Isolation and immunomodulatory effect of flavonoids from Syzygium samarangense.
Sixteen flavonoids were isolated from the acetone extract of the leaves of Syzygium samarangense Merr. et Perry. The isolated flavonoids were evaluated for immunopharmacological activity. Human peripheral blood mononuclear cells (PBMC) were used as target cells, and cell proliferation was determined by 3H-thymidine uptake. Among them, (-)-strobopinin (2), myricetin 3-O-(2''-O-galloyl)-alpha-rhamnopyranoside (8), (-)-epigallocatechin 3- O-gallate (10) and myricetin 3-O-alpha-rhamnopyranoside (11) showed inhibitory potency on PBMC proliferation activated by phytohemagglutinin (PHA). The IC50 values of compounds 2, 8, 10, and 11 on activated PBMC proliferation were 36.3, 11.9, 28.9, and 75.6 microM, respectively. The inhibitory mechanisms may involve the blocking of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production, since compounds 2, 8, 10 and 11 reduced IL-2 and IFN-gamma production in PBMC in a dose-dependent manner.
Kuo
Yuh-Chi
YC
National Research Institute of Chinese Medicine, Pettou, Taipei, Taiwan.
Yang
Li-Ming
LM
Lin
Lie-Chwen
LC
D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D020128:Inhibitory Concentration 50; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008213:Lymphocyte Activation; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D027842:Syzygium
D005419:Flavonoids; D007155:Immunologic Factors; D007376:Interleukin-2; D010936:Plant Extracts; D007371:Interferon-gamma