Garcinia kola: a critical review on chemistry and pharmacology of an important West African medicinal plant.

Garcinia kola Heckel (Clusiaceae) is a tree indigenous to West and Central Africa. All plant parts, but especially the seeds, are of value in local folklore medicine. Garcinia kola is used in treatment of numerous diseases, including gastric disorders, bronchial diseases, fever, malaria and is used to induce a stimulating and aphrodisiac effect. The plant is now attracting considerable interest as a possible source of pharmaceutically important drugs. Several different classes of compounds such as biflavonoids, benzophenones, benzofurans, benzopyran, vitamin E derivatives, xanthones, and phytosterols, have been isolated from G. kola, of which many appears to be found only in this species, such as garcinianin (found in seeds and roots), kolanone (fruit pulp, seeds, roots), gakolanone (stem bark), garcinoic acid, garcinal (both in seeds), garcifuran A and B, and garcipyran (all in roots). They showed a wide range of pharmacological activities (e.g. analgesic, anticancer, antidiabetic, anti-inflammatory, antimalarial, antimicrobial, hepatoprotective and neuroprotective effects), though this has only been confirmed in animal models. Kolaviron is the most studied compound and is perceived by many studies as the active principle of G. kola. However, its research is associated with significant flaws (e.g. too high doses tested, inappropriate positive control). Garcinol has been tested under better conditions and is perhaps showing more promising results and should attract deeper research interest (especially in the area of anticancer, antimicrobial, and neuroprotective activity). Human clinical trials and mechanism-of-action studies must be carried out to verify whether any of the compounds present in G. kola may be used as a lead in the drug development.

Domestication Potential of Garcinia kola Heckel (Clusiaceae): Searching for Diversity in South Cameroon.

Seeds and bark of Garcinia kola Heckel (Clusiaceae) are popular products in West and Central Africa. Despite the tree's economic and cultural importance, little is known about its phenotypic and genotypic variation. This study characterised the morphological and genetic diversity of G. kola in South Cameroon, searching for traits and populations that might be used for domestication. Morphological assessment and amplified fragment length polymorphism (AFLP) markers were applied to characterise diversity among geographic populations from Central and South regions, and between managed and wild trees. AFLP-SURV and analysis of molecular variance results indicated that a major part of genetic diversity is harboured within populations rather than between them. Bayesian analysis, principal component analysis and t-SNE identified three clusters where Ebolowa emerged as the transition population, combining features from both regions. Trees from the south had a higher prevalence of morphological domestication-related characteristics. Trees from the central region, on the other hand, demonstrated greater genetic diversity. No significant differences in phenotype and genotype were revealed between wild and managed populations, suggesting G. kola is still in the early stages of its domestication process.

Correction: Manourová et al. Domestication Potential of Garcinia kola Heckel (Clusiaceae): Searching for Diversity in South Cameroon. Plants 2023, 12, 742.

The original version on the publication [...].

Genetic Diversity and Population Structure of Myanmar Rice (Oryza sativa L.) Varieties Using DArTseq-Based SNP and SilicoDArT Markers.

Myanmar is well known as a primary center of plant genetic resources for rice. A considerable number of genetic diversity studies have been conducted in Myanmar using various DNA markers. However, this is the first report using DArTseq technology for exploring the genetic diversity of Myanmar rice. In our study, two ultra-high-throughput diversity array technology markers were employed to investigate the genetic diversity and population structure of local rice varieties in the Ayeyarwady delta, the major region of rice cultivation. The study was performed using 117 rice genotypes with 7643 SNP and 4064 silicoDArT markers derived from the DArT platform. Genetic variance among the genotypes ranged from 0 to 0.753 in SNPs, and from 0.001 to 0.954 in silicoDArT. Two distinct population groups were identified from SNP data analysis. Cluster analysis with both markers clearly separated traditional Pawsan varieties and modern high-yielding varieties. A significant divergence was found between populations according to the Fst values (0.737) obtained from the analysis of molecular variance, which revealed 74% genetic variation at the population level. These findings support rice researchers in identifying useful DNA polymorphisms in genes and pinpointing specific genes conferring desirable phenotypic traits for further genome-wide association studies and parental selection for recombination breeding to enhance rice varietal development and release.

The influence of land-use on tropical soil chemical characteristics with emphasis on aluminium.

Composition of soil vegetation cover and land management directly influences the cycling of chemical elements and is a key factor for soil biogeochemistry and also Al behaviour. Moreover, Al is an important factor limiting the growth of cultural plants. Our results are based on long-term observations of soils translocated from selected small areas of eight 1 ha plots of different land-use gradient, with identical geological, climatic and geographical conditions, located in the North of Congo Basin (near Mbalmayo, Cameroon). The plots are established in primary and secondary forests, cocoa agroforestry systems and a maize field (two plots per habitat). All soil plots were exchanged between each other in two layers; A. 0-5 cm, and B. 5-20 cm of depths. The soil was sampled at the times 0, +3, +6 months, and soil chemical parameters were determined. The most important differences between the particular habitats comprise of vegetation cover as a consequence of the land management. Particular plots differed mainly in their pH, organic C, exchangeable Al and contents of base cations. The most marked trends comprise of significant decrease of pH, increase of Al and decrease of the Ca/Al ratio in A layer after translocation to the agricultural plots. All translocations resulted into rapid loss of organic C and release of Al, which was more obvious when the forest-to-agriculture translocation took place.

Genetic diversity and structure of baobab (Adansonia digitata L.) in southeastern Kenya.

Baobab (Adansonia digitata L.) is an iconic tree of African savannahs. Its multipurpose character and nutritional composition of fruits and leaves offer high economic and social potential for local communities. There is an urgent need to characterize the genetic diversity of the Kenyan baobab populations in order to facilitate further conservation and domestication programmes. This study aims at documenting the genetic diversity and structure of baobab populations in southeastern Kenya. Leaf or bark samples were collected from 189 baobab trees in seven populations distributed in two geographical groups, i.e. four inland and three coastal populations. Nine microsatellite loci were used to assess genetic diversity. Overall, genetic diversity of the species was high and similarly distributed over the populations. Bayesian clustering and principal coordinate analysis congruently divided the populations into two distinct clusters, suggesting significant differences between inland and coastal populations. The genetic differentiation between coastal and inland populations suggests a limited possibility of gene flow between these populations. Further conservation and domestications studies should take into consideration thegeographical origin of trees and more attention should be paid to morphological characterization of fruits and leaves of the coastal and inland populations to understand the causes and the impact of the differentiation.

Morphological and genetic diversity of camu-camu [Myrciaria dubia (Kunth) McVaugh] in the Peruvian Amazon.

Camu-camu [Myrciaria dubia (Kunth) McVaugh] is currently an important and promising fruit species grown in the Peruvian Amazon, as well as in Brazil, Colombia, and Bolivia. The species is valued for its high content of fruit-based vitamin C. Large plantations have been established only in the last two decades, and a substantial part of the production is still obtained by collecting fruits from the wild. Domestication of the species is at an early stage; most farmers cultivate the plants without any breeding, or only through a simple mass selection process. The main objective of the study was to characterize morphological and genetic variation within and among cultivated and natural populations of camu-camu in the Peruvian Amazon. In total, we sampled 13 populations: ten wild in the Iquitos region, and three cultivated in the Pucallpa region in the Peruvian Amazon. To assess the genetic diversity using seven microsatellite loci, we analyzed samples from ten individual trees per each population (n = 126). Morphological data was collected from five trees from each population (n = 65). The analysis did not reveal statistically significant differences for most of the morphological descriptors. For wild and cultivated populations, the observed heterozygosity was 0.347 and 0.404 (expected 0.516 and 0.506), and the fixation index was 0.328 and 0.200, respectively. Wild populations could be divided into two groups according to the UPGMA and STRUCTURE analysis. In cultivated populations, their approximate origin was determined. Our findings indicate a high genetic diversity among the populations, but also a high degree of inbreeding within the populations. This can be explained by either the isolation of these populations from each other or the low number of individuals in some populations. This high level of genetic diversity can be explored for the selection of superior individuals for further breeding.

Identificación molecular y diversidad genética de las especies de nematodos Globodera rostochiensis y G. pallida en regiones productoras de papa de Guatemala / Molecular identification and genetic diversity of the species of nematodesGlobodera rostochiensisandG. pallidain potato growing regions of Guatemala

En Guatemala, la producción del cultivo de papa se ve afectada por los nematodos Globodera rostochiensis y Globo-dera pallida. La capacidad de ambas especies para formar quistes complica su control y provoca el aumento de sus poblaciones. En Guatemala se reporta la presencia de ambas especies de nematodos por identificación morfológica, sin embargo, no se ha realizado una confirmación molecular. Este es el primer estudio para validar la presencia de ambas especies de nematodos por PCR múltiple y la determinación de la diversidad y estructura genética de las poblaciones utilizando marcadores moleculares. Se realizaron muestreos en cuatro departamentos productores de papa del país. La identificación por PCR se realizó con el cebador común ITS5 y los cebadores PITSr3 específico para G. rostochiensisy PITSp4 para G. pallida. La caracterización molecular se realizó con el marcador AFLP. Se confirmó la presencia de las dos especies de nematodos en los cuatro departamentos. Los índices de diversidad Shannon y heterocigosidad esperada revelaron mayor diversidad genética en G. rostochiensis (H = 0.311, He = 0.301) que en G. pallida (H = 0.035, He = 0.223). Los métodos NJ, DAPC y PCA exhibieron una débil estructura entre las poblaciones de ambas especies de nematodos. Los resultados sugieren un patrón de dispersión desde Quetzaltenango hacia el resto del país, atribuido a la comercialización de semilla contaminada con nematodos. Se sugiere promover programas de socialización sobre los beneficios del uso de semilla certificada, además de constantes monitoreos moleculares para un diagnóstico certero de ambas especies de nematodos.

In Guatemala, potato crop production is affected by the nematodes Globodera rostochiensis and Globodera pallida. The ability of both species to form cysts complicates their control and causes an increase in their populations. In Guatemala, both species of nematodes have been reported by morphological identification; however, molecular confirmation has not been carried out. It is the first study to validate the presence of both nematode species by multiplex PCR and determine the diversity and genetic structure of the populations using molecular markers. Sampling was carried out in four pota-to-producing departments of the country. PCR identification was performed with the common primer ITS5 and the primers PITSr3 specific for G. rostochiensis and PITSp4 for G. pallida. We performed molecular characterization with the AFLP marker. We confirmed the presence of the two nematode species in the four departments. Shannon diversity and expected heterozygosity indices revealed higher genetic diversity in G. rostochiensis (H = 0.311, He = 0.301) than in G. pallida (H = 0.035, He = 0.223). The NJ, DAPC, and PCA methods exhibited weak structure among populations of both nematode species. The results suggest a dispersal pattern from Quetzaltenango to the rest of the country, attributed to the commer-cialization of seed contaminated with nematodes. We suggest promoting socialization programs on the benefits of using certified seeds and constant molecular monitoring for an accurate diagnosis of both species of nematodes.

Eficiencia de solubilización de fósforo de aislados nativos guatemaltecos de Pseudomonas fluorescens / Phosphorus solubilization efficiency of native Guatemalan isolates of Pseudomonas fluorescens

El fósforo (P) es un elemento esencial en la producción agrícola, pero debido a su compleja dinámica en el suelo, solo una pequeña cantidad es aprovechable para las plantas, ya que la mayoría del P se encuentra en formas insolubles, especialmente, en suelos Andisoles de origen volcánico. Los microorganismos con capacidad solubilizadora de fósforo (MSF) son una alternativa para transformar el P a formas solubles y aprovechables por las plantas; además de brindar múltiples beneficios ambientales. Este trabajo identificó y evaluó in vitro, aislados nativos de Pseudomonas fluorescens Mingula, obtenidos de regiones guatemaltecas con suelos Andisoles que limitan la producción agrícola por la alta fijación de P. Se realizaron cultivos in vitro de la bacteria en medio National Botanical Research Instituteís phosphate growth (NBRIP), con fosfato tricálcico Ca3(PO4)2 como fuente de P insoluble y se midió el índice de solubilización de fósforo (ISF). Un total de 35 aislados de P. fluorescensfueron identificados y confirmados por PCR específico. El análisis de relaciones genéticas con el marcador AFLP, mostró dos grupos: el grupo A incluyó a los aislados con ISF mayores a 1.75, mientras el grupo B incluyó a aquellos con ISF menor a 1.75. La comparación de ISF entre los aislados y departamentos, demostró diferencia estadísticamente significativa (p < .001), con el aislado Pf_33 como más eficiente. Debido al potencial de solubilización de los aislados nativos del grupo genético A (ISF > 1.75), estos se recomiendan para futuras investigaciones que determinen su respuesta a condiciones de campo y estrategias para el desarrollo de biofertilizantes.

Phosphorus (P) is an essential element in agricultural production, but due to its complex dynamics in the soil, only a tiny amount is usable by plants. This is because most P is in insoluble forms, especially in volcanic Andisol soils. Microorganisms with phosphorus solubilizing capacity (MSF) are an alternative for transforming P into soluble forms usable by plants and providing multiple environmental benefits. This research identified and evaluated in vitro native isolates of Pseudomonas fluorescens Mingula, obtained from Guatemalan regions with Andisol soils that limit agricultural production due to high P fixation. In vitro cultures of the bacteria were grown on the National Botanical Research Instituteís phosphate medium (NBRIP), with tricalcium phosphate Ca3(PO4)2 as a source of insoluble P, and We measured the phosphorus solubilization index (PSI). We identified and confirmed a total of 35 isolates of P. fluorescens by specific PCR. Using the AFLP marker, genetic relationship analysis showed two groups: group A included isolates with PSI greater than 1.75, while group B included those with FSI less than 1.75. Comparing of PSI between isolates and departments showed statistically significant dif-ferences (p < 0.001), respectively, with the Pf_33 isolate as the most efficient. Because of the high solubilization potential of the native isolates of genetic group A (FSI > 1.75), We recommend future research to determine their response to field conditions and strategies for biofertilizer development.

Diversidad genética de materiales nativos de aguacate guatemalteco a través del marcador molecular AFLP / Genetic diversity of native Guatemalan avocado through AFLP molecular marker

El aguacate es un cultivo de consumo a nivel mundial, y según teorías recientes, se sugiere a la región de la Sierra Nevada, en California, como centro de origen y, a Guatemala, como uno de los principales centros de domesticación. Mediante caracterizaciones morfológicas se ha reportado una alta diversidad genética en el país, pero debido al comportamiento de polinización cruzada e hibridaciones interraciales, no se ha podido detallar el estado genético actual de la especie. Sin embargo, los marcadores moleculares son útiles para este tipo de estudios al enfocarse en las diferencias a nivel del ADN. Este estudio analizó la diversidad genética del aguacate nativo guatemalteco de siete poblaciones geográficas con el marcador molecular AFLP. Los datos de estructura poblacional mostraron un alto grado de diversidad a nivel de individuos (Ht = 0.1933, Hw = 0.1872) y baja diferenciación entre poblaciones (Hb = 0.0061). Los resultados sugieren una alta tasa de migración que influye directamente en el grado de mezcla genética de los materiales analizados. El bajo índice de estructura poblacional apunta a un alto flujo genético entre las poblaciones, por lo que la especie no presenta mayor riesgo ante la deriva genética, minimizándose el riesgo de pérdida de alelos por fijación. Se sugiere el resguardado del recurso fitogénetico total y no únicamente de materiales promisorios, evitando así el riesgo de erosión genética de la especie y garantizando la permanencia de la diversidad genética, la cual será la base de futuros programas de mejoramiento.

Avocado is one of the most widely consumed crops worldwide and according to new theories, the Sierra Nevada region in California is suggested as the center of origin and Guatemala as one of the main domestication cen-ters. Through morphological characterizations, a high genetic diversity has been reported in the country, but due to the behavior of cross pollination and interracial hybridizations, it has not been possible to detail the current genetic status of the species. Molecular markers are useful for this type of study by focusing on differences at DNA level. This study analyzed the genetic diversity of the native Guatemalan avocado from seven geographic populations with AFLP molecular marker. Population structure data showed a high degree of diversity at the individual level (Ht = 0.1933, Hw = 0.1872) and low differentiation between populations (Hb = 0.0061). The results suggest a high rate of migration that directly influences the degree of genetic mixing of the analyzed materials. The low index of population structure points to a high genetic flow between populations, so that the species does not present a greater risk due to genetic drift, minimizing the risk of loss of alleles due to fixation. The protection of the total genetic resource is suggested, and not only of promising materials, thus avoiding the risk of genetic erosion of the species and guaranteeing the permanence of genetic diversity, which will be the basis of future breeding programs.

Phenolic composition, antioxidant and anti-proliferative activities of edible and medicinal plants from the Peruvian Amazon

ABSTRACT Among 23 extracts of medicinal and edible plants tested, Mauritia flexuosa L.f., Arecaceae, showed significant antioxidant ability (DPPH and ORAC = 1062.9 and 645.9 ± 51.4 µg TE/mg extract, respectively), while Annona montana Macfad., Annonaceae, demonstrated the most promising anti-proliferative effect (IC50 for Hep-G2 and HT-29 = 2.7 and 9.0 µg/ml, respectively). However, combinatory antioxidant/anti-proliferative effect was only detected in Oenocarpus bataua Mart., Arecaceae (DPPH = 903.8 and ORAC = 1024 µg TE/mg extract; IC50 for Hep-G2 and HT-29 at 102.6 and 38.8 µg/ml, respectively) and Inga edulis Mart., Fabaceae (DPPH = 337.0 and ORAC = 795.7 µg TE/mg extract; IC50 for Hep-G2 and HT-29 at 36.3 and 57.9 µg/ml, respectively). Phenolic content was positively correlated with antioxidant potential, however not with anti-proliferative effect. None of these extracts possessed toxicity towards normal foetal lung cells, suggesting their possible use in development of novel plant-based agents with preventive and/or therapeutic action against oxidative stress-related diseases.