Haris Saslis-Lagoudakis

Previous studies have found similarities in medicinal plant use between geographic regions and cultures at different spatial scales. Furthermore, it has been shown that phylogeny constrains plant use and some lineages are richer in medicinal plants than others. This thesis investigates evolutionary and cross-cultural patterns in medicinal plant use using taxonomic and phylogenetic tools at different scales of human cultural proximity, plant phylogenetic relatedness and space.

Brownea jaramilloi, a new species, endemic to the northeastern Ecuadorian Amazon, is described and illustrated, and its placement in the genus discussed. It is unique in the genus Brownea in being characterised by yellow flowers. In a 25-ha plot in Yasuni National Park, this new species averaged 20 individuals (with dbh ≥ 1 cm) per hectare.

There is controversy about whether traditional medicine can guide drug discovery, and investment in bioprospecting informed by ethnobotanical data has fluctuated. One view is that traditionally used medicinal plants are not necessarily efficacious and there are no robust methods for distinguishing those which are most likely to be bioactive when selecting species for further testing. Here, we reconstruct a genus-level molecular phylogenetic tree representing the 20,000 species found in the floras of three disparate biodiversity hotspots: Nepal, New Zealand, and the Cape of South Africa. Borrowing phylogenetic methods from community ecology, we reveal significant clustering of the 1,500 traditionally used species, and provide a direct measure of the relatedness of the three medicinal floras. We demonstrate shared phylogenetic patterns across the floras: related plants from these regions are used to treat medical conditions in the same therapeutic areas. This finding strongly indicates independent discovery of plant efficacy, an interpretation corroborated by the presence of a significantly greater proportion of known bioactive species in these plant groups than in random samples. We conclude that phylogenetic cross-cultural comparisons can focus screening efforts on a subset of traditionally used plants that are richer in bioactive compounds, and could revitalize the use of traditional knowledge in bioprospecting.

Ethnopharmacological relevance
Envenomation causes an estimated 1.8–2.5 million incidences per year with a mortality level of 100–125,000 persons annually and more than 100,000 individuals suffer from severe complications, which may end in amputation of the attacked limb. The use of plants is a major part of the traditional practitioners’ treatment of snakebites.

Materials and methods
A database was created for plants used to treat snakebites worldwide. From this database, we selected five countries with a high number of entries and representing different cultures, geography and floristic zones: Brazil, Nicaragua, Nepal, China and South Africa. The datasets were analysed by regression and binominal analysis to see if any family or genus used against snakebites was overrepresented in the respective traditional medicinal systems relative to the abundance in the local flora. The families from the different geographical areas were compared to ascertain whether the same plant families are preferred by different peoples.

Results
Three ‘hot’ families (Apocynaceae, Lamiaceae and Rubiaceae) were recovered in at least two of the five compared countries in the regression analyses and one ‘hot’ family (Zingiberaceae) was recovered in two of the compared countries in the binomial analyses. Four out of five floras possess families identified as outliers in both regression and binomial analyses. Eight families were recovered by both the binomial and the regression analysis (40–62% of all highlighted families respectively). At the genus level, only Piper (Piperaceae) was recovered as a ‘hot’ genus in at least two floras. Seven genera were highlighted by both analyses (25–44% of the highlighted genera).

Conclusions
Cross-cultural comparison of medicinal floras used against snakebites appears to be useful for highlighting candidate families and genera for further studies.

Background
The study of traditional knowledge of medicinal plants has led to discoveries that have helped combat diseases and improve healthcare. However, the development of quantitative measures that can assist our quest for new medicinal plants has not greatly advanced in recent years. Phylogenetic tools have entered many scientific fields in the last two decades to provide explanatory power, but have been overlooked in ethnomedicinal studies. Several studies show that medicinal properties are not randomly distributed in plant phylogenies, suggesting that phylogeny shapes ethnobotanical use. Nevertheless, empirical studies that explicitly combine ethnobotanical and phylogenetic information are scarce.

Methodology/Principal Findings
In this study, we borrowed tools from community ecology phylogenetics to quantify significance of phylogenetic signal in medicinal properties in plants and identify nodes on phylogenies with high bioscreening potential. To do this, we produced an ethnomedicinal review from extensive literature research and a multi-locus phylogenetic hypothesis for the pantropical genus Pterocarpus (Leguminosae: Papilionoideae). We demonstrate that species used to treat a certain conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic relationships.

Conclusions/Significance
This study provides techniques that enable the application of phylogenies in bioscreening, but also sheds light on the processes that shape cross-cultural ethnomedicinal patterns. This community phylogenetic approach demonstrates that similar ethnobotanical uses can arise in parallel in different areas where related plants are available. With a vast amount of ethnomedicinal and phylogenetic information available, we predict that this field, after further refinement of the techniques, will expand into similar research areas, such as pest management or the search for bioactive plant-based compounds.

ETHNOPHARMACOLOGICAL RELEVANCE:
One of the major drawbacks of using ethnomedicinal data to direct testing of plants which may find pharmaceutical use is that certain plants without bioactivity might be traditionally used. An accepted way of highlighting bioactive plants is to compare usage in different cultures. This approach infers that presumed independent discovery by different cultures provides evidence for bioactivity. Although several studies have made cross-cultural comparisons, they focussed on closely related cultures, where common patterns might be the result of common cultural traditions. The aim of this study was to compare three independent ethnomedicinal floras for which similarities can be more robustly interpreted as independent discoveries, and therefore likely to be indication for efficacy.

MATERIALS AND METHODS:
Data from the literature were compiled about the ethnomedicinal floras for three groups of cultures (Nepal, New Zealand and the Cape of South Africa), selected to minimise historical cultural exchange. Ethnomedicinal applications were divided in 13 categories of use. Regression and binomial analyses were performed at the family level to highlight ethnomedicinal "hot" families. General and condition-specific analyses were carried out. Results from the three regions were compared.

RESULTS:
Several "hot" families (Anacardiaceae, Asteraceae, Convolvulaceae, Clusiaceae, Cucurbitaceae, Euphorbiaceae, Geraniaceae, Lamiaceae, Malvaceae, Rubiaceae, Sapindaceae, Sapotaceae and Solanaceae) were recovered in common in the general analyses. Several families were also found in common under different categories of use.

CONCLUSIONS:
Although profound differences are found in the three ethnomedicinal floras, common patterns in ethnomedicinal usage are observed in widely disparate areas of the world with substantially different cultural traditions. As these similarities are likely to stem from independent discoveries, they strongly suggest that underlying bioactivity might be the reason for this convergent usage. The global distribution of prominent usage of families used in common obtained by this study and the wider literature is strong evidence that these families display exceptional potential for discovery of previously overlooked or new medicinal plants and should be placed in high priority in bioscreening studies and conservation schemes.

Platymiscium is a neotropical legume genus of forest trees in the Pterocarpus clade of the pantropical “dalbergioid” clade. It comprises 19 species (29 taxa), distributed from Mexico to southern Brazil. This study presents a molecular phylogenetic analysis of Platymiscium and allies inferred from nuclear ribosomal (nrITS) and plastid (trnL, trnL-F and matK) DNA sequence data using parsimony and Bayesian methods. Divergence times are estimated using a Bayesian method assuming a relaxed molecular clock (multidivtime). Within the Pterocarpus clade, new sister relationships are recovered: Pterocarpus + Etaballia, Inocarpus + Tipuana and Paramachaerium + Maraniona. Our results support monophyly of Platymiscium, which is resolved into three major clades, each with distinct geographic ranges and ecological preferences. Diversification in Platymiscium has been driven by habitat fragmentation, invasion of novel geographic regions, and ecological diversification, revealing general patterns of diversification in the neotropics. We hypothesize that Platymiscium arose in dry habitats of South America and radiated northward. The Amazon basin was invaded twice both within the last 5.6 My and Central America twice before the closure of the Isthmus of Panama. Divergence times of the P. pubescens complex, restricted to seasonally dry tropical forests of South America, support pre-Pleistocene divergence in this biome.