8‐(3,3‐Dimethylallyl)‐Substituted Flavonoid Glycosides from the Aerial Parts of Epimedium koreanum

Ten 8‐(3,3‐dimethylallyl)‐substituted flavonoid glycosides, including the four new flavonol glycosides 1 and 3 – 5 and the new flavanonol glycoside 2 , besides five known flavonol glycosides, were isolated from the aerial parts of Epimedium koreanum Nakai . Their structures were determined by spectroscopic methods, including UV, IR, 1D‐ and 2D‐NMR, ESI‐MSⁿ, HR‐ESI‐MS, and circular dichroism (CD) experiments.     

朝藿甙－C的分离和结构

从朝鲜淫羊蕾的地上部分分离得到４个化合物。经化学和光谱方法鉴定它们为：５，７，３＇－三羟基－４＇－甲氧基－８－异戊烯基黄酮醇－３－Ｏ－α－Ｌ－鼠李吡喃糖甙（Ⅰ）、ＩｃａｒｉｓｉｄｅＣ１（Ⅱ）、Ｅｐｉｍｅｄｏｋｏｒｅａｎｏｓｉｄｅ－Ⅰ（Ⅲ）和Ｄｅｓｍｅｔｈｙｌｉｃａｒｉｔｉｎ（Ⅳ）。其中Ⅰ是未见报道的新化合物，命名为朝藿甙－Ｃ；Ⅱ、Ⅲ和Ⅳ首次从该植物中获得。     

Prenylated flavonoids and dihydrophenanthrenes from the leaves of Epimedium brevicornu and their cytotoxicity against HepG2 cells

Phytochemical study on the leaves of Epimedium brevicornu finally led to the isolation of four prenylated flavonoids (1–4) and three dihydrophenanthrenes (5–7), of which 1, 2, 5 and 7 were new compounds. The structures of these compounds were established mainly by spectroscopic techniques, including NMR spectroscopy and mass spectrometry. These isolates exhibited the cytotoxic activities against HepG2 cells with the IC₅₀ values of 32.8–87.3 μM.     

Comparison between HPLC and HPTLC densitometry for the determination of icariin from Epimedium koreanum extracts

Dry extracts of the aerial parts of Epimedium koreanum were quantified by HPLC and high performance TLC (HPTLC). A gradient HPLC method was used for the quantification of the prenylflavone glycoside icariin at 270 nm. A direct HPTLC assay was developed for the determination of icariin at 270 nm. The UV detection of both analytical assays were used to examine the purity of icariin peaks and compared with the standards. The assays provide good accuracy, reproducibility, and selectivity for the quantitative analysis of icariin. The icariin contents of five different dry extracts were compared by HPLC and HPTLC densitometry. The quantitative results of both analytical methods did not show any statistically significant differences between them, although a trend to slightly lower mean values could be found for the HPLC method.     

Synthesis of Moracin C and Its Derivatives with a 2-arylbenzofuran Motif and Evaluation of Their PCSK9 Inhibitory Effects in HepG2 Cells

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key factor in several cardiovascular diseases, as it is responsible for the elevation of circulating low-density lipoprotein cholesterol (LDL-C) levels in blood plasma by direct interaction with the LDL receptor. The development of orally available drugs to inhibit this PCSK9-LDLR interaction is a highly desirable objective. Here, we report the synthesis of naturally occurring moracin compounds and their derivatives with a 2-arylbenzofuran motif to inhibit PCSK9 expression. In addition, we discuss a short approach involving the three-step synthesis of moracin C and a divergent method to obtain various analogs from one starting material. Among the tested derivatives, compound 7 (97.1%) was identified as a more potent inhibitor of PCSK9 expression in HepG2 cells than berberine (60.9%). These results provide a better understanding of the structure–activity relationships of moracin derivatives for the inhibition of PCSK9 expression in human hepatocytes.     

Anthraquinones from the Aerial Parts of Rubia cordifolia with Their NO Inhibitory and Antibacterial Activities

The present study aimed to identify the composition of the aerial parts of Rubia cordifolia L. A chemical investigation on the EtOAc extracts from the aerial parts of Rubia cordifolia resulted in the isolation of four new anthraquinones, namely Cordifoquinone A–D (1–4), along with 16 known anthraquinones. Their structures were elucidated on the basis of NMR and HR-ESIMS data. All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds 1, 3 and 10 exhibited significant inhibitory activities with IC₅₀ values of 14.05, 23.48 and 29.23 μmol·L⁻¹, respectively. Their antibacterial activities of four bacteria, Escherichia coli (ATCC 25922), Staphylococcus aureus subsp. aureus (ATCC 29213), Salmonella enterica subsp. enterica (ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853), were also evaluated. Our results indicated that the antibacterial activity of these compounds is inactive.