An overview of the biological activities and essential-oil composition of three South African Salvia species

Essential oils produced by aromatic plants have been used to treat various ailments such as malaria and microbial infections for many years. In South Africa, there are 26 indigenous Salvia species and most of them have been reported for use in the treatment of malaria, tumors, microbial infections. Among those of ethnomedicinal value are S. repens, S. stenophylla and S. runcinata which form a species complex. The current study aimed to profile the essential-oil composition and investigate the bioactivities related to the traditional uses. The essential oil of the three species (S. repens, S. stenophylla and S. runcinata) was isolated by hydrodistillation and the antimalarial, anti-inflammatory, antimicrobial activities and the toxicity profiles were evaluated using the [3H]hypoxanthine incorporation assay, 5-lipoxygenase assay, minimum inhibitory concentration assay and the MTT colorimetric method, respectively. The essential-oil composition was analyzed using the GC-MS and GC-FID methods. The oil of S. repens was dominated by 1,8-cineole (12.8%), p-cymene (9.5%) and limonene (9.4%), while α-bisabolol (65.0%) and β-caryophyllene (10.5%) were the major constituents of S. runcinata. α-Bisabolol (26.1%) and δ-3-carene (22.6%) were the dominant constituents of S. stenophylla. The anti-inflammatory activity of the three oils (IC50 value) ranged from 22.8 to 49 µg/mL with S. runcinata exhibiting the best activity. The three oils also inhibited the growth of Plasmodium falciparum FCR-3 strain with IC50 values ranging from 1.2-4.1 µg/mL with the oil of S. runcinata showing the best antimalarial activity. The essential oils showed poor antimicrobial activity (MIC value > 32 mg/mL) and were also toxic to normal kidney epithelial cells (IC50 value < 6.6 µg/mL). The essential oils displayed some degree of activity, however, the toxicity exhibited against kidney cells indicated that the oils should be used with caution

The In Vitro

The antimicrobial activity of Lavandula angustifolia essential oil was assessed in combination with 45 other oils to establish possible interactive properties. The composition of the selected essential oils was confirmed using GC-MS with a flame ionization detector. The microdilution minimum inhibitory concentration (MIC) assay was undertaken, whereby the fractional inhibitory concentration (ΣFIC) was calculated for the oil combinations. When lavender oil was assayed in 1 : 1 ratios with other oils, synergistic (26.7%), additive (48.9%), non-interactive (23.7%), and antagonistic (0.7%) interactions were observed. When investigating different ratios of the two oils in combination, the most favourable interactions were when L. angustifolia was combined with Cinnamomum zeylanicum or with Citrus sinensis, against C. albicans and S. aureus, respectively. In 1 : 1 ratios, 75.6% of the essential oils investigated showed either synergistic or additive results, lending in vitro credibility to the use of essential oil blends in aroma-therapeutic practices. Within the field of aromatherapy, essential oils are commonly employed in mixtures for the treatment of infectious diseases; however, very little evidence exists to support the use in combination. This study lends some credence to the concomitant use of essential oils blended with lavender

Anti-seizure activity of African medicinal plants: The identification of bioactive alkaloids from the stem bark of Rauvolfia caffra using an in vivo zebrafish model

Epilepsy is one of the major chronic diseases that does not have a cure to date. Adverse drug reactions have been reported from the use of available anti-epileptic drugs (AEDs) which are also effective in only two-thirds of the patients. Accordingly, the identification of scaffolds with promising anti-seizure activity remains an important first step towards the development of new anti-epileptic therapies, with improved efficacy and reduced adverse effects. Herbal medicines are widely used in developing countries, including in the treatment of epilepsy but with little scientific evidence to validate this use. In the search for new epilepsy treatment options, the zebrafish has emerged as a chemoconvulsant-based model for epilepsy, mainly because of the many advantages that zebrafish larvae offer making them highly suitable for high-throughput drug screening

Evaluation of the wound healing properties of South African medicinal plants using zebrafish and in vitro bioassays

Ethnopharmacological relevance In South Africa, medicinal plants have a history of traditional use, with many species used for treating wounds. The scientific basis of such uses remains largely unexplored. Aim of the study To screen South African plants used ethnomedicinally for wound healing based on their pro-angiogenic and wound healing activity, using transgenic zebrafish larvae and cell culture assays

INDIGO-DataCloud: A data and computing platform to facilitate seamless access to e-infrastructures

This paper describes the achievements of the H2020 project INDIGO-DataCloud. The project has provided e-infrastructures with tools, applications and cloud framework enhancements to manage the demanding requirements of scientific communities, either locally or through enhanced interfaces. The middleware developed allows to federate hybrid resources, to easily write, port and run scientific applications to the cloud. In particular, we have extended existing PaaS (Platform as a Service) solutions, allowing public and private e-infrastructures, including those provided by EGI, EUDAT, and Helix Nebula, to integrate their existing services and make them available through AAI services compliant with GEANT interfederation policies, thus guaranteeing transparency and trust in the provisioning of such services. Our middleware facilitates the execution of applications using containers on Cloud and Grid based infrastructures, as well as on HPC clusters. Our developments are freely downloadable as open source components, and are already being integrated into many scientific applications

A chemotaxonomic study of phenolic leaf compounds in the genus Aloe

Ph.D.This chemotaxonomic study of the leaf phenolic compounds in the genus Aloe is introduced by presenting a review of Aloe taxonomy, followed by a second review of all known leaf compounds. A chemotaxonomic study of virtually all species of Aloe has made it possible to define several chemical groups in the genus of 420 species. The chemical groups are either identified by a single marker compound or by a series of unique compounds. The following groups have been identified and the chemotaxonomic value of each group is discussed: • An aloin / aloinoside / microdontin group, comprising 36 species, mostly of tropical origin. This group includes species not previously associated with one another. • An 8-O-methyl-7-hydroxyaloin group. Here the co-occurrence of some leaf compounds suggests that 8-O-methyl-7-hydroxyaloin is not homologous in the 18 species where it has been detected. Evidence is presented illustrating that 8-O-methyl-7-hydroxyaloin is an 'hybrid compound' which forms when two chemically divergent species (aloin- and homonataloincontaining parents) are crossed. • An aloenin group, comprising 16 species which are believed to be a monophyletic group. • A microstigmin group, indicating a taxonomic alliance between series Purpurascentes and series Anguialoe, with A. broomii an intermediate between the two. • A 10-hydroxyaloin B group, represented by series Asperifoliae and related species, which appears to be a drought adapted Glade of tropical origin. • A homonataloside group, comprising 14 species, suggesting a biochemical link between the aloes of north Africa and southern Africa. • An aloeresin E and F group, indicating a taxonomic alignment between series Mitriformes and five anomalous species. • A plicataloside group, with its single marker compound indicating a taxonomic relationship between 20 mostly tropical east African species. • A flavone group. The large number of species with flavones (sections Leptoaloe Graminialoe, Lomatophyllum and series Macrifoliae) are suggested to be basal in the genus. • A flavanone group. A few anomalous species produce flavanones but it is unlikely that they form a monophyletic group. A concluding review of leaf exudate compounds (not mentioned above) is also presented which includes hypotheses on the chemotaxonomic value of chromones and anthrones in general. A chemical re-arrangement of species is presented in the form of a new 'chemical classification' for Aloe based on chemotypes. These chemical groups have lead to an improved understanding of natural relationships in a genus where no satisfactory infrageneric classification has hitherto been available

In vitro drug absorption enhancement effects of Aloe vera and Aloe ferox

The effect of whole leaf and gel materials from two aloe species (Aloe vera and A. ferox) was compared with that of the precipitated polysaccharides from these aloe materials on the transepithelial electrical resistance (TEER) as well as transport of a model compound (atenolol) in the apical-to-basolateral direction across rat intestinal tissue. All the aloe leaf materials and precipitated polysaccharides had a statistically significant effect of lowering the TEER (P < 0.05) compared to the control group, which indicates their ability to open tight junctions between adjacent epithelial cells. In contrast to the expectation from the TEER results, only the precipitated polysaccharides from dehydrated A. vera gel (Daltonmax 700®) had a statistically significant effect of enhancing the transport of atenolol (P < 0.05). These in vitro results therefore indicate that A. vera gel polysaccharides have potential as drug absorption enhancing agents in novel pharmaceutical drug delivery systems.The National Research Foundation (South Africa) and Tshwane University of Technology (South Africa) are acknowledged for financial support