Novel report of Bipolaris heliconiae causing frog-eye-like leaf spot on Dypsis lutescens in Indian Sub-Continent.

Dypsis lutescens, commonly known as areca palm, is a highly valued ornamental species due to its aesthetic value. However, the foliage is vulnerable to various pathogens, particularly those responsible for fungal leaf spot diseases. In October 2023, a severe incidence (93 %) of destructive leaf spots was recorded on Dypsis lutescens at the University of Agricultural Sciences, GKVK, Bangalore, and surrounding areas. The leaf spot symptoms manifested as frog-eye-like lesions, leading to complete leaf desiccation and significantly reducing the palms ornamental value. The pathogen exhibited the highest radial growth (90.00 mm) and prominent sporulation on oat meal agar, whereas Richard's synthetic agar resulted in the lowest radial growth (38.00 mm) with no sporulation. Morphological and multilocus phylogenetic analyses confirmed the pathogen as Bipolaris heliconiae. Pathogenicity tests fulfilled Koch's postulates, confirming that Bipolaris heliconiae is the causative agent of leaf spot disease in Dypsis lutescens in India. This novel finding underscores the emergence of a new disease and highlights the urgent need for effective management strategies.

Cytotoxic flavone-C-glycosides from the leaves of Dypsis pembana (H.E.Moore) Beentje & J.Dransf., Arecaceae: in vitro and molecular docking studies.

BACKGROUND: Cancer poses a health threat, with an increased incidence worldwide. Thus, it is essential to develop new natural anticancer agents. Dypsis pembana (H.E.Moore) Beentje & J.Dransf (DP) is an ornamental plant belonging to the family Arecaceae. This study aimed to isolate and identify phytoconstituents from the leaves of this plant and evaluate their in vitro cytotoxic activities. METHODS: Different chromatographic techniques were applied to fractionate the hydro-alcoholic extract of DP and separate the major phytoconstituents. The isolated compounds were structurally elucidated based on their physical and spectroscopic data. The in vitro cytotoxic activities of the crude extract and fractions thereof were evaluated against human colon carcinoma (HCT-116), human breast carcinoma (MCF-7), and human hepatocellular carcinoma (HepG-2) cell lines via MTT assay. Moreover, selected isolates were tested against HepG-2 cell line. Molecular docking analysis was performed to investigate the interactions of these compounds with two potential targets, the human topoisomerase IIα and cyclin-dependent kinase 2 enzymes. RESULTS: Thirteen diverse compounds were reported for the first time from DP, providing significant chemotaxonomic biomarkers. Among tested compounds, vicenin-II (7) was the most cytotoxic against HepG-2 cell line, with an IC50 value of 14.38 µg/mL, followed by isovitexin (13) (IC50 of 15.39 µg/mL). These experimental findings were complemented by molecular docking, which demonstrated that vicenin-II exhibited superior enzyme-binding affinities to the studied vital targets and shed light on the structure-activity relationships among the investigated flavone-C-glycosides members. CONCLUSION: The phytochemical profile of DP was characterized for the first time, reflecting chemotaxonomic data about the concerned species, genus, or even the family. Biological and computational findings revealed that vicenin-II and isovitexin are possible lead structures as inhibitors of the human topoisomerase IIα and cyclin-dependent kinase 2 enzymes.

Antioxidant and antidiabetic flavonoids from the leaves of Dypsis pembana (H.E.Moore) Beentje & J.Dransf., Arecaceae: in vitro and molecular docking studies.

BACKGROUND: Oxidative stress and diabetes are medical conditions that have a growing prevalence worldwide, significantly impacting our bodies. Thus, it is essential to develop new natural antioxidant and antidiabetic agents. Dypsis pembana (H.E.Moore) Beentje & J.Dransf (DP) is an ornamental palm of the family Arecaceae. This study aimed to broaden the understanding of this plant's biological properties by evaluating its in vitro antioxidant and antidiabetic activities. METHODS: The in vitro antioxidant activities of the crude extract, fractions, and selected isolates were evaluated by DPPH method. While the in vitro antidiabetic activities of these samples were evaluated by assessing the degree of inhibition of α-glucosidase. Additionally, molecular docking analysis was performed to investigate the interactions of tested compounds with two potential targets, the cytochrome c peroxidase and alpha glucosidase. RESULTS: The crude extract displayed the highest antioxidant activity (IC50 of 11.56 µg/ml), whereas among the fractions, the EtOAc fraction was the most potent (IC50 of 14.20 µg/ml). Among tested compounds, isoquercetrin (10) demonstrated the highest potency, with an IC50 value of 3.30 µg/ml, followed by rutin (8) (IC50 of 3.61 µg/ml). Regarding antidiabetic activity, the EtOAc (IC50 of 60.4 µg/ml) and CH2Cl2 fractions (IC50 of 214.9 µg/ml) showed activity, while the other fractions did not demonstrate significant antidiabetic effects. Among tested compounds, kaempferol-3-O-neohesperidoside (9) showed the highest antidiabetic activity, with an IC50 value of 18.38 µg/ml, followed by kaempferol (4) (IC50 of 37.19 µg/ml). These experimental findings were further supported by molecular docking analysis, which revealed that isoquercetrin and kaempferol-3-O-neohesperidoside exhibited strong enzyme-binding affinities to the studied enzyme targets. This analysis provided insights into the structure-activity relationships among the investigated flavonol-O-glycosides. CONCLUSION: The biological and computational findings revealed that isoquercetrin and kaempferol-3-O-neohesperidoside have potential as lead compounds for inhibiting cytochrome c peroxidase and alpha glucosidase enzymes, respectively.

Population genetics data help to guide the conservation of palm species with small population sizes and fragmented habitats in Madagascar.

BACKGROUND: The need to incorporate genetic data into conservation management decisions is increasingly recognised. However, many published studies represent a 'gold standard' of sampling, techniques, and analyses. Such rigour is often not possible with limited funding and resourcing available for developing plans for the increasing number of threatened species requiring conservation management. Two endemic palm species of the Itremo Massif in central Madagascar, Dypsis ambositrae and D. decipiens, are known to be threatened with extinction and conservation management for these species is a priority for the newly created protected area in the region. METHODS: The genetic diversity of these two species was studied using the relatively low-cost and rapid AFLP technique. DNA fragments generated using three primer combinations were analysed for 20 and 50 individuals of the two species, respectively, from across their ranges. RESULTS: Genetic diversity was relatively low for both species. The two sites where the highly restricted D. ambositrae grows were found to be genetically distinct (although overall heterozygosity was low). Despite having a much wider distribution and relatively large population, D. decipiens did not show clear geographical nor genetic groupings and had similarly low genetic heterozygosity to D. ambositrae. DISCUSSION AND RECOMMENDATIONS: With so few individuals remaining in the wild and two genetically distinct subpopulations, it is recommended that both sites of D. ambositrae are conserved and that seed are collected from both for ex situ conservation and potential future reintroduction. It may be less important to focus resources on conserving or collecting ex situ material from all sites where D. decipiens is found, as the genetic diversity represented by each subpopulation is limited and increasing sampling may not protect significantly higher levels of genetic diversity. This study provides data that inform and support conservation decisions taken for both species within this region, and in the management of the newly designated Itremo Massif Protected Area, which covers most of the sites where these two species remain in the wild.

Germinação de sementes de Dypsis decaryi (Jum. ) Beentje & J. Dransf. (Arecaceae) / Germination of Dypsis decaryi (Jum. ) Beentje & J. Dransf. (Arecaceae) seeds

Dypsis decaryi (Jum.) Beentje & J. Dransf. é uma importante palmeira comercializada para fins ornamentais. Embora seja propagada sexuadamente, não há informações na literatura sobre os fatores que afetam a germinação das sementes dessa espécie. Objetivou-se, neste trabalho estudar o efeito da temperatura e do substrato na germinação de sementes de Dypsis decaryi. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 6 x 2 (seis temperaturas: 25ºC, 30ºC, 35ºC, 20-30ºC e 25-35ºC e ambiente combinadas com dois substratos: vermiculita e areia), com 5 repetições de 20 sementes. Anotou-se, diariamente, o número de sementes germinadas adotando como critério de germinação a protrusão do botão germinativo. Após 35 dias houve estabilização dos dados e foi calculado o Índice de Velocidade de Germinação (IVG) e a porcentagem de germinação (dados transformados em arc sen √x/100) cujas médias foram comparadas pelo teste de Scott-Knott, a 5 por cento de probabilidade. Observou-se que maiores porcentagens de germinação de sementes de Dypsis decaryi foram obtidas quando colocadas para germinar em areia nas temperaturas ambiente de laboratório (93 por cento), 25-35ºC (92 por cento) e 25ºC (86 por cento), e em vermiculita, nas temperaturas de ambiente (91 por cento), 20-30ºC (87 por cento), 30ºC (83 por cento), 25-35ºC (80 por cento) e 25ºC (76 por cento). As sementes germinaram mais rápido em condições de ambiente de laboratório independentemente do substrato. Na temperatura de 35ºC a porcentagem de germinação foi bastante reduzida tanto em areia (21 por cento) como em vermiculita (38 por cento); as sementes germinaram mais lentamente e a germinação foi desuniforme.

Dypsis decaryi (Jum.) Beentje & J. Dransf. is an important palm with ornamental commercial value. Although it reproduces sexually, there are no data available as far as what are the factors that affect this species seed germination. The purpose of this work is to study the potential effects of temperature and substrate in Dypsis decaryi seed germination. The research framework is based on randomization, using a 6 X 2 factorial schema (six different temperatures, 25ºC, 30ºC, 35ºC, 20-30ºC, 25-35ºC and room temperature, combined with two types of substratum, sand and vermiculite) with 5 repetitions of 20 seeds. The researcher made daily records on the number of germinated seeds, and the criteria used was protusion of the germination plug. After 35 days data become stable. The Index of Germination Speed (IVG) and germination percentage were then calculated (data were converted to sen). The averages for these two indexes were compared using the Scott-Knott method with a probability of 5 percent. The data show that the higher percentages of germination were obtained with a sand substratum at temperatures of 25ºC (86 percent), 25-35ºC (92 percent) and lab room temperature (93 percent), and with a vermiculite substratum, at temperatures of 25ºC (76 percent), 30ºC (83 percent), 20-30ºC (87 percent), 25-35ºC (80 percent) and room temperature (91 percent). The seeds germinated sooner in the lab environment, for both substrates. The percentage of germination at 35ºC was markedly lower, both on sand (21 percent) and vermiculite (38 percent). In this case, the seeds took longer to germinate and germination was not uniform.