In vitro effects ofAsparagus racemosusethanolic root extract on cellular immune response and immune‐related gene expression ofLabeo rohita(Hamilton, 1822) leucocytes and anti‐Aeromonas hydrophilaactivity

Abstract

Asparagus racemosus is an important herb, the medicinal properties of which have been reported in traditional systems of medicine. The potential application of this plant as an immunostimulant for fish was explored in this study, using in vitro assay methods. Based on the extraction yield, phytochemical properties and antioxidant potentials, the ethanolic root extract of the plant (AREE) was selected and subsequently used to observe in vitro cellular immune responses, immune-related gene expression of Labeo rohita head kidney (HK) leucocytes, and anti-Aeromonas hydrophila activity. Different cellular immunological parameters (nitric oxide production, superoxide anion production and myeloperoxidase activity) of the HK leucocytes showed significantly enhanced responses when incubated with different concentration of AREE (6.25, 12.5, 25, 50 and 100 µg ml−1). Additionally, the leucocyte proliferation assay confirmed polyclonal activation of leucocytes by AREE, indicating the absence of any negative impact of the extract on leucocyte viability. Immune-related genes viz. IL-1β, IFN-γ and C3 showed significantly higher upregulation following incubation of AREE with the leucocytes, indicating enhancement of immune responses at the molecular level. The results collectively suggest the potential of AREE as an effective immunostimulant for use in aquaculture.