Differentiation of Tarchonanthus camphoratus L. and Tarchonanthus parvicapitulatus P.P.J. Herman (Asteraceae) using electron microscopy, and comparison of their biological activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Tarchonanthus camphoratus L. complex has numerous medicinal uses amongst the sub-Saharan African populace, including treatment for bronchospasm. This study focused on providing scientific rationale for the traditional use of the extracts of T. camphoratus and T. parvicapitulatus. T. camphoratus L. complex has been published under diverse names by various taxonomists. Tarchonanthus parvicapitulatus was one of the newly described taxa, leaving Tarchonanthus camphoratus L. sens. strict. as a homogenous taxon. However, some of the morphological characters used tend to overlap, making it difficult to identify the different taxa. AIMS: The aim of this study was to evaluate the bronchodilatory, antioxidant and toxicological properties of the leaves of T. camphoratus L. and T. parvicapitulatus. This study also aimed to use scanning electron microscopy (SEM) to assess the differences between T. camphoratus L. and T. parvicapitulatus. MATERIALS AND METHODS: Thin layer chromatography (TLC) with vanillin as visualizing agent was used to qualitatively compare the phytoconstituents of the plant acetone extracts. The free radical scavenging antioxidant qualitative assay was done by spraying TLC plates with DPPH free radical. The bronchodilatory effects of the aqueous extracts were assessed using pre-contracted guinea pig trachea. The effects of the extracts of T. camphoratus L. and T. parvicapitulatus on superoxide and ATP production was also investigated on isolated human neutrophils. A micromorphology study was done using scanning electron microscopy to study the leaves. RESULTS: Different compounds were visualized on the TLC plates with more than 40 compounds of intermediate polarity. The TLC plates sprayed with DPPH revealed the presence of 20 and 23 antioxidant compounds for T. camphoratus and T. parvicapitulatus respectively. Upon pre-contraction of the tracheal smooth muscles, the aqueous extracts of T. parvicapitulatus significantly relaxed the trachea while the relaxation observed for T. camphoratus was not significant. All the tested concentrations had a dose dependent inhibitory effect on superoxide production. The crude extract of T. parvicapitulatus at the highest concentration (10 mg/ml) significantly decreased ATP production while a non-significant increase in ATP production was observed for T. camphoratus at the highest concentration (10 mg/ml) when compared with the control. The micromorphology study was useful in revealing the presence of trichomes on the upper leaf surface of the studied taxa. CONCLUSIONS: The results obtained from this study showed that the studied plant extracts had bronchodilatory effects on contracted guinea pig trachea and could also inhibit the production of free radicals including superoxide anions. To the best of our knowledge, this is the first report on the bronchodilatory activity of T. camphoratus and T. parvicapitulatus. The micromorphological studies were useful in distinguishing between the two species, confirming that T. camphoratus L. and T. parvicapitulatus are different taxa. This study provides evidence to support the traditional use of T. camphoratus and T. parvicapitulatus in managing bronchospasm.

Pittosporum viridiflorum Sims (Pittosporaceae): A review on a useful medicinal plant native to South Africa and tropical Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Pittosporum viridiflorum Sims, a Pittosporaceae species, is used extensively in African traditional medicine (ATM) by various tribes. This review is an appraisal of the information concerning the description, distribution, conservation status, traditional uses, phytochemistry, pharmacology and toxicology of this species with the aim of reconciling it with its traditional use. MATERIALS AND METHODS: A wide-ranging literature search was conducted using database platforms such as Scopus, Google Scholar, Web of Science, ScienceDirect, PubMed and books including local reports and thesis submissions. RESULTS: Ten categories to which P. viridiflorum finds use in traditional medicine (TM) were found, and they include well-being, wounds, treatment of veterinary ailments, gastrointestinal and sexually transmitted diseases, kidney, circulatory and inflammatory disorders, as well as diseases such as cancer, tuberculosis, and malaria. Pharmacological tests conducted include those investigating antimicrobial, antidiarrhoeal, antimalarial, anticancer, anti-inflammatory, antioxidant and acaricidal properties. Promising activity was shown in a number of assays. Toxicological effects have also been reported from this species. However, it is recommended to conduct a detailed toxicological study, including genotoxicity, as this has not yet been evaluated. Compound(s) with antimalarial, anticancer and acaricidal properties have been isolated from P. viridiflorum. CONCLUSIONS: The collective pharmacological and phytochemical properties of P. viridiflorum gives credence to the use of this plant species against various diseases in ATM, thus steering significant interest towards in vivo studies and further research.

Ethnobotany, phytochemistry, toxicology and pharmacological properties of Terminalia sericea Burch. ex DC. (Combretaceae) - A review.

ETHNOPHARMACOLOGICAL REFERENCE: The use of medicinal plants in the treatment of infections is ancient. A wide variety of ethnotherapeutic properties and pharmacological actions has been attributed to Terminalia sericea. Studies by various groups of investigators reveal that it is a multipurpose medicinal plant used mostly in the treatment of diarrhoea, sexually transmitted infections, skin rashes, tuberculosis and other infections. The current paper is aimed at providing an overview of the ethnomedicinal uses, toxicology, pharmacology and the phytochemistry of Terminalia sericea. MATERIALS AND METHODS: Information was retrieved using various search engines, including Pubmed, Science Direct, Google Scholar, Scielo, SciFinder and Scopus. The key words used included Terminalia sericea, secondary metabolites, phytochemistry, biological activity, pharmacology, ethnobotanical survey, medicinal uses, safety, toxicology and other related words. RESULTS: Terminalia sericea is an important medicinal plant which possesses anti-HIV, anti-fungal, anti-bacterial, anticancer, lipolytic, wound healing, antiparasitic, anti-inflammatory and anti-oxidant activity, as the most valuable biological activities, thus lending pharmacological support to the plant's folkloric uses in indigenous medicine. Toxicologically, the extracts and isolated compounds from the plant species may have mild toxic effects. Phytochemically, the plant species possesses valuable compounds including triterpenes, alkaloids and flavonoids which may well contribute to its biological activity. CONCLUSIONS: Terminalia sericea contains secondary metabolites which are valuable in the treatment of a variety of human infections, including community acquired infections which may be prevalent in developing countries. The degree of toxicity reported in various extracts warrants further exploration of the cytotoxicity of the plant species, both against normal human cell lines and in vivo. Moreover, the acetylcholinesterase inhibitory and anti-inflammatory effects also need to be further investigated as there are only a few reports from the literature on these aspects. There is also a need to further understand the mode of action of the extracts against various enzymes relating to inflammation. Antioxidant activity of the plant extracts against various forms of free radicals needs to be investigated. Although T. sericea is reported to be used for ethnoveterinary infections, there are no scientific reports on the anti-parasitic activity of the plant species against common animal parasites.

The value of plant extracts with antioxidant activity in attenuating coccidiosis in broiler chickens.

Coccidiosis remains one of the most important diseases in the poultry industry and results in the annual loss of millions of US dollars by the poultry industry. In South Africa and other developing countries where a large percentage of the population is unemployed, cheap food production is necessary. If the control of the coccidian parasite could be made more economical, these savings could be passed on to the consumer. In Europe, where the economics are different, people are becoming more aware of the potential dangers of using antimicrobials in producing animal protein. A solution to both these problems could be the use of plant products that function by mechanisms other than those of chemotherapeutics, with the additional advantage of a natural origin. Antioxidant compounds could hold promise for the control of Eimeria infections due to the association of coccidial infection with lipid peroxidation of the intestinal mucosa. Four plant extracts with antioxidant activity were screened for their anticoccidial activity in vivo with toltrazuril as the positive control. Combretum woodii (160 mg/kg) proved to be extremely toxic to the birds, while treatment with Tulbaghia violacea (35 g/kg), Vitis vinifera (75 mg/kg) and Artemisia afra (150 mg/kg) resulted in feed conversion ratios similar to toltrazuril, and higher than the untreated control. T. violacea also significantly decreased the oocyst production in the birds. From this study we conclude that antioxidant-rich plant extracts have potential benefits in treating coccidial infections. The promising results obtained with T. violacea justify further studies on the potential value of the plant as a therapeutic or prophylactic anticoccidial agent.

In vitro anthelmintic, antibacterial and cytotoxic effects of extracts from plants used in South African ethnoveterinary medicine.

Many plants are used for ethnoveterinary purposes in South Africa, particularly in rural areas. Extracts of 17 plant species employed to treat infectious diseases were prepared using three solvents and the antibacterial activity of the extracts was determined against two Gram-positive and two Gram-negative bacteria. Anthelmintic activity was evaluated against the free-living nematode Caenorhabditis elegans and toxicity was determined using the brine shrimp larval mortality test. Most of the plant extracts demonstrated antibacterial activity, with the best minimum inhibitory concentration (MIC) being 0.1 mg mL(-1). More than a third of the extracts displayed anthelmintic activity. Toxic effects against brine shrimp larvae were shown by 30% of extracts, with the lowest LC(50) recorded as 0.6 mg mL(-1). The promising biological activity displayed by a number of plant extracts supports the ethnoveterinary use of these plants but in vivo tests are required to ascertain fully their medicinal properties and potential toxicity.