Two new isobenzofurans, 5-(methoxymethyl)-2,2-dimethyl-2H-furo[3,4-h]chromen-7(9H)-one (1) and 5-(2-methoxyethyl)-2,2-dimethyl-2H-furo[3,4-h]chromen-7(9H)-one (2), together with two known isobenzofurans (3 and 4), were isolated from the roots of Yunnan local sun cured tobacco. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1–4 were tested for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results revealed that compound 4 showed strong inhibition with IZD of 16.5 ± 2.2. Compounds 1–3 also showed good inhibition with IZD of 13.6 ± 2.0, 14.0 ± 2.3, and 11.8 ± 1.6 mm, respectively. Compounds 1–4 were also tested for their antioxidant activity, and they showed good antioxidant activity with IC50 value of 4.38, 4.57, 4.46, and 4.28 μg/mL, respectively.

中文翻译：

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云南地方晒烟根中两种新型异苯并呋喃及其生物活性

两种新的异苯并呋喃，5-(甲氧基甲基)-2,2-二甲基-2H-呋喃[3,4-h]色烯-7(9H)-一 (1) 和 5-(2-甲氧基乙基)-2,2-二甲基-2H-呋喃[3,4-h]chromen-7(9H)-one (2) 连同两种已知的异苯并呋喃（3 和 4），是从云南当地晒烟的根中分离出来的。它们的结构是通过 HR-ESI-MS 和广泛的 1D 和 2D NMR 光谱研究确定的。测试了化合物 1-4 的抗甲氧西林金黄色葡萄球菌（抗 MRSA）活性。结果表明，化合物4显示出强烈的抑制作用，IZD为16.5±2.2。化合物 1-3 也显示出良好的抑制作用，IZD 分别为 13.6 ± 2.0、14.0 ± 2.3 和 11.8 ± 1.6 mm。还测试了化合物 1-4 的抗氧化活性，它们显示出良好的抗氧化活性，IC50 值分别为 4.38、4.57、4.46 和 4.28 μg/mL。