Glycine tomentella Hayata inhibits IL-1β and IL-6 production, inhibits MMP-9 activity, and enhances RAW264.7 macrophage clearance of apoptotic cells.

Background: To assess the effects of Glycine tomentella Hayata (GTH), a traditional herbal medicine for treatment of rheumatic diseases on the expression of the proinflammatory cytokines and on the clearance of apoptotic cells by macrophages.

Methods: RAW264.7 cells were cultured with lipopolysaccharide (LPS) in the presence or absence of ethanol extract of GTH. The expression of proinflammatory cytokines IL-1β, IL-6, and TNF-α, and inducible nitric oxide synthase (iNOS) and transglutaminase 2 (TG2) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Matrix metalloproteinase (MMP)-2 and MMP-9 were assayed by gelatin zymography. For detecting uptake of apoptotic cells, RAW264.7 cells were cultured with carboxyfluorescein diacetate (CFDA)-stained apoptotic cells and assayed by flow cytometry.

Results: The major components of GTH analyzed by high-performance liquid chromatography (HPLC) chromatogram were daidzein (42.5%), epicatechin (28.8%), and naringin (9.4%).GTH treatment inhibited the expression of proinflammatory cytokines IL-1β, IL-6 and MMP-9 but did not affect the expression of TNF-α and iNOS. GTH significantly enhanced the expression of TG2 and the clearance of apoptotic cells by RAW264.7 macrophages.

Conclusions: GTH inhibits proinflammatory cytokine secretion and MMP-9 activity, enhances apoptotic cell uptake and up-regulates TG2 expression. Our data show that GTH might have beneficial effects on rheumatic diseases.