Purpose: To investigate
in vivo immunomodulatory effect and histopathological feature of mouse liver
and kidney following treatment with 2 neolignans (Pc-1 and Pc-2) isolated from red betel (
Piper crocatum
Ruiz & Pav) leaf.
Methods: Balb/c mice immune response was induced with Listeria monocytogenes. Immunomodulatory
effect was tested by using macrophage phagocytic, nitric oxide, and lymphocyte proliferation assays.
The morphological features of liver and kidney were observed with light microscope and then compared
with the liver and kidney of control group.
Results: At the dose of 5 and 10 mg/kg body weight, both Pc-1 and Pc-2 significantly increased the
activity and the capacity of macrophages (p < 0.05). Both Pc-1 and Pc-2 significantly increased
phagocytic activity of macrophage by 25% and 23%, respectively, and phagocytic index to 38 and 52,
respectively at a dose of 5 mg/kg body weight. Increases in nitric oxide production due to Pc-1 and Pc-
2 (at doses of 2.5, 5, and, 10 mg/kg body weight) were also observed although no lymphocyte
proliferation effect was observed. Histopathological examination of liver and kidney of mice given Pc-1
demonstrated normal features. On the other hand, hydropic degeneration and liver necrosis were seen
in mice given Pc-2 treatment. Based on this result and the structure similarity of the two compounds
(Pc-1 and Pc-2), an interesting presumption was made that the –OH functional group (Pc-2) was
responsible for the toxicity that caused liver damage.
Conclusion: The two neolignans (Pc-1 and Pc-2) isolated from the leaves of P. crocatum Ruiz & Pav.
are capable of increasing macrophage phagocytosis as well as nitric oxide production but not
lymphocyte proliferation. Histophatological features of liver given Pc-2 demonstrate hydropic
degeneration and necrosis, possibly due to the –OH group on Pc-2.
