Screening of the Pan-African Natural Product Library Identifies Ixoratannin A-2 and Boldine as Novel HIV-1 Inhibitors

The continued burden of HIV in resource-limited regions such as parts of sub-Saharan Africa, combined with adverse effects and potential risks of resistance to existing antiretroviral therapies, emphasize the need to identify new HIV inhibitors. Here we performed a virtual screen of molecules from the pan-African Natural Product Library, the largest collection of medicinal plant-derived pure compounds on the African continent. We identified eight molecules with structural similarity to reported interactors of Vpu, an HIV-1 accessory protein with reported ion channel activity. Using in vitro HIV-1 replication assays with a CD4+ T cell line and peripheral blood mononuclear cells, we confirmed antiviral activity and minimal cytotoxicity for two compounds, ixoratannin A-2 and boldine. Notably, ixoratannin A-2 retained inhibitory activity against recombinant HIV-1 strains encoding patient-derived mutations that confer resistance to protease, non-nucleoside reverse transcriptase, or integrase inhibitors. Moreover, ixoratannin A-2 was less effective at inhibiting replication of HIV-1 lacking Vpu, supporting this protein as a possible direct or indirect target. In contrast, boldine was less effective against a protease inhibitor-resistant HIV-1 strain. Both ixoratannin A-2 and boldine also inhibited in vitro replication of hepatitis C virus (HCV). However, BIT-225, a previously-reported Vpu inhibitor, demonstrated antiviral activity but also cytotoxicity in HIV-1 and HCV replication assays. Our work identifies pure compounds derived from African plants with potential novel activities against viruses that disproportionately afflict resource-limited regions of the world

In vitro effects of 2-methyl-3-propylbutane-1,4-diol purified from Alstonia boonei on erythrocyte membrane stabilization and mitochondrial membrane permeabilization

A recent review on the ethnomedicinal, chemical, pharmacological, and toxicological properties of Alstonia boonei revealed the plant's potential in the treatment and management of a range of diseases. However, most of these pharmacological effects are only traceable to the crude form of the plant extract and not specific natural products. Phytochemical investigation of the methanol fraction of the methanol extract of the stem-bark of Alstonia boonei led to the isolation and identification of 2-methyl-3-propylbutane-1,4-diol. The structures were elucidated by the application of 1D-, and 2D-NMR spectroscopic analyses and by comparison with literature data. In this study, the membrane stabilizing activity, mitochondrial membrane permeability transition pore opening, cytochrome c release, mitochondrial ATPase activity, and prevention of mitochondrial lipid peroxidation activity of 2-methyl-3-propylbutane-1,4-diol (MPBD) isolated from A. boonei were determined. The results showed that MPBD significantly (p < .05) prevented peroxidation of mitochondrial membrane lipids and hemolysis using both the heat-induced and hypotonic solution-induced membrane stabilization assays. On the contrary, the compound caused large amplitude swelling of rat liver mitochondria in the absence of calcium, significant (p < .05) cytochrome c release and enhancement of mitochondrial ATPase activity in vitro. Our findings suggest that MPBD showed characteristic biological properties useful in modulating cell death.http://wileyonlinelibrary.com/journal/cbdd2023-11-02hj2023Chemistr

Ursane-Type Triterpenes, Phenolics and Phenolic Derivatives from Globimetula braunii Leaf

Globimetula braunii is a hemi-parasitic plant used in African ethnomedicine for the management of microbial infections, rheumatic pain and tumors amongst others. We report the isolation and characterization of eight compounds with their antioxidant and antimicrobial activities. The air-dried powdered leaf was macerated in EtOH/H20 (4:1). The extract was solvent-partitioned into n-hexane, EtOAc, n-BuOH and aqueous fractions. The fractions were screened for their antioxidant properties, using DPPH, FRAP, TAC and FIC assays. Antimicrobial analysis was performed using the micro-broth dilution method. The active EtOAc fraction was purified for its putative compounds on a repeated silica gel column chromatography monitored with TLC-bioautography. The isolated compounds were characterized using spectroscopic methods of UV, FT-IR, NMR and MS. Eight compounds (1–8) were isolated and characterized as 13,27-cycloursane (1), phyllanthone (2), globraunone (3), three phenolics: methyl 3,5-dihydroxy-4-methoxybenzoate (4), methyl 3-methyl-4-hydroxybenzoate (5) and guaiacol (6), as well as two phenol derivatives: 4-formaldehyde phenone (7) and 6-methoxy-2H-inden-5-ol (8). The study identified 4 and 6 as natural antioxidant compounds with potential as antimicrobial agents.Other UBCNon UBCReviewedFacult

A novel compound purified from <i>Alstonia boonei</i> inhibits <i>Plasmodium falciparum</i> lactate dehydrogenase and plasmepsin II

A novel compound purified from <i>Alstonia boonei</i> inhibits <i>Plasmodium falciparum</i> lactate dehydrogenase and plasmepsin I

Effects of p-ANAPL compounds on cell viability and <i>in vitro</i> HIV-1 replication.

<p><b>A,</b> CEM-GXR cell viability at Day 4 in the presence of p-ANAPL compounds at defined concentrations. Data are normalized to the percent of viable cells in an HIV-1_NL4-3-infected culture plus 0.1% DMSO. <b>B,</b> HIV-1 replication in CEM-GXR cells at Day 4 in the presence of compounds. Data are normalized to percent HIV-1_NL4-3-infected cells plus 0.1% DMSO. Dose-response plots of ixoratannin A-2 and boldine are highlighted with blue and green arrows, respectively. <b>C</b>, PBMC viability at Day 5 in the presence of p-ANAPL compounds. Data are normalized to the percent of viable cells in an uninfected culture plus 0.1% DMSO. <b>D</b>, HIV-1 replication in PBMCs at Day 12 in the presence of p-ANAPL compounds, as measured by p24^Gag levels in cell culture supernatants. Data are normalized to percent HIV-1_NL4-3-infected cells plus 0.1% DMSO.</p

Replication of HIV-1_NL4-3, HIV-1_Δvpu, and drug-resistant HIV-1 strains in CEM-GXR cells.

<p>Data shown are at Day 4 in the presence of 0.1 μM of established ARVs, relative to the replication rate of each HIV-1 strain in the presence of 0.1% DMSO vehicle control. *, p < 0.004 vs. HIV-1_NL4-3 replication.</p

Putative HIV-1 Vpu inhibitors identified from virtual screening of the p-ANAPL.

<p><b>A,</b> Structures of four molecules predicted to interact with the Vpu ion channel [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121099#pone.0121099.ref020" target="_blank">20</a>]. <b>B,</b> Alignment of four molecules. Chemical substituents that define a shared pharmacophore are highlighted. <b>C,</b> Eight p-ANAPL molecules containing aspects of the shared pharmacophore. For each compound, root mean square deviation (RMSD) values are shown in parentheses.</p

Effects of ixoratannin A-2 and boldine on replication of HIV-1_Δvpu and ARV-resistant HIV-1 strains in CEM-GXR cells.

<p>In all experiments, data are normalized to the replication rate of each HIV-1 strain plus 0.1% DMSO at Day 4. <b>A-B,</b> effects of ixoratannin A-2 (<b>A</b>) and boldine (<b>B</b>) on HIV-1_NL4-3 and HIV-1_Δvpu replication. <b>C-D,</b> effects of ixoratannin A-2 (<b>C</b>) and boldine (<b>D</b>) on replication of ARV-resistant HIV-1 strains.*, p < 0.008 vs. HIV-1_NL4-3 at the same concentration of ixoratannin A-2 or boldine. ǂ, p < 0.008 for strain HIV-1_PR+RT and HIV-1_INT vs. HIV-1_NL4-3 at same concentration of ixoratannin A-2.</p

Effects of compounds on HCV replication.

<p><b>A,</b> Cell viability at 72 h post-infection in the presence of compounds at defined concentrations. Data are normalized to the percent of viable cells in a HCV-infected culture plus 0.1% DMSO. <b>B,</b> HCV replication at 72 h post-infection in the presence of compounds. Data are normalized to percent HCV-infected cells plus 0.1% DMSO.</p

Impact of the COVID-19 pandemic on patients with paediatric cancer in low-income, middle-income and high-income countries: a multicentre, international, observational cohort study

OBJECTIVES: Paediatric cancer is a leading cause of death for children. Children in low-income and middle-income countries (LMICs) were four times more likely to die than children in high-income countries (HICs). This study aimed to test the hypothesis that the COVID-19 pandemic had affected the delivery of healthcare services worldwide, and exacerbated the disparity in paediatric cancer outcomes between LMICs and HICs. DESIGN: A multicentre, international, collaborative cohort study. SETTING: 91 hospitals and cancer centres in 39 countries providing cancer treatment to paediatric patients between March and December 2020. PARTICIPANTS: Patients were included if they were under the age of 18 years, and newly diagnosed with or undergoing active cancer treatment for Acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, Wilms' tumour, sarcoma, retinoblastoma, gliomas, medulloblastomas or neuroblastomas, in keeping with the WHO Global Initiative for Childhood Cancer. MAIN OUTCOME MEASURE: All-cause mortality at 30 days and 90 days. RESULTS: 1660 patients were recruited. 219 children had changes to their treatment due to the pandemic. Patients in LMICs were primarily affected (n=182/219, 83.1%). Relative to patients with paediatric cancer in HICs, patients with paediatric cancer in LMICs had 12.1 (95% CI 2.93 to 50.3) and 7.9 (95% CI 3.2 to 19.7) times the odds of death at 30 days and 90 days, respectively, after presentation during the COVID-19 pandemic (p<0.001). After adjusting for confounders, patients with paediatric cancer in LMICs had 15.6 (95% CI 3.7 to 65.8) times the odds of death at 30 days (p<0.001). CONCLUSIONS: The COVID-19 pandemic has affected paediatric oncology service provision. It has disproportionately affected patients in LMICs, highlighting and compounding existing disparities in healthcare systems globally that need addressing urgently. However, many patients with paediatric cancer continued to receive their normal standard of care. This speaks to the adaptability and resilience of healthcare systems and healthcare workers globally