African Tree Research Articles

Germination Dynamics of Crateva adansonii D.C. and Sarcocephalus latifolius (Smith) Buce: Key Forest Trees of Burkina Faso

Crateva adansonii D.C. (Capparaceae) and Sarcocephalus latifolius (Smith) Buce (Rubiaceae) are two African tree species widely known as multipurpose species for rural populations. Unfortunately, these species are threatened in their natural stands by inappropriate management practices. In addition, their germination capacities are poor in their natural stands Our hypothesis is that the seeds of both species are capable of germination under certain conditions of temperature, light and germination medium. This work aims to study the germination capacity of these species under different conditions. Germination tests were carried out in the laboratory and in the field. 400 seeds of C. adansonii were used in five treatments and 960 seeds of S. latifolius in six treatments. Blotting papers and soil were used as media. Seeds were germinated under different temperature and light conditions over a period of 30 days. A seed was germinated when part of the embryo appeared. The maximum germination rate was obtained after 28 days for C. adansonii and 22 days for S. latifolius. The results show that the best germination rates of C. adansonii (85%) and S. latifolius (82%) are obtained when the seeds are exposed to white light for 12 hours, alternating with 12 hours of darkness. For generative propagation of these plants, it is recommended to germinate the seeds under optimal conditions and then to plant them instead of sowing them in the field.

Draft genome sequence of Kei apple, an underutilized African tree crop

To address food and nutrition security in the face of burgeoning global populations and erratic climatic conditions there is a need to include nutrient dense, climatic resilient but neglected indigenous fruit trees in agrifood systems. Here we present the draft genome sequence of Kei Apple, Dovyalis afra, a neglected indigenous African fruit tree with untapped potential to contribute to nutrient security and improved livelihoods. Our long-read-based genome assembly comprises 440 Mbp sequence across 1190 contigs with a N50 and L50 of 13.3 Mbp and 11, respectively. We also annotated the genome and identified 27,449 protein-coding genes. Our genome assembly provides a valuable resource for unlocking the food security and nutraceutical potential of Kei apple.

A Novel Study on the Chemical Profiling of Okoubaka Aubrevillei Edible Seed Oil Using GC-MS Analysis and Evaluation of its Corrosion Inhibition Properties on Mild Steel Using Molecular Dynamic (MD) Studies

Tropical African parasitic tree species known as Okoubaka aubrevillei has both culinary and medical purposes. The oil in the seeds of this tree is abundant yet little is understood. Gas chromatographymass spectrometry (GC- MS) was used in this work to examine the chemical makeup and physical characteristics of Okoubaka aubrevillei seed oil and molecular dynamic (MD) simulations were used to assess the capacity of the oil to inhibit corrosion on mild steel. It was discovered that the oil contains additional components like sterols and phenolic compounds in addition to being high in unsaturated fatty acids, particularly linoleic acid (39.67 %). These substances function as antioxidants and may have positive impacts on human health. With a high adsorption energy value of -353.55 Kcal/ mol, it was also discovered that the oil could firmly adsorb on mild steel surfaces and offer a degree of protection against corrosion. The energy of the lowest unoccupied molecular orbital (ELUMO), the energy of the highest occupied molecular orbital (EHOMO), the energy gap (ΔE) between LUMO and HOMO, and the Mulliken charges on the backbone atoms were all determined through optimization with HOMO and LUMO energy values of -5.377 and -0.824 eV, respectively. The findings of this study point to Okoubaka aubrevillei seed oil as a possible edible oil source with great potential for mild steel corrosion inhibition and potential for use in a variety of applications.

Species delimitation and phylogenomics of economically important African Pterocarpus trees, with an implication for the development of DNA-based species identification tools.

Reliable species delimitation is fundamental for establishing clear and equitable guidelines on the sustainable harvest of economically important organisms. Pterocarpus (Fabaceae) is a pantropical tree genus including several highly valuable timber-producing species, that face significant threats from intensive logging. However, a lack of taxonomic clarity has hindered the advance of logging regulations and has led to the inclusion of all African Pterocarpus populations under CITES regulations (CoP19). In our study, we addressed this issue by reassessing species delimitation of all twelve accepted African Pterocarpus species, including neotropical samples of the two trans-Atlantic species. Based on DNA sequences obtained by the Angiosperms353 probe set, we reconstructed a comprehensive phylogeny applying maximum likelihood and multispecies coalescent approaches. Additionally, we explored the potential of high-copy DNA for identifying African Pterocarpus species. This involved reconstructing chloroplast and ribosomal DNA phylogenies, using genome skimming and maximum likelihood approaches. Our results confirmed the monophyly of eleven Pterocarpus species and a paraphyletic P. rotundifolius, which presented geographically coherent subclades, suggesting the possibility of cryptic diversity within the complex. A similar situation arose in P. lucens, exhibiting two sister clades with disjunct distributions. Species delimitation based on high-copy DNA was congruent with the Angiosperms353 data for most species, indicating the reliability of chloroplast and ribosomal DNA markers for Pterocarpus species identification. Our findings give valuable insights into African Pterocarpus species delimitation, highlighting the need for further investigation of potential cryptic diversity within a clade including P. rotundifolius, P. brenanii and P. lucens. Finally, our study lays the groundwork for developing DNA-based tools aimed at improving logging regulations for African Pterocarpus species.

Tracing the range shifts of African tree ferns: Insights from the last glacial maximum and beyond

African tropical forests are experiencing rapid decline as a result of several factors, including increasing population pressure, recurrent wildfires, selective logging practices, land use changes, intensified agricultural activities, and other social and economic issues. Using MaxEnt, paleoclimatic data, and future climate scenarios, the present study seeks to explore the presence of tree ferns in tropical and Saharan Africa during the Last Glacial Maximum, African Holocene Humid Period (AHHP; ca. 14,500–5000 years ago) and to project the effects of climate change on the distribution of tree ferns in Africa under two future climatic scenarios, Representation Concentration Pathways (RCP) 4.5 and 8.5. Our study reveals that despite a significant increase in precipitation during the AHHP, precipitation distribution was variable and insufficient to support the five tree fern species examined in this study. While some tree fern species have experienced range shifts over time, we found that most of them have maintained their presence within refuge areas that probably endured the late Pleistocene extinction event. These refugia provided a haven for some tree ferns, allowing them to persist and survive amidst challenging and varying environmental conditions. This highlights tree ferns' remarkable adaptability in changing climate as well as the critical importance of these refugial areas in safeguarding their populations during climatic upheaval. Our study further demonstrates that different species respond to climate change differently, with some experiencing minimal range contractions of 2.0 %, up to more than 57.0 % range expansion in other species. Preserving refugia not only safeguards tree fern populations but also contributes to conserving overall forest biodiversity and ecosystem functioning. This knowledge is crucial for implementing targeted conservation actions that promote sustainable forest management and can mitigate the threats posed by climate change and anthropogenic activities in African closed wet forests.

Perception on the conservation of Phataginus tricuspis, reflections on OECM sites in Osun State, Nigeria

This study evaluates local communities’ knowledge, attitude, and perception towards the critically endangered African Tree Pangolin and its conservation in the 15 identified Other Effect Area Based Conservation Measures (OECM) sites in Osun State, Nigeria. 360 participants aged 20 and older participated in the study, which found that 90.33% supported the presence of African Tree Pangolin. However, 61% affirmed that their population is reducing due to hunting and habitat loss from poor agriculture. 67% of interviewees believed that benefits from wildlife through tourism, insect regulation, bush meat, and medicine influenced their attitudes and perceptions towards conservation. 33% of the local population changed their attitude and perception towards conservation. African Tree Pangolin conservation was deemed a priority by those with higher levels of education, but the majority of respondents claimed that the idea was unsupported because of the high revenue generated by Pangolin sales. Increasing public awareness through media, handbills, billboards, seminars, and films could help mitigate poor attitudes towards African Tree Pangolin conservation.

Energy Potential and Properties of Agro Biomass Briquettes with Nano Kaolin Binder for Sustainable Environment

The utilization of Tanner’s Cassia waste (T) and African Wonder tree waste (A) in the biomass production chain presents an opportunity for generating value-added products and enhancing productivity. Incinerating these wastes can pose environmental challenges; however, transforming them into briquettes offers a sustainable approach to produce high-energy fuel. This study investigated various mixtures of Tanner’s Cassia and African Wonder Tree waste, denoted as TA1 (0:100), TA2 (25:75), TA3 (50:50), TA4 (75:25), and TA5 (100:0), with the addition of 20% nano kaolin as a binder. The resulting briquettes underwent thorough analysis including physical, SEM and elemental analysis. The density of the TA briquettes ranged from 836.38 to 1105. 57 kg/m3. Key metrics evaluated include ash content, moisture content, volatile content, and fixed carbon content. The results for TA1 (0:100) are 11.22% ash, 5.73% moisture, 69.39% volatile, and 13.66% fixed carbon, while for TA5 (100:0), they are 14.17% ash, 9.87% moisture, 58.07% volatile, and 17.89% fixed carbon, showing a trend of increasing ash and fixed carbon content and decreasing moisture and volatile content across the samples. The SEM analysis of the briquettes reveals distinct characteristics for each mix ratio. Energy Dispersive X-ray analysis indicated carbon and oxygen as the major elements, with 54.48 wt.% and 37.92 wt.%, respectively. These findings highlight the potential of TA briquettes with a 20% nano kaolin binder as a viable alternative energy source due to their low moisture and ash content, coupled with a high calorific value.

Four new Geosmithia species from bark beetles infesting indigenous South African trees

Over the past two decades, numerous Geosmithia fungi have been isolated from the bodies and galleries of wood–boring beetles. However, this genus of asexual Sordariomycetes remains taxonomically and ecologically understudied, especially in the Southern Hemisphere. In South Africa, two prior surveys reported Geosmithia species from bark beetles, but neither thoroughly investigated species identities. In this study, we collected bark beetles from native trees in the Western Cape Province of South Africa and isolated, identified and described their associated Geosmithia species. Geosmithia spp. previously collected in South Africa were also re-examined. The ITS sequences of Geosmithia isolates from 13 beetle taxa infesting 10 host species were considered. Additional gene regions, BT, EF1a and RPB2, were sequenced for a subset of isolates. Four previously described species, G. flava, G. langdonii, G. omnicola and G. pumila were identified by phylogenetic analyses. Additionally, four novel taxa were identified and are here described as G. capensis, G. multisociorum, G. oroboidis and G. stellenboschiana. Geosmithia multisociorum appears to be a generalist associated with multiple beetle–host combinations in the Northern and Southern Hemisphere, whereas G. oroboidis is currently known only from a single beetle and tree host in South Africa. South African isolates of G. capensis and G. stellenboschiana appeared to be restricted to Lanurgus spp. and Hypothenemus sp. beetles, respectively, but both species are also known from beetles and hosts in other countries.

Leaf gas exchange, water use, and yield of Marula (Sclerocarya birrea) and Kei Apple (Dovyalis caffra): South African indigenous fruit trees with domestication potential

Conventional crop production is expected to decline in the future in sub-Saharan Africa due to the rising costs of inputs, soil degradation, and increasing water scarcity related to climate variability and change. South Africa has more than 30 species of indigenous fruit trees that are adapted to grow under harsh conditions, yet these species are currently underutilized. Their cultivation is constrained by the lack of detailed ecophysiological information required to develop effective management strategies that optimize tree performance. In this study we investigated how two species with domestication potential namely Marula (Sclerocarya birrea) and Kei apple (Dovyalis caffra) responded to climate and soil factors over a period of two years (2019–2021). Photosynthesis, transpiration, and yield were quantified for mature trees growing in experimental orchards in the Mpumalanga Province of South Africa. Leaf gas exchange data were collected at selected intervals during the growing season using an infrared gas analyser while whole tree transpiration rates were quantified using the heat ratio method of monitoring sap flow. These data were used to parameterize a big leaf Penman-Monteith (PM) model to estimate the transpiration dynamics of individual trees at the daily time step. S. birrea's transpiration responded strongly to both climatic and soil water content variations while the water use of D. caffra was driven mostly by climatic factors. Transpiration rates averaged 0.30 L/m2 of leaf area for S. birrea while that of D. caffra was around 0.45 L/m2. Both species exhibited significant alternate bearing with yield of individual trees fluctuating by more than 50 % between successive years. For the 2019/20 season, water productivity (grams of fruit per litre of water transpired) varied between 6.2 and 17.4 g/L for S. birrea and between 24.3 and 41.7 g/L for D. caffra. Whole tree transpiration by both species were accurately predicted using the PM model albeit with different parameters for each species. This study demonstrates that a simple PM model can accurately estimate the water requirements of these species in other growing regions.

Proximate Analysis and Occurrence of Antibiotic Resistant Escherichia coli in Street Vended Ready to Eat Edible Larvae of Rhynchophorus phoenicis in Port Harcourt, Nigeria

Rhynchophorus phoenicis, known as the African palm tree larva weevil or edible worm, is a popular edible insect in southern Nigeria and other African countries. These larvae, by-products of oil palm and palm trees, are consumed roasted or boiled and are known for their nutritional and medicinal properties. In Nigeria, they are widely sold along highways in states like Bayelsa, Delta, Edo, Imo, Rivers, and the upper Cross River basin. Preparation methods include consuming them raw, boiled, fried, smoked, or in stews and soups. Typically, the larvae are washed, skewered, sprinkled with salt and pepper, and grilled. They are juicy and have a taste reminiscent of Torzo or cow intestines. Despite their popularity, edible worms pose safety and health concerns due to contamination and the emergence of antimicrobial-resistant bacteria. The indiscriminate use of antimicrobials in animals and humans has led to the development of resistant microorganisms, including multidrug-resistant Escherichia coli, which has been increasingly reported in food poisoning outbreaks. There is limited data on the incidence and antibiotic resistance of Escherichia coli in ready-to-eat foods in Nigeria, prompting this study. The study aimed to determine the proximate composition, occurrence, and antibiotic-resistant pattern of Escherichia coli from edible larvae (Rhynchophorus phoenicis). Objectives included determining the proximate composition of the larvae, the occurrence of Escherichia coli in them, and their antibiotic susceptibility pattern. Fifty ready-to-eat food samples of edible larvae were randomly collected from hawkers. These samples, often partially exposed and poorly packaged, were transported to the microbiology laboratory for analysis. Sterilized glassware and media were used, including Nutrient Agar, Eosin Methylene Blue (EMB) Agar, and Mueller Hinton Agar. Samples were diluted using peptone water, and bacteriological determination involved homogenizing 25 grams of the sample in 225 ml of peptone water, followed by serial dilutions. Aliquots were inoculated on EMB Agar plates, and incubated at 37°C for 24 hours, and colonies were counted and recorded as colony-forming units per gram (cfu/g). Isolates were identified using standard microbiological methods and biochemical tests. Proximate analysis revealed moisture (35.49%), carbohydrate (6.01%), protein (20.73%), ash (1.25%), lipid (22.3%), and fiber (14.23%) content. Bacterial counts ranged from 8.1 x 10^7 to 6.34 x 10^8 cfu/g, with the highest count at the Checkpoint sample and the lowest at Elele-Alumini. Of the 27 isolates, 15 (55.56%) were confirmed as E. coli, with 18.52% of samples exceeding the acceptable microbiological limit (≥10^7 CFU/g). Antibiotic susceptibility tests showed all isolates resistant to augmentin, penicillin, cephalosporin, and ofloxacin, with 46.67% resistance to sulfamethoxazole and streptomycin.

Traditional taboos: informal and invisible protection of remaining patches of forest in Vhembe District in Limpopo, South Africa

IntroductionSince 1990, there has been a global decline in forest areas. Between 2010 and 2020, the greatest annual net loss of forests was on the African continent. Despite South African indigenous forests and trees being protected under the National Forests Act of 1998 (Act No. 84 of 1998), the country has also shown an increased annual net loss of forests. Although the Vhembe District Municipality in South Africa has lost forest owing to human-induced deforestation and other land use activities, sacred forests have not been affected. According to traditional beliefs, exploitation of such indigenous patches of sacred forests is taboo. This study aims to explore the role of taboos in the protection of the remaining patches of sacred forest.MethodsThe study relies on data collected between December 2022 and December 2023. Semi-structured interviews were conducted with key informants (n = 61) and local communities in Tshidzivhe and Duthuni villages (n = 60). Observations were used as a further data collection tool. The interview questions were prepared to assess the role of taboos in the protection and management of sacred forests. Data collected through interviews were analysed using thematic content analysis, while field observations helped to corroborate the results from the interviews. Results and discussionThe study identified two main taboos – one that restricts entry into the sacred forests (i.e. preventing entry into the sacred forests, and harvesting, hunting and hiking in these areas), and another that prohibits noise or activities that disrespect sacred forests. The study found that believers and non-believers alike, for fear of retribution by the spirits, still obey these taboos and their related myths. This has allowed these areas to develop dense stands of closed-canopy evergreen forest that support more diverse flora and fauna than found in surrounding areas. Although sacred forests are not meant for biodiversity conservation, they offer opportunities to be integrated into global conservation targets of “30x30” and “Half-Earth” by 2030. They also offer the opportunity of serving as carbon sinks which is key to climate change mitigation. Recommendations for protecting sacred forests and associated taboos are drawn up based on these results.

Millettia dubia De Wild. (Fabaceae): Structural analysis of the oleanane-type glycosides and stimulation of the sweet taste receptors TAS1R2/TAS1R3

From the root barks of a Central African tree Millettia dubia De Wild. (Fabaceae), ten previously undescribed oleanane-type glycosides were isolated by various chromatographic protocols. Their structures were elucidated by spectroscopic methods, mainly 2D NMR experiments and mass spectrometry, as mono- and bidesmosidic glycosides of mesembryanthemoidigenic acid, hederagenin and oleanolic acid. The stimulation of the sweet taste receptor TAS1R2/TAS1R3 by these glycosides was evaluated, and structure/activity relationships were proposed. Two of them showed an agonist effect on TAS1R2/TAS1R3.

Effects of habitat biotic features on hymenopteran diversity in East Africa

PurposeOriginally, the coastal region of East Africa was largely covered with coastal forest. With the human settlement, the majority of these forests have been transformed into agricultural land for subsistence farming. Today, only small and geographically isolated forest remnants exist and form a mosaic of different habitat types, including natural, semi-natural and anthropogenic ones. The forest remnants may still represent valuable habitats for typical forest plant and animal species.MethodsIn this study, we surveyed hymenopteran diversity and community composition in different habitat types in southern Kenya. Hereby we considered a small remnant of East African coastal forest, adjoining orchards, shrublands, tree plantations, agricultural fields, and settlements. Hymenoptera represent a large variety of taxa and provide relevant ecosystem services such as pollination to the local people. Hymenoptera were collected with coloured pan traps, identified to family or genus level, and sorted to morphospecies. Habitat parameters such as dead wood, leaf litter, vegetation structure, and the availability of flowers has been assessed for each study site.ResultsIn total, we found 419 Hymenoptera individuals of 153 morphospecies. The different habitat types showed distinct species communities of Hymenoptera. Increasing shrub layer and increasing herb cover had a negative effect on hymenopteran species richness and abundance. Flowers, trees, leave litter, and deadwood showed no significant effect on hymenopteran diversity.ConclusionOur results underline that small-scale habitat diversity lead to high overall diversity of Hymenoptera. Implications for insect conservation: The coastal forest remnant still holds a unique hymenopteran community with 20 Hymenoptera species exclusively found in this habitat type. It is thus of very high conservation value.

Arbuscular mycorrhizal fungal diversity and potential association networks among African tropical forest trees.

Tropical forests represent one of the most diverse and productive ecosystems on Earth. High productivity is sustained by efficient and rapid cycling of nutrients, which is in large part made possible by symbiotic associations between plants and mycorrhizal fungi. In these associations, an individual plant typically associates simultaneously with multiple fungi and the fungi associate with multiple plants, creating complex networks among fungi and plants. However, there are few studies that have investigated mycorrhizal fungal composition and diversity in tropical forest trees, particularly in Africa, or that assessed the structure of the network of associations among fungi and trees. In this study, we collected root and soil samples from Ise Forest Reserve (Southwest Nigeria) and used a metabarcoding approach to identify the dominant arbuscular mycorrhizal (AM) fungal taxa in the soil and associating with ten co-occurring tree species to assess variation in AM communities. Network analysis was used to elucidate the architecture of the network of associations between fungi and tree species. A total of 194 Operational Taxonomic Units (OTUs) belonging to six AM fungal families were identified, with 68% of all OTUs belonging to Glomeraceae. While AM fungal diversity did not differ among tree species, AM fungal community composition did. Network analyses showed that the network of associations was not significantly nested and showed a relatively low level of specialization (H2 = 0.43) and modularity (M = 0.44). We conclude that, although there were some differences in AM fungal community composition, the studied tree species associate with a large number of AM fungi. Similarly, most AM fungi had great host breadth and were detected in most tree species, thereby potentially working as interaction network hubs.

The medical use of Málaka wine and cola nuts in late 19th/early 20th century Greece

The lands of Malaka in Spain have been renowned for their wine since the 8th century BC. Malaka wine gained popularity among merchants and consumers since the 17th century, becoming one of Europe’s favourites. The seeds (nuts) of the African Cola acuminata trees had been used in daily life as an invigorating and stimulating chewing or eating delicacy. In the late 19th century, Stamatios Krinos, who had opened one of the first (or the first) pharmacies in Athens in 1836, and his son Athanasios, produced an Elixir named Krinos Cola Wine to treat neurasthenia, chlorosis, anaemia, indigestion, gastralgia, chronic diarrhoea, cardiopathies, weakness and infertility. The properties of both the wine and the nuts, along with the chemical compounds of cola, were already known by the mid-19th century and the Krinos family took advantage of this knowledge to introduce a novel herbal drug (cola seeds) to the Hellenic pharmacopeia. The properties attributed to the Krinos elixir are de novo and in depth validated today by a series of modern medical studies. The fact that cola was not included as a therapeutic agent in the Hellenic textbooks of pharmacology of that era suggests that Krinos made an innovative addition to the timelessly popular Hellenic herbal medicine and pharmacopeia.

Diversity of Uses and Local Knowledge Associated with Wild African Plum Trees, Dacryodes edulis, Among Different Ethnic Groups in the Congo Basin

Diversity of Uses and Local Knowledge Associated with Wild African Plum Trees, Dacryodes edulis, Among Different Ethnic Groups in the Congo Basin

African Vulture Optimization-Based Decision Tree (AVO-DT): An Innovative Method for Malware Identification and Evaluation through the Application of Meta-Heuristic Optimization Algorithm

Abstract Malware remains a big threat to cyber security, calling for machine learning-based malware detection. Malware variations exhibit common behavioral patterns indicative of their source and intended use to enhance the existing framework’s usefulness. Here we present a novel model, i.e., African Vulture Optimization-based Decision Tree (AVO-DT) to increase the overall optimization. The datasets from Android apps and malware software train the AVO-DT model. After training, the datasets are pre-processed by removing training errors. The DT algorithm is used by the developed AVO model to carry out the detection procedure and predict malware activity. To detect malware activities and improve accuracy, such an AVO-DT model technique employs both static and dynamic methodologies. The other measurements on Android applications might be either malicious or benign. Here we also developed malware prevention and detection systems to address ambiguous search spaces in multidimensionality difficulties and resolve optimization challenges.

In vitro toxicity of latex, its terpenoidal fractions and isolated phorbol esters from Euphorbia umbellata (Pax) Bruyns on monocytic and melanoma cells

In Brazil, latex from Euphorbia umbellata (African milk tree) has been increasingly used in folk medicine to treat several types of cancer, including melanoma. The effect of lyophilized latex (LL), its hydroethanolic extract (E80), triterpene (F-TRI)- and diterpene (F-DIT)-enriched fractions, along with six isolated phorbol esters from LL and phorbol 12-myristate 13-acetate (PMA) on J774A.1, THP-1, SK-MEL-28, and B16-F10 cell line viability were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The compounds were identified by 2D-NMR and HRESIMS. The effect of the LL, extract and fractions on cell viability was also assessed through a resazurin reduction assay. At 100 μg/ml, LL, and its fractions moderately inhibited J774A.1 (37.5–59.5%) and THP-1 (12.6–43.6%) metabolism. LL (IC50 70 μg/ml) and F-TRI (IC50 68 μg/ml) were barely more effective against B16-F10 cells, and only F-TRI exerted an inhibitory effect on SK-MEL-28 cells (IC50 66–75 μg/ml). The samples did not effectively inhibit THP-1 growth (IC50 69–87 μg/ml, assessed by MTT). B16-F10 was susceptible to PMA (IC50 53 μM) and two 12-phenylacetate esters (IC50 56–60 μM), while SK-MEL-28 growth was inhibited (IC50 58 μM) by one of these kinds of esters with an additional 4β-deoxy structure. Synagrantol A (IC50 39 μM) was as effective as PMA (IC50 47 μM) in inhibiting J774A.1 growth in a dose-dependent manner. Furthermore, an in silico study with target receptors indicated a high interaction of the compounds with the PKC proteins. These results provide useful knowledge on the effect of tigliane-type diterpenes on tumor cell from the perspective of medicinal chemistry.

Generalist southern African temperate forest canopy tree species have distinct pollinator communities partially predicted by floral traits

AbstractForest canopies provide important resources for insect communities via flowers. Yet, pollination systems of tall forest trees are poorly studied, resulting from the difficulties in observing pollinator activity at the canopy level and great temporal variation in flower production. In temperate forest canopies of the southern hemisphere, small, whitish and generalist flowers seem to dominate. Here, we observed insect flower visitors, at the canopy level, to four southern Afrotemperate forest tree species bearing small, white to green flowers in a large, indigenous forest. Additionally, we quantified flower traits and collected pollen from representative insect visitors. A total of 105 insect species, from 48 families and 7 orders, were observed visiting flowers. In terms of total flower visits, the generalist Cape honey bee (Apis mellifera capensis) made up ca. 57% of all flower visits. A third of the total observation time covered crepuscular to nocturnal flower visits; yet only 12.68% of total visits took place during this time. Interestingly, despite both trees and insects being largely generalist in their interactions with one another (supported by the presence of conspecific and heterospecific pollen on most flower visitors), some insect species showed strong preferences for specific species of tree, driving dissimilar, interspecific assemblages of flower visitors. The pollinator community disparity may be explained through the unique and dissimilar floral traits for each tree species, both in flower size and in petal reflectance. We conclude that within generalist pollination systems, distinct and non‐random mutualisms can develop between different species of plants and a diverse suite of pollinators, and that floral traits could partially predict such interactions.

Disturbance sensitivity shapes patterns of tree species distribution in Afrotropical lowland rainforests more than climate or soil.

Understanding how tropical forests respond to abiotic environmental changes is critical for preserving biodiversity, mitigating climate change, and maintaining ecosystem services in the coming century. To evaluate the relative roles of the abiotic environment and human disturbance on Central African tree community composition, we employ tree inventory data, remotely sensed climatic data, and soil nutrient data collected from 30 1-ha plots distributed across a large-scale observational experiment in forests that had been differently impacted by logging and hunting in northern Republic of Congo. We show that the composition of Afrotropical plant communities at this scale responds to human disturbance more than to climate, with particular sensitivities to hunting and distance to the nearest village (a proxy for other human activities, including tree-cutting and gathering). These findings contrast neotropical predictions, highlighting the unique ecological, evolutionary, and anthropogenic history of Afrotropical forests.