Phytochemical Profiling and In Vitro Bioactivity Testing of the Ethanolic Extract of the Seed of Carica papaya Integrated with Silver Nanoparticles

Abstract

Carica papaya seeds have long been valued in traditional medicine. Although silver nanoparticles (AgNPs) boost plant extract stability and bioactivity, the hybrid of C. papaya ethanolic seed extract (EE) and AgNPs remains underexplored. The study aims to evaluate the biological activities (cytotoxic, antioxidant, antimicrobial and anthelmintic) of EE, both alone and in combination with AgNPs, relative to reference drugs. The study measured cytotoxicity via brine shrimp lethality bioassays (determining LC50), assessed antioxidant capacity with DPPH scavenging (IC50), tested antimicrobial effects on gram-positive and gram-negative strains (by inhibition zone) and evaluated anthelmintic activity using earthworms (recording paralysis and death times). EE was assessed both alone and in combination with AgNPs and its performance was compared against reference drugs (vincristine sulfate, ascorbic acid, kanamycin and albendazole). EE displayed mild cytotoxicity (LC50 = 89.96 µg/ml), yet AgNPs integration markedly boosted its activity (LC50 = 66.42 µg/ml), indicating synergy; similarly, EE-AgNPs outperformed EE in DPPH scavenging (IC50 = 25.761 vs. 41.977 µg/ml), approaching ascorbic acid’s efficacy. Moreover, EE-AgNPs inhibited bacterial growth dose-dependently, being most effective against E. coli (but surpassed by kanamycin) and induced paralysis 31% faster and death 41% quicker than EE alone, despite albendazole showing superior activity overall. The study highlights C. papaya EE's therapeutic promise, especially with AgNPs, but requires further mechanistic, in vivo and safety studies for clinical use. Bangladesh Pharmaceutical Journal 29(2): 193-204, 2026 (July)