Kniphofia leucocephala (Asphodelaceae): a new white-flowered red-hot poker from South Africa

Kniphofia leucocephala Baijnath, from the Zululand region, is described. It is a white-flowered species which may be included in section 3 of Codd’s groupings within the genus. It is closely related to K. pauciflora Bak., but differs markedly in floral and vegetative characters. Some of these characters are illustrated and discussed

Antidiabetic potential of Brachylaena discolor

Background: The traditional African herbal medicinal system has many reports of anti-diabetic food plants with no known side effects. Such plants and their products have been widely prescribed for diabetic treatment with little known mechanistic basis of their functioning. Therefore, these natural products need to be evaluated scientifically in order to confirm antidiabetic property claims.Materials and Methods: In this study, leaves of Brachylaena discolor were evaluated for potential to inhibit α-amylase and α-glucosidase. The leaves were also screened for toxicity and free radical scavenging capacity.Results: Results from the study show that the methanolic extract gave a higher α-glucosidase inhibition potential and was able to effectively scavenge free radicals better than the aqueous extract. The toxicity, cytotoxicity and mutagenicity screen also showed that both plant extracts are safe for use.Conclusion: These results therefore indicate that B. discolor has the potential for use as a potential dietary adjunct or therapy for the treatment of diabetes.Key words: Brachylaena discolor, α-amylase, α-glucosidase, DPPH, toxicit

Antibacterial and Anti-Biofilm Activity of Flavonoids and Triterpenes Isolated from The Extracts of Ficus Sansibarica Warb. Subsp. Sansibarica (Moraceae) Extracts

Background: Ficus species are used in African traditional medicine in the treatment of a wide variety of ailments and diseases such as convulsive disorder, wound healing, gonorrhea, tuberculosis, diabetes, diarrhoeal infections, dysentery, malaria and HIV. The aim of this study was to isolate the phytochemical constituents in the plant and test them for their antibacterial activity.Materials and methods: The fruits, leaves and stem bark were extracted with organic solvents and the compounds in the extracts separated and purified by column chromatography before being identified by NMR spectroscopy and by comparison of the NMR data against values reported in the literature. The antibacterial activity of the pure compounds and extracts were tested using the disk diffusion method.Results: Three triterpenes and three flavonoids: lupeol acetate (1); cycloart-23-ene-3,25-diol (2); β-sitosterol (3); 5,7,4'-trihydroxyflavan-3-ol (4); epicatechin (5); and isovitexin (6) were isolated in this study. Antimicrobial activity was observed at 8 mg mL-1 for Staphylococcus aureus ATCC 29213 with four of the six isolated compounds, with no activity being observed at 1 – 4 mg mL-1 against Escherichia coli ATCC 25922, E. coli ATCC 35218 and S. aureus ATCC 43300. Epicatechin (5) was found to decrease adhesion of E. coli ATCC 25922 and S. aureus ATCC 29213. Decreased adhesion of S. aureus ATCC 29213 was also observed with 5,7,4'-trihydroxyflavan-3-ol (4) and isovitexin (6).Conclusions: The results of this study provide baseline information on F. sansibarica’s potential validity in the treatment of infections associated with Gram-positive microorganisms.Key words: Moraceae, Ficus sansibarica, antimicrobial, anti-adhesion properties, flavonoids, triterpenoids

ANTIDIABETIC POTENTIAL OF BRACHYLAENA DISCOLOR

Background: The traditional African herbal medicinal system has many reports of anti-diabetic food plants with no known side effects. Such plants and their products have been widely prescribed for diabetic treatment with little known mechanistic basis of their functioning. Therefore, these natural products need to be evaluated scientifically in order to confirm antidiabetic property claims. Materials and Methods: In this study, leaves of Brachylaena discolor were evaluated for potential to inhibit α-amylase and α-glucosidase. The leaves were also screened for toxicity and free radical scavenging capacity. Results: Results from the study show that the methanolic extract gave a higher α-glucosidase inhibition potential and was able to effectively scavenge free radicals better than the aqueous extract. The toxicity, cytotoxicity and mutagenicity screen also showed that both plant extracts are safe for use. Conclusion: These results therefore indicate that B. discolor has the potential for use as a potential dietary adjunct or therapy for the treatment of diabetes

TRAV1-2⁺ CD8⁺ T-cells including oligoconal expansions of MAIT cells are enriched in the airways in human tuberculosis

Mucosal-associated invariant T (MAIT) cells typically express a TRAV1-2+ semi-invariant TCRα that enables recognition of bacterial, mycobacterial, and fungal riboflavin metabolites presented by MR1. MAIT cells are associated with immune control of bacterial and mycobacterial infections in murine models. Here, we report that a population of pro-inflammatory TRAV1-2+ CD8+ T cells are present in the airways and lungs of healthy individuals and are enriched in bronchoalveolar fluid of patients with active pulmonary tuberculosis (TB). High-throughput T cell receptor analysis reveals oligoclonal expansions of canonical and donor-unique TRAV1-2+ MAIT-consistent TCRα sequences within this population. Some of these cells demonstrate MR1-restricted mycobacterial reactivity and phenotypes suggestive of MAIT cell identity. These findings demonstrate enrichment of TRAV1-2+ CD8+ T cells with MAIT or MAIT-like features in the airways during active TB and suggest a role for these cells in the human pulmonary immune response to Mycobacterium tuberculosis

Aspects of pollination and floral development in <i>Ficus capensis</i> Thunb. (Moraceae)

A unique obligatory symbiosis exists between Ficus capensis Thunb., and its pollinator, Ceratosolen capensis Grandi. Flowers from both aerial and geocarpic syconia may be pollinated and produce seeds. Females of C. capensis possess specialized mesothoracic pockets in which pollen is transferred from ripening syconia to receptive ones. A second primary sycophile, Sycophaga cyclostigma Waterston, appears to be ineffective in pollination.Several secondary sycophiles oviposit through the syconial wall. Strong sexual dimorphism exists in most sycophilous wasps. All female flowers have the potential to produce either seeds or galls and variation is merely one of gross morphology. Flowering is distinctly asynchronous. Seeds are dispersed by various fruit predators and germinate very easily under warm humid conditions

COMPOSITION AND BIOLOGICAL ACTIVITY OF THE ESSENTIAL OIL FROM CYMBOPOGON NARDUS (L.) RENDLE

The essential oil from the leaves, culms and rhizomes of Cymbopogon nardus were extracted and volatile oils were investigated for the first time using Gas Chromatography-Mass Spectroscopy (GC/MS). Alpha-Cubebene, Camphene, Geraniol, Limonene, Myrcene, Palmitic acid and Sabinen were the major compounds identified . The essential oil was investigated for its antioxidant (DPPH assay), anti-inflammatory (5-lipoxygenase assay), antimicrobial (disk diffusion) and anti-mosquito properties (insecticidal, larvicidal and repellency assays). The oil showed poor antimicrobial activity and inhibited the growth of Bacillus, Micrococcus and Staphylococcus with minimum inhibitory concentration of 0.0625 (vol/vol). The oil showed antioxidant activity, scavenging more than 80% of DPPH free radicals and did not show any anti-inflammatory activity. It also showed good adulticidal activity (53.7% mortality) and excellent larvicidal (100% mortality) and repellent activity (100% repellency) against Anopheles arabiensis mosquitoes which is a malarial vector. The results of this study show that the essential oil from C. nardus possesses, antioxidant, antibacterial and anti-mosquito activities which may be associated with its predominant compounds viz., α-cubebene, camphene, geraniol, limonene, myrcene, palmitic acid and sabinen. These results lead the way for exploiting C. nardus oil as a multi-functional agent