Amsonia orientalis (European Bluestar) is a critically endangered plant species with medicinal and ornamental properties. The rare availability of the species in nature limits its potential to be used for various purposes. However, plant tissue culture is an effective method for the cultivation of such vulnerable species without damaging their natural populations, which are very limited in nature for scientific purposes. By taking advantage of plant tissue culture, this study aimed to measure the phenolic substance and flavonoid contents in leaf extracts of in vitro-propagated Amsonia orientalis, and to investigate their antioxidant potentials through phosphomolybdate and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The crude extracts prepared in water, aqueous ethanol, methanol, and acetone were tested. The highest phenolic substance content was found in the ethanolic extracts, while statistically the same flavonoid contents were found in the ethanolic, methanolic, and acetone extracts. Although the water extract had lesser flavonoid content, it exhibited a notable antioxidant property. The ethanolic leaf extract gave the highest antioxidant and DPPH radical scavenging activity, especially when used at 1 mg mL⁻¹ concentration. Also, the TLC fingerprint profile validated the presence of valuable phytoconstituents in the leaves of the plant. This study indicated that ultrasound-assisted extraction of minimal amounts of dried leaf samples from in vitro-propagated plants might be adequate for the pre-screening of the antioxidant capacity of rare plant species.

侧柏（欧洲蓝星）是一种具有药用和观赏性的极度濒危植物。自然界中该物种的稀有可用性限制了其用于各种目的的潜力。然而，植物组织培养是在不损害其自然种群的情况下培育此类脆弱物种的有效方法，而自然种群出于科学目的是非常有限的。通过利用植物组织培养的优势，本研究旨在衡量的叶提取物中的酚类物质和类黄酮含量在体外-propagated水甘草属侧柏，并通过磷钼酸盐和2,2-二苯基-1-吡啶并肼基（DPPH）自由基清除试验研究其抗氧化能力。测试了在水，乙醇，甲醇和丙酮中制备的粗提取物。在乙醇提取物中发现了最高的酚类物质含量，而在乙醇，甲醇和丙酮提取物中发现了相同的黄酮含量。尽管水提取物中的类黄酮含量较少，但仍表现出显着的抗氧化性能。乙醇叶提取物具有最高的抗氧化剂和DPPH自由基清除活性，尤其是当以1 mg mL ^-1使用时浓度。此外，TLC指纹图谱验证了植物叶片中有价值的植物成分的存在。这项研究表明，超声辅助提取从体外繁殖的植物中提取的少量干叶样品可能足以对稀有植物物种的抗氧化能力进行预筛选。