Authors: Leonora P. Nudo, Elena S. Catap, Ph.D
Abstract: Gardenia longiflora S. Vidal (Rubiaceae) is an endemic plant species with no known medicinal significance yet, although reports have confirmed that most species of Gardenia has been traditionally used to treat various diseases. The present study, therefore, assessed possible immunomodulatory activities of G. longiflora leaf ethyl acetate and hexane fractions by employing a number of in vitro immune response assays namely macrophage phagocytosis and extracellular superoxide production, and lymphocyte proliferation.
The immunomodulatory responses triggered by G. longiflora extract treatment are dependent on the nature and concentration of biologically active molecules in each fraction. The ethyl acetate fraction significantly promoted macrophage phagocytosis and lymphocyte proliferation in the absence of any mitogen, while inhibition of these immune activities was observed in hexane fraction-treated cells. Suppression of lymphocyte proliferation in mitogen-stimulated cells, specifically in B-lymphocyte proliferation, resulted to a marked reduction in reactive oxygen species production. Pathogen clearing through oxidative burst was only evident in cells treated with the lowest concentration (50μg/mL) of ethyl acetate fraction. However, this observation as well as possible induction of other microbiocidal pathways by each fraction warrants further examination.
Keywords: immunomodulation, Gardenia longiflora, macrophage, lymphocyte, phagocytosis, reactive oxygen species