Colin W. Wright

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease of the pulmonary vasculature characterized by obliterative remodeling of small pulmonary arteries, leading to sustained elevation of pulmonary vascular resistance, right ventricular failure, and premature death. The diagnostic gold standard remains right heart catheterization, requiring a mean pulmonary artery pressure greater than 20 mmHg at rest, a pulmonary arterial wedge pressure of 15 mmHg or below, and a pulmonary vascular resistance exceeding 2 Wood units. PAH is an autosomal dominant disorder with markedly incomplete penetrance of approximately 20–30%, indicating that germline mutations alone are insufficient to cause disease. Disease manifestation requires additional “second hits”, including chronic hypoxia, systemic inflammation, hemodynamic stress, hormonal influences, and common genetic modifiers such as single-nucleotide polymorphisms (SNPs). This genetic and environmental complexity underpins the broad clinical heterogeneity observed across PAH subtypes, which include idiopathic PAH, heritable PAH, and disease associated with connective tissue disorders, HIV infection, portal hypertension, congenital heart disease, schistosomiasis, and drug or toxin exposure. This review provides a comprehensive and critical appraisal of the molecular-genetic architecture of PAH. Thirty genes have now been implicated in disease pathogenesis, spanning seven functional categories: receptors of the TGF-β/BMP signaling family (BMPR2, ACVRL1, ENG, BMPR1B); circulating BMP ligands (GDF2, BMP10); transcription factors (TBX4, SOX17, KLF4, FOXF1, SMAD1, SMAD4, SMAD9); membrane and polyamine transporters (ATP13A3, AQP1); potassium channel regulators (KCNA5, KCNK3, ABCC8); metabolic and mitochondrial genes (EIF2AK4, NFU1, GGCX); signaling receptors and structural proteins (NOTCH3, KDR, CAV1, PLEKHH2); vasoactive and extracellular matrix regulators (KLK1, CBLN2, CD248); and epigenetic regulators (TET2, TOPBP1). Among these, BMPR2 is the dominant contributor, accounting for 53–86% of heritable PAH and 14–35% of idiopathic cases. The remaining genes each account for fewer than 5% of cases individually, collectively reflecting a broad landscape of rare and ultra-rare genetic contributions. For each gene, we critically evaluate the strength of genetic evidence, pathogenic mechanisms, degree of mechanistic resolution, and clinical relevance. We further discuss the contribution of emerging technologies, including whole-genome sequencing, single-cell and spatial transcriptomics, multi-omics integration, iPSC-derived vascular models, and artificial intelligence, to expanding the PAH genetic architecture beyond single-gene discovery. A key theme across this landscape is convergence: despite mechanistic diversity at the gene level, most PAH-associated variants ultimately impair endothelial quiescence, promote smooth muscle proliferation, and drive apoptosis resistance through disruption of BMP signaling amplitude, transcriptional stability, ion channel homeostasis, metabolic integrity, or epigenetic regulation. This convergence supports both a unified therapeutic rationale and a precision medicine framework for genotype-stratified intervention in PAH.

The roots of the climbing shrub Cryptolepis sanguinolenta are traditionally used in West Africa for the treatment of malaria. The principal constituent, cryptolepine ( 1 ), has been shown to have antimalarial activity but there are concerns regarding its toxicity on account of its DNA‐intercalating property. The synthetic analogue, 2,7‐dibromocryptolepine, ( 2 ) does not intercalate into DNA and is markedly more active than the parent against Plasmodium sp. in vitro and in vivo. The aim of this study was to carry out a pre‐clinical assessment of 1 and 2 , and if appropriate, carry out in vivo pharmacokinetic studies. Cryptolepine ( 1 ) and 2,7‐dibromocryptolepine ( 2 ), were evaluated in a range of in vitro assays in line with those recommended by Medicines for Malaria Venture (MMV) for the profiling of a Validated Hit Compound ( https://www.mmv.org/frontrunner-templates ). In vitro profiling of 1 and 2 showed that 2 is superior to 1 with respect to antiplasmodial activities, and the parasite rate of kill (fast for 2 , in contrast with modest for 1 ); however 2 exhibited potent inhibition of the hERG potassium channel, (IC ₅₀ = 1.0 µM compared with 7.8 µM for 1 ), raising concerns that 2 may be cardiotoxic, so that 2 was not selected for in vivo pharmacokinetic profiling. The studies of cryptolepine ( 1 ) pharmacokinetics in the rat revealed a second peak, especially with oral administration, indicating that enterohepatic circulation following biliary excretion may be taking place. This study complements previous pharmacokinetic data of 1 and presents novel data on 2,7‐dibromocryptolepine ( 2 ) that will inform the development of cryptolepine analogues as potential antimalarial agents.

Pulmonary arterial hypertension (PAH) is a progressive and rare condition characterised by the occlusion of pulmonary arterioles, with clinical manifestations resulting from the cross-sectional area reduction of the small pulmonary arteries. The disease is driven by a combination of factors including vasoconstriction, thrombosis, inflammation, proliferation, and the obstructive remodelling of the pulmonary artery walls. Heterozygous mutations in the type II bone morphogenetic protein receptor (BMPR2) underlie the majority of the inherited and familial forms of PAH. Current evidence indicates that in PAH, the BMPR2-mediated-signalling is diminished and the TGFβ signalling is heightened. Even when managed with current therapeutic approaches, the disease eventually results in increased pulmonary vascular resistance, right heart failure, and premature death. Natural products act as vascular disease treatment agents and have been used in clinical practice following compelling clinical trials. The rationale for the selection of natural compounds derives from their multi-targeted approach and synergistic effects. Although novel medicines licenced by the FDA (USA) between 1981 and 2010, constitute approximately 34% natural products or derivatives of natural products, their potentials for the treatment of PAH are not fully explored. The objective of this review is to emphasise the significance of natural products in the therapeutic resolution of PAH.

The prospect of eradicating malaria continues to be challenging in the face of increasing parasite resistance to antimalarial drugs so that novel antimalarials active against asexual, sexual, and liver-stage malaria parasites are urgently needed. In addition, new antimalarials need to be affordable and available to those most in need and, bearing in mind climate change, should ideally be sustainable. The West African climbing shrub Cryptolepis sanguinolenta is used traditionally for the treatment of malaria; its principal alkaloid, cryptolepine (1), has been shown to have antimalarial properties, and the synthetic analogue 2,7-dibromocryptolepine (2) is of interest as a lead toward new antimalarial agents. Cryptolepine (1) was isolated using a two-step Soxhlet extraction of C. sanguinolenta roots, followed by crystallization (yield 0.8% calculated as a base with respect to the dried roots). Semi-synthetic 7-bromo- (3), 7, 9-dibromo- (4), 7-iodo- (5), and 7, 9-dibromocryptolepine (6) were obtained in excellent yields by reaction of 1 with N-bromo- or N-iodosuccinimide in trifluoroacetic acid as a solvent. All compounds were active against Plasmodia in vitro, but 6 showed the most selective profile with respect to Hep G2 cells: P. falciparum (chloroquine-resistant strain K1), IC₅₀ = 0.25 µM, SI = 113; late stage, gametocytes, IC₅₀ = 2.2 µM, SI = 13; liver stage, P. berghei sporozoites IC₅₀ = 6.13 µM, SI = 4.6. Compounds 3–6 were also active against the emerging zoonotic species P. knowlesi with 5 being the most potent (IC₅₀ = 0.11 µM). In addition, 3–6 potently inhibited T. brucei in vitro at nM concentrations and good selectivity with 6 again being the most selective (IC₅₀ = 59 nM, SI = 478). These compounds were also cytotoxic to wild-type ovarian cancer cells as well as adriamycin-resistant and, except for 5, cisplatin-resistant ovarian cancer cells. In an acute oral toxicity test in mice, 3–6 did not exhibit toxic effects at doses of up to 100 mg/kg/dose × 3 consecutive days. This study demonstrates that C. sanguinolenta may be utilized as a sustainable source of novel compounds that may lead to the development of novel agents for the treatment of malaria, African trypanosomiasis, and cancer.

Background: Cissus incisa is a Vitaceae with a pantropical distribution. In northern Mexico, its leaves have traditionally been used to treat skin infections, abscesses and tumors. Despite its medicinal uses, few studies have been reported. Objective: The objective of this study is to summarize the phytochemical and biological studies carried out so far on the leaves of C. incisa, since this part of the plant is the one frequently used, and awaken scientific interest towards the plant. Methods: Since C. incisa was an undocumented species, most of the information comes from reports of our research group. Databases, books, and websites were also consulted. The information collected was organized and presented in a synthesized way. Plant name was checked with the database “The Plant List”. Results: 171, 260, and 114 metabolites were identified by UHPLC-QFTOF-MS in the hexane, chloroform/ methanol, and aqueous extracts, respectively. Fatty acyls, sphingolipids, sterols, glycerolipids, prenol lipids, and terpenes are common metabolites found in these extracts. 2-(2´-hydroxydecanoyl amino)-1,3,4-hexadecanotriol-8-ene, 2,3-dihydroxypropyl tetracosanoate, β-sitosterol, β-sitosterol-D-glucopyranoside, α-amyrin-3-O-β-D-glucopyranoside were also isolated and characterized. Extracts, phytocompounds and semi-synthetic derivatives showed antimicrobial activity against multi-drug resistant bacteria and various cancer cell lines. Results from Perturbation- Theory-Machine Learning-Information-Fusion model (PTMLIF), molecular docking, and vesicular contents assay identified potential targets on the cell membrane, suggesting an antibacterial mechanism of action for ceramides from C. incisa leaves. Conclusion: This review reports the efforts of the scientific community in authenticating species used in traditional medicine. Moreover, it gives a compendium of phytochemistry and the biological activities of the components from C. incisa leaves.

The common fern, bracken (Pteridium aquilinum), is well known for its toxic effects on livestock due principally to the carcinogenic constituent ptaquiloside (1), although other toxins are present including the cyanogenic glycoside, prunasin (2). Here, we report an improved and relatively “green” process for the isolation of 1 and 2 from fresh bracken fronds and the evaluation of 1 for cytotoxicity against several cancer cell lines. The results indicate that 1 displays selective toxicity against cancer cells relative to noncancer retinal epithelial cells, and the improved method for the isolation of 1 is expected to facilitate further exploration of its pharmacological properties. ^# Dedicated to Professor Arnold Vlietinck on the occasion of his 80th birthday. Received: 22 January 2021 Accepted after revision: 21 April 2021 Publication Date: 21 May 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Cryptolepine, the principal constituent of the West African climbing shrub Cryptolepis sanguinolenta, continues to be of interest as a lead to new therapeutic agents, especially for the treatment of protozoal infections and cancer. This contribution reviews the research published in the last decade, highlighting new synthesis routes to cryptolepine and to analogs of this alkaloid, as well as their pharmacology. Studies relating to the use of C. sanguinolenta as an herbal medicine for the treatment of malaria are discussed, as well as the development of analogs of cryptolepine as leads to new agents for the treatment of malaria, trypanosomiasis, and cancer with an emphasis on the pharmacological mechanisms involved. Other potential therapeutic applications include antimicrobial, antidiabetic, and anti-inflammatory activities; the pharmacokinetics and toxicity of cryptolepine are also reviewed.