Nutritional, phytochemical and diverse health-promoting qualities of Cleome gynandra.

Cleome gynandra (Syn. Gynandropsis gynandra) is fast emerging as one of the most widely consumed leafy vegetables due to its nutrition and health-promoting properties. In addition to its high nutritional content, the plant has a rich pool of diverse antioxidant phytochemicals. The current review provides a critical appraisal on the increasing nutritional significance of Cleome gynandra due to its rich pool of natural bioactive compounds and beneficial health-promoting qualities. The rich nutritional content especially the high levels of macro- and micronutrients is an indication of its potential to mitigate malnutrition and the increasing incidence of diet-related obesity and non-communicable diseases. The presence of health-promoting natural compounds, notably polyphenols, glucosinates and terpernoids has been confirmed in Cleome gynandra using different analytical methods. Cleome gynandra possesses high levels of α-tocopherol, ß-tocopherol and γ-tocopherol, ascorbic acid, α-carotene, ß-carotene, lutein, violaxanthin, and ß-cryptoxanthin. These nutritional compounds could be useful in food applications as supplements, colorants and extending shelf-life of food products. Cleome gynandra extracts have demonstrated promising effects in several biological assays using in vitro and in vivo systems. Clearly, diversified diets that include a regular intake of dark green leafy vegetables including Cleome gynandra, holds great promise in ensuring food and nutrition security.

Health benefits and biological activities of spiny monkey orange (Strychnos spinosa Lam.): An African indigenous fruit tree.

ETHNOPHARMACOLOGICAL RELEVANCE: Spiny monkey orange (Strychnos spinosa Lam.) is an African endemic fruit tree that is widely consumed by humans and animals for its nutritional value. In folk medicine, different parts of S. spinosa are widely used for the management of the health and well-being of humans and livestock. AIM: We provide a critical appraisal on the ethnobotanical uses, nutritional and pytochemical as well as the biological activities of S. spinosa. METHODS: Articles were mined from online databases such as Google Scholar, PubMed, Science Direct, SciELO and SpringerLink. We captured research outputs that aligned with the scope of the review. RESULTS: Strychnos spinosa remains a commonly consumed fruit due to its high nutritional (e.g. carbohydrates, crude protein and fats) content and energy. In folk medicine, different parts of S. spinosa are prescribed as remedy for diverse medical conditions especially for treating malaria, diabetes, snakebites, skin-related conditions and sexually transmitted infections in humans as well as sleeping sickness in livestock. Together with essential oils, more than 25 compounds have been profiled using Gas chromatography-mass spectrometry (GC-MS), and approximately 45 compounds have been isolated and structurally elucidated using diverse spectroscopic techniques such as UV-visible, Infrared (IR), Nuclear Magnetic Resonance (NMR) and mass spectroscopy (MS). Strychnos spinosa exerts varying degrees of biological activities against different microorganisms (bacteria and fungi) and parasites (plasmodia, trypanosomes and ticks) responsible for many diseases in humans and livestock. Furthermore, low to moderate enzyme-inhibitory effects of S. spinosa extracts suggest its ability to mitigate pains, inflammations and diabetics as well as snakebite venom. Increasing evidence from the in vivo studies support the use of the plant as a popular remedy for managing diabetics in folk medicine. The low cytotoxic effect of the plant extracts against different cell lines could be an indication of its relative safety. CONCLUSION: Strychnos spinosa exhibits various health-promoting benefits due to its diverse nutritional and phytochemical constituents. Given that the majority of the existing evidence on these aforementioned therapeutic properties and safety are in vitro-based, the clinical significance of these results remain limited.

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.

Deciphering the growth pattern and phytohormonal content in Saskatoon berry (Amelanchier alnifolia) in response to in vitro cytokinin application.

Clonal propagation plays a critical integral role in the growth and success of a global multi-billion dollar horticulture industry through a constant supply of healthy stock plants. The supply chain depends on continuously improving the micropropagation process, thus, understanding the physiology of in vitro plants remains a core component. We evaluated the influence of exogenously applied cytokinins (CKs, N6-benzyladenine = BA, isopentenyladenine = iP, meta-topolin = mT, 6-(3-hydroxybenzylamino)-9-(tetrahydropyran-2-yl)purine = mTTHP) in Murashige and Skoog (MS)-supplemented media on organogenic response and accumulation of endogenous CK and indole-3-acetic acid (IAA) metabolites. The highest shoot proliferation (30 shoots/explant) was obtained with 20 µM mT treatment. However, the best quality regenerants were produced in 10 µM mT treatment. Rooting of Amelanchier alnifolia in vitro plantlets was observed at the lowest CK concentrations, with the highest root proliferation (3 roots/explant) in 1 µM mTTHP regenerants. Similar to the organogenic response, high levels of endogenous bioactive CK metabolites (free bases, ribosides, and nucleotides) were detected in mT and mTTHP-derived regenerants. The level of O-glucosides was also comparatively high in these cultures. All CK-treated plants had high levels of endogenous free IAA compared to the control. This may suggest an influence of CKs on biosynthesis of IAA.

An overview on Leucosidea sericea Eckl. & Zeyh.: A multi-purpose tree with potential as a phytomedicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Leucosidea sericea (the sole species in this genus) is a tree species found in southern Africa and possesses several therapeutical effects against infectious diseases in humans and livestock. This review aims to document and summarize the botany, phytochemical and biological properties of Leucosidea sericea. MATERIALS AND METHODS: Using the term 'Leucosidea sericea', we systematically searched literature including library catalogues, academic dissertations and databases such as PubMed, SciFinder, Web of Science, Google Scholar and Wanfang. Taxonomy of the species was validated using 'The Plant List' (www.theplantlist.org). RESULTS: Leucosidea sericea remains a widely used species among the different ethnic groups in southern Africa. The species is a rich source of approximately 50 essential oils and different classes of phytochemicals (phenolics, phloroglucinols, cholestane triterpenoids, alkaloids and saponins) which may account for their diverse biological properties. Documented biological activities which were mainly observed under in vitro systems included antimicrobial, anti-parasitic, antioxidant, acetylcholinesterase (AChE) inhibition and anti-inflammatory properties. Preliminary safety tests on Leucosidea sericea extracts suggest moderate cytotoxic effects based on a few cell lines that were investigated. CONCLUSIONS: Leucosidea sericea possesses diverse medicinal potential with the antimicrobial, anti-parasitic, antioxidant and anti-inflammatory activities being the most prominent. The relative abundance and tendency of Leucosidea sericea to evade in nature suggest an abundant reservoir of raw materials for potential commercialization (upon validation of its pharmacological potential). However, more stringent investigations on the extracts (and isolated bioactive compounds) focusing on the mode of actions, which will inevitably unravel their pharmacokinetics, pharmacodynamics and clinical relevance remain pertinent.

Phytochemical Characterization, Antibacterial, Acetylcholinesterase Inhibitory and Cytotoxic Properties of Cryptostephanus vansonii, an Endemic Amaryllid.

Cryptostephanus vansonii I. Verd., an endemic Amaryllidaceae species from Zimbabwe, was evaluated for its acetylcholinesterase (AChE) inhibitory and cytotoxicity properties using Ellman's colorimetric method and the tetrazolium-based colorimetric assay against Vero monkey kidney cells, respectively. The plant extracts were also evaluated for their antibacterial activity against five bacteria. Furthermore, phytochemical profiles of the extracts were determined using ultra-high performance liquid chromatography coupled with tandem mass spectrometry analysis. A plant part-dependent AChE inhibitory activity was observed, in the order, root > rhizome > basal leaf > leaf. Overall, C. vansonii extracts exhibited better antibacterial activity against Gram-negative compared with Gram-positive bacteria. Cytotoxic effects were not detected in Vero monkey kidney cell lines suggesting the possible absence of toxophores in C. vansonii extracts. Similar to the trend in biological activity, a distinct plant part-dependent variation in hydroxybenzoates, hydroxycinnamates and flavonoids was observed in the plant extracts. In addition, 5-hydroxymetylfurfural and eucomic acid were detected in the different plant parts of C. vansonii. The results of the present study provide valuable AChE inhibition activity, toxicological and phytochemical profiles of C. vansonii. Further studies on isolation of bioactive compounds and their subsequent evaluation in other pharmacological and toxicological model systems are required. Copyright © 2017 John Wiley & Sons, Ltd.

Determination of Mineral Constituents, Phytochemicals and Antioxidant Qualities of Cleome gynandra, Compared to Brassica oleracea and Beta vulgaris.

The study compared mineral, chemical and antioxidant qualities of Cleome gynandra, a wild leafy vegetable, with two widely consumed commercial vegetables, Brassica oleracea and Beta vulgaris. Mineral nutrients were quantified with inductively coupled plasma mass spectrometry (ICP-MS), phenolic compounds using ultra-high performance liquid chromatography coupled to a mass spectrometer (UHPLC-MS) and ß-carotene and vitamin C using high performance liquid chromatography with a photodiode array detector (HPLC-PDA). The antioxidant potential was evaluated using 2,2-diphenyl-1-picryl hydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Cleome gynandra had highest concentrations of phosphorus, potassium, calcium, iron, zinc, ascorbic acid, total phenolics, and flavonoids; whereas sodium, magnesium, manganese, copper and ß-carotene were higher for B. vulgaris. The significantly higher antioxidant activity (P ≤ 0.05) exhibited by C. gynandra in comparison to the two commercial vegetables may be due to its significantly high levels of vitamin C and phenolic acids. These findings on the mineral, chemical and antioxidant properties of C. gynandra provide compelling scientific evidence of its potential in adding diversity to the diet and contributing toward the daily nutritional requirements of millions of people for food and nutritional security.

Ethnobotany, therapeutic value, phytochemistry and conservation status of Bowiea volubilis: A widely used bulbous plant in southern Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Bowiea volubilis Harv. ex Hook.f. (Family: Asparagaceae) is a bulbous medicinal plant widely used against numerous ailments including headache, muscular pains, infertility, cystitis and venereal diseases in southern Africa. AIM OF THE REVIEW: To provide a critical and updated review of Bowiea volubilis with regards to its abundance, medicinal importance, conservation status and potential means to sustain its availability for future generations. METHODS: A comprehensive literature search using online databases such as Web of Science, Google Scholar, Scopus and Springerlink as well as ethnobotanical literature was done in order to obtain, collate, synthesize and critically analyze available information on Bowiea volubilis. RESULTS: On the basis of its wide distribution in many Provinces in South Africa, Bowiea volubilis has a long history of applications among the different ethnic groups. These applications include its uses as purgatives and for the treatment or relief of microbial infections, skin disorders, pains and inflammation. Scientific validation of its diverse uses in traditional medicine has been demonstrated via antimicrobial, anti-inflammatory and toxicity assays. Available results indicate a general poor antimicrobial activity especially with the bulb extracts while the anti-inflammatory activity appears promising. Phytochemical screenings revealed that Bowiea volubilis contains cardiac glycosides and related compounds while reports of other classes of compounds are unavailable. In line with its usage in traditional medicine, the majority of available studies on the species have focused on the use of different solvent extracts from the bulbs. The destructive harvesting of bulbs has led to a continuous decimation of wild populations. Consequently, there are increasing conservational concerns on the sustainability of this species for continuous supply to meet escalating demands. CONCLUSIONS: Bowiea volubilis remains a widely used medicinal plant and available but limited scientific evidence indicates its anti-inflammatory potential. The abundance of cardiac glycosides in its phytochemical composition provides an indication on the therapeutic potential. More research efforts including the application of different biotechnological techniques are still required in order to guarantee its sustainable use over time.

Insights into the multifaceted application of microscopic techniques in plant tissue culture systems.

MAIN CONCLUSION: Microscopic techniques remain an integral tool which has allowed for the better understanding and manipulation of in vitro plant culture systems. The recent advancements will inevitably help to unlock the long-standing mysteries of fundamental biological mechanisms of plant cells. Beyond the classical applications in micropropagation aimed at the conservation of endangered and elite commercial genotypes, plant cell, tissue and organ cultures have become a platform for elucidating a myriad of fundamental physiological and developmental processes. In conjunction with microscopic techniques, in vitro culture technology has been at the centre of important breakthroughs in plant growth and development. Applications of microscopy and plant tissue culture have included elucidation of growth and development processes, detection of in vitro-induced physiological disorders as well as subcellular localization using fluorescent protein probes. Light and electron microscopy have been widely used in confirming the bipolarity of somatic embryos during somatic embryogenesis. The technique highlights basic anatomical, structural and histological evidence for in vitro-induced physiological disorders during plant growth and development. In this review, we discuss some significant biological insights in plant growth and development, breakthroughs and limitations of various microscopic applications and the exciting possibilities offered by emergent in vivo live imaging and fluorescent protein engineering technologies.

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

ETHNOPHARMACOLOGICAL RELEVANCE: The use of plant species for different therapeutic/medicinal purposes is well-entrenched in sub-Saharan Africa. AIM OF THE REVIEW: To provide a critical and updated review of the enormous medicinal plant heritage in sub-Saharan Africa with regards to the abundance, importance, conservation status and potential means to help sustain their availability for future generations. METHODS: A comprehensive literature search involving different online databases, books and theses were conducted in order to obtain, collate and synthesize available information on various fundamental aspects pertaining to African medicinal plants. RESULTS: African biodiversity hotspots are endowed with a high level of endemic species with a significant portion possessing medicinal value. Apart from the extensive ethnobotanical uses of medicinal plants found in Africa, scientific validation of their biological potential such as antimicrobial, antioxidant, anti-inflammatory and anti-diabetic properties have been recognized. Together with the demand arising from their biological efficacies, other anthropogenic factors are exerting conservation strains of the wild population of these medicinal plants. Even though researchers have acknowledged the importance and value of conserving these medicinal plants, several challenges have hampered these efforts on the Continent as a whole. CONCLUSIONS: The rich flora occurring in sub-Saharan Africa suggests enormous potential for discovery of new chemical entity with therapeutic value. However, concerted efforts focused on documenting the conservation status of African medicinal plants are pertinent. Application of different biotechnological techniques is needed to sustain these valuable botanical entities, especially to meet increasing pharmaceutical demand. Most importantly, increased public enlightenment and awareness may help eradicate the prejudice against cultivation of medicinal plants.

Plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in Hypoxis hemerocallidea organ and callus cultures.

Micropropagation of Hypoxis hemerocallidea Fisch. and C.A. Mey was used as a model system to study the influence of cytokinins (CKs) on plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in organ and callus cultures and their antioxidant activity. Fourteen free phenolic acids were detected using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) while antioxidant activity was evaluated using oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Cytokinins had a significant effect on the biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in H. hemerocallidea organ cultures. In particular, meta-topolin-treated organ cultures produced high concentrations of gallic, protocatechuic, gentisic, p-hydroxybenzoic, m-hydroxybenzoic, salicylic, chlorogenic and trans-cinnamic acids. The isoprenoid CK, N(6)-(2-isopentenyl)-adenine significantly increased the accumulation of hydroxycinnamic acid derivatives, namely, caffeic, p-coumaric, sinapic and ferulic acids. Cytokinin-treated organ cultures exhibited a significant increase in antioxidant activity, particularly in the ORAC model. In callus cultures, CKs decreased the concentrations of hydroxycinnamic acid derivatives and antioxidant activity when compared to the control. Overall, both CK type and concentration had a significant effect on plant regeneration, callus proliferation, biochemical accumulation of free phenolic acids and antioxidant activity of the resultant extracts.

Medicinal properties and conservation of Pelargonium sidoides DC.

ETHNOPHARMACOLOGICAL RELEVANCE: Pelargonium sidoides DC. (Geraniaceae), a popular medicinal plant used in traditional medicine in the treatment of gastrointestinal ailments has been transformed into a phytopharmaceutical (EPs(®) 7360) for treating respiratory tract infections. The increasing international demand for Pelargonium sidoides has led to localised overexploitation of its wild populations in southern Africa. The aim of the review is to provide a synthesis of the current state of scientific knowledge on the phytochemical, pharmacological and toxicological properties of Pelargonium sidoides as well as the potential role of plant biotechnology in its conservation. The review highlights knowledge gaps in these research areas. MATERIALS AND METHODS: A comprehensive literature search involving mainly electronic and library sources of information were used to collate and synthesise published data. RESULTS: Experimental results from in vitro studies indicate that bioactive phytochemical constituents of Pelargonium sidoides may not possess a direct antimicrobial effect, but instead act by interfering with microbial binding to host cell receptors, inhibition of key enzymes and the production of antimicrobial effector molecules such as nitric oxide and interferons (IFNs) by the host cells. Furthermore, clinical evaluations in randomised, double-blind, placebo-controlled trials have demonstrated the beneficial effect of Pelargonium sidoides in the treatment of respiratory tract infections with few side effects. However, there is lack of adequate information on the safety evaluation of the plant. On the other hand, the increasing demand for Pelargonium sidoides has led to localised illegal harvesting of wild plants. CONCLUSIONS: Pharmacological data reported in literature suggest that Pelargonium sidoides shows a beneficial effect in the treatment of respiratory tract infections. However, more studies are required to elucidate the mode of action of the active constituents exhibited in the treatment of respiratory tract infections and other health conditions caused by microbial attack. Furthermore, the pharmacological usefulness of Pelargonium sidoides must take cognisance of the broader context involving the need for conservation-friendly approaches in its utilisation. In this regard, plant biotechnology applications can play a meaningful role in a holistic conservation strategy.

Conservation strategy for Pelargonium sidoides DC: phenolic profile and pharmacological activity of acclimatized plants derived from tissue culture.

ETHNOPHARMACOLOGICAL RELEVANCE: Pelargonium sidoides DC (Geraniaceae), a popular medicinal plant used in folk medicine in the treatment of respiratory-related infections has gained international prominence due to its usage in several herbal formulations. This has led to high demand and the subsequent decimation of wild populations. AIM OF THE STUDY: Using plant tissue culture techniques, Pelargonium sidoides plants were cloned in vitro, acclimatized under greenhouse conditions and evaluated for their phytochemical content and pharmacological activity. METHODS: Phenolic content in extracts of in vitro-derived, greenhouse-acclimatized and wild Pelargonium sidoides plants were analyzed using UPLC-MS/MS. The oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and minimum inhibitory concentration (MIC) of the extracts against bacterial and fungal strains were evaluated. RESULTS: Similarities in phenolic profiles were identified confirming the chemical signatures that characterize Pelargonium sidoides plants. Extracts of greenhouse-acclimatized and wild plants exhibited comparable antimicrobial and antioxidant properties. CONCLUSIONS: Overall, the study highlights the potential of integrating plant tissue culture technologies in conservation strategies of medicinal plants. In particular, the results strongly suggest the feasibility of both large-scale cultivation and plant part substitution as alternative solutions to the current destructive overharvesting practices of wild Pelargonium sidoides populations.

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.

Natural antioxidants: fascinating or mythical biomolecules?

Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18(th) century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are frequently fortified with synthetic or natural antioxidants. However, some research outcomes have led to the belief that antioxidants exist as mythical biomolecules. This review provides a critical evaluation of some common in vitro antioxidant capacity methods, and a discussion on the role and controversies surrounding non-enzymatic biomolecules, in particular phenolic compounds and non-phenolic compounds, in oxidative processes in an attempt of stemming the tidal wave that is threatening to swamp the concept of natural antioxidants.