The vulnerable plant Dalbergia tonkinensis Prain is a rare species in Vietnam. In the course of our studies on biologically active plants, we performed serine protease enzyme screenings. The results suggest that at concentrations of 25–250 ng/mL, methanol extracts of leaf and root, root ethanol extract and its dichloromethane fraction, and heartwood water decoction extract can serve as useful sources to stimulate trypsin enzyme activity. In addition, water decoction extracts of leaf and stem bark may explain unknown ethno-pharmacology due to the high inhibitory effects in enzyme assays using trypsin, chymotrypsin, and elastase. Among 23 isolated compounds and two semi-synthetic derivatives tested, quercetin (17) inhibits the activities of trypsin and chymotrypsin with IC₅₀ 9.7 µM. Flavonoids categorized as flavanone, isoflavanone, flavone, isoflavone, pretocarpan, aurone, and neoflavanone demonstrated variable activities. Several substitutions are closely correlated with protease actions, including hydroxylation at C-3 and C-3′ in flavone and C-5 and C-3′ in isoflavone, hydroxylation at C-3, C-5 and C-3′, carboxylation at C-6 and C-8, and 7-substitution in flavanone; 7-substitution and methoxylation at C-3′ in isoflavanone; and lactone ring opening in neoflavanone. In the assessment of casein cleavage, at a dose of 25 ng/mL, leaf water decoction extract demonstrates an inhibitory effect on casein cleavage by trypsin, whereas ethanol and methanol extracts of the root caused activation.

中文翻译：

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来自黄檀（Dalbergia tonkinensis）物种的丝氨酸蛋白酶抑制剂和活化剂。

易受伤害的植物Dalbergia tonkinensis Prain是越南的稀有物种。在我们对具有生物活性的植物的研究过程中，我们进行了丝氨酸蛋白酶筛选。结果表明，在浓度为25–250 ng / mL的情况下，叶和根的甲醇提取物，根乙醇提取物及其二氯甲烷级分以及心材水煎剂可作为刺激胰蛋白酶活性的有用来源。此外，由于在使用胰蛋白酶，胰凝乳蛋白酶和弹性蛋白酶的酶分析中具有很高的抑制作用，因此，叶和茎皮的水煎剂可能会解释未知的民族药理作用。在测试的23种分离的化合物和两种半合成衍生物中，槲皮素（17）通过IC抑制胰蛋白酶和胰凝乳蛋白酶的活性₅₀ 9.7 µM。类黄酮分类为黄烷酮，异黄烷酮，黄酮，异黄酮，前果皮，金黄色酮和新黄烷酮表现出可变的活性。几种取代作用与蛋白酶作用密切相关，包括黄酮中C-3和C-3'的羟基化以及异黄酮中C-5和C-3'的羟基化，C-3，C-5和C-3'的羟基化，羧化在C-6和C-8处，在黄烷酮中被7取代；异黄烷酮中C-3'处的7-取代和甲氧基化；和新黄烷酮中的内酯开环。在25 ng / mL剂量的酪蛋白裂解评估中，叶水煎剂提取物显示出对胰蛋白酶裂解酪蛋白的抑制作用，而根的乙醇和甲醇提取物则引起了活化。