Pakistan Journal of Pharmaceutical Sciences

Background: Halophilic microorganisms thriving in high-saline environments are recognized as a significant source of novel bioactive metabolites. The rise in antimicrobial resistance and the increasing burden of cardiovascular diseases cause health challenges worldwide. Commercially available antimicrobial and thrombolytic drugs have many side effects and high costs. Objectives: To explore halophilic bacteria as a source of bioactive compounds with thrombolytic and antimicrobial potential. Methods: Halophilic Gram-positive bacteria isolated from the salt mine of Khewra, Punjab, Pakistan, were characterized morphologically and biochemically and molecular identification was performed by 16S ribosomal RNA gene sequencing. Antimicrobial activities of extracts were checked against pathogenic bacteria, including Staphylococcus aureus, Bacillus subtilis, Pasteurella multocida and Escherichia coli, as well as Aspergillus niger. The thrombolytic potential of extracts was also investigated. Results: Bacteria showed maximum homology with Salinicoccus roseus strain. The sequence was submitted to GenBank (accession number PQ636913). Bacterial extracts were prepared using methanol (ME), ethyl acetate (EAE) and aqueous layer (AE). EAE showed the highest antibacterial activity against P. multocida with a zone of inhibition (ZOI) of 24.06 ± 0.35 mm. However, ME exhibited the highest antibacterial activity against E. coli (19.20 ± 0.36 mm), S. aureus (16.06 ± 0.25 mm) and B. subtilis (13.46 ± 0.35 mm). No antifungal activity was observed for any extract. Thrombolytic potential was also assessed and EAE (33.72% ± 1.94) represented the highest thrombolytic activity, followed by AE (25% ± 0.81) and ME (16% ± 1.75). Cytotoxicity of extracts was analyzed; EAE exhibited maximum hemolysis of 11.81% ± 0.41. Conclusion: The results suggest that bioactive metabolites from the halophilic bacterium Salinicoccus roseus BMRL-13 strain may be candidates for developing new therapeutic agents for infectious and thrombolytic disorders. All the experiments were carried out in triplicate and results were presented as the mean with standard deviation.

Abstract: Background: Alpha-glucosidase is an essential enzyme in carbohydrate metabolism, responsible for hydrolyzing disaccharides into monosaccharides (glucose). Inhibition of this enzyme is an effective approach to control postprandial hyperglycemia in type 2 diabetes. Previous studies have reported that some antiviral agents, including tenofovir, exhibit potent α-glucosidase inhibitory activity comparable to that of acarbose. Objectives: This study employed both in-vitro and in-silico methods to design, synthesize and assess new tenofovir ester conjugates as potential α-glucosidase inhibitors. Method: In this study, 22 ester derivatives of tenofovir were synthesized by masking the hydroxyl group with hydroxyl, amino and phenolic groups, as well as with fatty acid chains. The synthesized compounds were thoroughly characterized using mass spectrometry, ¹H-NMR, ¹³C-NMR, NOESY, COSY, HSQC, HMBC, UV and IR spectroscopy. To assess in-vitro α-glucosidase activity, an enzyme from yeast (Saccharomyces cerevisiae) was used. Results: All synthesized derivatives (2–22) demonstrated significant α-glucosidase inhibition, with IC₅₀ values ranging from 7.80 ± 0.42 to 342.59 ± 2.19 µM, exhibiting greater potency than the standard inhibitor acarbose (IC₅₀ = 875.75 ± 2.09 µM). Molecular docking studies supported these findings, showing binding energies ranging from −9.1 to −11.7 kcal/mol, greater than those achieved with acarbose (−8.4 kcal/mol). Among them, compounds 2 and 6 displayed the highest inhibitory activities (IC₅₀ = 10.50 ± 0.46 µM and 7.80 ± 0.42 µM, respectively) with strong binding affinities (−11.5 and −11.7 kcal/mol). Conclusion: The findings suggest that tenofovir-derived ester compounds, particularly 2 and 6, are promising candidates for the continued development of potent α-glucosidase inhibitors for the management of type 2 diabetes.

Abstract: Background: Dual antiplatelet therapy (DAPT) is essential for secondary prevention of coronary artery disease (CAD), but gastrointestinal (GI) intolerance often leads elderly patients to self-reduce the dose or discontinue medication. Objectives: To compare the effects of monthly alternating aspirin and clopidogrel versus continuous DAPT on GI symptoms, medication adherence and 6‑month major adverse cardiovascular events (MACE) in elderly community patients with stable CAD. Methods: This retrospective cohort study included 160 elderly patients with stable CAD, who were non-randomly assigned to alternating DAPT (n=80) or continuous DAPT (n=80) according to their documented antiplatelet regimens in clinical practice. GSRS, MMAS-8 and adverse events were evaluated at baseline and 6 months. Results: At 6 months, the observation group’s GSRS total score remained stable (15.14±4.52 to 15.84±4.89, +0.70, P>0.05), while the control group significantly worsened (15.18±4.48 to 19.59±5.67, +4.41, P<0.05); the between-group difference was significant (P<0.05). The MMAS-8 score was higher in the observation group (7.58±0.76 vs. 6.94±1.15, P<0.001), with higher adherence rates (72.50% vs. 51.25%, P=0.006). Total GI adverse events were lower in the observation group (6.25% vs. 18.75%, P=0.017), but GI bleeding did not differ significantly. MACE occurred in 3 cases (3.75%) in each group (P=1.000); however, statistical power was severely insufficient to infer cardiovascular non‑inferiority. Conclusion: Alternating monthly use of aspirin and clopidogrel during the 6-month observation period of this study did not show a significant increase in the risk of MACE. Under these conditions, this regimen attenuated the progressive worsening of gastrointestinal symptoms in elderly patients (scores remained stable rather than significantly worsening) and significantly improved medication adherence. Within this study's specific population (stable elderly CAD patients) and 6-month observation window, this strategy offers a promising alternative worthy of further investigation. Its long-term benefits and cardiovascular safety require confirmation by prospective large-scale trials.