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A preliminary investigation into the use of RAPD to assess the genetic diversity of a threatened African tree species: Prunus africana
... Recruitment is low or sporadic (Ewusi et al., 1992). Because of deforestation at lower elevations, P. africana is confined to distinct "forest islands" that differ genetically (Barker et al., 1994), with the Madagascar population being the most distinct (Dawson et al., 2000). The tree occurs at altitudes between 1000 and 2500m in montane forests (Sunderland and Tako, 1999). ...
... The CITES management authority for Kenya objected to the continued harvest without a Detriment Study and halted the harvest at the end of 2002. Cultivation trials have been conducted, but large-scale plantations are not yet in production (Barker et al., 1994;Dawson, 1997). Mature trees are also exploited for their timber. ...
... Based on the historical annual bark volumes processed at Plantecam (1923 tons per year), they calculated that a 12-year-old stand on 820 ha with 1363 trees planted per hectare would supply enough bark for a 12-year rotation. (Barker et al., 1994) and (Dawson and Powell, 1999) showed the genetic uniqueness of each country"s populations. Even within an area, the species demonstrates differences (Cunningham et al., 2002) discusses three different varieties in Cameroon reported by harvesters. ...
... Units (PAU's) are the basis of continued wild harvest, it was apparent from CIFOR research (Cerutti et al., 2008) published before the National Management Plan of the massive gap between goals of the 1994 Forestry Policy, which required detailed forest management plans (FMPs) from logging companies and the reality: 14 years after the legislation was in place, the government had not implementing "effective minimum sustainability safeguards and that, in 2006, 68% of the timber production was still carried out as though no improved management rules were in place". The same applies to P. africana today. ...
... The range of the species has been affected by past climate change and the modeled distribution of P. africana indicates that the species is likely to be negatively affected in future, with an expected decrease in distribution by 2050 (Vinceti et al., 2013). Secondly, although pioneering work had been undertaken on chemtotypic (Martinelli et al., 1986) and genetic variation in P. africana (Barker et al., 1994), the extent of variation across different sites, the need for conserving this variation of P. africana populations remains. This genetic and chemotypic variation reflects ancient dispersal routes and evolution of P. africana in separate and vulnerable montane forest "islands" in Africa and Madagascar (Kadu et al., 2011(Kadu et al., , 2012aVinceti et al., 2013). ...
... In Cameroon, there are many parallels between policy and practice of trade in timber and in P. africana bark. As Cerutti et al. (2008) points out for timber, Cameroon "needs more than approved management plans". So does P. africana. ...
Ethnopharmacological relevance:
After almost 50 years of international trade in wild harvested medicinal bark from Africa and Madagascar, the example of Prunus africana holds several lessons for both policy and practice in the fields of forestry, conservation and rural development. Due to recent CITES restrictions on P. africana exports from Burundi, Kenya and Madagascar, coupled with the lifting of the 2007 European Union (EU) ban in 2011, Cameroon's share of the global P. africana bark trade has risen from an average of 38% between 1995 and 2004, to 72.6% (658.6 metric tons) in 2012. Cameroon is therefore at the center of this international policy arena.
Methods and materials:
This paper draws upon several approaches, combining knowledge in working with P. africana over a 30-year period with a thorough literature review and updated trade data with "ground-truthing" in the field in 2013 and 2014. This enabled the construction of a good perspective on trade volumes (1991-2012), bark prices (and value-chain data) and the gaps between research reports and practice. Two approaches provided excellent lenses for a deeper understanding of policy failure and the "knowing-doing gap" in the P. africana case. A similar approach to Médard's (1992) analyses of power, politics and African development was taken and secondly, studies of commodity chains that assess the power relations that coalesce around different commodities (Ribot, 1998; Ribot and Peluso, 2003).
Results:
Despite the need to conserve genetically and chemically diverse P. africana, wild populations are vulnerable, even in several "protected areas" in Burundi, Cameroon, the Democratic Republic of Congo and in the forest reserves of Madagascar. Secondly, hopes of decentralized governance of this forest product are misplaced due to elite capture, market monopolies and subsidized management regimes. At the current European price, for P. africana bark (US3.9 million, with the majority of this accruing to a single company. In contrast to lucrative bark exports, the livelihood benefits and financial returns to local harvesters from wild harvest are extremely low. For example, in 2012, the 48 active harvesters working within Mount Cameroon National Park (MCNP) received less than 1US per kg (or 43% of the farm gate price for wild harvested bark). In addition, the costs of inventory, monitoring and managing sustainable wild harvests are far greater than the benefits to harvesters.
Conclusion:
Without the current substantial international donor subsidies, sustainable harvest cannot be sustained. What is required to supply the current and future market is to develop separate, traceable P. africana bark supply chains based on cultivated stocks. On-farm production would benefit thousands of small-scale farmers cultivating P. africana, including local women, for whom wild harvesting is too onerous. This change requires CITES and EU support and would catalyze P. africana cultivation in across several montane African countries and Madagascar, increasing farm-gate prices to harvesters compared to economic returns from wild harvest.
... Prior to the discovery in 1966 that it is an effective herbal remedy, Prunus africana was a relatively common, but never abundant, montane species. Prunus africana has been the subject of several studies addressing inventories (Geldenhuys, 1981; Ewusi et al., 1992; Tchouto, 1996; Kilum-Ijim Forest Project, unpublished data), ecology (Fraser et al., 1996; Stewart, 2001), cultivation potential (Sunderland and Nkefor, 1996; Dawson, 1997; Dawson et al., 2000), genetic characteristics (Barker et al., 1994; Dawson and Powell, 1999), traditional uses (Mbenkum and Fisiy, 1992; Nsom and Dick, 1992; Iverson, 1993; Cunningham, 1996; Stewart, 2001), chemical constituents (Longo and Tira, 1981; Catalano et al., 1984; Fourneau et al., 1996), bark yield studies (Ewusi et al., 1996), and harvest effects (Parrott and Parrott, 1989; Cunningham and Mbenkum, 1993; Stewart, 2001). From the beginning, the harvest has been known to be destructive (Macleod, 1987; Ngengwe, 1996; Walter and Rakotonorina, 1995). ...
... Recruitment is low or sporadic (Ewusi et al., 1992). Because of deforestation at lower elevations, Prunus africana is confined to disjunct " forest islands " that differ genetically (Barker et al., 1994 ), with the Madagascar population being the most distinct (Martinelli et al., 1986). The tree occurs at altitudes between 1000 and 2500 m in montane forests (Kalkman, 1965; Cunningham and Mbenkum, 1993; Sunderland and Tako, 1999). ...
... Bark is harvested on privately owned forest land when it is converted to tea estates , resettlement lands, and other uses; harvest is forbidden from protected areas (Cunningham et al., 1997). The species is exported as dried bark, chipped bark, and tim- ber.Barker et al., 1994; Dawson, 1997). Mature trees are also exploited for their timber. ...
For the last 35 years, the African cherry (Prunus africana (Hook. f.) Kalm.) has been used in the treatment of benign prostatic hyperplasia and other disorders. The bark, from which the treatment is derived, is entirely wild-collected. The major exporters of bark include Cameroon, Madagascar, Equatorial Guinea, and Kenya. Groupe Fournier of France and Indena of Italy produce 86% of the world's bark extract, both for their own products and for the free market. Worldwide exports of dried bark in 2000 have been estimated at 1350-1525 metric tons per year, down from its peak of 3225 tons in 1997. Bark extracts (6370-7225 kg per year) are worth an estimated $4.36 million US dollars per year. In 2000, Plantecam, the largest bark exporter in Africa, closed its extraction factory in Cameroon, due to complex ecological, social, and economic factors. Wild-collection is no longer sustainable (and probably never was) where harvest seriously affects morbidity and mortality rates of harvested populations. Since 1995, it has been included in CITES Appendix II as an endangered species. In this paper, alternatives to wild-collection to meet future market demand are investigated, including conservation practices, enrichment plantings, small- and large-scale production, and protection of genetic resources. The species is at the beginning of a transition from an exclusively wild-collected species to that of a cultivated medicinal tree.
... La discontinuité de l'aire de distribution de P. africana amène à prévoir une divergence conséquente dans la base génétique des populations (Dawson et al., 2000). Les études préliminaires, effectuées à l'aide des marqueurs moléculaires Rapd (Random amplified polymorphic Dna), révèlent l'existence d'une grande variation génétique d'un pays à l'autre, et entre les populations à l'intérieur des pays, d'où la nécessité d'envisager des approches régionale et nationale de conservation (Barker et al., 1994 ;Dawson, Powell, 1999 ;Dawson et al., 2000). L'utilisation des marqueurs Rapd pour l'évaluation de la diversité et de la structure génétiques des populations des arbres forestiers est parfois remise en question à cause des faibles taux de polymorphisme produits et de la faible reproductibilité de cette technique (Gillet, 1999). ...
... En effet, les travaux de Cipriani et al. (1999) Une analyse comparée de la variabilité obtenue à l'aide de ces marqueurs, auxquels nous avons associé quelques amorces Rapd, permettra de discuter de l'utilisation des différents types de marqueurs pour des études plus fines visant à définir des stratégies fiables de conservation des ressources génétiques de P. africana à des échelles locale, nationale ou régionale. Les populations camerounaises utilisées servent comme test d'efficacité des différentes techniques, car certaines d'entre elles ont déjà été échantillonnées dans les études antérieures (Barker et al., 1994 ;Dawson, Powell, 1999). ...
GENETIC DIVERSITY IN PRUNUS AFRICANA (HOOK. F.) KALKMAN,
CAMEROON
A comparative analysis of genetic diversity in four Cameroonian populations of the species Prunus africana – using Rapd, Aflp and microsatellite molecular markers – was undertaken in the CIRAD-Forêt genetics laboratory in Montpellier. The study has
shown that all three molecular markers divide the populations studied into two main groups corresponding to two of the forest stands making up the Cameroonian ridge. The
microsatellite markers show the highest indexes of diversity. The microsatellites were developed for peach trees (Prunus persica) and adapted to P. africana to preserve their polymorphism. These markers thus appear to be the most appropriate, both technically and financially, for more detailed molecular studies aiming to define effective conservation strategies for the species, which is currently under threat of extinction.
Keywords: genetic diversity, Prunus africana, Cameroon.
... Before other considerations, the conservation and in situ management of P. africana requires a good knowledge of the genetic structure of this species with low potential of colonization. For Prunus africana, many studies have been carried out on genetic diversity (Barker et al. 1994;Dawson 1999;Avana et al. 2004;Muchugi et al. 2006;Atnafu 2007;Clair and Howe 2011;Kadu et al. 2013;Mihretie et al. 2015, Nantongo et al. 2016, biochemical property (Tchouakionie 2014; Nzweundji 2015) but cytogenetic studies are still lacking, hence the present study. ...
Prunus africana is a multipurpose evergreen species endemic to Africa and
an endangered species because of overexploitation. The great importance of this species
resides particularly in the use of its bark against benign prostatic hyperplasia. As for
most tropical trees and generally woody species, cytogenetic studies are scarce. Standard
and molecular cytogenetic approaches have been implemented for the first time to study
P. africana from Cameroon. This is the tetraploid species with a chromosome number
of 2n=4x=32. Genome size estimated by flow cytometry was 2C=1.44 pg. Five loci (ten
signals) of 35S rRNA genes were observed after fluorescence in situ hybridization. Ten
G-C rich DNA regions were detected by chromomycin A3 fluorochrome banding. All
chromomycin positive bands were co-localized with 35 S rDNA signals. Prunus africana,
the only strict African representative of genus Prunus, is in need of the conservation
strategy and in situ management that we are also discussing in this work.
... Before other considerations, the conservation and in situ management of P. africana requires a good knowledge of the genetic structure of this species with low potential of colonization. For Prunus africana, many studies have been carried out on genetic diversity (Barker et al. 1994;Dawson 1999;Avana et al. 2004;Muchugi et al. 2006;Atnafu 2007;Clair and Howe 2011;Kadu et al. 2013;Mihretie et al. 2015, Nantongo et al. 2016, biochemical property (Tchouakionie 2014; Nzweundji 2015) but cytogenetic studies are still lacking, hence the present study. ...
Prunus africana is a multipurpose evergreen species endemic to Africa and an endangered species because of overexploitation. The great importance of this species resides particularly in the use of its bark against benign prostatic hyperplasia. As for most tropical trees and generally woody species, cytogenetic studies are scarce. Standard and molecular cytogenetic approaches have been implemented for the first time to study P. africana from Cameroon. This is the tetraploid species with a chromosome number of 2n=4x=32. Genome size estimated by flow cytometry was 2C=1.44 pg. Five loci (ten signals) of 35S rRNA genes were observed after fluorescence in situ hybridization. Ten G-C rich DNA regions were detected by chromomycin A3 fluorochrome banding. All chromomycin positive bands were co-localizedwith 35 S rDNA signals. Prunus africana, the only strict African representative of genus Prunus, is in need of the conservation strategy and in situ management that we are also discussing in this work.
... It is a hermaphroditic species supposed to be mainly out-crossing, pollinated by insects (especially by bees) or perhaps birds and dispersed by birds and mammals. The species presents a sub-population structure over its range [3,10]. ...
The Convention on Biological Diversity confirms the sovereign rights of States over their biological resources. This implies duties of conservation and management. The tools placed at their disposal are often lacking, especially in developing countries with low technical and financial means. The work undertaken here, by a multidisciplinary Franco-Malagasy team, made it possible to give a diagnosis of the current conditions of in-situ management of two species exploited in Madagascar for their pharmaceutical interest: Prunus africanum and Centella asiatica. We developed tools for fast and indirect evaluation of the impact of the harvesting practices on the dynamics of the genetic diversity. A matrix was established to analyze the complexity of legal aspects. Economic features of commodities were surveyed. We showed that the management of populations of economically significant species is often alarming. Harvesting practices take little account of the risks incurred by a reduction in genetic diversity. The sharing of benefits arising from the exploitation of the genetic resources is far from equitable.
... A high level of molecular diversity is still maintained in the species despite its heavy exploitation. Previous studies using randomly amplified polymorphic DNA (RAPD) markers indicated high diversity levels within certain regions of its native range (Barker et al. 1994;Dawson and Powell 1999;Muchugi et al. 2006). More recent studies using microsatellite markers also pointed to high genetic diversity (Farwig et al. 2008;Kadu et al. 2011Kadu et al. , 2013. ...
We studied the genetic pattern of 21 Ethiopian populations of Prunus africana by using six nuclear and five plastid microsatellites. In total, 89 alleles were found in the nuclear and 16 haplotypes in the plastid genome. High levels of diversity both in cpSSRs (h
T
= 0.703) and nSSR (H
T
= 0.725) were detected. Genetic differentiation among populations at the nuclear and plastid level was moderate (F
ST = 0.122 vs. G
ST = 0.478). While Ethiopian populations harbored the highest plastid haplotype diversity throughout Africa, the level of nuclear diversity was lower than in the remaining part of the species’ range. Ten of the observed 16 plastid haplotypes were unique to Ethiopia, suggesting an isolated plastid evolution. Remarkably, all plastid haplotypes found in Ethiopia belonged to one single lineage, while other populations from East Africa and Madagascar contain haplotypes from up to four more divergent lineages. This suggests that in contrast to previous expectations, the Horn of Africa is a hot spot of plastid diversity but not the ancestral origin for present populations of P. africana. The ratio between pollen to seed flow was estimated to be 7.1, indicating predominant gene flow by pollen. The exhaustive pollen flow also facilitated gene exchange with West African nuclear lineages probably in the early Holocene. The Ethiopian rift formed a genetic barrier resulting in population differentiation east and west of the rift; however, it was less effective in disrupting gene flow than the Eastern Rift in more southern parts of the East African range.
... Prunus africana bark extracts from Cameroon and Democratic Republic of Congo were far more difficult to distinguish apart, but were considered to differ due to variations in ursolic acid, B-sitosterol and 3-0glucoside content. Differences between geographically (and genetically) isolated Prunus africana populations have also been shown from DNA fingerprinting of leaf-chloroplast DNA (BARKER et al., 1994 ). ...
The report reviews the current international trade in Prunus africana and makes recommendations for a better implementation of its listing in Appendix II of CITES. Trade structure and volumes are summarized and identification help for the main commodities unprocessed bark and bark extracts is presented.
... At a country level, Kenya has unique opportunities to contribute to the conservation of the species, as discussed also in Muchugi et al. [101]. The patterns of genetic variation found in P. africana [40,42,101,102] are associated with the Afromontane habitats occupied by the species, which play the role of islands of genetic diversity [58]. The slight differences in clustering of populations based on the two types of markers used (nuclear or chloroplast SSRs) may be explained by the fact that cpDNA markers tend to reflect gene flow patterns that are more historically remote than the nuclear markers [103]. ...
... The range of the species has been affected by past climate change and the modeled distribution of P. africana indicates that the species is likely to be negatively affected in future, with an expected decrease in distribution by 2050 (Vinceti et al. 2013). Second, although pioneering work had been undertaken on chemotypic (Martinelli et al. 1986) and genetic variation in P. africana (Barker et al. 1994), the extent of variation across different sites, and the need for conserving this variation of P. africana populations remains. This genetic and chemotypic variation reflects ancient dispersal routes and evolution of P. africana in separate and vulnerable montane forest " islands " in Africa and Madagascar (Kadu et al. 2011Kadu et al. , 2012a Vinceti et al. 2013). ...
... It is also a point of concern that already isolated populations on montane islands are becoming further isolated due to the destruction of almost all large, reproductively mature trees from intervening 'islands'. Barker et al. (1994) and more recently and in more detail, Dawson and Powell (1999), used Random Amplified Polymorphic DNA (RAPD) analysis of leaf chloroplast DNA to show distinct differences between isolated Prunus africana populations from different parts of the range of this species, with less variation between populations from more closely situated montane 'islands'. The most unusual populations are those in Madagscar (Dawson and Powell, 1999). ...
... The patterns of genetic variation found in P. africana [40,42,101,102] are associated with the Afromontane habitats occupied by the species, which play the role of islands of genetic diversity [58]. The slight differences in clustering of populations based on the two types of markers used (nuclear or chloroplast SSRs) may be explained by the fact that cpDNA markers tend to reflect gene flow patterns that are more historically remote than the nuclear markers [103]. ...
Conservation priorities for Prunus africana, a tree species found across Afromontane regions, which is of great commercial interest internationally and of local value for rural communities, were defined with the aid of spatial analyses applied to a set of georeferenced molecular marker data (chloroplast and nuclear microsatellites) from 32 populations in 9 African countries. Two approaches for the selection of priority populations for conservation were used, differing in the way they optimize representation of intra-specific diversity of P. africana across a minimum number of populations. The first method (S1) was aimed at maximizing genetic diversity of the conservation units and their distinctiveness with regard to climatic conditions, the second method (S2) at optimizing representativeness of the genetic diversity found throughout the species' range. Populations in East African countries (especially Kenya and Tanzania) were found to be of great conservation value, as suggested by previous findings. These populations are complemented by those in Madagascar and Cameroon. The combination of the two methods for prioritization led to the identification of a set of 6 priority populations. The potential distribution of P. africana was then modeled based on a dataset of 1,500 georeferenced observations. This enabled an assessment of whether the priority populations identified are exposed to threats from agricultural expansion and climate change, and whether they are located within the boundaries of protected areas. The range of the species has been affected by past climate change and the modeled distribution of P. africana indicates that the species is likely to be negatively affected in future, with an expected decrease in distribution by 2050. Based on these insights, further research at the regional and national scale is recommended, in order to strengthen P. africana conservation efforts.
... DNA markers were generated for native Australian spinifex grasses as an aid for ensuring genetic representativeness of species in ecosystem restoration programmes in the northern Kimberley region of Western Australia. The number of bands produced from the number of samples assessed for each species compares favourably with previous studies (Barker et al. 1994;Rossetto et al. 1995) indicating that an adequate number of bands were generated to allow meaningful analyses to be conducted. ...
Summary Studies were undertaken to develop genetic principles for the restoration of spinifex grasses (Triodia spp.) at the Argyle Diamond Mines in northern Australia. The study used random amplified polymorphic DNA (RAPD) DNA markers to provide a molecular delineation of provenance boundaries for two species Curly Spinifex (Triodia bitextura) and Triodia bynoei and to provide measures which ensure replacement of local genetic diversity. Within-population diversity measures (0.44 ± 0.03 T. bitextura and 0.32 ± 0.04 T. bynoei) and the proportion of diversity attributed to between-population differences (≈ 12%) by analysis of molecular variance (AMOVA) indicate extensive out-crossing in these seeder species. As such, both species should be restored using seed-based methods to maintain natural diversity. Significant groups of populations (P < 0.05) identified by AMOVA correspond directly to clustering of populations in a dendogram drawn using UPGMA, indicating significant provenances in both species. For T. bitextura, a significant genotypic variation identified at 60 km from mine populations was not evident at 30 km. Seed for restoration at the mine should, therefore, be harvested from within 30 km of the area to be restored to ensure maintenance of the local provenance. Two T. bynoei populations located 2 km apart were found to represent a single genotype, all other populations were identified as separate genotypes. The majority of the isolated T. bynoei populations, therefore, represent distinct provenances. For both species, in excess of 80% of the measured species diversity occurred in just 20 individuals. As restoration of these grasses will necessitate harvesting seed from thousands of plants the species capacity for evolutionary change should be maintained. With continuing improvements in the effectiveness of molecular genetics technology, the assessment of provenance boundaries through the use of genetic markers is becoming a realistic option for the development of more genetically representative sourcing of genotypes in plant restoration programmes.
... However, new DNA-based molecular techniques capable of detecting polymorphism in species with limited genetic variability have recently become more popular in conservation genetics studies. RAPD analysis (Williams et al., 1990) has already proved useful in conservation studies as it does not require prior knowledge of the target genome, uses small amounts of DNA and can detect low levels of polymorphism (Brauner et al., 1992;Barker et al., 1994;Gustafsson and Gustafsson, 1994;Glover and Abbott, 1995;Rossetto et al., 1995;James and Ashburner, 1997). This technique has already been successfully applied to investigate the hybrid origin of an extremely rare south-western Australian eucalypt (Rossetto et al., 1997) and to verify clonal identity of other eucalypt species (Keil and Grif-®n, 1994;Nesbitt et al., 1997;Tyson et al., 1998). ...
Extensive agricultural development has endangered species diversity in the highly endemic south-western Australian flora. Many relict species with restricted distribution are now on the brink of extinction. Eucalyptus phylacis and E. dolorosa are both known from single locations within pockets of native vegetation surrounded by agricultural land. The development of appropriate conservation strategies required the appraisal of the extent of clonality within both species as well as the definition of species identity for E. phylacis. The use of RAPD analysis revealed contrasting stories for these two threatened species. E. phylacis, for which species identity was successfully established, was shown to be a single clone and as a result, possibly the rarest, largest, potentially oldest mallee eucalypt known. Whereas, despite its isolation, E. dolorosa still retained sufficient genetic variability to enable the production of highly outcrossed seed. Different conservation strategies are suggested for the two species and the importance of understanding basic genetic variability in rare clonal species is discussed.
Ethnopharmacological relevance:
Prunus africana (Hook.f.) Kalkman (Rosaceae), commonly known as "Pygeum" or "African cherry", occurs in mainland montane forest "islands" scattered across sub-Saharan Africa, Madagascar, and some surrounding islands. Traditionally, decoctions of the stem-bark are taken orally for the treatment of a wide variety of conditions, such as benign prostatic hyperplasia (BPH), stomach ache, chest pain, malaria, heart conditions, and gonorrhoea, as well as urinary and kidney diseases. The timber is used to make axe handles and for other household needs. The dense wood is also sawn for timber.
Aim:
The fragmented information available on the ethnobotany, phytochemistry, and biological activities of the medicinally important P. africana was collated, organised, and analysed in this review, to highlight knowledge voids that can be addressed through future research.
Materials and methods:
A bibliometric analysis of research output on P. africana was conducted on literature retrieved, using the Scopus® database. The trend in the publications over time was assessed and a network analysis of collaborations between countries and authors was carried out. Furthermore, a detailed review of the literature over the period 1971 to 2021, acquired through Scopus, ScienceDirect, SciFinder, Pubmed, Scirp, DOAJ and Google Scholar, was conducted. All relevant abstracts, full-text articles and various book chapters on the botanical and ethnopharmacological aspects of P. africana, written in English and German, were consulted.
Results:
A total of 455 documents published from 1971 to 2021, were retrieved using the Scopus search. Analysis of the data showed that the majority of these documents were original research articles, followed by reviews and lastly a miscellaneous group comprising conference papers, book chapters, short surveys, editorials and letters. Data were analysed for annual output and areas of intense research focus, and countries with high research output, productive institutions and authors, and collaborative networks were identified. Prunus africana is reported to exhibit anti-inflammatory, analgesic, antimicrobial, anti-oxidant, antiviral, antimutagenic, anti-asthmatic, anti-androgenic, antiproliferative and apoptotic activities amongst others. Phytosterols and other secondary metabolites such as phenols, triterpenes, fatty acids, and linear alcohols have been the focus of phytochemical investigations. The biological activity has largely been ascribed to the phytosterols (mainly 3-β-sitosterol, 3-β-sitostenone, and 3-β-sitosterol-glucoside), which inhibit the production of prostaglandins in the prostate, thereby suppressing the inflammatory symptoms associated with BPH and chronic prostatitis.
Conclusions:
Many of the ethnobotanical assertions for the biological activity of P. africana have been confirmed through in vitro and in vivo studies. However, a disparity exists between the biological activity of the whole extract and that of single compounds isolated from the extract, which were reported to be less effective. This finding suggests that a different approach to biological activity studies should be encouraged that takes all secondary metabolites present into consideration. A robust technique, such as multivariate biochemometric data analysis, which allows for a holistic intervention to study the biological activity of a species is suggested. Furthermore, there is a need to develop rapid and efficient quality control methods for both raw materials and products to replace the time-consuming and laborious methods currently in use.
I studied the uses of the African cherry (Prunus africana) by four ethnic groups who live near the Kilum-Ijim Forest Preserve on Mount Oku, Cameroon. Prunus africana is valued for its timber, which is used for tool handles and for fuel, and it is an important wildlife food. However, its greatest value is for traditional medicines. Healers use the bark and leaves to treat more than 30 human ailments and several animal diseases and it is the most important plant used in their practices. This study is the first to document this importance, particularly for animal medicines. I also examined the growing worldwide herbal use to treat benign prostatic hyperplasia. Market demand has caused resource depletion and an erosion of traditional resource protection practices. Preservation of the species will depend on sustainable harvesting methods and on cultivation.
The recent discovery of a population of Aloe with an unusual morphology in the Gamkapoort Nature Reserve has raised some interesting issues concerning its origin. The intermediate morphology of these plants suggested that they were of hybrid origin, the hypothesized parent species being A. ferox and A. claviflora, both of which are found in the region. In this study, the hypothesis that the Gamkapoort population is a hybrid originating from these two species is corroborated by data obtained using the RAPD (random amplified polymorphic DNA) method.
The Convention on Biological Diversity confirms the sovereign rights of States over their biological resources. This implies duties of conservation and management. The tools placed at their disposal are often lacking, especially in developing countries with low technical and financial means. The work undertaken here, by a multidisciplinary Franco-Malagasy team, made it possible to give a diagnosis of the current conditions of in-situ management of two species exploited in Madagascar for their pharmaceutical interest: Prunus africanum and Centella asiatica. We developed tools for fast and indirect evaluation of the impact of the harvesting practices on the dynamics of the genetic diversity. A matrix was established to analyze the complexity of legal aspects. Economic features of commodities were surveyed. We showed that the management of populations of economically significant species is often alarming. Harvesting practices take little account of the risks incurred by a reduction in genetic diversity. The sharing of benefits arising from the exploitation of the genetic resources is far from equitable.
Molecular information is now providing powerful new ways of exploring biodiversity, particularly at the species level and below. The importance of biosystematic studies is discussed, and a number of previously published criteria are used explicitly to list several southern African plant families which are considered to deserve a high priority in research programmes. Our botanical diversity is a unique asset which has the potential to make a substantial contribution towards improving our economic position in the 'global village'. Biosystematics can play tin important role to ensure that we grasp the commercial opportunities provided by our genetically diverse flora.
ABSTRACT The bark of the montane trees species, Prunus africana is utilised for the treatment of benign prostate hyperplasia, and has a current market value of around $150 million per annum. (Cunningham et al., 1997). Until 1992, the exploitation of Prunus bark was concentrated primarily in Cameroon, Kenya and Madagascar, Tanzania and, to a lesser extent, the Democratic Republic of Congo (ibid.). However, recent reports have indicated that the island of Bioko, Equatorial Guinea is becoming of increasing importance for the supply of Prunus bark to Europe and may become increasingly important as sources of supply from other countries become scarce or are subject to increased regulation. This report presents the findings of a field-based study of the exploitation of Prunus africana on Bioko in the latter part of 1998.
Prunus africana's bark extract is used in treatment of prostate gland disorders among other uses. The dwindling of the species abundance in the wild necessitates its domestication. The first step is identification of desired germplasm. In this study, bark extracts from different Kenyan forest zones were compared for yield and chemical composition. Extraction was done using Debat (1974) procedure, while chemical composition was determined using chromatographic procedures. The extract yield showed a positive correlation with tree age, the best source being medium sized trees (30–50 cm dbh). Timboroa provenance had the highest extract yield (1.9%) while Kobujoi had the least (0.73%). Gas Liquid Chromatography analysis showed that Kakamega's extract had the highest number of compounds (8) and Eburu had the highest β-Sitosterol content. With Thin Layer Chromatography, Kinale provenance showed the highest number of compounds (11). The species diversity is therefore important for breeding purposes and should be conserved.
An understanding of the patterns of variation within and among populations of tropical trees is essential for devising optimum genetic management strategies for their conservation and sustainable utilization. Here, random amplified polymorphic DNA (RAPD) analysis was used to partition variation within and among 10 populations of the endangered Afromontane medicinal tree, Prunus africana, sampled from five countries across the geographical range of the species (Cameroon, Ethiopia, Kenya, Madagascar and Uganda). Analysis of molecular variance ( AMOVA) employed 48 RAPD markers and revealed most variation among countries (66%, P < 0.001). However, variation among individuals within populations and among populations within Cameroon and Madagascar was also highly significant. Analysis of population product frequency data indicated Ugandan material to be more similar to populations from Cameroon than populations from Kenya and Ethiopia, while Malagash populations were most distinct. The implications of these findings for determining appropriate approaches for conservation of the species, particularly in Cameroon and Madagascar, are discussed.
This paper provides an analysis of some current trends in political ecology and then illustrates the intermingling of politics and ecology using a case study of the exploitation and conservation of Prunus africana in Cameroon. It argues that political ecology is still a lively field, but that some recent attempts to chart a way forward for this perspective risk shifting it away from its liminal position in relation to natural and social science by being disinclined to engage with ecological processes. The case study draws attention to the strengths and shortcomings in existing attempts to weave political and economic analysis into environmental debates over the sustainable management of this tree species, which has been incorporated into phytomedical markets in Europe. The fortunes of the tree reflect its botany and ecology as well as the trajectories of the local economy, intercontinental markets for alternative health products, the policies and practices of the Cameroonian state and the politics of international aid.
A review of the existing literature available on the bibliographic CD-ROM PlantGeneCD on the use of protein and molecular markers on plant material from sub-Saharan Africa was undertaken. The review showed that these molecular techniques have been used in a wide range of studies, from measurement of genetic diversity within single population to the elucidation of phylogenetic relationship among species in a genus or group of genera. The review revealed that 67% of the 146 studies examined used protein electrophoresis (58% isozymes, the rest mostly seed proteins), 20% used RFLPs, 8% RAPDs and 3% sequencing. Isozymes have been used for a whole range of applications, whereas electrophoresis of other proteins has mainly been used to study ecogeographic distribution of diversity in crops. RAPDs have been used particularly in the investigation of genetic relationship among accessions of a single species and phylogentic relationship among species. RFLPs of cpDNA have mostly been used at the interspecific level and nuclear markers at the intraspecific level. The studies covered most of the major crop species of Africa and their wild relatives, though important gaps remain, for example sweet potato. So-called minor crops were not well represented. Wild taxa not related to crops were also covered, in particular agroforestry and forest species.
I studied the uses of the African cherry (Prunus africana) by four ethnic groups who live near the Kilum-Ijim Forest Preserve on Mount Oku, Cameroon. Prunus africana is valued for
its timber, which is used for tool handles and for fuel, and it is an important wildlife food. However, its greatest value
is for traditional medicines. Healers use the bark and leaves to treat more than 30 human ailments and several animal diseases
and it is the most important plant used in their practices. This study is the first to document this importance, particularly
for animal medicines. I also examined the growing worldwide herbal use to treat benign prostatic hyperplasia. Market demand
has caused resource depletion and an erosion of traditional resource protection practices. Preservation of the species will
depend on sustainable harvesting methods and on cultivation.
J’ai etudié I’emploi de la cerise africaine (Prunus africana) par quatre groupes ethniques residant prés de la préserve forestiére Kilum-Ijim surle Mont Oku, au Cameroun. Prunus africana
est prisé pour son bois, qui est utilisé pour fabriquer des manches d’outils, et comme combustible. C’est également un aliment
important pour la faune sauvage. Pourtant, sa plus grande valeur est dans la medecine traditionnelle. Les guerisseurs en utilisent
l’écorce et les feuilles pour trailer plus de 30 maladies humaines et plusieurs maladies animates; c’est la plante la plus
importante utilisée dans leurs cures. Cette étude est la premiére á documenter cette importance, particuliérement dans le
domaine des médicaments pour les animaux. J’ai aussi examiné son usage mondial croissant comme traitement de I’hypertrophie
bénigne de la prostate. La demande économique a causé une dépletion des ressources et une érosion des pratiques traditionnelles
de protection des ressources. La préservation de cette espéce exigera des méthodes de moisson soutenables ainsi que la cultivation.
Bark extracts from the African cherry, Prunus africana (Rosaceae), are a popular treatment for enlarged prostates. Harvests of the bark began in Cameroon in the 1970s. Because of concerns regarding the sustainability of the trade, the species is included on the IUCN Red List and in CITES Appendix II. This study followed five P. africana populations in the Kilum-Ijim Forest Preserve on Mount Oku, Cameroon, examining growth, mortality and reproductive parameters, as well as response to harvest and other human activities. During the first part of the study (1998–1999), the forest had limited human activity; by the second part (2007–2008), more activity was apparent, including wildfires, grazing and a forest-wide bark harvest in 2005/2006. Over the study period, population structure differed from a typical J-shaped frequency curve for long-lived species, which may reflect past harvesting. After the 2005/2006 harvest, the population structure had shifted slightly toward the smaller size classes. In addition, the number of surviving trees was reduced in all size classes. About half of the reproductive trees died during the study. Size class was not a significant predictor of death, but the location of the harvest (plot) was. All trees affected by wildfires died, suggesting that the species is not adapted to fire. Trees that were harvested without disrupting the vascular cambium survived better and had minimal loss of crown. Thus, the fate of the trees in a given plot may lie in the care taken by an individual harvester. Average growth (0.34 cm per year) was not significantly different among the size classes. Crown die-back significantly reduced fruit production, obscuring the asynchronous alternating fruiting pattern. Seedling numbers followed a similar alternating pattern, but survival was negligible due to grazing. The combined factors of mortalities of a large percentage of reproductive trees (especially the largest ones), highly reduced fruit production and poor seedling survival offer a bleak prognosis for future regeneration and long-term persistence of the species in this forest. Only after decades of harvest are existing standing crop inventories and scientifically based annual quotas now being determined. It is known that the trees are easily domesticated. Efforts have been intensified to train villagers and community forest managers in vegetative propagation techniques and nursery practices, offering some hope that the species can be successfully managed to provide for sustainable harvests and dependable rural livelihoods.
Listed as vulnerable under Appendix II of CITES, populations of the commercially valuable African highland medicinal tree Prunus africana are threatened by over-exploitation in a number of countries. Here, random amplified polymorphic DNA (RAPD) analysis was used to assess patterns of genetic variation in the species in Cameroon and Kenya, two countries where exploitation has been particularly high and where information on genetic structure is a crucial input for developing the national management plans that are a requirement of CITES listing. Analysis of molecular variance (AMOVA), which employed 39 RAPD markers, indicated that a significantly greater proportion of total country variation partitioned among eight stands in Kenya than among nine stands in Cameroon (values of 55% and 24%, respectively), with important implications for conservation strategies. Kenyan stands appear to represent a particularly diverse resource for conservation, evaluation and domestication, although possible human movement of germplasm during cultivation raises integrity concerns. Data also shed light on the evolutionary history of P. africana stands. A genetic disjunction between western and central Kenyan populations was observed, with individuals from western Kenya more similar to geographically distant stands from Cameroon (> 2000 km) than to central Kenya (< 400 km). In the context of present-day floristic distributions and the historical data available, this disjunction appears more consistent with genetic exchange between east and west African highlands via migration (associated with climate change) than via long distance seed dispersal. Data suggested that conservation strategies for P. africana should place relatively more emphasis than currently on the status of surrounding phytochoria.
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