In-vitro Antimicrobial Properties of Methanol extracts of three Medicinal Plants from Kilifi District - Kenya

Multidrug resistant microbes are a health management challenge in immunocopromised individuals. The study aimed to evaluate antimicrobial potential and toxicity of the methanol extracts of Hosludia opposita, Rhus natalensis and Combretum illairii. The plants were collected from Kilifi District and authenticated at East African Herbarium. Samples collected were extracted in methanol. Quantitative bioassay was done using disc diffusion method; minimum inhibition concentration was done using broth dilution methods. The isolates used for bioactivity testing were Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Trichophyton mentarophyte. Phytochemical screening was done using thin layer chromatograpy and cell toxicity was done using human embryonic lung cells. The H. opposita and C. illairii had terpenoids, flavonoids and anthaquinones. All the extracts were safe to the mammalian cells. Combretum illairii plant extracts had good activity against S. aureus and P. aeruginosa with inhibition zones diameters of 15.60 mm and 17.00 mm respectively. Rhus natalensis had an MIC of 6.25mg/ against both S. aureus and P. aeruginosa. The plant extracts were active against both bacteria and fungi. The result indicates that’s the plants extracts have potential for managing infections caused by the tested microbes. Isolation of compounds present and determination of their bioactivity should be done together with conservation initiatives

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

ETHNOPHARMACOLOGICAL IMPORTANCE : Infections and gastrointestinal (GIT) disorders such as diarrhoea causes many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat various diseases by rural people in Africa and Asia. Much of the work done to date on some species to validate their ethnopharmacological use was on the non-polar or intermediate polarity components. Many species are yet to be studied against relevant disease parameters using more polar extracts. AIMS : The polar components were extracted and fractionated by solvent-solvent fractionation to yield fractions of different polarities. The activity of these fractions on different parameters that could be involved in infectious and gastrointestinal track (GIT) disorders was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals. MATERIALS AND METHODS : Phenolic-enriched leaf extracts of Combretum bracteosum (Cob), Combretum padoides (Cop), Combretum vendae (Cov) and Combretum woodii (Cow) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. The extract was sequentially treated by solvent-solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures. The antioxidant activities were determined using various standard methods. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out. RESULT : Some of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21-12 μg/ml (Cop), 0.25-16 μg/ml (Cov), 0.33-9.41 μg/ml (Cow) and 4.97-85 μg/ml (Cob) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28-1.51 and 1.02-1.19 μg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 μg/ml. Even though some crude extracts had relatively low antimicrobial activity, fractions from these had high activity. Cop had the highest antibacterial activity with MICs ranging between 19-2500 μg/ml,followed by Cov with MICs ranging between 39-625 μg/ml. Cop also had the highest antifungal activity with MICs between 19-625 μg/ml. The MIC for Cow and Cov ranged from 19 to 1250 μg/ml. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentrations of hydrolysable tannin (gallotannin). A good correlation (R2= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity. CONCLUSION : The results obtained in this study provided a scientific basis for the use of leaf extracts from these plant species to treatinfectious and GIT disorders. In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity.South African Medical Research Council and the National Research Foundation (NRF), South Africa.http://www.elsevier.com/locate/jephb201

The effectiveness of mathematics teaching: a cross-national investigation in primary schools in England and China

This study focuses on the effectiveness of mathematics teaching to children aged 9-10 years, applies a mixture of six methods to classroom-level data collected in England and China, correlates observable teacher behaviours with pupil mathematics performance and collects multiple perceptions that indirectly connect with the differences of teaching and learning cross-nationally. It has been found in the study that 9-to 10-year-olds (n = 343) from China outscored their English peers (n = 236) at the same age by over 20 per cent in each of two mathematics tests derived from TIMSS 2003. Structured analysis of lesson videos has revealed that Chinese mathematics teachers scored much higher than their English colleagues on an internationally validated observation instrument which focused on the quality of six dimensions of teacher behaviours. Furthermore, the quantity of teacher behaviours was also measured and the subsequent correlational analysis on pooled data indicated a positive effect of whole-class interactive teaching (r = 0.97, p < 0.01) and pupil time on task (r = 0.95, p < 0.01) and a negative impact of whole-class lecture (r = -0.91, p < 0.01), individual/group work (r=-0.81, p < 0.05) and classroom management (r = -0.77, p < 0.05) on pupils’ mathematics performance cross-nationally. Qualitative findings are connected with quantitative results to explain how teachers think, how this relates to the way they teach and how the differences of teaching result in the performance gap cross-nationally. The study replicated previous TER findings from the West across two geographically and culturally different countries, suggested possible directions for future enquiries, and recommended potential ways for practice and policy innovations