Immunosuppressive Effects of Annona muricata L. Leaf Extract on Cellular and Humoral Immune Responses in Male Wistar Rats



Annona muricata L. (Annonaceae) (AM) 's remarkable anti-inflammatory and anti-cancer activities make it a targeted plant to be explored for its immunomodulatory properties. Traditional practitioners have employed various components of AM to cure a variety of ailments, including cancer, diabetes, and inflammation.



The present study evaluated the immunosuppressive effects of 80% ethanol extract of of AM leaves in male Wistar rats on different parameters of humoral and cellular immune responses.



AM leaf extract (AMLE) was analyzed using UHPLC-MS/MS to profile its secondary metabolites. AMLE was rich in polyphenols which include (epi)catechin-(epi)catechin-(epi)catechin, caffeic acid, coumaroylquinic acid, hyperin, kaempferol, quinic acid and rutin. The rats were administered 100, 200 and 400 mg/kg bw of the extract daily for 14 days. The effects of AMLE on innate immune responses were determined by evaluating phagocytosis, neutrophils migration, reactive oxygen species (ROS) release, CD11b/CD18 integrin expression, and ceruloplasmin, lysozyme and myeloperoxidase (MPO) levels. The adaptive immune parameters were evaluated by immunizing the rats with sheep red blood cells (sRBC) on day 0 and administered orally with AMLE for 14 days.



AMLE established significant immunosuppressive effects on the innate immune parameters by inhibiting the neutrophil migration, ROS production, phagocytic activity and expression of CD11b/CD18 integrin in a dose-dependent pattern. AMLE also suppressed ceruloplasmin, MPO and lysozyme expressions in the rat plasma dose-dependently. AMLE dose-dependently inhibited T and B lymphocytes proliferation, Th1 and Th2 cytokine production, CD4+ and CD8+ co-expression in splenocytes, immunoglobulins (IgM and IgG) expression and the sRBC-induced swelling rate of rat paw in delayed-type hypersensitivity (DTH).
