IMMUNOMODULATORY BENEFITS OF ULVA LACTUCA: A STUDY ON CELLULAR AND HUMORAL IMMUNE RESPONSES

Abstract

The immune system plays a critical role in protecting the body against infections and maintaining physiological homeostasis. Natural products, particularly marine algae, have gained increasing attention due to their diverse bioactive constituents and potential immunomodulatory properties. Ulva lactuca, commonly known as sea lettuce, is a green marine alga rich in phytoconstituents such as flavonoids, saponins, alkaloids, and steroids, which are known to exhibit various pharmacological activities. However, its role in modulating immune responses has not been comprehensively investigated. The present study was designed to evaluate the immunomodulatory potential of hydroalcoholic extract of Ulva lactuca (HUL) using established in vivo models of cellular and humoral immunity. Immunomodulatory activity was assessed through delayed-type hypersensitivity response (DTH), hemagglutinating antibody titer assay, and cyclophosphamide-induced immunosuppression model. HUL at doses of 150 and 300 mg/kg significantly enhanced DTH response, restored leukocyte function in immunosuppressed animals, and increased antibody titers compared to the control group. Furthermore, HUL treatment resulted in a dose-dependent increase in spleen and thymus indices, indicating improved immune organ function. Histopathological examination of immune organs revealed protective effects against cyclophosphamide-induced immunological damage. These findings suggest that Ulva lactuca possesses significant immunomodulatory activity by enhancing both cellular and humoral immune responses. The observed effects may be attributed to the presence of bioactive phytoconstituents, supporting its potential as a natural immunotherapeutic agent.