Explore the vast range of titles available.

The preparation of gold nanoparticles (AuNPs) involves a variety of chemical and physical methods. These methods use toxic and environmentally harmful chemicals. Consequently, the synthesis of AuNPs using green chemistry has been under investigation to develop eco-friendly nanoparticles. One approach to achieve this is the use of plant-derived phytochemicals that are capable of reducing gold ions to produce AuNPs. The aim of this study was to implement a facile microtitre-plate method to screen a large number of aqueous plant extracts to determine the optimum concentration (OC) for the bio-synthesis of the AuNPs. Several AuNPs of different sizes and shapes were successfully synthesized and characterized from 17 South African plants. The characterization was done using Ultra Violet-Visible Spectroscopy, Dynamic Light Scattering, High Resolution Transmission Electron Microscopy and Energy-Dispersive X-ray Spectroscopy. We also studied the effects of temperature on the synthesis of the AuNPs and showed that changes in temperatures affect the size and dispersity of the generated AuNPs. We also evaluated the stability of the synthesized AuNPs and showed that some of them are stable in biological buffer solutions.

In this study, procyanidins fractions of dimers and trimers (F1–F2) from the Leucosidea sericea total extract (LSTE) were investigated for their chemical constituents. The total extract and the procyanidins were employed in the synthesis of gold nanoparticles (Au NPs) and fully characterized. Au NPs of 6, 24 and 21 nm were obtained using LSTE, F1 and F2 respectively. Zeta potential and in vitro stability studies confirmed the stability of the particles. The enzymatic activity of LSTE, F1, F2 and their corresponding Au NPs showed strong inhibitory alpha-amylase activity where F1 Au NPs demonstrated the highest with IC50 of 1.88 µg/mL. On the other hand, F2 Au NPs displayed the strongest alpha-glucosidase activity at 4.5 µg/mL. F2 and F2 Au NPs also demonstrated the highest antioxidant activity, 1834.0 ± 4.7 μM AAE/g and 1521.9 ± 3.0 μM TE/g respectively. The study revealed not only the ability of procyanidins dimers (F1 and F2) in forming biostable and bioactive Au NPs but also, a significant enhancement of the natural products activities, which could improve the smart delivery in future biomedical applications.

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases and affects approximately 6.3 million people worldwide. To date, the treatment of PD remains a challenge, as available treatment options are known to be associated with serious side effects; hence, the search for new treatment strategies is critical. Extracts from the Amaryllidaceae plant family as well as their alkaloids have been reported to have neuroprotective potentials. This study, therefore, investigated the biological activities of Crossyne flava and its isolated alkaloids in an in vitro MPP+ (1-methyl-4-phenylpyridinium) PD model using SH-SY5Y cells. The effects of the total extract as well as the four compounds isolated from Crossyne flava (i.e., pancratinine B (1), bufanidrine (2), buphanisine (3), and epibuphanisine (4)) were evaluated for cell viability, neuroprotection, levels of reactive oxygen species (ROS), adenosine triphosphate activity (ATP), and caspase 3/7 activity in SH-SY5Y cells. The results obtained showed that pre-treatment with both the extract and the isolated compounds was effective in protecting the SH-SY5Y cells from MPP+-induced neurotoxicity and inhibited ROS generation, ATP depletion as well as apoptosis induction in the SH-SY5Y cells. The results of this study show that the Amaryllidaceae plant family may be a source of novel compounds for the treatment of neurodegenerative diseases, which validates the reported traditional uses.

Polhillia , Wiborgia and Wiborgiella species are shrub legumes endemic to the Cape fynbos of South Africa. They have the ability to fix atmospheric N 2 when in symbiosis with soil bacteria called ‘rhizobia’. The aim of this study was to assess the morpho-physiological and phylogenetic characteristics of rhizobia associated with the nodulation of Polhillia , Wiborgia and Wiborgiella species growing in the Cape fynbos. The bacterial isolates from root nodules consisted of a mixture of fast and intermediate growers that differed in colony shape and size. The isolates exhibited tolerance to salinity (0.5–3% NaCl) and pH (pH 5–10) and different antibiotic concentrations, and could produce 0.51 to 51.23 µg mL −1 of indole-3-acetic acid (IAA), as well as solubilize tri-calcium phosphate. The ERIC-PCR results showed high genomic diversity in the rhizobial population and grouped them into two major clusters. Phylogenetic analysis based on 16S rRNA, atpD , gln II, gyrB , nifH and nodC gene sequences revealed distinct and novel evolutionary lineages related to the genus Rhizobium and Mesorhizobium , with some of them being very close to Mesorhizobium australicum . However, the phylogenetic analysis of glnII and nifH genes of some isolates showed incongruency.

Diabetes mellitus (DM) is a group of systemic metabolic disorders with a high rate of morbidity and mortality worldwide. Due to the detrimental side effects of the current treatment, there is a great need to develop more effective antidiabetic drugs with fewer side effects. Natural products are a well-known source for the discovery of new scaffolds for drug discovery, including new antidiabetic drugs. The genus Helichrysum has been shown to produce antidiabetic natural products. In this investigation, the methanolic extract of H. cymosum and H. pandurifolium resulted in the isolation and identification of eleven known compounds viz 5,8-dihydroxy-7-methoxy-2-phenyl flavanone (1), pinostrobin (2), dihydrobaicalein (3), glabranin (4), allopatuletin (5), pinostrobin chalcone (6), helichrysetin (7), 5-hydroxy-3,7-dimethoxyflavone (8), 3,5-dihydroxy-6,7,8-trimethoxyflavone (9), 3-O-methylquercetin (10), and 3-methylethergalangin (11). The in vitro bio-evaluation of isolated compounds against alpha-glucosidase showed that 10, 5, and 11 demonstrated the highest alpha-glucosidase inhibitory activity with IC50 values of 9.24 ± 0.4, 12.94 ± 0.2, and 16.00 ± 2.4 μM respectively, followed by 7 and 3 with IC50 values of 18.16 ± 1.2 and 44.44 ± 0.2 μM respectively. However, none of these compounds showed a measurable inhibitory effect on alpha-amylase under the experimental conditions used except compound 10 which showed a poor alpha-amylase inhibitory activity with an IC50 value of 230.66 ± 15.8 μM. Additionally, strong total antioxidant capacities were demonstrated by 10, 5 and 7 in ferric-ion reducing antioxidant power assay (374.34 ± 69.7; 334.37 ± 1.7; 279.93 ± 0.8) µmol AAE/mmol. This is the first scientific report to be carried out on alpha-glucosidase inhibitory activities and antioxidant capacities of H. cymosum constituents and a first report on the isolation and identification of methoxyflavanoids from H. pandurifolium. Our findings suggest that these compounds are promising candidates to inhibit alpha-glucosidase as well as oxidative stress related to diabetes. Results from molecular docking provided insight into the observed in vitro alpha-glucosidase inhibitory activities for 5, 7, 10, and 11. It is envisaged that the isolated phytochemicals from these plants may contribute to the development of hypoglycemic lead compounds with anti-diabetic potential.

Unlike conventional physical and chemical methods, the biogenic synthesis of gold nanoparticles (GNPs) is considered a green and non-toxic approach to produce biocompatible GNPs that can be utilized in various biomedical applications. This can be achieved by using plant-derived phytochemicals to reduce gold salt into GNPs. Several green synthesized GNPs have been shown to have antibacterial effects, which can be applied in wound dressings to prevent wound infections. Therefore, the aim of this study is to synthesize biogenic GNPs from the South African Galenia africana and Hypoxis hemerocallidea plants extracts and evaluate their antibacterial activity, using the Alamar blue assay, against bacterial strains that are known to cause wound infections. Additionally, we investigated the toxicity of the biogenic GNPs to non-cancerous human fibroblast cells (KMST-6) using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. In this paper, spherical GNPs, with particle sizes ranging from 9 to 27 nm, were synthesized and fully characterized. The GNPs from H. hemerocallidea exhibited antibacterial activity against all the tested bacterial strains, whereas GNPs produced from G. africana only exhibited antibacterial activity against Pseudomonas aeruginosa. The GNPs did not show any significant toxicity towards KMST-6 cells, which may suggest that these nanoparticles can be safely applied in wound dressings.

The re-investigation of a methanolic extract of Salvia africana-lutea collected from the Cape Floristic Region, South Africa (SA), afforded four new abietane diterpenes, namely 19-acetoxy-12-methoxycarnosic acid (1), 3β-acetoxy-7α-methoxyrosmanol (2), 19-acetoxy-7α-methoxyrosmanol (3), 19-acetoxy-12-methoxy carnosol (4), and two known named clinopodiolides A (5), and B (6), in addition to four known triterpenes, oleanolic, and ursolic acids (7, 8), 11,12-dehydroursolic acid lactone (9) and β-amyrin (10). The chemical structural elucidation of the isolated compounds was determined on the basis of one and two dimensional nuclear magnetic resonance (1D and 2D NMR), high-resolution mass spectrometry (HRMS), ultra violet (UV), fourier transform infrared (IR), in comparison with literature data. The in vitro bio-evaluation against alpha-glucosidase showed strong inhibitory activities of 8, 10, and 7, with the half inhibitory concentration (IC50) values of 11.3 ± 1.0, 17.1 ± 1.0 and 22.9 ± 2.0 µg/mL, respectively, while 7 demonstrated the strongest in vitro alpha-amylase inhibitory activity among the tested compounds with IC50 of 12.5 ± 0.7 µg/mL. Additionally, some of the compounds showed significant antioxidant capacities. In conclusion, the methanolic extract of S. africana-lutea is a rich source of terpenoids, especially abietane diterpenes, with strong antioxidant and anti-diabetic activities that can be helpful to modulate the redox status of the body and could therefore be an excellent candidate for the prevention of the development of diabetes, a disease where oxidase stress plays an important role.

The Cape fynbos biome in South Africa is home to highly diverse and endemic shrub legumes, which include species of Aspalathus, Polhillia, Wiborgia and Wiborgiella. These species play a significant role in improving soil fertility due to their ability to fix N2. However, information regarding their microbiome is still unknown. Using the 16S rRNA Miseq illumina sequencing, this study assessed the bacterial community structure associated with the rhizospheres of Polhillia pallens, Polhillia brevicalyx, Wiborgia obcordata, Wiborgia sericea and Wiborgiella sessilifolia growing at different locations during the wet and dry seasons in the Cape fynbos. The results showed that the most dominant bacterial phylum was Actinobacteria during both the dry (56.2–37.2%) and wet (46.3–33.3%) seasons. Unclassified bacterial genera (19.9–27.7%) were the largest inhabitants in the rhizospheres of all five species during the two seasons. The other dominant phyla included Bacteroidetes, Acidobacteria, Proteobacteria and Firmicutes. Mycobacterium and Conexibacter genera were the biggest populations found in the rhizosphere soil of all five test species during both seasons, except for W. obcordata soil sampled during the dry season, which had Dehalogenimonas as the major inhabitant (6.08%). In this study plant species and growth season were the major drivers of microbial community structure, with W. obcordata having the greatest influence on its microbiome than the other test species. The wet season promoted greater microbial diversity than the dry season.

The genus Helichrysum Mill comprises hundreds of species that are mostly flowering perennial shrubs. Some of these plants that belong to the Helichrysum species are used in traditional medicine to treat cough, back pain, diabetes, asthma, digestive problems, menstrual pain, chest pain, kidney disorders, skin disorders, wounds, open sores, among other conditions, but, only a few scientific studies are reported in the literature with sufficient information that validates the acclaimed folkloric benefits of these plants. This review, therefore, provides a comprehensive update of the available information on the cytotoxicity, genotoxicity, anti-proliferative, anti-bacterial, anti-fungal, anti-viral, anti-HIV, anti-malarial, anti-ulcerogenic, anti-tyrosinase, anti-inflammatory, and anti-oxidant activities of selected Helichrysum species of interest: H. petiolare, H. cymocum, H. foetidum, and H. pandurifolium Schrank, using scientific databases as well as electronic and print sources. The ethnobotanical and morphological characteristics as well as the phytochemical composition and biological activities of these plants are elucidated. The scientific rationale for their current use is discussed based on the evidence in the literature. This review highlights the putative use of the Helichrysum species as a reliable source of bioactive compounds for the production of standard commercial drugs to treat many ailments, including those reported in folkloric uses. Further research on the many plants in the genus Helichrysum is recommended to explore their economic importance both as edible crops and medicinal botanicals.

Evidence is presented to support the exclusion of Prismatocarpus crispus from Prismatocarpus and placing it in a new monotypic genus, Kencodon. It is distinct from Prismatocarpus in its annual growth form, three or rarely two or four pairs of style glands, capsule dehiscence via numerous longitudinal segments not corresponding to the calyx lobes, pericarp sclerenchyma arranged in discrete bundles and a rugose-like Type IE seed coat sculpturing pattern. The closely related P. hildebrandtii is placed in synonymy with Kencodon crispus.