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

Detection of Glutathione S-Transferase gene (GST2, GST3) during induction of somatic embryogenesis in grape (Vitis vinifera L.)

Glutathione S-transferases (GSTs) are an important group of multifunctional enzymes that belong to diverse multigene families. In plants these enzymes are involved in the detoxification of xenobiotic compounds, herbicide detoxification, and primary and secondary metaboplism and play an important role in plant growth and development. There are several reports that show that the expression of GST is linked to the developmental phases of somatic embryogenesis. This study highlights the detection of transcript abundances of glutathione S-transferase genes GST2 and GST3 in the process of somatic embryogenesis of Vitis vinifera, and the lack thereof in non-embryogenic tissue of leaf cultures of grape (control). These results indicate that the expression of GST2 and GST3 could be used as a molecular signal for the identification of embryogenic cultures during the early development of somatic embryos

A chromosome-level Amaranthus cruentus genome assembly highlights gene family evolution and biosynthetic gene clusters that may underpin the nutritional value of this traditional crop

Traditional crops historically provided accessible and affordable nutrition to millions of rural dwellers but have been neglected, with most modern agricultural systems over reliant on a small number of internationally-traded crops. Traditional crops are typically well-adapted to local agro-ecological conditions and many are nutrient-dense. They can play a vital role in local food systems through enhanced nutrition (especially where diets are dominated by starch crops), food security and livelihoods for smallholder farmers, and a climate-resilient and biodiverse agriculture. Using short-read, long-read and phased sequencing technologies we generated a high-quality chromosome-level genome assembly for Amaranthus cruentus, an under-researched crop with micronutrient- and protein-rich leaves and gluten-free seed, but lacking improved varieties, with respect to productivity and quality traits. The 370.9 MB genome demonstrates a shared whole genome duplication with a related species, Amaranthus hypochondriacus. Comparative genome analysis indicates chromosomal loss and fusion events following genome duplication that are common to both species, as well as fission of chromosome 2 in A. cruentus alone, giving rise to a haploid chromosome number of 17 (versus 16 in A. hypochondriacus). Genomic features potentially underlying the nutritional value of this crop include two A. cruentus-specific genes with a likely role in phytic acid synthesis (an anti-nutrient), expansion of ion transporter gene families, and identification of biosynthetic gene clusters conserved within the amaranth lineage. The A. cruentus genome assembly will underpin much-needed research and global breeding efforts to develop improved varieties for economically viable cultivation and realisation of the benefits to global nutrition security and agrobiodiversity

African Journal of Food Science The effect of thermal processing on fumonisin B 1 (FB 1 ) levels in maize-based foods

Fumonisin B 1 (FB 1 ) is a mycotoxin fro

Co-occurring mycotoxins in animal feeds

Mycotoxin contamination of feeds results in economic loss and transmission of toxins in the food chain. Animal feeds, the raw ingredients used in their manufacture, namely, maize, wheat, sunflower seeds, cottonseeds, bagasse, wheaten bran, gluten feed and pet foods from South Africa were surveyed for contaminating mycotoxin-producing fungi and their toxins: aflatoxins, fumonisins, zearalenone andochratoxins. Toxins were extracted and analysed by high performance liquid chromatography and fluorometry. Twenty-one of the twenty-three samples were contaminated by Aspergillus flavus which cooccurredwith A. parasiticus in two samples, A. tamarii in seven and Fusarium moniliforme in one. Rhizopus stolonifer, R. oryzae and yeast were also isolated. Aflatoxins were detected in seventeen samples, fumonisin in six and zearalenone in three. Aflatoxin levels ranged between 0.8 ± 0.2 and 156 ± 8 ìg/kg (ppb), zearalenone between 100 ± 10.5 and 165 000 ± 200 ìg/kg and fumonisin B1 between 15 ± 3.0 and 5 900 ± 40ìg/kg. Ochratoxins were not detected in any of the samples. In most countries worldwide, legislated levels for aflatoxins and patulin are 20 ìg/kg and 50 ìg/kg, respectively, for human foods. Fumonisins,zearalenone and other toxins are not legislated in most of the countries. Ten of the feeds contain toxin levels above legislated limits (for Canada and the USA) and guidelines set by other countries. The results ofthis study highlight the need for mycotoxin legislation in the animal feed industry

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

Aflatoxin B1-induced toxicity in HepG2 cells inhibited by carotenoids: morphology, apoptosis and DNA damage.

Aflatoxin B1 (AFB1) is a fungal toxin that has been associated with primary hepatocellular carcinoma (HCC) in humans. This study was undertaken to determine the cellular and molecular mechanisms by which the antioxidants beta-carotene and lycopene inhibit AFB1-induced toxic changes in human hepatocytes (HepG2 cells). An in vitro system was optimized to test the chemoprotective effects of lycopene and beta-carotene on HepG2 cells exposed to different concentrations of AFB1. Ultrastructurally, HepG2 cells cultured in the presence of AFB1 showed mitochondrial damage, nuclear condensation and a loss of cell-to-cell contact; the latter was reflected in the observation of dysfunctional gap junctions, resulting in a loss of cell-to-cell communication. At the genomic level, AFB1 formed AFB1-N7-guanine adducts, caused apoptotic cell death and suppressed p53 protein expression. In the presence of the carotenoids, survival of cells exposed to AFB1 was increased, and there was also a significant increase in cellular mitochondrial activity. Our results demonstrate that HepG2 cells pretreated with lycopene and beta-carotene are protected from the toxic effects of AFB1 at both the cellular and molecular levels

CHEMICAL 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 a 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 are malarial vectors. 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

Functional and physical properties of instant beverage powder made from two different varieties of pearl millet

Abstract The objective of this experiment was to assess the effects of malting, extrusion and a combination of both processes on the physical and functional properties of the pearl millet flour (PMF) and pearl millet based instant beverage powder (PMIBP) produced. PMF and PMIBP were prepared by malting, extrusion and a combination of malting and extrusion cooking from two different varieties of pearl millet (Agrigreen (AgG) and Babala (Ba)). Malted pearl millets were produced by germinating at 30°C and 98% RH for 36 h, kilned at 50°C for 48 h then cooled to room temperature, ground and stored in a chiller at 5°C until used. Extrusion was carried out using a corotating twin-screw extruder under different parameters to obtain the pearl millet instant beverage powder. The different processes significantly (p ≤ 0.05) affected the colour (L, a & b) of AgG and Ba. Malting and extrusion significantly (p ≤ 0.05) reduced the peak viscosity of the starches from the raw pearl millet of both varieties of pearl millet as measured by rapid visco analyser (RVA). This can be considered as advantageous with respect to producing an instant beverage powder with a high nutrient content