Background: Buruli ulcer is a tissue necrosis infection caused by an environmental mycobacterium calledMycobacterium ulcerans(MU). The disease is most prevalent in rural areas with the highest rates in West and Central African countries. The bacterium produces a toxin called mycolactone which can lead to the destruction of the skin, resulting in incapacitating deformities with an enormous economic and social burden on patients and their caregivers. Even though there is an effective antibiotic treatment for BU, the control and management rely on early case detection and rapid diagnosis to avert morbidities. The diagnosis ofMycobacterium ulceransrelies on smear microscopy, culture histopathology, and PCR. Unfortunately, all the current laboratory diagnostics have various limitations and are not available in endemic communities. Consequently, there is a need for a rapid diagnostic tool for use at the community health centre level to enable diagnosis and confirmation of suspected cases for early treatment. The present study corroborated the diagnostic performance and utility of fluorescent-thin layer chromatography (f-TLC) for the diagnosis of Buruli ulcer.Methodology/Principal findings: The f-TLC method was evaluated for the diagnosis of Buruli ulcer in larger clinical samples than previously reported in an earlier preliminary study Wadagni et al. (2015). A total of 449 patients suspected of BU were included in the final data analysis out of which 122 (27.2%) were positive by f-TLC and 128 (28.5%) by PCR. Using a composite reference method generated from the two diagnostic methods, 85 (18.9%) patients were found to be truly infected withM.ulcerans, 284 (63.3%) were uninfected, while 80 (17.8%) were misidentified as infected or noninfected by the two methods. The data obtained was used to determine the discriminatory accuracy of the f-TLC against the gold standard IS2404PCR through the analysis of its sensitivity, specificity, positive (+LR), and negative (–LR) likelihood ratio. The positive (PPV) and negative (NPV) predictive values, area under the receiver operating characteristic curve Azevedo et al. (2014), and diagnostic odds ratio were used to assess the predictive accuracy of the f-TLC method. The sensitivity of f-TLC was 66.4% (85/128), specificity was 88.5% (284/321), while the diagnostic accuracy was 82.2% (369/449). The AUC stood at 0.774 while the PPV, NPV, +LR, and–LR were 69.7% (85/122), 86.9% (284/327), 5.76, and 0.38, respectively. The use of the rule-of-thumb interpretation of diagnostic tests suggests that the method is good for use as a diagnostic tool.Conclusions/Significance: Larger clinical samples than previously reported had been used to evaluate the f-TLC method for the diagnosis of Buruli ulcer. A sensitivity of 66.4%, a specificity of 88.5%, and diagnostic accuracy of 82.2% were obtained. The method is good for diagnosis and will help in making early clinical decisions about the patients as well as patient management and facilitating treatment decisions. However, it requires a slight modification to address the challenge of background interference and lack of automatic readout to become an excellent diagnostic tool.

The pressing global challenges of parasitic diseases, particularly prevalent in tropical and subtropical regions, underscore the critical urgent need for innovative therapeutic strategies in identifying and developing new treatments. The immense chemical diversity inherent in nature has rendered natural product (NP) chemistry a promising avenue for the discovery of novel antiparasitic chemotypes. Despite challenges such as sourcing, synthetic complexity, and drug resistance, NPs continue to offer invaluable contributions to antiparasitic therapy. This review focuses on recent advancements in NP chemistry and their application in the development of antiparasitic therapeutics. Key highlights include the identification of new molecular targets such as enzymes, membrane proteins, and metabolic pathways in parasites, as well as the role of metabolomics, genomics, and high-throughput screening in accelerating drug development. Additionally, the exploration of microorganisms (including soil bacteria and fungi) and marine organisms as a latent reserve of bioactive compounds with potent antiparasitic activity is discussed. The review further examines emerging strategies such as chemoinformatics and combination and polypharmacology therapies, aimed at addressing the challenges of antiparasitic chemotherapeutic treatment and advancing the development of new and effective treatments. Ultimately, NP chemistry represents a frontier for the design of novel antiparasitic drugs, offering the potential for more effective and sustainable therapies for combating parasitic diseases.

Background: Mycobacterium ulcerans is the causative agent of Buruli ulcer. The pathology of M. ulcerans disease has been attributed to the secretion of a potent macrolide cytotoxin known as mycolactone which plays an important role in the virulence of the disease. Mycolactone is a biomarker for the diagnosis of BU that can be detected using the fluorescent-thin layer chromatography (f-TLC) technique. The technique relies on the chemical derivatization of mycolactone A/B with 2-naphthylboronic acid (BA) which acts as a fluorogenic chemosensor. However, background interferences due to co-extracted human tissue lipids, especially with clinical samples coupled with the subjectivity of the method call for an investigation to find an alternative to BA. Methods: Twenty-six commercially available arylboronic acids were initially screened as alternatives to BA using the f-TLC experiment. UV–vis measurements were also conducted to determine the absorption maximum spectra of mycolactone A/B and myco-boronic acid adducts followed by an investigation of the fluorescence-enhancing ability of the boronate ester formation between mycolactone A/B and our three most promising boronic acids (BA15, BA18, and BA21). LC–MS technique was employed to confirm the adduct formation between mycolactone and boronic acids. Furthermore, a comparative study was conducted between BA18 and BA using 6 Polymerase Chain Reaction (PCR) confirmed BU patient samples. Results: Three of the boronic acids (BA15, BA18, and BA21) produced fluorescent band intensities superior to BA. Complexation studies conducted on thin layer chromatography (TLC) using 0.1 M solution of the three boronic acids and various volumes of 10 ng/µL of synthetic mycolactone ranging from 1 µL – 9 µL corresponding to 10 ng – 90 ng gave similar results with myco-BA18 adduct emerging with the most visibly intense fluorescence bands. UV–vis absorption maxima (λ_max) for the free mycolactone A/B was observed at 362 nm, and the values for the adducts myco-BA15, myco-BA18, and myco-BA21 were at 272 nm, 270 nm, and 286 nm respectively. The comparable experimental λ_max of 362 nm for mycolactone A/B to the calculated Woodward-Fieser value of 367 nm for the fatty acid side chain of mycolactone A/B demonstrate that even though 2 cyclic boronates were formed, only the boronate of the southern side chain with the chromophore was excited by irradiation at 365 nm. Fluorescence experiments have demonstrated that coupling BA18 to mycolactone A/B along the 1,3-diols remarkably enhanced the fluorescence intensity at 537 nm. High-Resolution Mass Spectrometer (HR-MS) was used to confirm the formation of the myco-BA15 adduct. Finally, f-TLC analysis of patient samples with BA18 gave improved BA18-adduct intensities compared to the original BA-adduct. Conclusion: Twenty-six commercially available boronic acids were investigated as alternatives to BA, used in the f-TLC analysis for the diagnosis of BU. Three (3) of them BA15, BA18, and BA21 gave superior fluorescence band intensity profiles. They gave profiles that were easier to interpret after the myco-boronic acid adduct formation and in experiments with clinical samples from patients with BA18 the best. BA18, therefore, has been identified as a potential alternative to BA and could provide a solution to the challenge of background interference of co-extracted human tissue lipids from clinical samples currently associated with the use of BA.

Mycolactone is a complex macrolide toxin produced by Mycobacterium ulcerans, the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities. The review focuses on pioneering studies of Kishi which elaborate first-, second-, and third-generation approaches to the synthesis of mycolactones A/B. The three generations focused on the construction of the key intermediates required for the mycolactone synthesis. Synthesis of the first generation involves assignment of the relative and absolute stereochemistry of the mycolactones A and B. This was accomplished by employing a linear series of 17 chemical steps (1.3% overall yield) using the mycolactone core. The second generation significantly improved the first generation in three ways: (1) by optimizing the selection of protecting groups; (2) by removing needless protecting group adjustments; and (3) by enhancing the stereoselectivity and overall synthetic efficiency. Though the synthetic route to the mycolactone core was longer than the first generation, the overall yield was significantly higher (8.8%). The third-generation total synthesis was specifically aimed at an efficient, scalable, stereoselective, and shorter synthesis of mycolactone. The synthesis of the mycolactone core was achieved in 14 linear chemical steps with 19% overall yield. Furthermore, a modular synthetic approach where diverse analogues of mycolactone A/B were synthesized via a cascade of catalytic and/or asymmetric reactions as well as several Pd-catalyzed key steps coupled with hydroboration reactions were reviewed. In addition, the review discusses how mycolactone is employed in the diagnosis of Buruli ulcer with emphasis on detection methods of mass spectrometry, immunological assays, RNA aptamer techniques, and fluorescent-thin layer chromatography (f-TLC) methods as diagnostic tools. We examined studies of the structure–activity relationship (SAR) of various analogues of mycolactone. The paper highlights the multiple biological consequences associated with mycolactone such as skin ulceration, host immunomodulation, and analgesia. These effects are attributed to various proposed mechanisms of actions including Wiskott–Aldrich Syndrome protein (WASP)/neural Wiskott–Aldrich Syndrome protein (N-WASP) inhibition, Sec61 translocon inhibition, angiotensin II type 2 receptor (AT2R) inhibition, and inhibition of mTOR. The possible application of novel mycolactone analogues produced based on SAR investigations as therapeutic agents for the treatment of inflammatory disorders and inflammatory pain are discussed. Additionally, their therapeutic potential as anti-viral and anti-cancer agents have also been addressed.

Background: Pediatric liquid medicines are indispensable and widely used in childhood disease management, but often contain fermentable sugars and acidic excipients that may increase the risk of dental caries and tooth erosion. This study conducted a physicochemical evaluation of pediatric liquid medicines marketed in Ghana to determine their potential contribution to dental caries and tooth erosion, conditions associated with acidic and sugar-containing formulations. Methods: Thirty pediatric liquid medicines across six therapeutic classes (analgesics, antitussives, antihistamines, antibiotics, antimalarials, and non-steroidal anti-inflammatory drugs) were analysed. Physicochemical parameters assessed included pH, total titratable acidity (TTA; % citric acid equivalents), sucrose content (%), and total soluble solids content (TSSC; °Brix). All analyses were performed in triplicate, and comparisons across therapeutic classes were conducted using one-way analysis of variance (ANOVA) followed by post hoc multiple comparison tests, with statistical significance set at p < 0.05. Results: The pH of the medicines ranged from 2.76 to 7.57, with 70% below the critical enamel demineralisation threshold (pH 5.5). TTA varied from 0.01% to 1.66%, with antibiotics and non-steroidal anti-inflammatory drugs exhibiting the highest mean values. Sucrose content ranged from 0.0% to 75.6%, with 43.3% of products exceeding the 10% cariogenic threshold. TSSC values ranged from 4.2°Brix to 61.8°Brix, with several formulations exceeding the high-risk threshold of 30°Brix. Comparative analyses revealed no statistically significant differences in pH ( p = 0.130), TTA ( p = 0.063), or sucrose content ( p = 0.952) across therapeutic classes. However, a statistically significant difference was observed for TSSC ( p = 0.010), indicating variability in overall soluble solid concentration among the therapeutic categories. Antitussives and NSAIDs showed the highest overall erosive potential, while antihistamines and non-steroidal anti-inflammatory drugs demonstrated elevated cariogenic risk. Locally manufactured products generally had higher sucrose content, whereas some imported formulations exhibited higher titratable acidity. Conclusions: Many pediatric liquid medicines marketed in Ghana exhibit physicochemical properties that may contribute to dental caries and tooth erosion. These findings underscore the need for targeted public health interventions, including regulatory policies to limit sugar and acidity in paediatric formulations, promotion of sugar-free alternatives, and integration of oral health counselling into paediatric prescribing practices, particularly in low- and middle-income settings.