The genus Landolphia P.Beauv. (Apocynaceae): A comprehensive review on its ethnobotanical utilizations, pharmacology and nutritional potential.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Landolphia is an important resource for African traditional medicine. Among the 60 different accepted species, nearly every plant part of the genus (bark, fruit, latex, leaf, leaf sap, root, rootbark, twig) from 13 species is utilized by traditional healers around Africa. Accordingly, many pharmacological studies (42) were performed on the most common species (11). AIM OF THE STUDY: This comprehensive literature review summarizes all publications dealing on one of the 60 plant species from the genus Landolphia. An overview about already performed analysis is given and important aspects and knowledge gaps are highlighted for the direction of future research activities. MATERIALS AND METHODS: A systematic web search taking into account the major platforms Web of Science, Scopus, PubMed, SciFinder and Google Scholar was performed for the term Landolphia. All relevant datasets, published between 1804 and 2022, were ordered according to their topics in different sections and compared to each other. A network visualization of the keywords via VOS Viewer was additionally performed. RESULTS: In total, 209 publications were retrieved from the search engines, mainly written in English. Predominant are ethnopharmacological studies, which identified 292 phytochemicals in plant parts of the whole genus. Diverse biological activities were detected in different plant extracts, and five species were determined as of special interest for the treatment of malaria. Further research topics identified are botanical aspects, ethnobotanical utilizations, ecological aspects, the potential as source for human and animal nutrition, the manufacturing of rubber, economic aspects, biomechanical studies and others. L. owariensis is the most studied plant as it is abundant in continental Africa. CONCLUSIONS: This review serves as a database for upcoming research on the genus Landolphia and directs existing knowledge gaps. A wide range of chemical components are already identified, but their exact content in the respective plant parts and their biological activity remains mainly unknown. Utilization patterns from traditional medicine are only partially analyzed as demonstrated for the applications as aphrodisiac, to treat skin diseases or as antidiabetic. Nutritional analyses likewise focus on several species of Landolphia and lack for the wide range of known edible fruits. The demand for new natural products in terms of medicine, rubber and nutrition is still high and the genus Landolphia seems to be a promising resource covering many aspects at once.

Bioassay-Guided Isolation of Anti-Inflammatory Constituents of the Subaerial Parts of Cyperus articulatus (Cyperaceae).

Based on data from a previous ethnobotanical study in northern Angola, phytochemical investigations into the methanolic rhizomes and roots extract of Cyperus articulatus, monitored by in vitro assays, resulted in the recovery of 12 sesquiterpenes, 3 stilbenes, 2 phenolic acids, 1 monoterpene, and 1 flavonoid. Among them, 14 compounds were isolated for the first time from this species. Their inhibitory potential against nitric oxide (NO) production, as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, was evaluated in LPS-treated J774A.1 murine macrophages. Especially, both stilbene dimer trans-scirpusin B and trimer cyperusphenol B showed promising inhibitory activity against the production of the inflammatory mediator, NO, in a concentration-dependent manner (10−1 µM). The obtained data are the first results confirming the anti-inflammatory potential of C. articulatus and support its indigenous use as a traditional remedy against inflammation-related disorders.

Plants, food and treatments used by BaKongo tribes in Uíge (northern Angola) to affect the quality and quantity of human breast milk.

BACKGROUND: Angola has one of the highest annual under-five mortality rates in in the world and malnutrition poses a severe problem in the country. This study is the first to focus on the traditional knowledge of plants, foods, and treatments used by the local population in the province of Uíge to affect the quality and quantity of human breast milk, since decades of independence and civil war impeded ethnobotanical studies in this area. METHODS: This study was conducted in eight municipalities in the province of Uíge, Northern Angola in February and March 2018. In 265 semi-structured interviews, 360 informants in 40 rural villages were asked about plants, food, and treatments used to affect the quality and quantity of human breast milk. Additionally, information on child mortality and the duration of breastfeeding were collected. Whenever possible, plant specimens were collected for later identification. To determine the local importance of the collected plants, food, and treatments, the Relative Frequency of Citations was calculated. RESULTS: Most women reported to have no problems with their breast milk production. The duration of breastfeeding meets the recommendations of the World Health Organization (WHO). Across all use categories, 69 plants from 36 plant families, and 21 other foods and treatments could be identified. CONCLUSIONS: The study shows an overview of a variety of plants, foods, and treatments used by mothers as galactagogues, to "clean" or to reduce their breast milk and those which they avoided to use during the lactation period. There is great potential for further research into this traditional knowledge. Also, further analysis of some of the plants could be of interest.

Stories told by plants on graveyards in Northern Angola.

BACKGROUND: Worldwide, different traditions of symbolic statements in graveyards can be found. However, studies on sub-Saharan Africa are rare. For BaKongo cemeteries, it is only known that they traditionally do not exhibit plants for decoration purposes. Our study wanted to inspect the influence of Portuguese culture due to the long shared colonial past. METHODS: During 2015 and 2019, plant use in 87 graveyards in 13 municipalities of the province Uíge was documented. Five expert interviews with the village eldest in five municipalities completed the data collection. RESULTS: While 24% of the graveyards didn´t have any planting, 27 plant species were found in the remaining ones, including a high percentage of alien species (59%), mainly from the Americas. The most abundant plant species are Euphorbia tirucalli (23%) and Agave sisalana (22%). With increasing distance from the city Uíge (especially towards the Democratic Republic of the Congo), the utilization of living plants in cemeteries is decreasing except along the road. In most of the cases, just one plant species per gravesite was found. CONCLUSIONS: This unexpected high number of plants might be interpreted as a strong evidence of outside influence. Cultural symbols of the BaKongo cosmology and Christianism appear to coexist or coalesce. Furthermore, plants are used as a marker for graveyards. Modern influences like the use of concrete in proximity to urban areas indicate a certain wealth.

Umbrella leaves-Biomechanics of transition zone from lamina to petiole of peltate leaves.

In this study we aim to show how the peltate leaves of Colocasia fallax Schott and Tropaeolum majus L., despite their compact design, achieve a rigid connection between petiole and lamina. We have combined various microscopy techniques and computed tomography (CT) scanning for the analysis of the basic structure of the plant's stabilization system. Mechanical tests yielded key mechanical parameters and allowed us to assess the mode of failure. The results of the tests were further processed in a finite element method (FEM) analysis. We were able to show that both plants are able to endure high loads irrespective of the different composition of the supporting structure. C. fallax forms many separate branched strands, whereas T. majus forms fewer strands of greater diameter interconnected in the centre of the transition area, forming a bundle of irregular orientation. This results in different ways to dissipate loads on the lamina. In C. fallax we observed the outer strands of the strengthening tissue under high stress while the inner bundle carries little load. In T. majus the load is distributed more evenly through the juncture in the middle of the transition area. Potential applications include the construction of biomimetical flying roofs.

First large-scale ethnobotanical survey in the province of Uíge, northern Angola.

BACKGROUND: Angola suffered a long-lasting military conflict. Therefore, traditional knowledge of plant usage is still an important part of cultural heritage, especially concerning the still very poor health care system in the country. Our study documents for the first time traditional knowledge of plant use of local Bakongo communities in the northern province of Uíge on a large scale with a focus on medicinal plants and puts data in context to different parameters of age, gender and distance to the provincial capital. METHODS: Field work was carried out during nine field trips in 13 municipalities between October 2013 and October 2016. In 62 groups, 162 informants were interviewed. Herbarium specimens were taken for later identification. Database was analysed using Relative Frequency of Citations, Cultural Importance Index, and Informant Consensus Factor. Furthermore, significances of influence of age, gender and distance were calculated. RESULTS: Our study presents 2390 use-reports, listing 358 species in 96 plant families, while just three out of 358 mentioned species are endemic to Angola about one-fifth are neophytes. The larger the distance, the higher the number of use citations of medical plants. Although women represent just a fifth of all citations (22%), their contribution to medicinal plants was proportionally even higher (83%) than those of men (74%). Fifty percent of all plants mentioned in the study were just listed by men, 12% just by women. We made some new discoveries, for example. Gardenia ternifolia seems to be promising for treatment of measles, and Annona stenophylla subsp. cuneata has never been ethnobotanically nor phytochemically investigated. CONCLUSIONS: While the study area is large, no significant influence of the distance in regard to species composition in traditional healer's concepts of the respective village was pointed out. Although several plants were just mentioned by women or men, respectively, no significant restriction to gender-specific illnesses in medical plant use could be found. Merely concerning the age of informants, a slight shift could be detected. Visual representation of the ethnobotanical study in Uíge, northern Angola.

Medicinal plants of northern Angola and their anti-inflammatory properties.

ETHNOPHARMACOLOGICAL RELEVANCE: 32 plants, from which 30 are used in local traditional medicine - identified by interviews with the resident population - in the province of Uíge in northern Angola for the treatment of inflammation related disorders, were screened on different anti-inflammatory parameters. Three extracts were selected for a detailed ethnobotanical, pharmacological and phytochemical investigation based on their in vitro activity. AIM OF THE STUDY: We aimed to assess the in vitro anti-inflammatory activity of these plants and highlight the active principles of the three most promising candidates. MATERIALS AND METHODS: Plant material was collected in northern Angola during eight field trips from 2013 to 2015 based on data documented in 61 interviews with 142 local informants. 36 methanol (MeOH) extracts were prepared and tested at different concentrations (100, 50, 10µg/mL) to evaluate their inhibition on cyclooxygenase (COX)-2 expression and on nitric oxide (NO) release in lipopolysaccharide (LPS)-stimulated J774A.1 macrophages. Five selected extracts were additionally tested at the lower concentrations of 5, 2.5, and 1.25µg/mL and for their potential on inhibition of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) release. The major compounds of three of those five extracts were either identified by HPLC coupled with (tandem) mass spectrometry and comparison with data from literature or isolated from the respective extracts and confirmed by NMR experiments (one and two dimensional). RESULTS: 30 plant species with in total 161 citations were mentioned by the informants to have anti-inflammatory properties. The predominantly used plant part is the leaf (39%), followed by underground organs like roots and rhizomes (25%), bark (18%) as well as fruits and seeds with 15%. With 47%, decoction is the most frequent preparation form. A large number of the MeOH extracts showed promising activities in our preliminary screening for the inhibition of COX-2 expression and NO release. Five extracts with high activities in both assays showed also concentration dependent inhibition at lower concentrations and a decreased release of two additional pro-inflammatory mediators (IL-6 and TNF-α) vs. LPS. Three leaf extracts where chosen for a detailed investigation, which lead to the identification of several constituents: verbascoside and isoverbascoside (Acanthus montanus), geraniin, chebulagic acid and a large flavonoid fraction (Alchornea cordifolia) as well as the four flavonoids astilbin, isovitexin, isoorientin and swertisin (Chaetocarpus africanus). Their implication in the observed biological activity was proved by comparison with published data of these compounds in identical or similar pharmacological models. CONCLUSIONS: The indigenous use of these plants against inflammation related ailments could be - at least partly - verified by our in vitro models for many of the investigated extracts. Acanthus montanus and Alchornea cordifolia particularly stood out with their high activity in all four performed assays, which was in accordance with pharmacological studies of their major constituents in literature. In addition, this study was the first phytochemical investigation of Chaetocarpus africanus and first description of the occurrence of the ellagitannins geraniin and chebulagic acid in Alchornea cordifolia. These results support the traditional use and should encourage further investigations of medicinal plants of northern Angola.

Plants from disturbed savannah vegetation and their usage by Bakongo tribes in Uíge, Northern Angola.

BACKGROUND: This study represents the first in-depth ethnobotanical study in the province of Uíge in northern Angola and documents the traditional knowledge of the Bakongo people living in the area. Due to deforestation and frequent fires, degraded savannahs dominate the landscape in the study region. Here we provide a list of useful plants from these savannahs including quantitative data about cultural importance of the respective species, aiming on the one hand to conserve the local knowledge and on the other hand to create a reliable basis for research projects in the region. METHODS: Field work was conducted in April and May 2014 in 5 municipalities of Uíge province. The study is based on 32 semi-structured and free-listing interviews, group discussions of varying scope and 14 field trips, involving a total of 82 informants. Throughout the course of the study herbarium specimens of the useful species were collected for later identification. Cultural importance index was applied to analyse the data sets recorded and to determine the best-known useful species in the region. All data sets were compared to the literature available for the region. RESULTS: The study documents a total of 498 citations for the use of 122 plants from 48 families, 34.0 % of which were unknown according to the literature used for comparison. The high amount (71 %) of medical use-reports indicates that plants still play a crucial role in rural health care. We identified 14 plant species of special interest for pharmacological analysis. Species of highest cultural importance are Annona senegalensis Pers. and Sarcocephalus latifolius (Sm.) E.A., both of which are frequently found in disturbed savannahs. CONCLUSIONS: The study points out the importance of savannahs even if degraded in terms of useful plants and provides a valuable addition to current knowledge of plant use in Northern Angola. This is not only essential for further studies, i.e. regarding pharmaceutical agents, but also for the design of a planned botanical garden of the University Kimpa Vita in Uíge, which aims at communicating the findings to the local people.