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- Diversity and biological activities of medicinal plants of Santiago island (Cabo Verde)Publication . Romeiras, Maria M.; Essoh, Anyse P.; Catarino, Sílvia; Silva, Joceline; Lima, Katelene; Varela, Eromise; Moura, Mónica; Gomesi, Isildo; Duarte, Maria Cristina; Duarte, Maria PaulaPlants continue to constitute key elements of medical practice in West African countries. The Cabo Verde archipelago hosts a great diversity of medicinal plants and local markets are considered important sites for trading plants harvested by rural communities. This study has two main goals: (i) to assess the medicinal uses of native species in Santiago, the biggest island of the archipelago, and (ii) to evaluate the antioxidant, antimicrobial and antidiabetic/antihyperglycemic activities of two native trees (Tamarix senegalensis and Sideroxylon marginatum) used in traditional medicine and traded in local markets. Our results revealed that on Santiago Island, 24 native plants are used in traditional medicine. The main uses of these species (e.g., forage, timber, food and fibres), their medicinal applications, the plant parts used, their mode of administration and conservation status are presented here for the first time. Moreover, the pharmacological characterization of two native tree species revealed that hydroethanolic extracts were richer in phenolic compounds and more active than their aqueous counterparts. All the studied extracts revealed significant antioxidant properties (DPPH and FRAP assays) and were generally moderately active against Gram-positive bacteria. All the extracts inhibited the activities of the carbohydrate digestive enzymes α-glucosidase and α-amylase in a dose-dependent manner. For α-glucosidase, the detected inhibitory activity (IC50 values from 2.0 ± 0.2 μg/mL
- Cashew as a high agricultural commodity in West Africa: insights towards sustainable production in Guinea-BissauPublication . Monteiro, Filipa; Catarino, Luís; Batista, Dora; Indjai, Bucar; Duarte, Maria Cristina; Romeiras, MariaIn Sub-Saharan Africa, the West African region has highly diverse agro-climatic conditions, which grant the potential for a remarkable agricultural production of a great diversity of crops. Since the 1980s, the production volumes of most crops have grown vigorously for both domestic and export markets. Traditional food crops—such as rice, groundnuts and sorghum—have been replaced by cash crops, namely cashew. Among the main cashew production areas, West Africa is the most recent and dynamic in the world, accounting for 45% of the worldwide production of cashew nuts in 2015. In consequence, cashew cultivation has acquired an important position in West African smallholder farming, providing positive economic and social effects. In this paper, we provide an overview of the cashew production system in the West African region, using Guinea-Bissau as a case study. In particular, we present some viewpoints concerning the impact of cashew production and discuss how the strong dependence on a single cash crop can compromise the local livelihoods and food security. Finally, some insights are given towards the sustainable production of cashew in the face of the recent risks affecting the agricultural sector in West Africa
- Present and future distribution of Faidherbia albida in Cabo Verde as revealed by climatic modelling and LULC analysisPublication . Varela, Danilson; Romeiras, Maria M.; Silva, LuísClimate change poses one of the most significant challenges to conserve biodiversity, especially in tropical dry islands, as is the case of Cabo Verde (northeast Atlantic Ocean). This archipelago has a low percentage of forest cover and hosts only seven native tree species, among them, Faidherbia albida (Delile) A.Chev. (Fabaceae). Therefore, protective afforestation is extremely important in Cabo Verde, one of the most vulnerable West African countries to climate change. With this work, we aimed to estimate the current distribution and potential shifts in suitable areas for F. albida under climate change, using species distribution models (i.e., random forest, generalized linear and additive models), covering its distribution range in Cabo Verde and mainland Africa. The best model was then projected for the studied area, at two different slice times, using Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Based on current bioclimatic variables, we estimated that almost two thirds of Cabo Verde’s territory is highly suitable for F. albida, which contrasts with its current occurrence. By overlaying the present habitat suitability with land use and land cover data, we concluded that habitat availability and suitability could be constrained by that factor. On average, the predicted suitable habitat for future distributions gradually decreases by 2080 under both scenarios compared with the current, with a smaller effect of RCP4.5 than of RCP8.5. Local authorities can benefit from this research and develop actions to promote sustainable reforestation in Cabo Verde, which should include native tree species that are best adapted to the local climate and could thus contribute to mitigate the effects of climate change.
- Recovering plant data for Guinea-Bissau: implications for biodiversity knowledge of West AfricaPublication . Romeiras, Maria; Duarte, Maria Cristina; Francisco-Ortega, Javier; Catarino, Luís; Havik, PhilipThe rich plant diversity that characterizes the West African Region and the inherent knowledge of their flora and vegetation has been the backbone of scientific explorations during the past centuries. The evolution of botanical knowledge on Guinea-Bissau, throughout the 16th and 20th centuries is reviewed. We present and discuss floristic data collected by scientific expeditions between the mid-1700s to 1974, when the Portuguese colonial period ended. Expeditions undertaken by French naturalists provided some of the earliest plant collections. A list of herbarium specimens collected by the French naturalist Jardin, in the Bijagós Islands in ca. 1847–1858 is presented here for the first time, while in the late 1800s some Portuguese naturalists also explored Guinea-Bissau. During the colonial period (1915–1974), Gomes e Sousa published the first comprehensive study of the territory’s flora while Espírito Santo assembled the largest plant collection. Our review applies a multi-disciplinary perspective to fill important lacuna regarding biodiversity knowledge of this under-researchedWest African country. It constitutes the first study tracing the long term evolution of knowledge on Guinea Bissau's plant diversity, which provides the basis for understanding trends and research priorities, in particular in conservation and botanical fields
- Plant species richness in the Cape Verde islands - ecogeographical determinantsPublication . Duarte, Maria Cristina; Rego, Francisco Castro; Romeiras, Maria; Moreira, IlídioPlant species richness in the Cape Verde archipelago is examined relative to island eco-geographical factors. Species-area and species-area-habitat relationships are analysed using the classical species-area model and the recently proposed species-choros model. The number of Xoristic zones (used to estimate the choros parameter) provides an adequate estimate of the potential habitat diversity, and the species-choros model achieved a better Wt with both total Xora and endemic species. In addition to area and habitat diversity, longitude also emerges as an important determinant of species diversity, whereas latitude, minimum distance to the nearest island, and total rural population do not display any correlation. As in other insular ecosystems, the species richness (about 140 per 100 km2) is lower than in nearby mainland regions; the proximity to the desert areas of the Sahel can also be seen as related with this low value. The Xoristic heterogeneity in Cape Verde is high, as is usual in island ecosystems. In a comparative analysis of the species richness on the diVerent islands (using -values), Brava stands out as having the highest total Xora species densities, while for endemic Xora Brava and São Nicolau jointly occupy the leading position. The high diversity for both total and endemic species on Santo Antão, São Vicente, São Nicolau, Fogo and Brava reinforces their importance in conservation terms - in the case of most of them, something that is already recognized in the established network of protected areas
- Antimalarial and Cytotoxic Activity of Native Plants Used in Cabo Verde Traditional MedicinePublication . Essoh, Anyse P.; Cassiano, Gustavo Capatti; Mandim, Filipa; Barros, Lillian; Gomes, Isildo; Medeiros, Márcia Melo; Moura, Mónica; Cravo, Pedro Vitor Lemos; Romeiras, Maria M.Medicinal plants have historically been a source of drugs in multiple applications, including the treatment of malaria infections. The Cabo Verde archipelago harbors a rich diversity of native plants, most of which are used for medicinal purposes. The present study investigated the in vitro antiplasmodial activities of four native plants from Cabo Verde (i.e., Artemisia gorgonum, Lavandula rotundifolia, Sideroxylon marginatum, and Tamarix senegalensis). Traditional preparations of these medicinal plants, namely aqueous extracts (infusions) and ethanolic extracts, were tested against both chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum strains using the SYBR Green detection method. The in vitro cytotoxicity was evaluated in Caco-2 and PLP2 cells using a sulforhodamine B colorimetric assay. An ethanolic extract of A. gorgonum and infusions of T. senegalensis exhibited high antiplasmodial activities (EC50 < 5 µg/mL) without cytotoxicity (GI50 > 400 µg/mL). Extracts of L. rotundifolia and S. marginatum exhibited moderate activities, with EC50 values ranging from 10–30 µg/mL. The A. gorgonum ethanolic extract showed activity toward early ring stages, and parasites treated with the T. senegalensis infusions progressed to the early trophozoite stage, although did not develop further to the late trophozoite or schizont stages. Antimalarial activities and the lack of cytotoxicity of the extracts are reported in the present study and support previous claims by traditional practitioners for the use of these plants against malaria while suggesting their ethnopharmacological usefulness as future antimalarials.
- Antimalarial and cytotoxic activity of native plants used in Cabo Verde traditional medicinePublication . Essoh, Anyse P.; Cassiano, Gustavo Capatti; Mandim, Filipa; Barros, Lillian; Gomes, Isildo; Medeiros, Márcia Melo; Moura, Mónica; Cravo, Pedro Vitor Lemos; Romeiras, Maria M.Medicinal plants have historically been a source of drugs in multiple applications, including the treatment of malaria infections. The Cabo Verde archipelago harbors a rich diversity of native plants, most of which are used for medicinal purposes. The present study investigated the in vitro antiplasmodial activities of four native plants from Cabo Verde (i.e., Artemisia gorgonum, Lavandula rotundifolia, Sideroxylon marginatum, and Tamarix senegalensis). Traditional preparations of these medicinal plants, namely aqueous extracts (infusions) and ethanolic extracts, were tested against both chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum strains using the SYBR Green detection method. The in vitro cytotoxicity was evaluated in Caco-2 and PLP2 cells using a sulforhodamine B colorimetric assay. An ethanolic extract of A. gorgonum and infusions of T. senegalensis exhibited high antiplasmodial activities (EC50 < 5 g/mL) without cytotoxicity (GI50 > 400 g/mL). Extracts of L. rotundifolia and S. marginatum exhibited moderate activities, with EC50 values ranging from 10–30 g/mL. The A. gorgonum ethanolic extract showed activity toward early ring stages, and parasites treated with the T. senegalensis infusions progressed to the early trophozoite stage, although did not develop further to the late trophozoite or schizont stages. Antimalarial activities and the lack of cytotoxicity of the extracts are reported in the present study and support previous claims by traditional practitioners for the use of these plants against malaria while suggesting their ethnopharmacological usefulness as future antimalarials.