Cassane‐Type Diterpenoids from the Seeds of Caesalpinia bonduc (L.) Roxb.

Abstract

Ten new cassane‐type diterpenoids were isolated from the seeds of Caesalpinia bonduc (L.) Roxb., including 6α‐hydroxycaesalpinin P (1), 14‐epi‐caesalpinin E1 (2), 6‐deacetylcaesalmin Z (3), 14‐epi‐caesalmin Z (4), caesalpinolides I (5), K (6), L (7), M (9) and N (10), and 14‐epi‐neocaesalpin L (8). Their planar structures and absolute configurations were fully determined by comprehensive spectroscopic methods, including 2D NMR and electronic circular dichroism spectra. Compounds 1–4 are tetracyclic cassane diterpenoids possessing a furan ring, and compounds 5–10 are tetracyclic cassane diterpenoids possessing a fused butenolide moiety. The anti‐inflammatory and cytotoxic activities of the isolates were evaluated, while none of them showed obvious effects. The current study identified ten new cassane‐type diterpenoids from the seeds of C. bonduc (L.) Roxb., which enriched the chemical diversity of the titled herbal medicine.

Synthesis of Neocaesalpin A, AA, and Nominal Neocaesalpin K**

“…It is interesting to note that most other butenolide cassane-type diterpenoids feature the (S)À C14 configuration as exemplified by neocaesalpin A and AA. [24] The published data employed in the structure elucidation studies of neocaesalpin K did not extend beyond 1 H and 13 C NMR data in tabular form. Consequently, implementation of a modified synthesis route would provide means to examine and potentially validate the structural assignment.…”

“…Neocaesalpin K with nominal structure 3 includes inverted configuration ( R ) at C14 and bears a methyl ether instead of a free alcohol (Scheme 7). It is interesting to note that most other butenolide cassane‐type diterpenoids feature the ( S)− C14 configuration as exemplified by neocaesalpin A and AA [24] . The published data employed in the structure elucidation studies of neocaesalpin K did not extend beyond 1 H and 13 C NMR data in tabular form.…”

Diverse Flavonoids from the Roots of Indigofera stachyodes

“…The theoretical calculation of ECD was conducted using TDDFT (time‐dependent density functional theory) at the B3LYP/6‐311+g (d, p) level with the CPCM model in methanol solution. ECD spectra were generated using the program SpecDis v1.71 and with a falf‐bandwidth of 0.15–0.30 eV, and the final ECD spectra were obtained after UV correction [23] …”

“…ECD spectra were generated using the program SpecDis v1.71 and with a falf-bandwidth of 0.15 -0.30 eV, and the final ECD spectra were obtained after UV correction. [23] ABTS + Free-Radical Scavenging Assay…”

Caesalpinbondin A, a Novel Diterpenoid Lactone With an Unprecedented Carbon Skeleton from the Seeds of Caesalpinia bonduc

“…Extracts or constituents of C. bonduc have been reported to possess cytotoxicity (Wu et al, 2014), antiproliferative (Yadav et al, 2009), anti-inflammatory (Liu et al, 2020), antistress (Kannur et al, 2006), antimicrobial (Simin et al, 2001;Arif et al, 2009), and anti-insecticidal effects (Essoung et al, 2020). Previous phytochemical investigations of C. bonduc have demonstrated the presence of cassane-type diterpenoids (Wu et al, 2014;Zhang et al, 2016;Liu et al, 2020;Cao et al, 2021), sterols (Udenigwe et al, 2007), and flavonoids (Ata et al, 2009). Among these chemical constituents, cassane-type diterpenoids were found to be the most important components and were considered to be active constituents of C. bonduc.…”