Cioffi Giuseppina, Morales Escobar Luis, Braca Alessandra, De Tommasi Nunziatina
Dipartimento di Scienze Farmaceutiche, Università di Salerno, Via Ponte Don Melillo, 84084 Fisciano (SA), Italy.
J Nat Prod. 2003 Aug;66(8):1061-4. doi: 10.1021/np030127c.
Four chalcone glycosides (1-4), including three new natural products, and three flavanones (5-7) were isolated from the methanol extract of stem bark of Maclura tinctoria. The new compounds have been characterized as 4'-O-beta-D-(2' '-p-coumaroyl)glucopyranosyl-4,2',3'-trihydroxychalcone (1), 4'-O-beta-D-(2' '-p-coumaroyl-6' '-acetyl)glucopyranosyl-4,2',3'-trihydroxychalcone (2), and 3'-(3-methyl-2-butenyl)-4'-O-beta-D-glucopyranosyl-4,2'-dihydroxychalcone (3); the known derivatives were elucidated as 4'-O-beta-D-(2' '-acetyl-6' '-cinnamoyl)glucopyranosyl-4,2',3'-trihydroxychalcone (4), eriodictyol 7-O-beta-D-glucopyranoside (5), naringenin (6), and naringenin 4'-O-beta-D-glucopyranoside (7). Their structures were determined by 1D and 2D NMR and ESIMS. The antioxidant activity of all the isolated compounds was determined by measuring free-radical-scavenging effects using two different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). The results showed that compound 3 was the most active in both antioxidant assays.
从染料桑茎皮的甲醇提取物中分离出四种查耳酮糖苷（1-4），包括三种新的天然产物，以及三种黄烷酮（5-7）。新化合物已被鉴定为4'-O-β-D-（2''-对香豆酰基）吡喃葡萄糖基-4,2',3'-三羟基查耳酮（1）、4'-O-β-D-（2''-对香豆酰基-6''-乙酰基）吡喃葡萄糖基-4,2',3'-三羟基查耳酮（2）和3'-（3-甲基-2-丁烯基）-4'-O-β-D-吡喃葡萄糖基-4,2'-二羟基查耳酮（3）；已知衍生物被鉴定为4'-O-β-D-（2''-乙酰基-6''-肉桂酰基）吡喃葡萄糖基-4,2',3'-三羟基查耳酮（4）、圣草酚7-O-β-D-吡喃葡萄糖苷（5）、柚皮素（6）和柚皮素4'-O-β-D-吡喃葡萄糖苷（7）。它们的结构通过一维和二维核磁共振以及电喷雾离子化质谱法确定。通过使用两种不同的测定方法，即特罗克斯等效抗氧化能力（TEAC）测定法和β-胡萝卜素与亚油酸的偶联氧化（自动氧化测定法）来测量自由基清除效果，从而确定所有分离化合物的抗氧化活性。结果表明，化合物3在两种抗氧化测定中活性最高。
