL), compared with the reference standards (0.55, 0.72 and 7.05 mg/mL, respectively). Molecular interactions established between the 11 phenolic compounds identifiable from the HPLC chromatogram of the extract and active site residues of the enzymes revealed higher binding affinity and more structural compactness with procyanidin (-69.834 ± 6.574 kcal/mol) and 1,3-dicaffeoxyl quinic acid (-42.630 ± 4.076 kcal/mol) as potential inhibitors of alpha-amylase and alpha-glucosidase, respectively, while isorhamnetin-3-O-rutinoside (-45.398 ± 4.568 kcal/mol) and luteolin-7-O-beta-d-glucoside (-45.102 ± 4.024 kcal/mol) for aldose reductase relative to respective reference standards. Put together, the findings are suggestive of the compounds as potential constituents of C. edulis phenolic extract responsible for the significant hypoglycemic effect in vitro; hence, they could be exploited in the development of novel therapeutic agents for type-2 diabetes and its retinopathy complication.

Natural Products from Medicinal Plants against Phytopathogenic Fusarium Species: Current Research Endeavours, Challenges and Prospects.

Many Fusarium species are pathogenic, causing crop diseases during crop production and spoilage of agricultural products in both commercial and smallholder farming. Fusarium attack often results into food contamination, yield loss and increases in food insecurity and food prices. Synthetic fungicides have been used as a control strategy for the management of crop diseases caused by Fusarium pathogens. The negative effects associated with application of many synthetic pesticides has necessitated the need to search for alternative control strategies that are affordable and environmentally safe. Research on medicinal plants as control agents for Fusarium pathogens has received attention since plants are readily available and they contain wide variety of secondary metabolites that are biodegradable. The activities of solvent extracts, essential oils and compounds from medicinal plants have been tested against Fusarium phytopathogenic species. A summary of recent information on antifungal activity of plants against Fusarium species is valuable for the development of biopesticides. This paper reviews the antifungal research conducted on medicinal plants against Fusarium pathogens, over a 10-year period, from January 2012 to May 2021. We also highlight the challenges and opportunities of using natural products from medicinal plants in crop protection. Several databases (Science Direct and Web of Science) were used to obtain information on botanical products used to control Fusarium diseases on crops. Keywords search used included natural products, antifungal, Fusarium, crops diseases, phytopathogenic, natural compounds and essential oil.

Antifungal Activity of Isolated Compounds from the Leaves of Combretum erythrophyllum (Burch.) Sond. and Withania somnifera (L.) Dunal against Fusarium Pathogens.

Crop diseases caused by Fusarium pathogens, among other microorganisms, threaten crop production in both commercial and smallholder farming. There are increasing concerns about the use of conventional synthetic fungicides due to fungal resistance and the associated negative effects of these chemicals on human health, livestock and the environment. This leads to the search for alternative fungicides from nature, especially from plants. The objectives of this study were to characterize isolated compounds from Combretum erythrophyllum (Burch.) Sond. and Withania somnifera (L.) Dunal leaf extracts, evaluate their antifungal activity against Fusarium pathogens, their phytotoxicity on maize seed germination and their cytotoxicity effect on Raw 264.7 macrophage cells. The investigation led to the isolation of antifungal compounds characterized as 5-hydroxy-7,4'-dimethoxyflavone, maslinic acid (21-hydroxy-3-oxo-olean-12-en-28-oic acid) and withaferin A (4ß,27-dihydroxy-1-oxo-5ß,6ß-epoxywitha-2-24-dienolide). The structural elucidation of the isolated compounds was established using nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS) and, in comparison, with the available published data. These compounds showed good antifungal activity with minimum inhibitory concentrations (MIC) less than 1.0 mg/mL against one or more of the tested Fusarium pathogens (F. oxysporum, F. verticilloides, F. subglutinans, F. proliferatum, F. solani, F. graminearum, F. chlamydosporum and F. semitectum). The findings from this study indicate that medicinal plants are a good source of natural antifungals. Furthermore, the isolated antifungal compounds did not show any phytotoxic effects on maize seed germination. The toxicity of the compounds A (5-hydroxy-7,4'-dimethoxyflavone) and AI (4ß,27-dihydroxy-1-oxo-5ß,6ß-epoxywitha-2-24-dienolide) was dose-dependent, while compound B (21-hydroxy-3-oxo-olean-12-en-28-oic acid) showed no toxicity effect against Raw 264.7 macrophage cells.

Physiological role of phenolic biostimulants isolated from brown seaweed Ecklonia maxima on plant growth and development.

MAIN CONCLUSION: Eckol, a major phenolic compound isolated from brown seaweed significantly enhanced the bulb size and bioactive compounds in greenhouse-grown Eucomis autumnalis. We investigated the effect of eckol and phloroglucinol (PG) (phenolic compounds) isolated from the brown seaweed, Ecklonia maxima (Osbeck) Papenfuss on the growth, phytochemical and auxin content in Eucomis autumnalis (Mill.) Chitt. The model plant is a popular medicinal species with increasing conservation concern. Eckol and PG were tested at 10(-5), 10(-6) and 10(-7) M using soil drench applications. After 4 months, growth parameters, phytochemical and auxin content were recorded. When compared to the control, eckol (10(-6) M) significantly improved bulb size, fresh weight and root production while the application of PG (10(-6) M) significantly increased the bulb numbers. However, both compounds had no significant stimulatory effect on aerial organs. Bioactive phytochemicals such as p-hydroxybenzoic and ferulic acids were significantly increased in eckol (10(-5) M) and PG (10(-6) M) treatments, compared to the control. Aerial (1,357 pmol/g DW) and underground (1,474 pmol/g DW) parts of eckol-treated (10(-5) M) plants yielded the highest concentration of indole-3-acetic acid. Overall, eckol and PG elicited a significant influence on the growth and physiological response in E. autumnalis. Considering the medicinal importance of E. autumnalis and the increasing strains on its wild populations, these compounds are potential tools to enhance their cultivation and growth.

Ethnobotanical insights on the management of plant pests and diseases by smallholder farmers in Mpumalanga Province of South Africa.

BACKGROUND: Pests and diseases are a major contributor to yield losses in sub-Saharan Africa, prompting smallholder farmers to seek cost-effective, accessible and ecologically friendly alternatives for crop protection. This study explored the management of pests and diseases affecting crops across eight selected villages in Ehlanzeni District, Mpumalanga Province, South Africa. METHODS: A total of 120 smallholder farmers were purposefully selected utilising the snowball technique. Information on the management of plant pests and diseases was collected through interviews and focus group discussions using semi-structured interview schedules. Ethnobotanical indices, including relative frequency of citation (RFC), use-value (UV) and informant consensus factor (Fic), were used to quantify and rank the plants used for crop protection in the study area. RESULTS: Twenty-three plant species (16 naturalised exotics and seven indigenous plants) belonging to 16 families were used for managing pests (vertebrates and invertebrates) and diseases (fungal and bacterial related) affecting crops in the study area. The dominant (100%) crops cultivated by the participants were Allium cepa L., Mangifera indica L., Solanum lycopersicum L. and Zea mays L. The RFC value ranged from 0.08 to 0.83 and the three most popular plants for crop protection were Capsium annuum L. (0.83), A. cepa (0.63) and Dichrostachys cinerea (L.) Wight & Arn. (0.43). In terms of the UV, the five most promising plants used as biocontrol were Tulbaghia violacea (0.13), A. cepa (0.12), C. annuum L. (0.09), Solanum campylacanthum Hochst. Ex A.Rich.(0.09) and Pinus pinaster (0.08). Based on the Fic, four categories were established and dominated by fungal diseases (0.64). Furthermore, T. violacea and A. cepa were the most often mentioned plants used against fungal conditions. Other categories cited were bacterial diseases (0.3), invertebrate pests (0.11) and vertebrate pests (0.14), an indication that smallholder farmers had limited agreement or common knowledge about the plants used for their management. The preparation methods included maceration (38%), decoction (38%) and burning (24%). Foliar application (67%) and soil drenching (33%) were used for administering plant extracts during the management of crop pests and diseases. CONCLUSION: The study highlights the importance of botanicals and associated indigenous knowledge among smallholder farmers in Mpumalanga Province, South Africa. It is pertinent to explore the valorisation of these botanicals by generating empirical data on their biological efficacies and phytochemical profiles.

Assessment of long-term storage on antimicrobial and cyclooxygenase-inhibitory properties of South African medicinal plants.

In traditional medicine, plant materials are often stored by traditional healers, plant gatherers and traders before they are eventually consumed or sold. The critical point is whether stored medicinal plants are as active as freshly harvested dried material. We evaluated the effects of long-term storage (12 or 16 years) on the antimicrobial (microplate dilution method) and anti-inflammatory (COX-1 and COX-2 inhibition) potencies of 21 extensively used traditional medicinal plants in treating pain and infection-related ailments. The minimum inhibitory concentration (MIC) values obtained against Staphylococcus aureus and Pseudomonas aeruginosa in the stored plant materials were generally either lower or roughly the same as in the fresh material. Most of the stored plant material had comparable minimum microbicidal concentration (MMC) values as the fresh material against S. aureus and P. aeruignosa. Similarly, the majority (71%) of the stored plant material had similar MIC and/or MMC values as fresh material against the fungus Candida albicans. The percentage inhibition of COX-1 by the majority (88%) of the stored material was not significantly different when compared to those freshly collected. Stored material of Clausena anisata, Ekebergia capensis and Trichilia dregeana showed a significantly higher COX-1 inhibition than the fresh material. The therapeutic and conservation implications of the results are discussed.

Antioxidant and acetylcholinesterase-inhibitory properties of long-term stored medicinal plants.

BACKGROUND: Medicinal plants are possible sources for future novel antioxidant compounds in food and pharmaceutical formulations. Recent attention on medicinal plants emanates from their long historical utilisation in folk medicine as well as their prophylactic properties. However, there is a dearth of scientific data on the efficacy and stability of the bioactive chemical constituents in medicinal plants after prolonged storage. This is a frequent problem in African Traditional Medicine. METHODS: The phytochemical, antioxidant and acetylcholinesterase-inhibitory properties of 21 medicinal plants were evaluated after long-term storage of 12 or 16 years using standard in vitro methods in comparison to freshly harvested materials. RESULTS: The total phenolic content of Artemisia afra, Clausena anisata, Cussonia spicata, Leonotis intermedia and Spirostachys africana were significantly higher in stored compared to fresh materials. The flavonoid content were also significantly higher in stored A. afra, C. anisata, C. spicata, L. intermedia, Olea europea and Tetradenia riparia materials. With the exception of Ekebergia capensis and L. intermedia, there were no significant differences between the antioxidant activities of stored and fresh plant materials as measured in the ß-carotene-linoleic acid model system. Similarly, the EC50 values based on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay were generally lower for stored than fresh material. Percentage inhibition of acetylcholinesterase was generally similar for both stored and fresh plant material. Stored plant material of Tetradenia riparia and Trichilia dregeana exhibited significantly higher AChE inhibition than the fresh material. CONCLUSIONS: The current study presents evidence that medicinal plants can retain their biological activity after prolonged storage under dark conditions at room temperature. The high antioxidant activities of stable bioactive compounds in these medicinal plants offer interesting prospects for the identification of novel principles for application in food and pharmaceutical formulations.

Acetylcholinesterase inhibition, antioxidant, antiinflammatory, antimicrobial and phytochemical properties of Huernia hystrix.

Huernia species are typical famine-food plants consumed in southern Ethiopia. H. hystrix is a heavily exploited ethnomedicinal succulent plant traded in traditional medicine systems especially on South Africa's eastern seaboard. This study investigated the acetylcholinesterase (AChE) inhibition, antioxidant, antiinflammatory and antimicrobial properties of extracts obtained from the stems and roots of this plant. At the same concentration level (625.0, 312.5 or 156.3 µg/mL), the whole plant extract showed higher AChE inhibitory activity when compared with the stem and root extracts; a finding suggesting the presence of AChE inhibitors acting additively or synergistically in the whole plant extract. The roots showed strong antioxidant activity (in DPPH and ß-carotene assays) comparable to that of butylated hydroxytoluene (BHT), indicating the presence of potent antioxidant compound(s) that can be exploited as alternatives for use in the food and cosmetic industries and/or as nutraceuticals. All the petroleum ether (PE) (except root PE) and dichloromethane (DCM) extracts demonstrated good inhibitory activity (> 70%) in cyclooxygenase (COX-1 and COX-2) assays at a 0.25 µg/µL concentration. Most of the extracts showed broad-spectrum inhibitory and lethal activities against the microorganisms used in this study. The observed biological activities might be due to the iridoid, phenolic and flavonoid contents of the plants.

Lantadene A and boswellic acid isolated from the leaves of Lantana camara L. have the potential to control phytopathogenic Fusarium species.

Phytopathogenic Fusarium species are restricting factors causing diseases and yield loss in crop production. As part of exploration for pesticides from medicinal plants, this study aimed to isolate and characterize bioactive compounds from Lantana camara L. and evaluate their efficiency against Fusarium phytopathogens. Phytochemical investigation of ethyl acetate leaf extract led to separation of lantadene A (22-angeloyloxy-9-hydroxy-3-oxo-olean-12-en-28-oic acid) and boswellic acid (11-keto-ß-boswellic acid). The chemical structures of the aforementioned compounds were confirmed using physical properties, spectroscopic analysis, and published data. Lantadene A exhibited significant antifungal activity against F. subglutinans, F. proliferatum, F. solani, F. graminearum, and F. semitectum with minimum inhibitory concentration (MIC) less than or equal to 0.63 mg/mL. Boswellic acid exhibited strong activity (MIC = 0.63 mg/mL) against F. subglutinans and F. semitectum. In terms of their toxicity towards Raw 264.7 cells, lantadene A and boswellic acid recorded half-maximal inhibitory concentration values of 84.2 µg/mL and 186.6 µg/mL, respectively. Both lantadene A and boswellic acid had no phytotoxic effect against seed germination and seedling root length. Lantadene A and boswellic acid have strong potential to be further investigated as lead natural fungicides (biopesticides) to control Fusarium crop diseases.

Cultivar and Postharvest Storage Duration Influence Fruit Quality, Nutritional and Phytochemical Profiles of Soilless-Grown Cantaloupe and Honeydew Melons.

There is an increasing demand for sweet melon (Cucumis melo L.) fruit in fruit and vegetable markets due to its nutritional content, resulting in different cultivars being grown in different production systems. This study evaluated the nutritional and phytochemical contents of soilless-grown cantaloupe and honeydew sweet melon cultivars at harvest and postharvest. At harvest, vitamin C and ß-carotene concentrations were higher in orange-fleshed (cantaloupe) cvs. Magritte, Divine, Majestic, Cyclone, MAB 79001, E25F.00185, E25F.00075 and Adore, compared to green-fleshed (honeydew) cvs. Honey Brew and Honey Star. The zinc (Zn), phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) contents were higher in orange-fleshed compared to green-fleshed cultivars. Total phenolics content (TPC) in cv. E25F.00075 was the highest (2.87 mg GAE∙g-1 dry weight). A significant, positive, correlation occurred between ß-carotene and Zn, P, K, Ca and Mg contents. Postharvest storage duration affected TPC and total soluble solid content. The interaction of cultivar and postharvest storage duration affected flavonoid, vitamin C and ß-carotene contents, free radical scavenging activity and fruit juice pH. Vitamin C and ß-carotene contents decreased with increased postharvest storage duration while flavonoid content increased. The cantaloupe cultivars performed significantly better compared to the honeydew cultivars as evident in their high mineral element content, and vitamin C and ß-carotene concentrations. Selection of appropriate cultivars in a production system should consider variation in nutritional traits of cultivars and postharvest storage duration. Soilless production of sweet melon cultivars in tunnels offers a viable alternative to open field to produce high-quality melons at harvest and postharvest.

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.

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.

Phytochemical Content, Antioxidant, Alpha-Glucosidase Inhibitory and Antibacterial Activities of Spineless Cactus Pear Cultivars.

Variation in cultivars can influence plant biological activities. This study aimed to identify superior cultivars while determining the variability in the phytochemical content, antioxidant, alpha-glucosidase inhibitory and antibacterial activities of cladode extracts from selected spineless Burbank cactus pear (Opuntia ficus-indica and Opuntia robusta) cultivars. Total phenolic and flavonoid contents were determined using the Folin-Ciocalteu and aluminum chloride spectrophotometric methods, respectively. Antioxidant activity was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ß-carotene linoleic acid assays. Alpha-glucosidase inhibition was determined using a spectrophotometric method and antibacterial activity using a non-polar (petroleum ether) and polar (50% methanol) extracts against two Gram-positive and two Gram-negative bacteria. Significant variation in phytochemical content, antioxidant, antidiabetic and antibacterial activities was observed amongst the cultivars. Alpha-glucosidase inhibitory activity varied widely with IC50 values ranging from 0.06 to 1.85 mg/mL. Radical scavenging activity of Polypoly cultivar was about seven fold higher than that recorded in other cultivars with low activity. Turpin and Berg x Mexican cultivars had the highest total phenolic and flavonoid contents, whilst the non-polar extract of Turpin also exhibited higher antibacterial activity against Bacillus subtilis and Escherichia coli. Sicilian Indian Fig was amongst the cultivars with a higher antioxidant activity, whilst also showing a strong inhibition against B. subtilis and E. coli. Polypoly cultivar demonstrated strong antioxidant and antidiabetic activities while its polar extract showed the highest total antibacterial activity against B. subtilis. The cultivar Malta was superior in terms of its antibacterial potency and efficacy against B. subtilis, Staphylococcus aureus and E. coli. The potential of using spineless cactus pear cladodes as a functional food with antioxidant, antidiabetic and antibacterial properties against pathogenic food spoilage bacteria in place of synthetic compounds was established. The significance of cultivar selection to increase this potential was highlighted.

An ethnobotanical survey of medicinal plants used by traditional healers for the treatment of cancer in Hammanskraal and Winterveld, Tshwane Metropolitan Municipality, South Africa.

Background: Knowledge of medicinal plants used by the traditional healers are mostly confined among the locals and the adherents, hence, proper enquiry and documentation can help the ever dynamic scientific world to find permanent cure to the menace of such deadly diseases such as cancer. This study aimed at (1) specifically recording medicinal plants traditionally used for the treatment of cancer in Hammanskraal and Winterveld, South Africa, and (2) documenting the different methods of preparation and administration of those medicinal plants as recorded during the study. Method: An open-ended semi-structured questionnaire was administered to 90 willing traditional healers in Hammanskraal and Winterveld area, Tshwane Municipality, South Africa to document plants used for cancer treatments. The study was conducted over a period of six months (July - December, 2018). Descriptive statistics was used to present the obtained data. Results: The study recorded twenty-eight plant species belonging to 18 families for the treatment of different types of cancer. Plant species in the Fabaceae family particularly Lessertia frutescens (L.) Goldblatt and J.C. Manning, Senna italica Mill and Trifolium pratense L. were the most prominently mentioned (highest citation frequency) by the traditional healers for lung, and skin cancer treatment. Based on the citation frequency, the most treated cancer by the traditional healers is in the order: skin cancer > lung cancer > breast cancer > prostate cancer > cervical cancer. The method of preparation included decoction (32.3%), infusion (29%), paste (16.1%) and maceration (22.6%). Conclusion: In addition to the documentation of indigenous knowledge related to the use of medicinal plants in the traditional management of cancer in South Africa, this study opens a vista for investigations into the phytochemical and pharmacological properties of the documented plants.

Biopriming with Seaweed Extract and Microbial-Based Commercial Biostimulants Influences Seed Germination of Five Abelmoschus esculentus Genotypes.

Seed germination is a crucial step in plant propagation, as it controls seedling production, stand establishment and ultimately crop yield. Approaches that can promote seed germination of valuable crops remain of great interest globally. The current study evaluated the effect of biostimulant (Kelpak® and plant-growth-promoting rhizobacteria-PGPR) biopriming on the seed germination of five (VI037996, VI046567, VI055421, VI050956, and VI033796) Abelmoschus esculentus genotypes. The germination responses of the bio-primed seeds were measured using six parameters, including final germination percentage (FGP), mean germination time (MGT), germination index (GI), coefficient of velocity of germination (CVG), germination rate index (GRI), and time spread of germination (TSG). Biostimulant application significantly affected MGT (1.1-2.2 days), CVG (1.4-5.9), and TSG (1.2-3.0 days). Genotype also significantly influenced the TSG (1-3 days). Significant interaction effect of biostimulant treatment and genotype was evident on the FGP, GI, and GRI of the germinated seeds. The most noteworthy effect was demonstrated by Kelpak® (1:100) applied to genotype VI037996, with significantly improved FGP (82%), GI (238), and GRI (77%/day) when compared to the control. Overall, the current findings suggest the potential stimulatory effect of biostimulants (especially Kelpak®) on the germination of Abelmoschus esculentus seeds. However, this influence was strongly dependent on the type of genotype.

Efficient Micropropagation Protocol for the Conservation of the Endangered Aloe peglerae, an Ornamental and Medicinal Species.

A number of Aloe species are facing an extremely high risk of extinction due to habitat loss and over-exploitation for medicinal and ornamental trade. The last global assessment of Aloe peglerae Schönland (in 2003) ranked its global conservation status as 'endangered' with a decreasing population trend. In the National Red List of South African Plants, the extremely rapid decline of this species has resulted in its conservation status being elevated from 'endangered' to 'critically endangered' based on recent or new field information. This dramatic decline necessitates the development of a simple, rapid and efficient micropropagation protocol as a conservation measure. An in vitro propagation protocol was therefore established with the regeneration of 12 shoots per shoot-tip explant within 8 weeks using Murashige and Skoog (MS) medium supplemented with 2.5 µM meta-topolin riboside (an aromatic cytokinin). The rooting of the shoots with a 100% frequency on half-strength MS medium without any plant growth resulted in additional six shoots produced per cultured shoot. The resultant plantlets were successfully acclimatized with a 100% survival frequency after 6 weeks. Overall, the developed protocol can result in the production of 3906 transplantable shoots that are ready for rooting per annum from a single shoot-tip explant. It is simple and efficient for seedling production in the ex situ cultivation and conservation of the endangered A. peglerae.

In Vivo Antifungal Activity of South African Medicinal Plant Extracts against Fusarium pathogens and Their Phytotoxicity Evaluation.

Smallholder farmers play a major role in crop production towards household food security, particularly in resource-poor communities. Maize is a common crop produced in smallholder farming and it is cultivated from seeds that has been stored and re-used for years. Spoilage of stored grains is a major challenge, which leads to yield loss and poor seed quality. The objectives of this study were to evaluate in vivo antifungal activity of selected plant extracts against Fusarium pathogens on maize seeds, and to evaluate their phytotoxicity on seed germination and seedling growth. Fresh leaves collected from eight medicinal plants were dried and selectively extracted with water, ethyl acetate or acetone. The dried extracts were evaluated for antifungal activity against Fusarium pathogens (F. proliferatum, F. oxysporum, F. subglutinans, F. verticilloides, F. semitectum, F. chlamydosporum, F. solani, F. equisite and F. graminearum) inoculated on maize seeds. Melia azedarach acetone extract showed strong antifungal activity (97% inhibition) against F. proliferatum while combined acetone extracts from Combretum erythrophyllum and Quercus acutissima exhibited 96%, 67% and 56% inhibition against F. verticilloides, F. proliferatum and F. solani, respectively. With the exception of Quercus acutissima ethyl acetate, none of the extracts significantly inhibited seed germination when compared to untreated seeds. This study showed that plant extracts could control Fusarium diseases without any adverse effects on maize seed germination or plant growth.

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.

Applications of Cytokinins in Horticultural Fruit Crops: Trends and Future Prospects.

Cytokinins (CKs) are a chemically diverse class of plant growth regulators, exhibiting wide-ranging actions on plant growth and development, hence their exploitation in agriculture for crop improvement and management. Their coordinated regulatory effects and cross-talk interactions with other phytohormones and signaling networks are highly sophisticated, eliciting and controlling varied biological processes at the cellular to organismal levels. In this review, we briefly introduce the mode of action and general molecular biological effects of naturally occurring CKs before highlighting the great variability in the response of fruit crops to CK-based innovations. We present a comprehensive compilation of research linked to the application of CKs in non-model crop species in different phases of fruit production and management. By doing so, it is clear that the effects of CKs on fruit set, development, maturation, and ripening are not necessarily generic, even for cultivars within the same species, illustrating the magnitude of yet unknown intricate biochemical and genetic mechanisms regulating these processes in different fruit crops. Current approaches using genomic-to-metabolomic analysis are providing new insights into the in planta mechanisms of CKs, pinpointing the underlying CK-derived actions that may serve as potential targets for improving crop-specific traits and the development of new solutions for the preharvest and postharvest management of fruit crops. Where information is available, CK molecular biology is discussed in the context of its present and future implications in the applications of CKs to fruits of horticultural significance.