Department of Agrofood Resources, National Institute of Agricultural Sciences, RDA, Wanju-gun, Jeollabuk-do, Korea.
Department of Food and Biotechnology, Korea University, Sejong, Korea.
J Chin Med Assoc. 2019 Apr;82(4):251-255. doi: 10.1097/JCMA.0000000000000051.
Yam (Dioscorea japonica Thunb) is a well-known health food in Korea and is widely distributed in the temperate and tropical regions. Although various medical effects of yam have been demonstrated, there is little current knowledge on the efficacy of Youngyeoja (YYJ; the aerial bulblets of the yam plant), their physiological effects, and their mechanism of action.
To investigate the anti-inflammatory effects of YYJ, we examined the level of inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells treated with YYJ extract. Nitric oxide (NO) and prostaglandin E2 (PGE2) levels were determined using enzyme-linked immunosorbent assays. Expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were evaluated using real-time polymerase chain reaction and western blotting. In addition, activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) was detected using western blotting.
Treatment of macrophages with LPS markedly induced the production of NO and PGE2. YYJ treatment inhibited the induction of inflammatory mediators and the expression of iNOS and COX-2. More importantly, LPS-induced phosphorylation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) was suppressed by treatment with YYJ, suggesting YYJ inhibited NF-κB activation. Furthermore, YYJ inhibited the LPS-induced phosphorylation of MAPKs.
YYJ was shown to have a potent anti-inflammatory effect in LPS-stimulated RAW 264.7 cells, which may be attributed to its inhibitory effect on NF-κB and MAPK activation, consequently blocking the production of inflammatory factors. Therefore, these results suggest that the YYJ extracts could be used as anti-inflammatory agents.
山药（薯蓣科薯蓣属植物）是韩国著名的保健食品，广泛分布于温带和热带地区。虽然山药具有多种医疗功效，但目前对山药地上球茎（YYJ）的功效、生理作用及其作用机制知之甚少。
为了研究 YYJ 的抗炎作用，我们检测了 YYJ 提取物处理的脂多糖（LPS）刺激的 RAW 264.7 细胞中炎症介质的水平。采用酶联免疫吸附试验测定一氧化氮（NO）和前列腺素 E2（PGE2）的水平。实时聚合酶链反应和蛋白质印迹法评估诱导型一氧化氮合酶（iNOS）和环氧化酶-2（COX-2）的表达。此外，采用蛋白质印迹法检测核因子-κB（NF-κB）和丝裂原活化蛋白激酶（MAPK）的激活。
LPS 处理巨噬细胞可显著诱导 NO 和 PGE2 的产生。YYJ 处理抑制了炎症介质和 iNOS 和 COX-2 的表达。更重要的是，YYJ 抑制了 LPS 诱导的核因子κ轻链增强子核因子 B（IκB）的磷酸化，表明 YYJ 抑制了 NF-κB 的激活。此外，YYJ 抑制了 LPS 诱导的 MAPKs 的磷酸化。
YYJ 对 LPS 刺激的 RAW 264.7 细胞具有强大的抗炎作用，这可能归因于其对 NF-κB 和 MAPK 激活的抑制作用，从而阻断了炎症因子的产生。因此，这些结果表明 YYJ 提取物可用作抗炎剂。
