Microencapsulation of lactic acid and ajwain essential oil: a novel strategy to attenuate oxidative damage and inflammatory responses in Clostridium perfringens pathogenesis

Abstract Clostridium perfringens is an important pathogen associated with foodborne disease and necrotic enteritis, with infection-related alterations in oxidative and inflammatory responses contributing to tissue damage. The present study aimed to develop and characterize spray-dried microcapsules co-encapsulating lactic acid (LA) and Ajwain ( Trachyspermum ammi ) essential oil (AEO) (LA-AEO-M) and to evaluate their antibacterial activity in vitro and their effects in a C. perfringens challenge model. LA-AEO-M was characterized using dynamic light scattering (DLS), zeta-potential analysis, and scanning electron microscopy (SEM). The microcapsules exhibited a mean particle diameter of 381.2 nm, a polydispersity index (PDI) of 0.574, and a zeta potential of − 35.4 ± 1.45 mV, with predominantly spherical and relatively smooth morphology. The encapsulation efficiency was 89.0 ± 4.62%. Gas chromatography–mass spectrometry analysis of AEO showed thymol (58.88%), p-cymene (24.02%), and γ-terpinene (13.78%) as the major constituents. In vitro, LA-AEO-M inhibited the growth of C. perfringens , Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae , producing inhibition zones of 9.33–14.33 mm. MIC values ranged from 150 to 400 μg/mL, while MBC values ranged from 300 to 400 μg/mL, with MBC/MIC ratios ≤ 4 under the conditions of the assay. In C. perfringens -challenged mice, dietary administration of LA-AEO-M (150 mg/kg diet) significantly improved average daily weight gain and feed intake compared with infected untreated animals. LA-AEO-M also attenuated infection-associated alterations in serum AST, ALT, and ALP activities and partially restored changes in SOD, CAT, and GPx activities and immunoglobulin levels. Histological and morphometric analyses showed partial improvement of infection-associated intestinal tissue alterations following LA-AEO-M administration. Furthermore, LA-AEO-M reduced the infection-associated upregulation of inducible nitric oxide synthase (iNOS) expression in intestinal tissue. Overall, these findings provide preliminary evidence that LA-AEO-M possesses antibacterial activity and may attenuate selected physiological, biochemical, histological, and inflammation-associated changes following C. perfringens challenge. However, bacterial burden, direct markers of oxidative damage and inflammatory cytokines, component-specific effects, and the contribution of microencapsulation to biological activity were not determined; therefore, further controlled studies are required to establish the underlying mechanisms and therapeutic potential of LA-AEO-M.