Phytochemical profiling and bioactivity assessment of crude methanolic extracts from different parts of Merremia emarginata: Antibacterial, antioxidant, thrombolytic, and cytotoxic evaluations

Introduction: Merremia emarginata, a member of the Convolvulaceae family, is used to combat various maladies associated with infection, oxidative stress, and inflammation. Methanolic extracts prepared from the leaves, roots, and stalks of M. emarginata were evaluated for their phytochemical constituents as well as antioxidant, antibacterial, thrombolytic, and cytotoxic activities. Methods: Total flavonoid content (TFC) and total phenolic content (TPC) were quantified using quercetin equivalent (QE) and gallic acid equivalent (GAE), respectively, using standard spectrophotometric procedures. Antioxidant capacity was quantified by the DPPH free radical scavenging method. The extracts were further screened for antibacterial effects against selected bacterial strains, thrombolytic activity using a clot lysis model, and cytotoxic potential against brine shrimp. Results: Among the tested samples, the methanolic leaf extract showed the highest TPC (۳۴۵±۸۹ mg GAE/g) and TFC (۲۴۳±۲۸ mg QE/g). The leaf extract also demonstrated superior antioxidant capacity, with an IC۵۰ value of ۱۳.۹۳±۰.۹۳ µg/mL. In tests for antibacterials, leaf extracts showed a considerable inhibitory effect against Pseudomonas aeruginosa (۱۳.۶۷ mm at ۵۰۰ µg/disc), whereas stalk extracts significantly inhibited Escherichia coli. Thrombolytic assays revealed that the stalk extract produced the highest clot lysis activity (۲۱ ± ۳.۳%) compared to the leaf and root extracts. The leaf extract had the highest cytotoxicity (LC۵۰ = ۱۳±۶.۱ µg/mL), whereas the stalk and root extracts were less effective. Conclusion: M. emarginata extracts showed strong antioxidant and measurable antibacterial, thrombolytic, and cytotoxic activities in vitro, which suggest potential bioactivity, but further studies are needed to evaluate in vivo effects and isolated active compounds.