Paul T Smith

Antioxidant and anti-inflammatory activities of selected medicinal plants containing phenolic and flavonoid compounds

The antioxidant, anti-inflammatory, and cytotoxic activities of water and ethanol extracts of 14 Chinese medicinal plants were investigated and also their total phenolics and flavonoid contents measured. The antioxidant activity was evaluated in a biological assay using Saccharomyces cerevisiae , whereas the radical scavenging activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Total phenolics and flavonoid contents were estimated by Folin-Ciocalteu and aluminum chloride methods, respectively. The anti-inflammatory activities of the plant extracts were determined by measuring the inhibition of production of nitric oxide (NO) and TNF-α in LPS and IFN-γ activated RAW 264.7 macrophages. Their cytotoxic activities against macrophages were determined by Alamar Blue assay. Four plants, namely, Scutellaria baicalensis , Taxillus chinensis , Rheum officinale , and Sophora japonica , showed significant antioxidant activity in both yeast model and also free radical scavenging methods. The ethanol extract of S. japonica showed highest levels of phenolics and flavonoids (91.33 GAE mg/g and 151.86 QE mg/g, respectively). A positive linear correlation between antioxidant activity and the total phenolics and flavonoid contents indicates that these compounds are likely to be the main antioxidants contributing to the observed activities. Five plant extracts (S. baicalensis, T. chinensis, S. japonica, Mahonia fortunei , and Sophora flavescens ) exhibited significant anti-inflammatory activity by in vitro inhibition of the production of NO and TNF-α with low IC(50) values. These findings suggest that some of the medicinal herbs studied in this paper are good sources of antioxidants.

Antioxidant and anti-inflammatory activities of selected Chinese medicinal plants and their relation with antioxidant content

BackgroundThe main aim of this study is to evaluate the antioxidant and anti-inflammatory properties of forty four traditional Chinese medicinal herbal extracts and to examine these activities in relation to their antioxidant content.MethodsThe antioxidant activities were investigated using DPPH radical scavenging method and yeast model. The anti-inflammatory properties of the herbal extracts were evaluated by measuring their ability to inhibit the production of nitric oxide and TNF-α in RAW 264.7 macrophages activated by LPS and IFN- γ, respectively. The cytotoxic effects of the herbal extracts were determined by Alomar Blue assay by measuring cell viability. In order to understand the variation of antioxidant activities of herbal extracts with their antioxidant contents, the total phenolics, total flavonoids and trace metal (Mg, Mn, Cu, Zn, Se and Mo) quantities were estimated and a correlation analysis was carried out.ResultsResults of this study show that significant levels of phenolics, flavonoids and trace metal contents were found in Ligustrum lucidum, Paeonia suffuticosa, Salvia miltiorrhiza, Sanguisorba officinalis, Spatholobus suberectus, Tussilago farfara and Uncaria rhyncophylla, which correlated well with their antioxidant and anti-inflammatory activities. Some of the plants displayed high antioxidant and anti-inflammatory activities but contained low levels of phenolics and flavonoids. Interestingly, these plants contained significant levels of trace metals (such as Zn, Mg and Se) which are likely to be responsible for their activities.ConclusionsThe results indicate that the phenolics, flavonoids and trace metals play an important role in the antioxidant activities of medicinal plants. Many of the plants studied here have been identified as potential sources of new antioxidant compounds.

Physical and chemical characteristics of sediments from prawn farms and mangrove habitats on the Clarence River, Australia

Abstract The culture of Penaeus monodon in earthen ponds produces a black, glutinous sediment which has caused degradation of waterways in some countries and is suspected of reducing farm productivity. Superficially, the sediment is similar to that found in mangrove habitats, however, there have been few studies which compare these materials. This study describes the physical and chemical characteristics of sediment from four Australian prawn farms and compares results with those from nearby sites in intertidal mangrove habitats of the Clarence River, Australia. At the farms, sediment accumulated in the centre of ponds and around drains at variable rates (20 × 103–180 × 103 kg ha−1 per crop), depending on the stability of pond walls, prevailing winds, type of soil and aeration rates. The main source of the sediment was soil eroded from the pond walls and from the periphery of pond bottoms. The accumulating sediment was a mixture of silt and clay size particles, with a median particle size of 13 μm. Chemical analysis showed it consisted of (by weight): quartz, feldspar and clay minerals (70–80%); amorphous oxides of silicon, iron and aluminium (5–10%); organic matter and volatile compounds (5–10%); elevated levels of trace metals and nutrients. Inputs of food, faeces and decaying plankton enriched the sediment, increasing the organic carbon content from 13.9 mg g−1 at the periphery of ponds to 22.8 mg g−1 in the centre. Fresh and dried sediment had neutral pH, although soil in the pond walls was often acidic. In the centre of ponds, total nitrogen (2.25 mg g−1) and total phosphorus (690 μg g−1) were significantly higher than at the periphery. There were abundant microalgal fragments and high levels of amorphous silica (10–15% by volume) on the bottom of ponds, and calculations suggest that weathering of clay provided 87% of the silicon used by diatoms. The sediment in intertidal mangrove habitats was physically and chemically similar to sediment from the periphery of prawn ponds, while sediment from inland forest mangrove habitats was similar to sediment which accumulated in the centre of prawn ponds.

Antioxidant and immunomodulatory activities of polysaccharides from the roots of Sanguisorba officinalis

The roots of Sanguisorba officinalis are used in traditional Chinese medicine for the treatment of diseases such as inflammation and internal haemorrhage. Several scientific investigations involving extraction and pharmacological studies of terpenoids and triterpenoid glycosides from this herb have been carried out. However, little is known regarding the immunomodulatory and antioxidant properties of polysaccharides from S. officinalis. Hence the polysaccharides from this herb have been investigated here. The hot water extract of S. officinalis has been fractionated using size-exclusion chromatography to obtain four polysaccharide fractions designated as SOP-1, SOP-2, SOP-3 and SOP-4. The range of molecular masses of these fractions were from 280 Da to 2000 kDa, and their sugar compositions consisted mainly of fructose, glucose, xylose, arabinose, and rhamnose. The antioxidant activities of the crude polysaccharide fractions were evaluated in a biological assay using Saccharomyces cerevisiae, whereas the radical scavenging activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Analysis of the immunomodulatory activities of these polysaccharide fractions were measured by using mouse macrophages. Most of the polysaccharide fractions have stimulated the production of nitric oxide and tumour necrosis factor-α (TNF-α), and also displayed antioxidant activities. These results suggest that the roots of S. officinalis are likely to have therapeutic value for the treatment of cancer.

Anti-fungal and anti-bacterial activities of ethanol extracts of selected traditional Chinese medicinal herbs.

OBJECTIVE To evaluate in vitro antimicrobial activities of selected 58 ethno-medicinal plant extracts with a view to assess their therapeutic potential. METHODS A total of 58 traditional Chinese medicinal plants were carefully selected based on the literature review and their traditional use. The antimicrobial activities of ethanol extracts of these medicinal plants were tested against fungi (Aspergillus fumigatus), yeast (Candida albicans), gram-negative (Acinetobacter baumannii and Pseudomonas aeruginosa) and gram-positive bacteria (Staphylococcus aureus). The activities were tested at three different concentrations of 1.00, 0.10 and 0.01 mg/mL. The data was analysed using Gene data Screener program. RESULTS The measured antimicrobial activities indicated that out of the 58 plant extracts, 15 extracts showed anti-fungal activity and 23 extracts exhibited anti-bacterial activity. Eight plant extracts have exhibited both anti-bacterial and anti-fungal activities. For instance, Eucommia ulmoides, Polygonum cuspidatum, Poria cocos and Uncaria rhyncophylla showed activity against both bacterial and fungal strains, indicating their broad spectrum of activity. CONCLUSIONS The results revealed that the ethanol extracts of 30 plants out of the selected 58 possess significant antimicrobial activities. It is interesting to note that the findings from the current study are consistent with the traditional use. A clear correlation has also been found between the antimicrobial activity and the flavonoid content of the plant extracts which is in agreement with the literature. Hence, the results presented here can be used to guide the selection of potential plant species for the isolation and structure elucidation of novel antimicrobial compounds in order to establish the structure-activity relationship. This in turn is expected to lead the way to the discovery of novel antimicrobial agents for therapeutic use.

Toxic effects of blooms of marine species of Oscillatoriales on farmed prawns (Penaeus monodon, Penaeus japonicus) and brine shrimp (Artemia salina).

Benthic and planktonic blooms of species of Oscillatoriales coincided with mortalities of Penaeus monodon during four episodes at Australian prawn farms. Oscillatoria corakiana was the dominant planktonic species at 65-90,000 cells/ml, but Spirulina sp., Lyngbya sp., Oscillatoria sp. and Nodularia sp. were also identified from the water column, benthic layers or surface mats. The levels and variety of Vibrionaceae in prawn tissue, suggest that mortalities were caused by secondary infections of bacteria. However, experimental results indicate that toxicity of the blooms of Oscillatoriales was the primary cause of disease. Pond water and extracts from a tank culture of benthic Oscillatoriales caused mortalities when injected into P. monodon and P. japonicus. Immersion of artemia in extracts from the tank culture also caused mortalities, with L.D50 values for the supernatant extract of 70 mg/litre for artemia cysts and 50 mg/litre for adult artemia, and LD50 values for the pellet extract of 110 mg/litre for artemia cysts and 200 mg/litre for adult artemia. Experiments with artemia suggested the blooms of Oscillatoriales produced water-soluble, heat-labile toxin/s. Mortalities may have been caused by a neurotoxin because: (a) there was a lack of histopathological evidence of damage to the digestive tracts of prawns during each episode; and (b) artemia cysts immersed in extracts of Oscillatoriales died before they developed digestive tracts. PSP toxin, anatoxin-a, homoanatoxin-a and microcystins were not detected when pond water from a diseased pond was tested. It is proposed that sub-lethal levels of toxin weakened the prawns, causing reduced feeding behaviour and an impaired immune system. As a result, prawns were prone to secondary infection by pathogenic bacteria. Because Oscillatoriales are ubiquitous in prawn farms, the findings have significant implications for the assessment of disease in the prawn farming industry.

Impacts of a Fish Kill at Lake Kutubu, Papua New Guinea

Abstract Lake Kutubu is a tropical freshwater lake that is internationally renowned for its biodiversity, 12 endemic species of fish, wetlands, and swamp forests. This study reports on a fish kill and the introduction of exotic species, and it assesses impacts on fish stocks and the artisanal fishery. The fish kill, which began in January 2013 and lasted for 6 months, was characterized by fish pathologies consistent with epizootic ulcerative syndrome. Sleeper gobies and gudgeons (i.e., Mogurnda variegata Nichols, Mogurnda furva Allen & Hoese, Mogurnda kutubuensis Allen & Hoese, and Oxyeleotris fimbriata [Weber]) had more obvious signs of disease than did Hephaestus adamsoni (Trewavas), Melanotaenia lacustris Munro, and Craterocephalus lacustris Trewavas. The event coincided with an inflow of a plume of white particulates from the northeast, where hydrocarbon companies carried out extensive horizontal drilling in 2012–2013. Six months after the event, the main species caught by fishers were Cherax papuanus Holthuis (16%), H. adamsoni (55%) and M. lacustris (28%), which is different from the mix of species found in previous surveys of 1995 and 1997. The recent fish kill, as well as socioeconomic changes, substantially reduced the fish catch and fishing effort. Small-scale fish farmers began raising the genetically improved farmed tilapia strain of tilapia (Oreochromis niloticus Linnaeus) and common carp (Cyprinus carpio Linnaeus) in earthen ponds in 2009 and introduced water hyacinth (Eichhornia crassipes [Mart.] Solms) as a food for these fish. Heavy rains in 2010–2012 released farmed fish into the lake, and in May 2015, fishers report that the fish catch is dominated by tilapia. Improved strategies are required to educate stakeholders, assess fish stocks, and protect biodiversity by reducing anthropogenic impacts.