The presence of antibacterial compounds in Anthocleista grandiflora (Loganiaceae)

In response to an unpublished report that Anthocleista grandiflora extracts had antimicrobial activity, leaves were dried, extracted and fractionated by a mild liquid/liquid extraction process into six fractions. Activity of components separated by thin layer chromatography was tested by bioautography using Staphylococcus aureus. Pseudomonas aeruginosa and Bacillus subtilis as test organisms. Growth of all three organisms were inhibited by compounds in the chloroform and carbon tetrachloride soluble fractions. One or two compounds had a high degree of inhibition. Up to eight other compounds with a lower level of inhibition were also separated. There was little or no activity in the highly polar (water) or non-polar (hexane) fractions

THE USE OF PLANTS TO PROTECT PLANTS AND FOOD AGAINST FUNGAL PATHOGENS: A REVIEW

Background: Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal diseases, farmers have used fungicides to manage the damage of plant pathogenic fungi. Drawbacks such as development of resistance and environmental toxicity associated with these chemicals have motivated researchers and cultivators to investigate other possibilities. Materials and Methods: Several databases were accessed to determine work done on protecting plants against plant fungal pathogens with plant extracts using search terms “plant fungal pathogen”, “plant extracts” and “phytopathogens”. Proposals are made on the best extractants and bioassay techniques to be used. Results: In addition to chemical fungicides, biological agents have been used to deal with plant fungal diseases. There are many examples where plant extracts or plant derived compounds have been used as commercial deterrents of fungi on a large scale in agricultural and horticultural setups. One advantage of this approach is that plant extracts usually contain more than one antifungal compound. Consequently the development of resistance of pathogens may be lower if the different compounds affect a different metabolic process. Plants cultivated using plants extracts may also be marketed as organically produced. Many papers have been published on effective antimicrobial compounds present in plant extracts focusing on applications in human health. More research is required to develop suitable, sustainable, effective, cheaper botanical products that can be used to help overcome the scourge of plant fungal diseases. Conclusions: Scientists who have worked only on using plants to control human and animal fungal pathogens should consider the advantages of focusing on plant fungal pathogens. This approach could not only potentially increase food security for rural farmers, lead to commercial rewards, but it is also much easier to test the efficacy in greenhouse or field experiments. Even if extracts are toxic it may still be useful in the floriculture industry

Nitric oxide inhibitory activity of Strychnos spinosa (loganiaceae) leaf extracts and fractions

Background: The study was aimed at determining the anti-inflammatory activity of fractions and extracts obtained from Strychnos spinosa leaves on a mediator of inflammation nitric oxide (NO).Materials and Methods: Leaves were extracted with acetone and separated into fractions with different polarities by solventsolvent fractionation. The Griess assay was used to determine the nitric oxide (NO) inhibitory activity. Cellular toxicity was determined by "using the MTT reduction assay".Results: With the exception of the ethyl acetate fraction which had an IC50 >750 μg/mL, all extracts and fractions had significant nitric oxide-inhibitory activity. The most active being the water fraction, chloroform fraction and the dichloromethane/methanol extracts with IC50 values of 88.43 μg/mL, 96.72 μg/mL and 115.62 μg/mL, respectively. The extracts and fractions had low cytotoxicity on macrophage U937 cell lines.Conclusion: Extracts and fractions of Strychnos spinosa leaves may be promising sources of natural anti-inflammatory agents. Findings obtained from this study showed that Strychnos spinosa leaves possess promising anti-inflammatory action and could be used in the treatment of inflammation-related conditions.Keywords: Strychnos spinosa, inflammation, nitric oxide, cytotoxicit

The variation in antimicrobial and antioxidant activities of acetone leaf extracts of 12 Moringa oleifera (Moringaceae) trees enables the selection of trees with additional uses

AbstractBackgroundThe aim of this study was to evaluate the variation in antimicrobial and antioxidant activities of the leaf acetone extracts of 12 Moringa oleifera trees harvested in order to select the best material for clonal propagation.MethodsA two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against a panel of fungal (Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans) and bacterial (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa) species. The radical scavenging capacity was determined using 2,2 diphenyl-1-picryhydrazyl (DPPH).ResultsThere was a large variation in antimicrobial activities with MICs between 0.04 and 2.50mg/ml against bacteria and from 0.16 to >2.50mg/ml against fungi. For samples harvested in winter: trees L3 and LP2 had significant activity against E. faecalis (MIC 0.08mg/ml) and E. coli (MIC 0.04mg/ml). Trees L5, LP1 and LP6 had weak activity against E. coli (MICs 1.25 and 2.50mg/ml), S. aureus (MIC 1.25mg/ml), and E. faecalis (MIC 2.50mg/ml), while other samples had moderate activity against the four bacteria (MICs 0.16–0.63mg/ml). From samples collected in summer: L5 (MIC 0.08mg/ml), L6 (MIC 0.08mg/ml after 1h incubation), LP1 (MICs 0.08mg/ml), LP2 (MICs 0.08mg/ml after 1h incubation), LP4 (0.08mg/ml) and LP5 (MICs 0.04 and 0.08mg/ml) had significant activity against E. faecalis (L5, L6, LP1, LP2, LP4, and LP5), S. aureus (LP1, and LP5), and E. coli (LP2, and LP5), respectively. Other extracts had weak antibacterial activity with MICs ranging from 0.16 to 0.63mg/ml. Most of the samples harvested in winter had moderate antifungal activity: L1, L2, L3, L4, L5, L6, LP1, LP2, and LP3 had moderate activity against C. albicans (ATCC strains) with MIC of 0.63mg/ml in all cases while L2, L3 and L4 as well as L6, LP1, LP2, LP3, LP5 and LP6 against A. fumigatus (MICs 0.63mg/ml) and C. neoformans (MICs 0.63mg/ml), respectively. Apart from L1 (MIC 0.31mg/ml), L2, L3 and LP6 (MICs 0.63mg/ml in all cases) with moderate activity, all the samples collected during summer had weak activity against A. fumigatus (MICs 1.25–2.50mg/ml). All the extracts had a low radical scavenging activity with the IC50 values ranging from 34.72 to 109.62μg/ml, compared to the reference standard l-ascorbic acid (IC50 2.41μg/ml). This may be related to the extractant used.ConclusionThe large variation in antimicrobial activity and antioxidant activities of 24 acetone leaf extracts of 12 M. oleifera trees may lead to the selection of clonal material to serve as a source of propagation materials. Successful propagation and growth of tree LP with very good activity against E. coli and a high total activity could provide an additional use of this valuable plant species to rural people

Novel Mycobacterium avium species isolated from Black Wildebeest (Connochaetes gnou) in 5 South Africa

A study was undertaken to isolate and characterize Mycobacterium species from black wildebeest suspected of being infected with tuberculosis in South Africa. This led to the discovery of a new Mycobacterium avium species, provisionally referred to as the Gnou isolate from black wildebeest (Connochaetus gnou). Sixteen samples from nine black wildebeest were processed for Mycobacterium isolation. Following decontamination; samples were incubated in an ordinary incubator at 37°C on Löwenstein-Jensen slants and in liquid medium tubes using the BACTECTM MGITTM 960 system respectively. Identification of the isolate was done by standard biochemical tests and using the line probe assay from the GenoType® CM/AS kit (Hain Life Science GmbH, Nehren, Germany). The DNA extract was also analyzed using gene sequencing. Partial gene sequencing and analysis of 16S rRNA gene, 16S-23S rRNA (ITS), rpoB and hsp65 and phylogenetic analyses by searching GenBank using the BLAST algorithm were conducted. Phylogenetic trees were constructed using four methods, namely Bayesian inference, maximum likelihood, maximum parsimony and neighbor-joining methods. The isolate was identified as Mycobacterium intracellulare using the GenoType® CM/AS kit and as Mycobacterium avium complex (MAC) by gene sequencing. The gene sequence targeting all the genes, ITS, 16S rRNA, rpoB and hsp65 and phylogenetic analyses indicated that this isolate presented a nucleotide sequence different from all currently published sequences, and its position was far enough from other MAC species to suggest that it might be a new species.NRF; Bilateral research collaboration between South Africa and the Japan Society for the Promotion of Science (JSPS); UnisaAgriculture and  Animal Healt

Application of direct bioautography and SPME-GC-MS for the study of antibacterial chamomile ingredients

The isolation and characterization of antibacterial chamomile components were performed by the use of direct bioautography and solid phase microextraction (SPME)-GC-MS. Four ingredients, active against Vibrio fischeri, were identified as the polyacetylene geometric isomers cis- and trans-spiroethers, the coumarin related herniarin, and the sesquiterpene alcohol (-)-alpha-bisabolol