Antioxidant properties, protein binding capacity and mineral contents of some plants traditionally used in the management of animal wounds

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Profiling of Phenolic Compounds and Antioxidant Activity of Dry Extracts from the Selected Sorbus Species

The antioxidant efficiency of dry extracts from inflorescences and/or leaves of seven Sorbus species was studied using four in vitro tests of SET (single electron transfer) and HAT-type (hydrogen atom transfer) mechanisms. The 70% methanol extracts and its diethyl ether, ethyl acetate, n-butanol and water fractions were tested in parallel with the phenolic standards, e.g., caffeic acid, quercetin, BHA, BHT, and TroloxÒ. The SET-type activity of the extracts depended primarily on the extraction solvent. The most valuable extracts were n-butanol and ethyl acetate ones, which activity was high in the DPPH (EC50 = 3.2–5.2 μg/mL), TEAC (2.8–4.0 mmol Trolox®/g), and FRAP (9.8–13.7 mmol Fe2+/g) tests, and strongly correlated with the total phenolic levels (39.6–58.2% of gallic acid equivalents). The HPLC-PDA analysis of the extracts led to the identification of chlorogenic acid, isoquercitrin, hyperoside, rutin, quercetin 3-O-sophoroside, and sexangularetin 3-O-b-D-glucopyranoside as the main components. Apart from flavonoids and hydroxycinnamic acids, proanthocyanidins have also a significant impact on the SET-type activity. The HAT-reactivity of the extracts in the linoleic acid peroxidation test (IC50 = 36.9–228.3 μg/mL) depended more strongly on the plant tissue than on the extraction solvent, and its correlation with the phenolic content was weak. Both SET and HAT-type activity of the most potent Sorbus extracts was comparable with the activity of the standards, indicating their great potential as effective sources for health products

Purification of supercritical-fluid carotenoid-rich extracts by hydrophobic interaction chromatography

Supercritical fluid extraction (SFE) has been widely used for extracting several valuable phytochemicals, including carotenoids. However, there is a scarcity of works dealing with the purification of SFE extracts. The aim of this work was to assess the feasibility and efficiency of a hydrophobic interaction chromatography (HIC) protocol for purifying carotenoid-rich extracts obtained by SFE. Initial batch experiments were carried out to calculate the resin adsorption capacity and adsorption kinetics. Subsequent runs were performed in a manually-packed chromatographic column, using the Amberlite XAD-1180N resin, where breakthrough curves and adsorption isotherms were obtained and fitted to the Langmuir model. The antioxidant activity and carotenoid degradation rates were monitored throughout the processes. In batch, the resin presented a maximum carotenoid adsorption capacity of 1.89 μg/mg, while in column, this value increased to 10.4 μg/mg. The global carotenoid adsorption rate was 93.3% and the elution rate, 94.7%, resulting in a global recovery of 88.4% for total carotenoids and 92.1% for carotenes. The Langmuir model fitted well the experimental data. Analysis of the extracts demonstrated that a 5.5-fold reduction in extract mass was achieved, accompanied by a 4.7-fold and 2.1-fold increase in carotenoid concentration and antioxidant activity, respectively. This work presents a novel process based on preparative HIC for the purification of carotenoid extracts and provides a fundamental understanding on process performance. It is potentially scalable and can be implemented in extraction and purification of carotenoids from natural sources, as an alternative to their production through chemical synthesis

Phytochemical studies and antioxidant activity of two South African medicinal plants traditionally used for the management of opportunistic fungal infections in HIV/AIDS patients

<p>Abstract</p> <p>Background</p> <p>It has been observed that perturbations in the antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Hence, the exogenous supply of antioxidants, as natural compounds that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection. The aim of this study was therefore to analyse the phytochemical constituents and antioxidant potential of <it>Gasteria bicolor </it>Haw and <it>Pittosporum viridiflorum </it>Sims., two South African plants traditionally used for the management of opportunistic fungal infections (OFIs) in AIDS patients.</p> <p>Methods</p> <p>The <it>in vitro </it>antioxidant properties of the two plants were screened through DPPH (1,1-diphenyl-2-picrylhydrazyl), NO (nitric oxide), H₂O₂(hydrogen peroxide) radical scavenging effects and reducing power assays. Phytochemical studies were done by spectrophotometric techniques.</p> <p>Results</p> <p>There were no significant differences in the flavonoid and proanthocyanidins contents between the leaves and bark extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively, while the total phenolic content of the bark extract of <it>P. viridiflorum </it>was significantly higher than that of <it>G. bicolor </it>leaf. The acetone extracts of both plants indicated strong antioxidant activities.</p> <p>Conclusion</p> <p>The results from this study indicate that the leaves and stem extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively possess antioxidant properties and could serve as free radical inhibitors, acting possibly as primary antioxidants. Since reactive oxygen species are thought to be associated with the pathogenesis of AIDS, and HIV-infected individuals often have impaired antioxidant defenses, the inhibitory effect of the extracts on free radicals may partially justify the traditional use of these plants in the management of OFIs in HIV patients in South Africa.</p

The chemistry and biological activity of the Hyacinthaceae

Covering: 1914 to 2012The Hyacinthaceae (sensu APGII), with approximately 900 species in about 70 genera, can be divided into three main subfamilies, the Hyacinthoideae, the Urgineoideae and the Ornithogaloideae, with a small fourth subfamily the Oziroëoideae, restricted to South America. The plants included in this family have long been used in traditional medicine for a wide range of medicinal applications. This, together with some significant toxicity to livestock has led to the chemical composition of many of the species being investigated. The compounds found are, for the most part, subfamily-restricted, with homoisoflavanones and spirocyclic nortriterpenoids characterising the Hyacinthoideae, bufadienolides characterising the Urgineoideae, and cardenolides and steroidal glycosides characterising the Ornithogaloideae. The phytochemical profiles of 38 genera of the Hyacinthaceae will be discussed as well as any biological activity associated with both crude extracts and compounds isolated. The Hyacinthaceae of southern Africa were last reviewed in 2000 (T. S. Pohl, N. R. Crouch and D. A. Mulholland, Curr. Org. Chem., 2000, 4, 1287-1324; ); the current contribution considers the family at a global level

ANTIMICROBIAL PROPERTIES OF A ZULU HERBAL MIXTURE ’IMBIZA EPHUZWATO’

Imbiza ephuzwato is a Zulu herbal preparation consisting of roots, bulbs, rhizomes and leaves of several medicinal plants extracted with boiling water. The herbal mixture, sold in muthi shops around KwaZulu-Natal is used to treat microbial and fungal infections, boost energy and relieve general body pains. Imbiza ephuzwato was tested against two Gram-positive (Bacillus subtilis and Staphylococcus aureus), two Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria and Candida albicans using the microdilution assay to evaluate its antimicrobial effects. The mixture showed antibacterial and antifungal activity with a minimum inhibitory concentration (MIC) of 0.78 mg/ml against the microbes tested. Six of the plant constituents (Corchorus aspleniifolius root, Cyrtanthus obliquus bulb, Drimia robusta bulb, Gunnera perpensa rhizome, Hypericum aethiopicum leaf and Zanthoxylum capense root) of Imbiza ehuzwato were extracted with petroleum ether, 80% ethanol and water. The extracts were subjected to similar tests to investigate the source of activity of the mixture. The aqueous extracts of G. perpensa rhizome showed MIC values of 0.78 mg/ml against the bacteria and fungus. The petroleum ether extract of C. aspleniifolius root showed MIC values of 0.195 mg/ml against all the bacteria and 0.39 mg/ml against C. albicans. The rest of the plants had MIC values ranging from 0.39 to 12.5 mg/ml against both the bacteria and fungus used. The results suggest G. perpensa rhizome could be the source of the activity detected in the product. G. perpensa rhizome contains several compounds with antibacterial activity. Isolation of active components will be attempted from the other active extracts

PHARMACOLOGICAL ACTIVITIES OF BURCHELLIA BUBALINE

Burchellia bubalina is an endemic, monotypic plant which is extensively used in traditional medicine. Extracts obtained from stems and leaves of Burchellia bubalina were evaluated for antibacterial, antifungal and anti-inflammatory (COX-1 and COX-2) activities in order to detect potential new sources of antimicrobial and anti-inflammatory agents. Antibacterial and antifungal activities were evaluated using micro-dilution assays against two Gram-positive (Bacillus subtilis, Staphylococcus aureus) and two Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae) and the fungus Candida albicans. The stem petroleum ether extract showed the lowest minimum inhibitory concentration (MIC) of 0.39 mg/ml against both Gram-positive bacteria. The dichloromethane (DCM) extract of the leaf and stem showed MIC of 0.15 mg/ml and 0.39 mg/ml respectively against the fungus. The dichloromethane extract of the leaf had the best fungicidal activity at a concentration of 0.20 mg/ml. The petroleum ether and DCM extracts of both the leaf and stem exhibited good inhibition (> 70%) of prostaglandin synthesis in both COX-1 and COX-2 assays. The presence of comparable antibacterial, antifungal and anti-inflammatory activities in both the stem and leaf extracts of this plant is in line with the idea of substituting bark, root and stems with leaves. Leaves can be harvested sustainably while using this plant for medicinal purposes without the inherent survival threat associated with the over-harvesting of parts like roots and stems

Anti-Oxidative and Cholinesterase Inhibitory Effects of Leaf Extracts and Their Isolated Compounds from Two Closely Related Croton Species

A comparative evaluation of the antioxidant and acetylcholinesterase inhibitory activity of the leaf extracts of Croton gratissimus and Croton zambesicus (subgratissimus) and compounds isolated from the extracts was carried out to determine their potential and suitability or otherwise as a substitute for each other in the management of oxidative and neurodegenerative conditions. Different antioxidant assays (DPPH, FRAP, β-carotene-linoleic and the lipid peroxidation models) and the microplate assay for acetylcholinesterase (AChE) inhibition were carried out separately to study the activities of the crude leaf extracts and four solvent fractions from each of the two Croton species. Bioassay guided fractionation was used to target antioxidant constituents of the crude extracts and ethyl acetate fractions of 20% aqueous methanol extract of C. gratissimus on silica gel and Sephadex LH-20 columns resulted in the isolation of kaempferol-3-O-β-6&#039;&#039;(p-coumaroyl) glucopyranoside (tiliroside, 2), apigenin-6-C-glucoside (isovitexin, 3) and kampferol (4). The extract of C. zambesicus yielded quercetin-3-O-β-6&#039;&#039;(p-coumaroyl) glucopyranoside-3&#039;-methyl ether (helichrysoside- 3&#039;-methyl ether, 1), kaempferol-3-O-β-6&#039;&#039;(p-coumaroyl) glucopyranoside (tiliroside, 2) and apigenin-6-C-glucoside (isovitexin, 3). Three of the isolated compounds and their different combinations were also included in the bioassays. In all the assays performed, the antioxidant capacity and AChE inhibitory effects of C. zambesicus extracts were weaker than those of C. gratissimus. This suggests that C. gratissimus may not be substituted by C. zambesicus, despite the similarity in some of their constituents. Generally, the combinations made from the isolated compounds showed better activities in most of the assays compared to the individual isolated compounds. This suggests mechanisms such as synergism and/or additive effects to be taking place. This study established low, moderate and high antioxidant activities as well as AChE inhibitory effects by the crude extracts, fractions, compounds and compound combinations. This means some of the extracts, isolated compounds and compound combinations could be useful in the management of neurodegenerative conditions and serve as sources of natural neurodegenerative agents