Fang Xuya, Yu Mabel Man-Shan, Yuen Wai-Hung, Zee Sze Yong, Chang Raymond Chuen-Chung
Laboratory of Neurodegenerative Diseases, Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong, SAR.
Int J Mol Med. 2005 Dec;16(6):1109-16.
Prunella vulgaris L. (Labiatae), a popular Western and Chinese herbal medicine, has long been associated with anti-viral and anti-bacterial effects. While its anti-viral effects are attributed mainly to the inhibition of virus replication, the biological mechanisms of its anti-bacterial effects remain unknown. As a biological response modifier (BRM), the polysaccharides isolated from P. vulgaris have been shown to up-regulate the immune responses of monocytes/macrophages. However, the immune stimulatory effects seem to contradict its well-known anti-inflammatory properties. We hypothesized that the anti-microbial effects exhibited by the polysaccharides isolated from P. vulgaris encompass both anti-inflammatory and immune stimulatory effects. One of the polysaccharide fractions PV2IV markedly stimulated the production of superoxide and nitrite representing nitric oxide from murine macrophage RAW264.7 and brain macrophage BV2 cells. The amount of nitrite and superoxide produced after PV2IV stimulation was as high as that stimulated by bacterial endotoxin lipopolysaccharide (LPS) in a dose-dependent manner. In addition, PV2IV also increased cellular protein levels of inducible nitric oxide synthase (iNOS) and mRNA for tumor necrosis factor-alpha (TNFalpha). Similar to the effects of a high dose of LPS, the fraction PV2 could trigger activation-induced cell death (AICD) by stimulating caspase-3 activity and reduction of MTT uptake in monocytes/macrophages. These results may help our understanding of the molecular mechanism of P. vulgaris, which exhibited both immune stimulatory and anti-inflammatory effects against microbial invasion.
夏枯草（唇形科）是一种在西方和中国都很常用的草药，长期以来一直被认为具有抗病毒和抗菌作用。虽然其抗病毒作用主要归因于对病毒复制的抑制，但其抗菌作用的生物学机制仍不清楚。作为一种生物反应调节剂（BRM），从夏枯草中分离出的多糖已被证明能上调单核细胞/巨噬细胞的免疫反应。然而，这种免疫刺激作用似乎与其众所周知的抗炎特性相矛盾。我们推测，从夏枯草中分离出的多糖所表现出的抗菌作用包括抗炎和免疫刺激作用。其中一个多糖组分PV2IV显著刺激了小鼠巨噬细胞RAW264.7和脑巨噬细胞BV2细胞中超氧化物的产生以及代表一氧化氮的亚硝酸盐的产生。PV2IV刺激后产生的亚硝酸盐和超氧化物的量与细菌内毒素脂多糖（LPS）刺激后的量一样高，且呈剂量依赖性。此外，PV2IV还增加了诱导型一氧化氮合酶（iNOS）的细胞蛋白水平以及肿瘤坏死因子-α（TNFα）的mRNA水平。与高剂量LPS的作用类似，组分PV2可通过刺激半胱天冬酶-3活性和降低单核细胞/巨噬细胞中MTT的摄取来触发激活诱导的细胞死亡（AICD）。这些结果可能有助于我们理解夏枯草对微生物入侵同时表现出免疫刺激和抗炎作用的分子机制。
