Characterization and anti-tumor activities of polysaccharide isolated from Brassica rapa L. via activation of macrophages through TLR2-and TLR4-Dependent pathways.

We have previously shown the immunostimulatory effects by Nozawana (Brassica rapa L.). In this report, we determined the characteristics of Nozawana polysaccharide (NPS) and evaluated the immunomodulatory effects and anti-tumor activity of NPS mediated by macrophage activation. The molecular weight of NPS was determined by gel filtration chromatography with an average molecular weight of approximately 100.6 kDa. HPLC analysis showed that NPS contained glucose, galacturonic acid, galactose, and arabinose. NPS increased cytokine and nitric oxide (NO) production by macrophages in a Toll-like receptor (TLR)2 and TLR4-dependent manner. Furthermore, NPS induced apoptosis significantly against 4T1 murine breast cancer cells cultured in conditioned medium from NPS-treated macrophages through tumor necrosis factor-α. In tumor-bearing mouse model, tumor growth was significantly reduced in NPS-treated mice compared with control mice. These results support the potential use of NPS as an immunotherapeutic material found in health food products.

Modulation of immune function and changes in intestinal flora by Brassica rapa L. (Nozawana).

Dietary foods have functions that can prevent disease and improve immune function, eg. increasing resistance to infection and preventing allergies. Brassica rapa L., known as Nozawana in Japan, is a cruciferous plant and a traditional vegetable of the Shinshu area. Nozawana leaves and stalks are processed mainly into pickled products called Nozawana-zuke. However, it is unclear whether Nozawana exerts beneficial effects on immune function. In this review, we discuss the evidence we have accumulated, which indicate Nozawana has effects on immunomodulation and gut microbiota. We have shown that Nozawana exerts an immunostimulatory effect by enhancing interferon-gamma production and natural killer activity. During the fermentation of Nozawana, the number of lactic acid bacteria increases and cytokine production by spleen cells is enhanced. Moreover, the consumption of Nozawana pickle was shown to modulate gut microbiota and improve the intestinal environment. Thus, Nozawana could be a promising food for improving human health.