Red betel leaves (Piper crocatum, Ruiz. & Pav.) have been traditionaly used as an ingredient in a Jamu preparation intended to maintain health. The red betel leaves are thought to boost the immune system , keeping the body stay healthy. The study is aimed to isolate and identify compounds that stimulate the immune system , and determine their potential as immunomodula tors in vivo .
Isolation of the active compounds was proceeded by bioassay - guided isolation . Activation of macrophage in vitro (phagocytic assay) was used to guide the isolation of active compounds . The isolated active compounds were tested for in vivo immunomodulatory effect on balb/c mice infected with Lysteria monocytogenes . In these assays, several parameters such as phagocytic index and capacity, concentration of nitric oxide and proliferation of lymphocyte were measured .
Two new neolignans , 2-allyl-4-(1’-hydroxy-1’-(3”,4”,5”-trimethoxyphenyl)propan-2’-yl)-3,5-dimethoxycyclohexa-2,5-dienone and its naturally occuring acetyl derivative were isolated and identified as active compounds. The two compounds separately (5 µg/mL) displayed immunomodulatory activity equal to Imboost (Echinaceae product), as positive control. In the in vivo immunomodulatory assay, the two compounds separately (5.0 and 10.0 mg/kgBW) increased the activity and capacity of macrophages. In addition, increases of nitric oxide and IL-12 productions were also observed in response to the two compounds (2.5, 5.0 and 10.0 mg/kgBW). However, there is no lymphocyte proliferation was observed, which might be due to inhibition on the binding between IL-12 and its receptor.