The leaves of Piliostigma thonningii are used in traditional medicine in Benin to treat inflammatory skin diseases and infections. So far, pharmacological studies of the anti-inflammatory and anti-infective effects of phytochemically characterized extracts of P. thonningii have been very limited. Therefore, we investigated the in vitro anti-inflammatory and antimicrobial effect of P. thonningii leaf extracts and analyzed the phytochemical composition of extracts of different polarities (water, 50% ethanol, and n-hexane). Quercetin-3-O-rhamnoside was confirmed as the main flavonoid in the polar extracts. GC-MS analysis identified 20 constituents of the aqueous extract and 28 lipophilic compounds of the n-hexane extract by comparison with authentic standards and spectral library data. The aqueous P. thonningii leaf extract inhibited the IL-8 and IL-6 secretion in TNF-α-stimulated HaCaT cells in a concentration-dependent manner with IC50 values of 74 µg/mL for IL-8 and 89 µg/mL for IL-6. However, an inhibitory effect of the identified quercetin-3-O-rhamnoside and its aglycone, quercetin, on the release of IL-8 and IL-6 could not be demonstrated. In the antimicrobial screening, inhibition zones for a 50% EtOH leaf extract of P. thonningii were found for Staphylococcus epidermidis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. For none of the microbial strains, however, the MIC was below 500 µg/mL, so that the antibacterial activity must be classified as low. As a result, our investigations primarily support the ethnomedical use of P. thonningii leaf extracts in topical inflammatory conditions. Further studies are required to identify the compounds responsible for the in vitro anti-inflammatory effects.

中文翻译：

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贝宁毛毛叶提取物的体外抗炎和抗菌活性

贝宁的传统医学使用 Piliostigma thonningii 的叶子来治疗炎症性皮肤病和感染。到目前为止，关于 P. thonningii 植物化学特征提取物的抗炎和抗感染作用的药理学研究非常有限。因此，我们研究了桑宁叶提取物的体外抗炎和抗菌作用，并分析了不同极性（水、50%乙醇和正己烷）提取物的植物化学成分。槲皮素-3-O-鼠李糖苷被证实是极性提取物中的主要黄酮类化合物。通过与真实标准品和光谱库数据进行比较，GC-MS 分析鉴定了水提取物的 20 种成分和正己烷提取物的 28 种亲脂性化合物。P. thonningii 叶提取物以浓度依赖性方式抑制 TNF-α 刺激的 HaCaT 细胞中 IL-8 和 IL-6 的分泌，IL-8 的 IC50 值为 74 µg/mL，IL-8 的 IC50 值为 89 µg/mL -6。然而，无法证明所鉴定的槲皮素-3-O-鼠李糖苷及其苷元槲皮素对IL-8和IL-6释放的抑制作用。在抗菌筛选中，发现 P. thonningii 50% EtOH 叶提取物对表皮葡萄球菌、金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌和大肠杆菌有抑菌圈。然而，没有任何微生物菌株的 MIC 低于 500 µg/mL，因此抗菌活性必须归类为低。因此，我们的研究主要支持 P. thonningii 叶提取物在局部炎症性疾病中的民族医学用途。需要进一步的研究来确定负责体外抗炎作用的化合物。