Anti-inflammatory effects of the plant family Amaryllidaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: Members of the plant family Amaryllidaceae are widely recorded in traditional systems of medicine. Their usage for inflammatory conditions is most prominent, with substantive evidence emerging from several locations around the world. AIM OF THE STUDY: This survey was undertaken to identify such plant taxa, highlight the countries from which they originate and afford details of the ailments against which they are utilized. The undertaking also sought to establish the in vitro and in vivo activities of Amaryllidaceae plant extracts in inflammation-based assays. Furthermore, it set out to unravel the molecular mechanisms used to explain these effects. MATERIALS AND METHODS: Over six-hundred articles were identified in searches carried out on SciFinder, Scopus, ScienceDirect, PubMed and Google Scholar. These were condensed to around 170 that formulated the basis of the text. The keyword engaged was 'Amaryllidaceae' in conjunction with 'inflammation' or 'anti-inflammatory', as well as the names of individual genera combined with the latter two. RESULTS: Fifty-one species from thirty-five countries were identified for their uses against inflammation. Twenty-four of such conditions were discernible, of which their applicability in wound healing and pain management was most conspicuous. The utilization of all plant parts was apparent, preparations of which were used primarily via topical application. Extracts of seventy-three species (from twenty-three genera) were examined in nearly thirty inflammation-based assays where their activities in vitro and in vivo were shown to be significant. They were effective in vivo against pain and swelling as well as wound healing, without detriment towards test subjects. The in vitro studies were carried out mainly in mononuclear cells such as macrophages, leukocytes, lymphocytes and neutrophils against which their cytotoxic effects were seen to be minimal. The modes of operation were shown to involve modulation of both pro-inflammatory (such as NF-κB, TNF-α, IL-6, IFN-γ, COX and NO) and anti-inflammatory (such as IL-10) factors. CONCLUSIONS: The Amaryllidaceae is showcased as a platform highly conducive towards studies in the inflammation arena. Potent activities in instances were observed via in vitro and in vivo models of study, bolstered by the significant amounts of information emerging from traditional forms of medicine. It is conceivable that the family may yield future anti-inflammatory chemotherapeutics, particularly those related to its alkaloid principles.

Propagation of Medicinal Plants for Sustainable Livelihoods, Economic Development, and Biodiversity Conservation in South Africa.

South Africa is blessed with vast plant resources and unique vegetation types. Indigenous South African medicinal plants have been well-harnessed to generate income in rural communities. Many of these plants have been processed into natural products to heal a variety of diseases, making them valuable export commodities. South Africa has one of the most effective bio-conservation policies in Africa, which has protected the South African indigenous medicinal vegetation. However, there is a strong link between government policies for biodiversity conservation, the propagation of medicinal plants as a source of livelihood, and the development of propagation techniques by research scientists. Tertiary institutions nationwide have played a crucial role in the development of effective propagation protocols for valuable South African medicinal plants. The government-restricted harvest policies have also helped to nudge natural product companies and medicinal plant marketers to embrace the cultivated plants for their medicinal uses, and thus have helped support the South African economy and biodiversity conservation. Propagation methods used for the cultivation of the relevant medicinal plants vary according to plant family and vegetation type, among others. Plants from the Cape areas, such as the Karoo, are often resuscitated after bushfires, and propagation protocols mimicking these events have been established through seed propagation protocols with controlled temperatures and other conditions, to establish seedlings of such plants. Thus, this review highlights the role of the propagation of highly utilized and traded medicinal plants in the South African traditional medicinal system. Some valuable medicinal plants that sustain livelihoods and are highly sought-after as export raw materials are discussed. The effect of South African bio-conservation registration on the propagation of these plants and the roles of the communities and other stakeholders in the development of propagation protocols for highly utilized and endangered medicinal plants are also covered. The role of various propagation methods on the bioactive compounds' composition of medicinal plants and issues of quality assurance are addressed. The available literature, media online news, newspapers, and other resources, such as published books and manuals, were scrutinized for information.

Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species Endostemon obtusifolius (E. Mey. ex Benth.) N. E. Br.

Endophytes are primarily endosymbiotic bacteria and fungi that colonize the interior tissues of their host plant. They enhance the host plant's growth and attenuate adverse effects of biological stress. Endophytic species of many indigenous plants are an untapped resource of plant growth-promoting microorganisms that can mitigate abiotic stress effects. Thus, this study aimed to isolate endophytes from the roots and leaves of the medicinal plant Endostemon obtusifolius to evaluate their in vitro growth-promoting capacities and drought tolerance and to characterize the most promising species. Twenty-six endophytes (fourteen bacteria and twelve fungi) were isolated and cultured from the roots and leaves of E. obtusifolius. All 26 endophytes produced flavonoids, and 14 strains produced phenolic compounds. Of the 11 strains that displayed good free radical scavenging capability (low IC50) in the 1-1-diphenyl-1-picryhydrazyl radical scavenging assay, only three strains could not survive the highest drought stress treatment (40% polyethylene glycol). These 11 strains were all positive for ammonia and siderophore production and only one strain failed to produce hydrogen cyanide and solubilize phosphate. Seven isolates showed aminocyclopropane-1-carboxylate deaminase activity and differentially synthesized indole-3-acetic acid. Using molecular tools, two promising symbiotic, drought stress tolerant, and plant growth-enhancing endophytic species (EORB-2 and EOLF-5) were identified as Paenibacillus polymyxa and Fusarium oxysporum. The results of this study demonstrate that P. polymyxa and F. oxysporum should be further investigated for their drought stress mitigation and plant growth enhancement effects as they have the potential to be developed for use in sustainable agricultural practices.

Chemical Principles of Boophone, Nerine, Crossyne, Clivia, Cryptostephanus, Haemanthus and Scadoxus of the South African Amaryllidaceae and Their Biological Properties.

The Amaryllidaceae features prominently amongst bulbous flowering plant families. Accommodating about a third of its species, South Africa affords a sound basis for Amaryllidaceae plant research. Boophone, Nerine, Crossyne, Clivia, Cryptostephanus, Haemanthus and Scadoxus have been well-represented in such endeavors. The account herein summarizes the studies undertaken between 2013 - 2020 on these genera in regards to their chemical and biological characteristics. A total of 136 compounds comprising 63 alkaloids and 73 non-alkaloid entities were described during this period from eighteen members of the title genera. The alkaloids were reflective of the structural diversity found in eight isoquinoline alkaloid groups of the Amaryllidaceae. Of these, the crinane (29 compounds), lycorane and homolycorine (11 compounds each) groups were the most-represented. The non-alkaloid substances were embracive of the same number of unrelated groups including, acids, phenolics, flavonoids and triterpenoids. A wide variety of assays were engaged to ascertain the biological activities of the isolated compounds, notably in regards to cancer and motorneuron-related diseases. There were also attempts made to determine the antimicrobial, anti-inflammatory and antioxidant effects of some of the substances. New information has also emerged on the herbicidal, insecticidal and plant growth regulatory effects of selected alkaloid principles. Coupled to the biological screening measures were in instances probes made to establish the molecular basis to some of the activities, particularly in relation to cancer and Parkinson's disease.

Antiviral alkaloid principles of the plant family Amaryllidaceae.

BACKGROUND: Viral-borne diseases are amongst the oldest diseases known to mankind. They are responsible for some of the most ravaging effects wrought on human health and well-being. The use of plants against these ailments is entrenched in both traditional and secular medicine around the globe. Their natural abundance and chemical diversity have also boosted their appeal in drug discovery. AIM: The plant family Amaryllidaceae is distinguished for its alkaloid principles, some of which are of considerable interest in the clinical arena. This account is the outcome of a literature review undertaken to establish the applicability of these substances as antiviral agents. METHODS: The survey utilized the search engines Google Scholar, PubMed, SciFinder, Scopus and Web of Science engaging the word 'antiviral' in conjunction with 'Amaryllidaceae' and 'Amaryllidaceae alkaloid'. The search returned over five hundred hits, of which around eighty were of relevance to the theme of the text. RESULTS: Over eighty isoquinoline alkaloids have been screened against nearly fifty pathogens from fourteen viral families, the majority of which were RNA viruses. Potent activities were reported in some instances, such as that of trans-dihydronarciclasine against Yellow fever virus (IC50 0.003 µg/ml), with minimal effects being manifested on host cells. There were also promising results obtained from in vivo studies, in most cases without lethal effects on test subjects. Structure-activity relationship studies afforded useful insight to the antiviral pharmacophore, with the phenanthridone alkaloid nucleus shown to be the most enabling. Although the mechanistic basis to these activities pertained mostly to inhibition of DNA, RNA and protein synthesis, evidence was also forthcoming about the inhibitory action of some of the alkaloids against viral neuraminidase, protease and reverse transcriptase. In silico methods of analysis have offered further perspectives of how some of the alkaloids interact at the active sites of their targets. CONCLUSION: The Amaryllidaceae offers a viable platform for plant-based antiviral drug discovery. Its cause is strengthened not only by its wide proliferation and exploitation of its members in alternative forms of medicine, but also by its rich chemical diversity which has already spawned useful antiviral drug leads.

Carbon dioxide expanded liquid: an effective solvent for the extraction of quercetin from South African medicinal plants.

BACKGROUND: Quercetin is one of the most important bioflavonoids having positive effects on the biological processes and human health. Typically, it is extracted from plant matrices using conventional methods such as maceration, sonication, infusion, and Soxhlet extraction with high solvent consumption. Our study aimed to optimize the environmentally friendly carbon dioxide-based method for the extraction of quercetin from quince fruit with an emphasis on extraction yield, repeatability, and short extraction time. RESULTS: A two-step design of experiments was used for the optimization of the key parameters affecting physicochemical properties, including CO2/co-solvent ratio, co-solvent type, temperature, and pressure. Finally, gas expanded liquid combining CO2/ethanol/H2O in a ratio of 10/81/9 (v/v/v) provided the best extraction yield. Extraction temperature 66 °C and pressure 22.3 MPa were the most suitable conditions after careful optimization, although both parameters did not significantly affect the process. It was confirmed by experiments in various pressure and temperature conditions and statistical comparison of obtained data. The optimized extraction procedure at a flow rate of 3 mL/min took 30 min. The repeatability of the extraction method exhibited an RSD of 20.8%. CONCLUSIONS: The optimized procedure enabled very fast extraction in 30 min using environmentally friendly solvents and it was successfully applied to 16 different plant samples, including 14 bulbs and 2 fruits from South Africa. The quercetin content in extracts was quantified using ultra-high performance liquid chromatography (UHPLC) with tandem mass spectrometry. UHPLC hyphenated with high-resolution mass spectrometry was used to confirm chemical identity of quercetin in the analyzed samples. We quantified quercetin in 11 samples of all 16 tested plants. The quercetin was found in Agapanthus praecox from the Amaryllidaceae family and its presence in this specie was reported for the first time.

Insights to the tribe Haemantheae of the South African Amaryllidaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: The family Amaryllidaceae has been documented in traditional systems of medicine around the globe. Its member tribe Haemantheae occurs chiefly in South Africa, where around twenty of its species are identifiable with a wide variety of functions in such practices. AIM OF THE STUDY: This account details work published from 2013 to 2020 on the tribe Haemantheae involving Clivia, Cryptostephanus, Haemanthus, Scadoxus and Gethyllis. Focus is maintained on the traditional medicinal aspects, pharmacological activities and identification of the active principles. Significant effort is also made to outline the molecular basis to some of these effects. MATERIALS AND METHODS: The major search engine platforms including, SciFinder, Scopus, ScienceDirect, PubMed and Google Scholar were utilized at the literature consolidation stage. Keywords engaged in the process included 'Amaryllidaceae' and 'Haemantheae' as well as individual genera and specie names. RESULTS: Twenty-four species of the five genera were encountered over the designated time frame. New traditional medicinal information has emerged on nine of these species, where usage ranged from the treatment of wounds and infections, circulatory and gastrointestinal issues to AIDS and TB. Significant amounts of new data also appeared in relation to the antimicrobial, anti-inflammatory, antioxidant, anticholinesterase, antidepressive and cytotoxic effects of these plants. Potent activities were observed in some instances, as they were in regards to the anti-inflammatory effects of some Gethyllis species in their cyclooxygenase-inhibitory effects. The entities behind these activities, with few exceptions, were shown to be isoquinoline alkaloids which are known to dominate the chemistry of the Amaryllidaceae. Interesting observations were also made for the mechanisms behind some of the effects, notably in the inflammatory and motorneuron disease arenas. CONCLUSIONS: The tribe Haemantheae has proved to be a rich and diverse platform for studies of the Amaryllidaceae in the key areas of traditional medicine, pharmacology and phytochemistry. Indigenous knowledge has played a significant role in guiding the biological evaluations, while identification of the active principles has been bolstered by the exceedingly rich alkaloid diversity of the Amaryllidaceae. As such, Haemantheae should continue to feature prominently in drug discovery efforts targeted at the family.

Chemical Composition and Cytotoxic Activity of the Essential Oil and Oleoresins of In Vitro Micropropagated Ansellia africana Lindl: A Vulnerable Medicinal Orchid of Africa.

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.

Interactive effects of plant growth-promoting rhizobacteria and a seaweed extract on the growth and physiology of Allium cepa L. (onion).

Detrimental effects caused by the overuse of synthetic agrochemicals have led to the development of natural biostimulants such as seaweed extracts and plant growth-promoting rhizobacteria (PGPR) being used as an alternative, environmentally-friendly technology to improve crop growth and increase agricultural yields. The present study aimed to investigate the interactions between PGPR and a commercial seaweed extract on the growth and biochemical composition of onion (Allium cepa). A pot trial was conducted under greenhouse conditions where onion plants were treated individually with the two PGPR, namely Bacillus licheniformis (BL) and Pseudomonas fluorescens (PF) and a seaweed extract Kelpak® (KEL) and combinations of KEL + BL and KEL + PF. Growth and yield parameters were measured after 12 weeks. KEL-treated plants showed the best growth response and overcame the inhibitory effects of BL treatment. KEL-treated plants also had the highest chlorophyll content. PGPR application improved the mineral nutrition of onion with these plants having the highest mineral content in the leaves and bulb. All biostimulant treatments increased the endogenous cytokinin and auxin content with the highest concentrations generally detected in the PF-treated plants. These results suggest that co-application of different biostimulant classes with different modes of action could further increase crop productivity with an improvement in both growth and nutrition content being achieved in onion with the co-application of a seaweed extract and PGPR.

Cytotoxic Agents in the Minor Alkaloid Groups of the Amaryllidaceae.

Over 600 alkaloids have to date been identified in the plant family Amaryllidaceae. These have been arranged into as many as 15 different groups based on their characteristic structural features. The vast majority of studies on the biological properties of Amaryllidaceae alkaloids have probed their anticancer potential. While most efforts have focused on the major alkaloid groups, the volume and diversity afforded by the minor alkaloid groups have promoted their usefulness as targets for cancer cell line screening purposes. This survey is an in-depth review of such activities described for around 90 representatives from 10 minor alkaloid groups of the Amaryllidaceae. These have been evaluated against over 60 cell lines categorized into 18 different types of cancer. The montanine and cripowellin groups were identified as the most potent, with some in the latter demonstrating low nanomolar level antiproliferative activities. Despite their challenging molecular architectures, the minor alkaloid groups have allowed for facile adjustments to be made to their structures, thereby altering the size, geometry, and electronics of the targets available for structure-activity relationship studies. Nevertheless, it was seen with a regular frequency that the parent alkaloids were better cytotoxic agents than the corresponding semisynthetic derivatives. There has also been significant interest in how the minor alkaloid groups manifest their effects in cancer cells. Among the various targets and pathways in which they were seen to mediate, their ability to induce apoptosis in cancer cells is most appealing.

Antibacterial, Mutagenic Properties and Chemical Characterisation of Sugar Bush (Protea caffra Meisn.): A South African Native Shrub Species.

Protea caffra is used as a diarrhoeal remedy in South African herbal medicine, however, its pharmacological properties remain largely unknown. In the present study, extracts from different Protea caffra organs were screened against drug-sensitive and -resistant diarrhoeagenic pathogens using the microdilution assay (minimum inhibitory concentration, MIC). Twig extracts (70% methanol, MeOH) of the plant were purified and the resultant fractions screened for antibacterial properties (MIC). The chemical profiles of the fractions were determined by Gas Chromatography-Mass Spectrometry (GC-MS), while ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to quantify the phenolic acids in the plant. The mutagenic properties of bioactive extracts were assessed using the Ames test. The extracts demonstrated weak-moderate antibacterial properties (MIC: 0.3-0.6 mg/mL). A cold ethyl acetate fraction of MeOH twig extract exhibited significant antibacterial properties (MIC = 0.078 mg/mL) against Enterococcus faecalis. The presence of antibacterial compounds (1-adamantane carboxylic acid, heptacosanol, levoglucosan, nonadecanol) in the plant was putatively confirmed based on GC-MS analysis. Furthermore, UHPLC-MS/MS analysis revealed varying concentrations of phenolic acids (0.08-374.55 µg/g DW). Based on the Ames test, the extracts were non-mutagenic thereby suggesting their safety. To a certain degree, the current study supports the traditional use of Protea caffra to manage diarrhoea among local communities in South Africa.

Flavonoids isolated from the South African weed Chromolaena odorata (Asteraceae) have pharmacological activity against uropathogens.

BACKGROUND: Urinary tract infections (UTIs) caused by opportunistic pathogens are among the leading health challenges globally. Most available treatment options are failing as a result of antibiotic resistance and adverse effects. Natural sources such as plants may serve as promising alternatives. METHODS: Compounds were isolated from the South African weed Chromolaena odorata through column chromatography. Purified compounds were tested for antimicrobial activity using the p-iodonitrotetrazolium chloride (INT) colorimetric method, against uropathogenic Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Aspergillus fumigatus and Cryptococcus neoformans. Anti-biofilm, anti-adhesion and metabolic inhibition activities were investigated against selected strains. Safety of the compounds was determined against Vero monkey kidney, C3A human liver and colon (Caco2) cells. RESULTS: Four compounds identified as pectolinaringenin (1), (±)-4',5,7-trimethoxy flavanone (2), 5-hydroxy-3,7,4'-trimethoxyflavone (3) and 3,5,7-trihydroxy-4'-methoxyflavone) (4) were isolated. Minimum inhibitory concentration (MIC) varied between 0.016 and 0.25 mg/mL. Compounds 2 and 3 showed promising antimicrobial activity against E. coli, S. aureus, K. pneumoniae, A. fumigatus and C. neoformans with MIC between 0.016 and 0.125 mg/mL, comparable to gentamicin, ciprofloxacin and amphotericin B used as positive controls. Compounds 2 and 3 showed good anti-biofilm and metabolic inhibition activities against E. coli and S. aureus but weak anti-adhesion activity against the organisms. Low toxicity with selectivity indexes between 1 and 12.625 were recorded with the compounds, indicating that the compounds were rather toxic to the microbial strains and not to the human and animal cells. CONCLUSION: Pharmacological activities displayed by compounds 2 and 3 isolated from C. odorata and low toxicity recorded credits it as a potential lead for the development of useful prophylactic treatments and anti-infective drugs against UTIs. Although known compounds, this is the first time these compounds have been isolated from the South African weed C. odorata and tested for antimicrobial, anti-biofilm, metabolic inhibition and anti-adhesion activities.

Phytomedicinal relevance of South African Cucurbitaceae species and their safety assessment: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: South Africa has a very rich flora. Many of these species such as those in the Cucurbitaceae family are exploited as medicines for the treatment of various infections. AIM OF THE REVIEW: The aim of the review was to synthesize the existing but scattered literature of some plant species in the Cucurbitaceae family used as sources of medicines in South Africa. MATERIALS AND METHODS: A literature survey was carried out on the ethnopharmacology, phytochemistry, pharmacological relevance and safety assessment of the South African Cucurbitaceae used as medicines. RESULTS: A total of 11 plants namely; Coccinia rehmannii Cogn., Cucumis africanus L.f., Cucumis anguria L. var. longaculeatus J.H.Kirkbr., Cucumis myriocarpus Naudin subsp. myriocarpus, Cucumis zeyheri Sond., Cucumis metuliferus E. Mey ex Naudin, Kedrostis nana (Lam) Cogn., Lagenaria siceraria (Molina) Standl., Momordica balsamina L., Momordica charantia L., and Momordica foetida Schumach. and Thonn were identified. Various traditional medicinal uses for these plants, from common ailments to life-threatening infections were reported. Biological activities including antidiabetic, antioxidant, antimicrobial, anticancer, anti-inflammatory and hepatoprotective were reported. However, some of the plants have not been investigated for some of the biological activities related to their traditional uses. In addition, most of the studies were carried out using non-standardized extracts. Thus, only a few studies on their bioactive constituents exist. Common compounds identified within the species are hydroxycinnamic and hydroxybenzoic acids such as sinapic, gallic, vanillic and salicylic acids; flavonoids such as naringenin, quercetin, kaempferol and rutin; fatty acids such as linoleic, palmitoleic, myristic and stearic acids; the saponin glycosides, momordicin alkaloids and cucurbitacins. However, most of these compounds have not been tested for biological activities. Cucurbitacins were implicated as a major class of toxic compounds present in the plants resulting in poisoning and death. CONCLUSIONS: Adequate knowledge of the traditional use of these plants in medicine and the parts used are very important due to the presence of toxic substances and their wide usage. Proper screening of the safety of these plants and products derived from them calls for urgent attention.

Phytochemical Profiles and Antioxidant Activity of Grasses Used in South African Traditional Medicine.

Grasses are a valuable group of monocotyledonous plants, used as nourishing foods and as remedies against diseases for both humans and livestock. Phytochemical profiles of 13 medicinal grasses were quantified, using spectrophotometric methods and ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS), while the antioxidant activity was done using DPPH and ferric-reducing-power assays. The phytochemical analysis included the total soluble phenolic content, flavonoids, proanthocyanidins, iridoids and phenolic acids. Among the 13 grasses, the root methanolic extracts of Cymbopogon spp., Cymbopogon nardus and Cenchrus ciliaris contained the highest concentrations of total soluble phenolics (27-31 mg GAE/g DW) and flavonoids (4-13 mg CE/g DW). Condensed tannins and total iridoid content were highest (2.3 mg CCE/g DW and 3.2 mg HE/g DW, respectively) in Cymbopogon nardus. The most common phenolic compounds in the grass species included ρ-coumaric, ferulic, salicylic and vanillic acids. In the DPPH radical scavenging assay, the EC50 values ranged from 0.02 to 0.11 mg/mL for the different grasses. The best EC50 activity (lowest) was exhibited by Cymbopogon nardus roots (0.02 mg/mL) and inflorescences (0.04 mg/mL), Cymbopogon spp. roots (0.04 mg/mL) and Vetiveria zizanioides leaves (0.06 mg/mL). The highest ferric-reducing power was detected in the whole plant extract of Cynodon dactylon (0.085 ± 0.45; r2 = 0.898). The observed antioxidant activity in the various parts of the grasses may be due to their rich pool of phytochemicals. Thus, some of these grasses provide a source of natural antioxidants and phytochemicals that can be explored for their therapeutic purposes.

Effect of cell disruption methods on the extraction of bioactive metabolites from microalgal biomass.

Microalgae synthesize a variety of potentially high-value compounds. Due to their robust cell wall, cell disruption is necessary to improve extraction of these compounds. While cell disruption methods have been optimized for lipid and protein extraction, there are limited studies for other bioactive compounds. The present study investigated the effect of freeze-drying combined with sonication or ball-milling on the extraction of antioxidant and plant biostimulating compounds from Chlorella sp., Chlorella vulgaris and Scenedesmus acutus. Both cell disruption methods resulted in higher extract yields from the biomass compared to freeze-dried biomass using 50% methanol as a solvent. Antioxidant activity of Chlorella extracts was generally higher than freeze-dried extracts based on the diphenylpicrylhydrazyl (DPPH) and ß-carotene linoleic acid assays. However, the effectiveness of each treatment varied between microalgae strains. Sonication resulted in the highest antioxidant activity in Chlorella sp. extracts. Ball-milling gave the best results for C. vulgaris extracts in the DPPH assay. Both cell disruption methods decreased antioxidant activity in S. acutus extracts. Plant biostimulating activity was tested using the mung bean rooting assay. Damaging the membrane by freeze-drying was sufficient to release the active compounds using water extracts. In contrast, both cell disruption methods negatively affected the biological activity of the extracts. These results indicate that bioactive compounds in microalgae are sensitive to post-harvest processes and their biological activity can be negatively affected by cell disruption methods. Care must be taken to not only optimize yield but to also preserve the biological activity of the target compounds.

Insight to the antifungal properties of Amaryllidaceae constituents.

BACKGROUND: Fungal pathogenesis continues to be a burden to healthcare structures in both developed and developing nations. The gradual and irreversible loss of efficacies of existing antifungal medicines as well as the emergence of drug-resistant strains have contributed largely to this scenario. There is therefore a pressing need for new drugs from diverse structural backgrounds with improved potencies and novel modes of action to fortify or replace contemporary antifungal schedules. AIM: Alkaloids of the plant family Amaryllidaceae exhibit good growth inhibitory activities against several fungal pathogens. This review focuses on the mechanistic aspects of these antifungal activities. It achieves this by highlighting the molecular targets as well as structural features of Amaryllidaceae constituents which serve to enhance such action. METHODS: During the information gathering stage extensive use was made of the three database platforms; Google Scholar, SciFinder and Scopus. In most instances articles were accessed directly from journals licensed to the University of KwaZulu-Natal. In the absence of such proprietary agreements the respective corresponding authors were approached directly for copies of papers. RESULTS: Although several classes of molecules from the Amaryllidaceae have been probed for their antifungal effects, it is the key constituents lycorine and narciclasine which have together afforded the most profound mechanistic insights. These may be summarized as follows: (i) effects on the fungal cell wall and cell membrane; (ii) effects on morphology such as budding and hyphal growth; (iii) effects on fungal organelles such as ribosomes; (iv) effects on macromolecules such as DNA, RNA and proteins and; (v) identification of the active sites for these constituents. CONCLUSION: The key feature in the antifungal effects of Amaryllidaceae alkaloids is the inhibition of protein synthesis. This involved the inhibition of peptide bond formation by binding to yeast ribosomes via the 60S subunit. Related effects involved the inhibition of both DNA and RNA synthesis. These adverse effects were reflected morphologically on both the fungal cell wall and cell membrane. Such observations should prove useful in the chemotherapeutic arena should efforts shift towards the development of a clinical candidate.

Potential of Smoke-Water and One of Its Active Compounds (karrikinolide, KAR1) on the Phytochemical and Antioxidant Activity of Eucomis autumnalis.

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 ß-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.

Antiprotozoal alkaloid principles of the plant family Amaryllidaceae.

Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC50 0.15 µg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.

Identification of Narciclasine as an in Vitro Anti-Inflammatory Component of Cyrtanthus contractus by Correlation-Based Metabolomics.

In this study, an extract from the bulbs of Cyrtanthus contractus showed strong anti-inflammatory activity in vitro. The extract was partially separated into 14 fractions and analyzed by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry metabolomics, and the correlation coefficients were calculated between biological activities and metabolite levels. As a result, the top-scoring metabolite narciclasine (1) is proposed as the active principle of C. contractus. This was confirmed by comparing the biological effect of crude extract with that of an authentic standard.

Antiplasmodial Lycorane Alkaloid Principles of the Plant Family Amaryllidaceae.

The spread of malaria is thought to have followed human expansion out of Africa some 60 - 80 thousand years ago. With its prevalence in pantropical countries of the world and epicenter localized in Africa, malaria is now considered an unnecessary burden to overworked and under-resourced healthcare structures. Plants have long afforded a fertile hunting ground for the search and identification of structurally diverse antimalarial agents, such as quinine and artemisinin. This survey examines the antiparasitic properties of the family Amaryllidaceae via the antiplasmodial activities demonstrated for its lycorane alkaloid principles. Of these, 24 were natural compounds identified in 20 species from 11 genera of the Amaryllidaceae family, whilst the remaining 28 were synthetically derived entities based on the lycorane skeleton. These were screened against ten different strains of the malarial parasite Plasmodium falciparum, wherein the parent compound lycorine was shown to be the most potent with an IC50 of 0.029 µg/mL in the FCR-3 strain seen to be the best. Structure-activity relationship studies revealed that good activities were detectable across both the natural compounds as well as the synthetically accessed derivatives. Such studies also highlighted that there are several inherent structural features that define the lycorane alkaloid antiplasmodial pharmacophore, such as the nature of its ring systems and properties of its substituents. Mechanistically, a limited number of studies confirmed that lycorane alkaloids manifest their action by targeting enzymes associated with the plasmodial FAS-II biosynthetic pathways. Overall, these alkaloids have provided useful, convenient, and accessible scaffolds for antimalarial-based drug discovery.