The status of bark in South African traditional health care

Bark products constitute nearly one third of plant material used in South African traditional medicine. Since the large majority of South Africans make use of traditional health care, bark is fundamental to the traditional pharmacopoeia. In this review we consider the status of bark resources, as reflected by the literature, and highlight the need for multi-disciplinary research to address the lack of available information on plant species used for their bark. The supply of bark to the medicinal plant trade has been rendered non-sustainable, due to increased user populations and reduced indigenous vegetation. Whilst conservation of the South African flora is paramount, natural resources cannot meet the current, nor foreseeable, demand for bark. Alternatives such as tree propagation and cultivation, strategic management and plant part substitution are discussed. Effective implementation of these action plans is reliant on the dissemination of existing and new knowledge. The prevailing scenario of a non-sustainable bark supply has impacted negatively on the quality of bark products available to the consumer, as problems of incorrect identification and purposeful adulteration arise. To facilitate monitoring and standardisation, phytochemical references should be established for bark authentication, and used in conjunction with morphological and anatomical characters for identification in the case of unknown specimens. The importance of bark in South African traditional health care warrants attention from all research sectors to conserve the country’s rich floral heritage, and the integrity of traditional health care

Bark medicines used in traditional healthcare in KwaZulu-Natal, South Africa: An inventory

Bark is an important source of medicine in South African traditional healthcare but is poorly documented. From thorough surveys of the popular ethnobotanical literature, and other less widely available sources, 174 species (spanning 108 genera and 50 families) used for their bark in KwaZulu-Natal, were inventoried. Vernacular names, morphological and phytochemical properties, usage and conservation data were captured in a database that aimed to synthesise published information of such species. Data specificity was found to be the major limiting factor in the study and resulted in uneven distribution of information in the database. Overlapping vernacular names recorded in the literature indicated that it may be unreliable in local plant identifications. Most (43%) bark medicines were documented for the treatment of internal ailments. Sixteen percent of species were classed in threatened conservation categories, but conservation and management data were limited or absent from a further 62%. There is a need for research and specialist publications to address the gaps in existing knowledge of medicinal bark species and their management to conserve the South African flora

Photosynthetic pathway variation among C4 grasses along a precipitation gradient in Argentina

Aim Based on the biochemical and physiological attributes of C4 grasses, and on the close association between decarboxylation pathways and the taxa in which they evolved, the hypotheses tested were: (1) that C4 grasses would become progressively more abundant as precipitation decreased, with grasses of the NADP-me subtype more abundant in wetter sites and those of the NAD-me subtype more common in arid regions; and (2) that the distribution of grass subfamilies would also be correlated with annual precipitation. Location The study was conducted along a precipitation gradient in central Argentina, from the eastern Pampas (>1000 mm year)1 ) to the western deserts and semi-deserts near the Andes (<100 mm year)1 ). Methods Percentage of species and relative cover of C3 and C4 grasses (including C4 subtypes) in local floras from 15 lowland sites of central Argentina were obtained from our own unpublished data and from recently published floristic surveys. Pearson correlation coefficients were obtained between grass distribution parameters and the available climatic data. Results The percentage of C4 grasses increased towards the arid extreme and showed a strong negative correlation with annual rainfall (r = )0.74, P < 0.01). Within the C4 subtypes, the NADP-me species showed a higher proportional representation at the wetter extreme, whereas the representation of NAD-me species increased towards the more arid extreme. The relationship of PEP-ck species with climatic parameters in central Argentina was less evident. The distributions of the Panicoideae and Chloridoideae subfamilies along the precipitation gradient were diametrically opposed, with the Panicoideae positively (r = 0.86, P < 0.001) and the Chloridoideae negatively (r = )0.87, P < 0.001) correlated with annual precipitation. Main conclusions Our data are consistent with the broad observation that C4 grasses tend to dominate in areas where the wet season falls in the warmer summer months. In agreement with previously reported results for Africa, Asia, Australia and North America, we describe here for the first time a significant relationship between annual precipitation and the prevalence of the NADP-me and NAD-me photosynthetic pathways along climatic gradients for the Neotropics. We also report for the first time that correlations between C4 species and annual rainfall are stronger when the relative cover of grass species is considered. The association of grass subfamilies Panicoideae and Chloridoideae with rainfall is as strong as that recorded for the NADP-me and NAD-me variants, respectively, suggesting that characteristics other than decarboxylation type may be responsible for the geographic patterns described in this studyFil: Cabido, Marcelo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pons, Stella Maris. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Cantarero, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; ArgentinaFil: Lewis, Juan Pablo. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Anton, Ana Maria Ramona. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin