Immunostimulatory activity of Sri Lankan wild type Carica papaya L. mature leaf concentrate in a rat model.

Abstract

Modulation of the immune system by plant based immunomodualtors is well accepted. The present study evaluated the immunomodulatory activity of the mature leaf concentrate (MLC) of Carica papaya Sri Lankan wild type variant, to fill an existing knowledge gap. Separate groups of albino Wistar rats (N=6) were orally administered with 3 doses (low: 0.18, mid: 0.36 and high: 0.72 ml/100 g body weight) of the MLC and distilled water as the control for 3 consecutive days. Selected nonfunctional and functional immunological parameters were determined at the 3rd day post treatment using standard methodology. Liver and kidney functional parameters were determined to assess the acute hepato and renal toxicities, respectively. The MLC elicited significant immunostimulatory activity for both nonfunctional and functional immunological assays. Rat platelet count was significantly (P<0.05) increased by all three doses at post treatment while total WBC, monocyte, lymphocyte and bone marrow cell counts were significantly (P<0.05) increased by mid and high doses of the MLC. Conversely, no significant (P>0.05) difference was observed for splenocyte counts in treated rats. The phagocytic activity based on functional assay was significantly (P<0.05) increased by all three doses compared to the control. Further, the oral administration of the MLC neither provoked acute hepato or renal toxicities. Thus, the present study confirmed that mature leaf concentrate (MLC) of Carica papaya Sri Lankan wild type variant is orally active and effectively stimulates the nonfunctional and functional immunological parameters tested with no acute liver and kidney toxicities.