Six new iridoid glycosides from the whole plants of Hedyotis diffusa.

Six new iridoid glycosides were isolated from the ethyl acetate fraction of the whole plants of Hedyotis diffusa Willd. They were identified as E-6-O-p-methoxycinnamoyl-10-O-acetyl scandoside acid methyl ester (1), Z-6-O-p-methoxycinnamoyl-10-O-acetyl scandoside acid methyl ester (2), E-6-O-caffeoyl scandoside methyl ester (3), E-6-O-p-coumaroyl-6'-O-acetyl scandoside methyl ester (4), Z-6-O-p-coumaroyl-6'-O-acetyl scandoside methyl ester (5), and E-6-O-p-coumaroyl-4'-O-acetyl scandoside methyl ester (6). The structures of them were elucidated based on unambiguous spectroscopic data (UV, IR, HRESIMS, and NMR). They were screened for anti-inflammatory effect, antioxidant effect, antitumor effect, and neuroprotective effect and did not show potent activities.

Two new cucurbitane-type triterpenoid saponins from the fruit of Citrullus colocynthis.

Two new cucurbitane-type triterpenoid saponins, 2,20ß,22ß-trihydroxy-16α,23(R)-epoxycucurbita-1,5,24-triene-3,11-dione 2-O-ß-D-glucopyranoside (1), 2,20ß,22α-trihydroxy-16α,23(S)-epoxycucurbita-1,5,11,24-tetraene-3-one 2-O-ß-D-glucopyranoside (2) were isolated from the fruit of Citrullus colocynthis (L.) Schrad. Their structures were elucidated by mass spectrometry, IR, 1D, and 2D NMR spectroscopy, etc. Besides, both of the compounds showed significant hepatoprotective activities at 10 µM against paracetamol-induced HepG2 cell damage.

Three new flavonoids from the roots of Sophora tonkinensis.

Three new flavonoids including two isoflavanones sophortones A and B (1 and 2), and one chalcone sophortone C (3) were isolated from the roots of Sophora tonkinensis. Their structures were established by UV, IR, HRESIMS, and NMR data. The absolute configurations of 1 and 2 were determined by electronic circular dichroism (ECD) calculations.

Seventeen undescribed iridoid derivatives with anti-inflammatory effects from Hedyotis diffusa and their structure-activity relationships.

Seventeen undescribed iridoid derivatives (1-17) and four known compounds (18-21) were isolated from the whole plant of Hedyotis diffusa Willd. Their structures were elucidated based on unambiguous spectroscopic data (UV, IR, HRESIMS, CD, and 1D and 2D NMR). It is noteworthy that compounds 1-8, which possess unique long-chain aliphatic acid moiety, were reported for the first time among the iridoid natural products. All compounds were evaluated for their anti-inflammatory activities in lipopolysaccharide-induced RAW 264.7 cells. Compounds 2, 4, and 6 showed significant suppression effects on nitric oxide production, with IC50 values of 5.69, 6.16, and 6.84 µM, respectively. The structure-activity relationships of these compounds indicated that long-chain aliphatic moieties at C-10 might be the key group for their anti-inflammatory activities. The therapeutic properties of these iridoid derivatives could give an insight into utilizing H. diffusa as a natural source of anti-inflammatory agents.

Glycnsisitin A: A promising bicyclic peptide against heart failure that facilitates TFRC-mediated uptake of iron in cardiomyocytes.

Zhigancao decoction is a traditional prescription for treating irregular pulse and palpitations in China. As the monarch drug of Zhigancao decoction, the bioactive molecules of licorice against heart diseases remain elusive. We established the HRESIMS-guided method leading to the isolation of three novel bicyclic peptides, glycnsisitins A-C (1-3), with distinctive C-C and C-O-C side-chain-to-side-chain linkages from the roots of Glycyrrhiza uralensis (Licorice). Glycnsisitin A demonstrated stronger cardioprotective activity than glycnsisitins B and C in an in vitro model of doxorubicin (DOX)-induced cardiomyocyte injury. Glycnsisitin A treatment not only reduced the mortality of heart failure (HF) mice in a dose-dependent manner but also significantly attenuated DOX-induced cardiac dysfunction and myocardial fibrosis. Gene set enrichment analysis (GSEA) of the differentially expressed genes indicated that the cardioprotective effect of glycnsisitin A was mainly attributed to its ability to maintain iron homeostasis in the myocardium. Mechanistically, glycnsisitin A interacted with transferrin and facilitated its binding to the transferrin receptor (TFRC), which caused increased uptake of iron in cardiomyocytes. These findings highlight the key role of bicyclic peptides as bioactive molecules of Zhigancao decoction for the treatment of HF, and glycnsisitin A constitutes a promising therapeutic agent for the treatment of HF.