Two diterpenoids and a cyclopenta[c]pyridine derivative from roots of Salvia digitaloids

A new anti-neuroinflammation labdane diterpenoid from Salvia tricuspis

One new labdane diterpenoid, tricuspion A (1), as well as five known triterpenoids (2-6) were isolated from Salvia tricuspis Franch (family Labiatae). The structure of tricuspion A was identified by extensive spectroscopic analysis and by comparison with previously reported data. Compounds 1-6 were evaluated for their inhibitory effects on the NO production in LPS-stimulated BV-2 microglia cells, and 1 exhibited potent inhibitory activity with IC50 value of 14.92 ± 0.51 μM. Compound 1 might exert anti-neuroinflammatory activity through inhibiting the excessive production of NO and down-regulating the protein expression of iNOS and COX-2. As such, labdane diterpenoid (tricuspion A) could provide promising anti-neuroinflammatory lead compound for further structural modification.

Sources, Transformations, Syntheses, and Bioactivities of Monoterpene Pyridine Alkaloids and Cyclopenta[c]pyridine Derivatives

Monoterpene pyridine alkaloids (MTPAs) are alkaloids derived from iridoid glycosides (IGs). The common molecular structure of MTPAs is the pyridine ring, while some of them have a cyclopenta[c]pyridine skeleton. Some compounds containing this structure are potentially bioactive medicinal agents. In this paper, seven drug candidates (A-G), ninety natural source products (1-90), thirty-seven synthesized compounds (91-127), as well as twenty-six key intermediates (S1-S26) were summarized. We categorized five types of MTPAs and one type of cyclopenta[c]pyridine alkaloids in all. Additionally, their possible genetic pathways were proposed. Then, the chemical transformation, biotransformation, chemical synthesis, as well as the bioactivity of MTPAs and cyclopenta[c]pyridine derivatives were analyzed and summarized. Cyclopenta[c]pyridine derivatives can be concisely and chirally synthesized, and they have shown potentials with antibacterial, insecticidal, antiviral, anti-inflammatory, and neuropharmacological activities.

Discovery of antibacterial agents targeting biofilm formation: total synthesis and in vitro investigation of amycolasporins

Three monoterpene alkaloids amycolasporin A and (±) amycolasporins B and C have been synthesized for the first time from commercially available materials in yields of 31%, 14% and 21%, respectively. Their six analogues (18, 19, 30a and 30d-30f) were synthesized through a similar protocol. Meanwhile, the antibacterial activity of all synthesized molecules was evaluated, showing different levels of bioactivity. Among them, analogue 30d was screened as the most effective antibacterial candidate against E. coli (MIC value, 12.5 μg mL^-1) and S. aureus (MIC value, 12.5 μg mL^-1). Further investigation showed that 30d obviously inhibited biofilm formation and disrupted the preformed biofilm of E. coli and S. aureus by promoting intracellular ROS release.

Nine new compounds from the whole plants of Rehmannia chingii

Nine new compounds, together with 16 known analogs, were isolated from the whole plants of Rehmannia chingii. The structures of compounds 1-9 were elucidated on the basis of their spectroscopic data and chemical evidence. In addition, the new compounds were tested for their hepatoprotective activities against APAP-induced HepG2 cell damage and their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line. Compounds 2 and 5 exhibited pronounced hepatoprotective activities against APAP-induced HepG2 cell damage at a concentration of 10 μM, and compounds 4 and 9 showed moderate inhibitory activity against microglial inflammation factor with IC50 values of 3.51 and 7.11 μM, respectively.

Five new iridoids from roots of Salvia digitaloides

Five new iridoids, salvialosides A-E (compounds 1-5), together with fifty known compounds were isolated from the roots of Salvia digitaloides. The structures of the new compounds were completely elucidated using a combination of 2D NMR techniques (COSY, NOESY, HMQC and HMBC) and HR-ESI-MS analyses. The known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature.