The Biological Effects of Forsythia Leaves Containing the Cyclic AMP Phosphodiesterase 4 Inhibitor Phillyrin

Forsythia fruit (Forsythia suspensa Vahl (Oleaceae)) is a common component of Kampo medicines for treating the common cold, influenza, and allergies. The main polyphenolic compounds in the leaves of F. suspensa are pinoresinol β-d-glucoside, phillyrin and forsythiaside, and their levels are higher in the leaves of the plant than in the fruit. It is known that polyphenolic compounds stimulate lipid catabolism in the liver and suppress dyslipidemia, thereby attenuating diet-induced obesity and polyphenolic anti-oxidants might attenuate obesity in animals consuming high-fat diets. Recently, phillyrin was reported as a novel cyclic AMP phosphodiesterase 4 (PDE4) inhibitor derived from forsythia fruit. It was expected that the leaves of F. suspensa might display anti-obesity effects and serve as a health food material. In this review, we summarized our studies on the biological effects of forsythia leaves containing phillyrin and other polyphenolic compounds, particularly against obesity, atopic dermatitis, and influenza A virus infection, and its potential as a phytoestrogen.     

Determination of forsythiaside in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of forsythiaside in rat plasma after intravenous administration. Hesperidin was used as the internal standard. The drugs were separated on a reversed-phase C(18) column and detected at 332 nm. Good linearity was achieved in the range of 0.067-26.667 microg/mL. The intra- and inter-assay variation coefficients for this analysis were no more than 10.94 and 14.56%, respectively. The average recovery for forsythiaside was 87.42% from plasma. The analytical sensitivity and accuracy of this assay were adequate for characterization of the pharmacokinetics of intravenous administration of forsythiaside to rats and the assay has been successfully applied to provide pharmacokinetic data. The mean t(1/2Z) was 20.36, 19.40 and 23.62 min for 2, 5 and 20 mg/kg for forsythiaside after i.v. administration, respectively. The AUC(0-t) increased linearly from 40.64 to 624.14 microg min/mL after administration of the three doses.     

Study on inclusion behaviour of forsythiaside A with β-cyclodextrin

Inclusion behaviour of forsythiaside A with β-cyclodextrin (β-CD) was investigated by fluorescence spectrum, nuclear magnetic resonance (NMR) and molecular modelling. A ratio of 1:1 stoichiometry has been proposed for the inclusion complex of forsythiaside A with β-CD in aqueous media according to the continuous variation Job’s method based on the fluorescence spectroscopy data. The stability constant (K) of the inclusion complex was 669 M^?1. The pH, ionic strength and temperature of solution showed great effect on the formation of inclusion complex. The spatial configuration of complex demonstrated that the B ring of forsythiaside A might be embedded inside the lipophilic cavity of β-CD and the A ring of the forsythiaside A might be exposed outside the cavity of β-CD according to NMR spectra and molecular modelling.     

连翘酯甙分离提取及抑制弹性蛋白酶活性研究

弹性蛋白酶是一种水解酶 ,具有降解胶原蛋白、弹性蛋白等多种蛋白质的能力。在体内 ,当弹性蛋白酶与天然抑制剂的平衡失衡后 ,酶活力增加 ,这是诱发包括肺气肿在内的多种疾病的病因之一[1] 。因此 ,寻找合适的弹性蛋白酶抑制剂 ,增强机体抑制弹性蛋白酶的能力 ,进而恢复体内弹性蛋白酶与天然抑制剂的平衡 ,是研究治疗肺气肿疾病药物的一条有效途径。据报道[2 ] 连翘水提液具有抑制弹性蛋白酶的作用 ,但尚未见进一步研究报道。我们对连翘中的主要有效成分连翘酯甙进行了分离提取 ,并初步研究了连翘酯甙对猪胰弹性蛋白酶 (ＰＰＥ)的抑制作用。…