Jang Chan Ho, Chung You Chul, Lee Ami, Hwang Youn-Hwan
Herbal Medicine Research Division, Korea Institution of Oriental Medicine (KIOM), Daejeon 34054, Republic of Korea.
Korean Convergence Medical Science Major, KIOM School, University of Science & Technology (UST), Daejeon 34054, Republic of Korea.
Plants (Basel). 2024 Nov 26;13(23):3314. doi: 10.3390/plants13233314.
L. (PAL), commonly known as knotgrass, has been utilized as a traditional folk medicine across Asian, African, Latin American and Middle Eastern countries to treat various inflammatory diseases, including arthritis and airway inflammation. Numerous medicinal herbs exert anti-inflammatory and antioxidative effects that are mediated through the activation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and the inhibition of nuclear factor kappa B (NF-κB). However, the underlying molecular mechanisms linking the antioxidative and anti-inflammatory effects remain poorly understood. Heme oxygenase-1 (HO-1) is an antioxidant enzyme that catalyzes heme degradation, ultimately leading to the production of carbon monoxide (CO). Elevated levels of CO have been correlated with the decreased level of inducible nitric oxide synthase (iNOS). In this study, we examined whether HO-1 plays a key role in the relationship between the antioxidative and anti-inflammatory properties of PAL. The anti-inflammatory and antioxidative activities of PAL in an in vitro system were evaluated by determining NF-κB activity, antioxidant response element (ARE) activity, pro-inflammatory cytokine and protein levels, as well as antioxidant protein levels. To examine whether HO-1 inhibition interfered with the anti-inflammatory effect of PAL, we measured nitrite, reactive oxygen species, iNOS, and HO-1 levels in RAW 264.7 murine macrophages pre-treated with Tin protoporphyrin (SnPP, an HO-1 inhibitor). Our results demonstrated that PAL increased ARE activity and the Nrf2-regulated HO-1 level, exerting antioxidative activities in RAW 264.7 macrophages. Additionally, PAL reduced cyclooxygenase-2 (COX-2) and iNOS protein levels by inactivating NF-κB in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. Further investigation using the HO-1 inhibitor revealed that HO-1 inhibition promoted iNOS expression, subsequently elevating nitric oxide (NO) generation in LPS-activated RAW 264.7 macrophages treated with PAL compared to those in the macrophages without the HO-1 inhibitor. Overall, our findings suggest that HO-1 induction by PAL may exert anti-inflammatory effects through the reduction of the iNOS protein level. Hence, this study paves the way for further investigation to understand molecular mechanisms underlying the antioxidative and anti-inflammatory activities of medicinal herbs.
扁蓄（Polygonum aviculare L.，PAL），俗称节节草，在亚洲、非洲、拉丁美洲和中东国家一直被用作传统民间药物，用于治疗包括关节炎和气道炎症在内的各种炎症性疾病。许多草药通过激活核因子红系2相关因子2（Nrf2）和抑制核因子κB（NF-κB）发挥抗炎和抗氧化作用。然而，将抗氧化和抗炎作用联系起来的潜在分子机制仍知之甚少。血红素加氧酶-1（HO-1）是一种抗氧化酶，催化血红素降解，最终产生一氧化碳（CO）。CO水平升高与诱导型一氧化氮合酶（iNOS）水平降低相关。在本研究中，我们研究了HO-1在PAL的抗氧化和抗炎特性之间的关系中是否起关键作用。通过测定NF-κB活性、抗氧化反应元件（ARE）活性、促炎细胞因子和蛋白质水平以及抗氧化蛋白水平，评估了PAL在体外系统中的抗炎和抗氧化活性。为了研究HO-1抑制是否会干扰PAL的抗炎作用，我们测量了用原卟啉锡（SnPP，一种HO-1抑制剂）预处理的RAW 264.7小鼠巨噬细胞中的亚硝酸盐、活性氧、iNOS和HO-1水平。我们的结果表明，PAL增加了ARE活性和Nrf2调节的HO-1水平，在RAW 264.7巨噬细胞中发挥抗氧化活性。此外，PAL通过使脂多糖（LPS）激活的RAW 264.7巨噬细胞中的NF-κB失活，降低了环氧化酶-2（COX-2）和iNOS蛋白水平。使用HO-1抑制剂的进一步研究表明，与未使用HO-1抑制剂的巨噬细胞相比，HO-1抑制促进了LPS激活的、用PAL处理的RAW 264.7巨噬细胞中iNOS的表达，随后提高了一氧化氮（NO）的生成。总体而言，我们的研究结果表明，PAL诱导的HO-1可能通过降低iNOS蛋白水平发挥抗炎作用。因此，本研究为进一步了解草药抗氧化和抗炎活性的分子机制铺平了道路。
