School of Pharmacy, Yantai University, Yantai, PR China.
Planta Med. 2012 Dec;78(18):1906-11. doi: 10.1055/s-0032-1327883. Epub 2012 Oct 31.
In our previous study, fourty-eight compounds have been isolated and identified from the roots of Picrasma quassioides, which have been widely used as a traditional Chinese medicine for clearing heat and for detoxification as described in the Chinese Pharmacopoeia. β-Carboline alkaloids are commonly considered as main active constituents of P. quassioides, but the molecular mechanism remains yet unknown. In the present paper, one new β-carboline alkaloid together with two known β-carboline alkaloids have been investigated for their anti-inflammatory effect and mechanism of action in cultured macrophage RAW 264.7 cells. Griess assay was used to evaluate the inhibitory effect on the overproduction of nitric oxide. ELISA was used to determine the level of proinflammatory cytokines including TNF-α and IL-6. The inhibitory effect on the enzymatic activity of COX-2 and inducible nitric oxide synthase were tested by colorimetric and fluorimetric methods, respectively. Western blot was used to detect the expression of inducible nitric oxide synthase and COX-2. All three β-carboline alkaloids suppressed LPS-stimulated nitric oxide production and proinflammatory cytokines secretion, including TNF-α and IL-6 in a dose-dependent manner. They also strongly inhibited the expression of inducible nitric oxide synthase and inducible nitric oxide synthase enzymatic activity, whereas the expression of COX-2 and COX-2 enzymatic activity were not affected. These results indicated that potent inhibition of nitric oxide, TNF-α, and IL-6, but not COX-2 expression and COX-2 activity, might constitute the anti-inflammatory mechanism of β-carboline alkaloids. β-Carboline alkaloids suppressed the overproduction of nitric oxide through downregulation of inducible nitric oxide synthase expression and inducible nitric oxide synthase enzymatic activity in an LPS-stimulated macrophage.
在我们之前的研究中，从苦木科鸦胆子属植物鸦胆子根中分离鉴定了四十八种化合物，这些化合物在《中国药典》中被广泛用作清热解毒的中药。β-咔啉生物碱通常被认为是鸦胆子属植物的主要活性成分，但分子机制尚不清楚。本研究采用细胞培养法，以 LPS 诱导的 RAW264.7 巨噬细胞为模型，对一种新的β-咔啉生物碱及两种已知的β-咔啉生物碱的抗炎作用及作用机制进行了研究。采用 Griess 法测定对一氧化氮生成的抑制作用；ELISA 法测定 TNF-α和 IL-6 等促炎细胞因子的水平；比色法和荧光法分别测定对 COX-2 和诱导型一氧化氮合酶活性的抑制作用；Western blot 法检测诱导型一氧化氮合酶和 COX-2 的表达。三种β-咔啉生物碱均能抑制 LPS 诱导的巨噬细胞 RAW264.7 一氧化氮生成和促炎细胞因子 TNF-α和 IL-6 的分泌，呈剂量依赖性。它们还能强烈抑制诱导型一氧化氮合酶的表达和诱导型一氧化氮合酶的活性，而对 COX-2 的表达和 COX-2 的活性没有影响。这些结果表明，抑制一氧化氮、TNF-α和 IL-6 的产生，而不影响 COX-2 的表达和 COX-2 的活性，可能是β-咔啉生物碱抗炎作用的机制。β-咔啉生物碱通过下调 LPS 诱导的巨噬细胞中诱导型一氧化氮合酶的表达和诱导型一氧化氮合酶的活性，抑制一氧化氮的过量产生。
