Exploring the phytochemical variation of non-volatile metabolites within three South African Salvia species using UPLC-MS fingerprinting and chemometric analysis.

The South African Salvia species, Salvia africana-lutea, S. lanceolata and S. chamelaeagnea, are widely used to treat fever and inflammation associated with skin and lung infections. The aim of this study was to explore the non-volatile secondary metabolites and the phytochemical variation within these lesser known species, to support product development and commercialisation. Chemical profiles of the methanol extracts of 81 wild-harvested samples were obtained using ultra performance-quadrupole-Time-of-Flight-mass spectrometry (UPLC-qToF-MS). Forty-one compounds, including caffeic acid, rosmarinic acid, carnosol, carnosic acid and ursolic acid, were detected and confirmed across the three species. Nineteen compounds were tentatively identified of which 14 have not been reported in these species. Principal component analysis revealed distinct clusters corresponding to the three species, confirming chemical differences. Marker compounds for each species were revealed using orthogonal projection to latent structures-discriminant analysis. Further chemometric analysis reflected a degree of intraspecies variation, although the chemistry within populations was mostly conserved. Potential chemotypes for each species were identified through unique compounds associated with each group. The concentrations of medicinally important metabolites, namely, rosmarinic acid, carnosol, carnosic acid and ursolic acid, were determined, using validated UPLC-PDA methods. Ursolic acid was present at levels up to 38.2 mg/g, confirming that these species are a rich source of this compound. No similar studies combining liquid chromatography with chemometric analysis, and utilising a large sample size from various habitats, have been reported for these three Salvia species. The results will guide selection of cultivars with the best attributes for the intended therapeutic application, thereby protecting wild populations from over-exploitation.

A chemometric assessment of essential oil variation of three Salvia species indigenous to South Africa.

Indigenous Salvia species from southern Africa are popular traditional medicines for the treatment of a variety of conditions. They produce fragrant volatiles that can be isolated as essential oils. Some of these volatile organic compounds may play a role in the biological activities of the extracts. Three indigenous Salvia species, Salvia africana-lutea, S. lanceolata and S. chamelaeagnea, were selected for this study as they are commonly used in traditional medicine in South Africa, and the essential oils from these species have potential for commercialisation. Although some studies have described the essential oil compositions and some biological activities, only single composite samples were used. The aim of this study was to investigate the intra- and interspecies variation of the essential oils, sampled over a wide geographical area and using a representative sample size, to encourage commercialisation of the essential oil. Essential oils were isolated from individual plants using conventional hydrodistillation of the aerial parts, harvested from several localities. Gas chromatography coupled simultaneously to mass spectrometry/flame ionisation detection (GC-MS/FID) was used to identify and quantify the volatile constituents. The essential oils of S. africana-lutea consisted mainly of terpinene-4-ol + ß-caryophyllene (1.4 - 29.0%), T-cadinol (1.2 - 20.0%), α-eudesmol (trace - 23.0%) and ß-eudesmol (trace - 26.0%), those of S. lanceolata comprised mainly terpinene-4-ol + ß-caryophyllene (4.3 - 31.0%), α-humulene (2.3 - 15.0%), bicyclogermacrene (trace - 37.0%) and spathulenol (trace - 25.0%), while the essential oils of S. chamelaeagnea were characterised by δ-3-carene (trace - 18.0%), limonene (1.6 - 36.0%), viridiflorol (9.8 - 61.0%) and 1,8-cineole (not detected - 11.0%). The compounds identified in the essential oils of the three selected Salvia species have been identified in other Salvia essential oils. To add to the novelty of this study, the superior resolving power of two-dimensional gas chromatography was demonstrated through analysis of selected essential oils. Many additional compounds were identified, and previously co-eluting compounds were clearly separated. Chemometric modelling of the GC-MS data using SIMCA P+ 14 software allowed distinct clustering patterns to be discerned. The unsupervised principal component analysis model revealed separate clusters for the three species, confirming substantial chemical differences between their essential oils. Quantitative, rather than qualitative differences were evident when individual essential oil samples representing the same species, were compared. For each species, two chemically distinct groups were observed and unique marker compounds could be identified. This study has contributed detailed information on the major and minor volatile compounds present in the essential oils of the three Salvia species investigated.

Antimicrobial activity and chemometric modelling of South African propolis.

AIMS: This study reports on the inhibitory and bactericidal properties of 39 South African (SA) propolis samples and three propolis samples from Brazil. METHODS AND RESULTS: Ethanolic extracts of propolis (EEP) were prepared and their antimicrobial activities tested using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Some samples displayed substantial antimicrobial activity with MIC and MBC values as low as 6 µg ml(-1) against Staphylococcus aureus. The correlation between liquid chromatography-mass spectrometry (LC-MS) chemical data and the antimicrobial activity of propolis extracts was investigated using multivariate data analysis tools. Orthogonal projections to latent structures (OPLS) models were created for the two Gram-positive bacteria (Enterococcus faecalis and S. aureus) and Candida albicans. Using the S-plot function, it was possible to identify the bioactive constituents in propolis as chrysin, pinocembrin, galangin and pinobanksin-3-O-acetate. CONCLUSION: The SA propolis samples tested displayed noteworthy antimicrobial activity, favourably comparable to that of the Brazilian comparator and 'gold standard'. The observed antimicrobial activity of SA propolis can possibly be attributed to its flavonoid content. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on the good antimicrobial activity observed for SA propolis, this natural resource shows promise and should be considered for development which may contribute to growing the bio-economy in the region.

The in vitro antibiofilm activity of selected culinary herbs and medicinal plants against Listeria monocytogenes.

AIMS: The antibiofilm activity of extracts obtained from selected herbs, spices, beverages and commercially important medicinal plants was investigated on Listeria monocytogenes. METHODS AND RESULTS: The growth and development of the biofilm was assessed using the crystal violet (CV) assay. The respiratory activity was assessed using the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The majority of extracts tested prevented cell adhesion to the polyvinyl chloride (PVC) surface. Seven of the 15 extracts reduced biofilm adhesion of both the clinical and the type strains by at least 50%. In contrast, inhibition of a preformed biofilm was more difficult to achieve, with only three extracts (Rosmarinus officinalis, Mentha piperita and Melaleuca alternifolia) inhibiting the growth of both strains by at least 50%. CONCLUSIONS: Although most extracts were able to reduce initial cell attachment, inhibition of growth in a preformed biofilm was more difficult to achieve. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability to reduce biofilm biomass as shown by several plant extracts warrants further investigation to explore the use of natural products in antibiofilm adhesion.

HIV and breastfeeding: individual and policy dilemmas.

PIP: In a public meeting held in February 1996 by the Women and AIDS Support Network (WASN) with the Ministry of Health and Child Welfare representation, participants argued that women should be given full information on HIV, breast-feeding and possible alternatives. To this effect, WASN and the South African AIDS Training organized four focus groups of 15-20 participants each and 2 further focus groups of 8-12 participants each. Participants were given printed summaries of existing HIV and breast-feeding data together with the official policies and were asked to relate personal experiences and discuss the issues involved. Overall, results showed that all participants preferred breast-feeding than bottle feeding, believing it to be biologically and psychologically healthier for their infants. They were also critical of the existing information on breast-feeding and HIV for women and health providers, which they saw as inadequate. Moreover, in several southern African countries, women are questioning the universal breast-feeding recommendation on the grounds that it fails to provide sufficient information for individual women to assess their own situation and offers no alternatives to HIV-positive mothers in developing countries. Thus, health policy makers and medical practitioners are called to make all women, full partners in decision-making around breast-feeding and vertical HIV transmission.^ieng