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Abstract: In vitro micropropagation and acclimatization for the ornamental Agapanthus praecox, are reported. The influence of different growth regulators on shoot multiplication from shoot-tip explants of A. praecox was investigated. Prolific shoot multiplication (47.3±1.96 shoots per explant) was achieved on Murashige and Skoog (MS) medium supplemented with 22.2μM benzyladenine (BA), 2.9μM indole-3-acetic acid (IAA), and 4.5μM thidiazuron (TDZ). Shoots were rooted on half-strength MS basal medium supplemented with 5.7μM IAA and 2.5μM 2-isopentenyladenine (2iP) with 11.3±0.78 roots per shoot. The in vitro-raised plants were established successfully in a 1:1 (v/v) vermiculite:sand mixture when maintained in a greenhouse with 100% survival. The elongated shoots (more than 5cm in length) were treated for rooting and acclimatization in a moistened (5.7μM IAA and 2.5μM 2iP) vermiculite:sand (1:1v/v) mixture, first in the misthouse and then in the greenhouse. Rooting and acclimatization was achieved simultaneously (100%) in the misthouse which was followed by greenhouse cultivation. This system can be used for rapid mass clonal propagation of A. praecox, for conservation strategies, commercial production, gene transformation studies and to produce phytomedicines. [Copyright &y& Elsevier]

The Brachystelma genus (family: Apocynaceae) consists of geophytes that are traditionally utilised among rural communities, especially in East Africa, southern Africa, West Africa, and northern and western India. Apart from being used as a food source, they are indicated as treatment for ailments such as colds, chest pains, and wounds. This review provides a critical appraisal on the ethnobotanical uses, nutritional value, phytochemical profiles, and biological activities of Brachystelma species. In addition, we assessed the potential of micropropagation as a means of ensuring the sustainability of Brachystelma species. An inventory of 34 Brachystelma species was reported as a source of wild food and traditional medicine (e.g., respiratory-related conditions, pains, and inflammation) across 13 countries, predominantly in Africa and Asia. Brachystelma circinnatum and Brachystelma foetidum were the most popular plants based on the high number of citations. Limited data for the nutritional content was only available for Brachystelma edulis and Brachystelma naorojii, as well as phytochemical profiles (based on qualitative and quantitative techniques) for five Brachystelma species. Likewise, a few Brachystelma species have evidence of biological activities such as antimicrobial, antioxidant, and acetyl cholinesterase (AChE) inhibitory effects. Extensive studies on Brachystelma togoense have resulted in the isolation of four compounds with therapeutic potential for managing different health conditions. As a means of contributing to the sustainability of Brachystelma species, micropropagation protocols have been devised for Brachystelma glabrum, Brachystelma pygmaeum, Brachystelma ngomense, and Brachystelma pulchellum. Nevertheless, continuous optimisation is required to enhance the efficiency of the micropropagation protocols for these aforementioned Brachystelma species. Despite the large number of Brachystelma with anecdotal evidence as food and medicine, a significant number currently lack empirical data on their nutritional and phytochemical profiles, as well as their biological activities. The need for new propagation protocols to mitigate the declining wild populations and ensure their sustainability remains pertinent. This is important should the potential of Brachystelma species as novel food and medicinal products be achieved. [ABSTRACT FROM AUTHOR]

Orchids are rich treasure troves of various important phytomolecules. Among the various medicinal orchids, Ansellia africana stands out prominently in the preparing of various herbal medicines due to its high therapeutic importance. The nodal explants of A. africana were sampled from asymbiotically germinated seedlings on basal Murashige and Skoog (MS) medium and were micropropagated in MS medium supplemented with 3% sucrose and 10 µM meta topolin (mT) + 5 µM naphthalene acetic acid (NAA) +15 µM indole butyric acid (IBA) + 30 µM phloroglucinol (PG). In the present study, the essential oil was extracted by hydrodistillation and the oleoresins by the solvent extraction method from the micropropagated A. africana. The essential oil and the oleoresins were analysed by Gas Chromatography (GC) and GC/MS (Mass spectrometry). A total of 84 compounds were identified. The most predominant components among them were linoleic acid (18.42%), l-ascorbyl 2,6-dipalmitate (11.50%), linolenic acid (10.98%) and p-cresol (9.99%) in the essential oil; and eicosane (26.34%), n-butyl acetate (21.13%), heptadecane (16.48%) and 2-pentanone, 4-hydroxy-4-methyl (11.13%) were detected in the acetone extract; heptadecane (9.40%), heneicosane (9.45%), eicosane (6.40%), n-butyl acetate (14.34%) and styrene (22.20%) were identified and quantified in the ethyl acetate extract. The cytotoxic activity of essential oil and oleoresins of micropropagated A. africana was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide) assay on Vero cells compared to the standard drug doxorubicin chloride. The present research contains primary information about the therapeutic utility of the essential oil and oleoresins of A. africana with a promising future research potential of qualitative and quantitative improvement through synchronised use of biotechnological techniques. [ABSTRACT FROM AUTHOR]

Eucomis autumnalis (Mill.) Chitt. subspecies autumnalis is a popular African plant that is susceptible to population decline because the bulbs are widely utilized for diverse medicinal purposes. As a result, approaches to ensure the sustainability of the plants are essential. In the current study, the influence of smoke-water (SW) and karrikinolide (KAR1 isolated from SW extract) on the phytochemicals and antioxidant activity of in vitro and greenhouse-acclimatized Eucomis autumnalis subspecies autumnalis were evaluated. Leaf explants were cultured on Murashige and Skoog (MS) media supplemented with SW (1:500, 1:1000 and 1:1500 v/v dilutions) or KAR1 (10−7, 10−8 and 10−9 M) and grown for ten weeks. In vitro regenerants were subsequently acclimatized in the greenhouse for four months. Bioactive phytochemicals in different treatments were analyzed using ultra-high performance liquid chromatography (UHPLC-MS/MS), while antioxidant potential was evaluated using two chemical tests namely: DPPH and the β-carotene model. Smoke-water and KAR1 generally influenced the quantity and types of phytochemicals in in vitro regenerants and acclimatized plants. In addition to eucomic acid, 15 phenolic acids and flavonoids were quantified; however, some were specific to either the in vitro regenerants or greenhouse-acclimatized plants. The majority of the phenolic acids and flavonoids were generally higher in in vitro regenerants than in acclimatized plants. Evidence from the chemical tests indicated an increase in antioxidant activity of SW and KAR1-treated regenerants and acclimatized plants. Overall, these findings unravel the value of SW and KAR1 as potential elicitors for bioactive phytochemicals with therapeutic activity in plants facilitated via in vitro culture systems. In addition, it affords an efficient means to ensure the sustainability of the investigated plant. Nevertheless, further studies focusing on the use of other types of antioxidant test systems (including in vivo model) and the carry-over effect of the application of SW and KAR1 for a longer duration will be pertinent. In addition, the safety of the resultant plant extracts and their pharmacological efficacy in clinical relevance systems is required. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Ethnopharmacological relevance: Aloe species (family: Xanthorrhoeaceae) are widely used in ethnomedicine for treating various ailments. Approximately 125 Aloe taxa are documented as indigenous to South Africa. This review was aimed at critically evaluating the available data on the ethnomedicinal uses, pharmacological activities, safety and conservation status of the documented South African Aloe species. Materials and methods: A detailed search using major electronic search engines (such as Google Scholar, Scopus and Scirus) and ethnobotanical literature was undertaken. Search terms used included ‘medicinal properties of Aloe species’, ‘biological activity of South African Aloe species’ and ‘safety and toxicological evaluation of aloes’. Results: Although Aloe species are widely used as laxatives and for treating wound and skin-related ailments, only about 20% of South African Aloe species have been clearly documented for their medicinal uses. The pharmacological potential including the antimicrobial, antiinflammatory, antiplasmodial and anthelmintic activities of some of the species has been established, providing a rationale for their use in traditional medicine. Successful micropropagation protocols have been developed as a conservation strategy, but only for a few species. Conclusions: The highlighted medicinal activities of some Aloe species indicate their therapeutic potential. Nonetheless, further research especially on the understudied species is required to properly document their ethnomedicinal uses and fully explore their pharmacological value. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Highlights: [•] A total of 47 endogenous cytokinin-forms grouped into 9 classes were quantified. [•] Tissue-cultured plants had more endogenous cytokinin levels than acclimatized plants. [•] 9-Glucosides were the major metabolites in tissue-cultured and acclimatized plants. [Copyright &y& Elsevier]

Abstract: Merwilla plumbea (Lindl.) Speta is an important medicinal plant widely used in traditional medicine. We evaluated the effect of five cytokinins [benzyladenine (BA), 2-isopentenyladenine (2iP), meta-topolin (mT), meta-topolin riboside (mTR), and meta-methoxy-9-tetrahydropyran-2-yl-topolin (MemTTHP)] on the level of phenolic acids and antioxidant activity of M. plumbea during the tissue culture and acclimatization stages. Two cytokinins (mT and mTR) significantly improved the antioxidant activity of tissue culture plantlets while the control plantlets were better after acclimatization. Using UPLC–MS/MS, the levels of hydroxybenzoic and hydroxycinnamic acid derivatives (phenolic acids) varied significantly during tissue culture and acclimatization, depending on the cytokinin and plant part analyzed. Vanillic acid (24.9μgg−1) detected in underground parts of tissue culture plants supplemented with BA was the most abundant phenolic acid detected. The current findings indicate that the phytochemicals together with the bioactivity during in vitro propagation of M. plumbea is influenced by the cytokinin type used and the stage of plant material collection. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The effect of five topolins (meta-Topolin= mT; meta-Topolin riboside= mTR; meta-Methoxy topolin=MemT; meta-Methoxy topolin riboside=MemTR and 6-(meta-methoxy)-9-(tetrahydropyran-2-yl)-topolin=MemTTHP) on the photosynthetic pigments and leaf structures of micropropagated ‘Williams’ bananas was compared with the commonly used benzyladenine (BA). Surface-decontaminated explants were cultured for 70 d on modified Murashige and Skoog (MS) basal medium and supplemented with 10, 20 or 30μM cytokinins (CKs). At 10 d intervals, the photosynthetic pigments were quantified via spectrophotometric methods for 7 cycles. Generally, the maximum pigment content was attained between 40 and 50 d. The control plantlets had the highest pigment content (1150μg/g FW). Among the CKs, 10μM MemTTHP generally had the best pigment stimulatory effect at the same period. After 40 d, scanning electron microscopy (SEM) of the foliar surface showed that the stomata density was highest in 10μM MemTTHP-treated and lowest in 10μM MemTR-treated plantlets. The stomatal structure and pore area also varied with the type and concentration of CK added. Generally, prolonging culture duration as well as increasing CK concentrations reduced the pigment content. However, the drastic breakdown in chlorophyll pigments beyond 50 d was slightly inhibited by the presence of mT, mTR, MemTTHP and BA compared to the control. The CK-treated plantlets at equimolar concentration had comparable chlorophyll a/b and total chlorophyll/carotenoid ratios after 10 d; probably as an adaptive measure. At the end of the current study, 10μM mT and mTR plantlets remained green as reflected by the higher total chlorophyll/carotenoid ratio as well as by the visual observations. A well-developed photosynthetic apparatus enhances the survival of in vitro plantlets during the acclimatization stage. Current findings provide some insight into the role of meta-topolins on photosynthetic parameters in vitro, which inevitably partly contributed to the better acclimatization capability of meta-topolin-regenerants. [Copyright &y& Elsevier]