Antiproliferative ent-Kauranoids from Isodon parvifolius

Bioactivity-guided isolation of anti-inflammatory constituents from the bark of Streblus zeylanicus

Based on anti-inflammatory activity to evaluate the effects to the release of NO, bio-assay guided separation of the bark of Streblus zeylanicus led to identify fifteen compounds, including four new terpenes (1, 2, 9, and 10), one new pentanoid glycoside (12), one new rumenic ester (13), together with nine known compounds (3-8, 11, 14, and 15). Their structures were elucidated using extensive NMR and HRESIMS spectroscopic data analyses. The stereochemistry of compound 10 was established by comparing the calculated and experimental ECD spectroscopic data. Compounds 1 and 2 showed moderate inhibition on nitric oxide (NO) production, with IC₅₀ values of 10.21 μM and 15.53 μM, respectively.

Diterpenoids from Isodon species: an update

Covering: December 2005 to June 2016. Previous review: Nat. Prod. Rep., 2006, 23, 673-698Over the last decade, great efforts have been made to conduct phytochemistry research on the genus Isodon, which have led to the isolation and identification of a number of diterpenoids. At the same time, these newly reported diterpenoids with diverse structures have led to new findings on their biological functions and chemical synthesis research. In this update, we review more than 600 new diterpenoids, including their structures, classifications, biogenetic pathways, bioactivities, and chemical synthesis.

Negative electrospray ionization tandem mass spectrometric investigation of ent-kaurane diterpenoids from the genus Isodon

ent-Kaurane diterpenoids are a class of natural compounds isolated from genus Isodon, which have been found to have important bioactivities. Negative electrospray ionization tandem mass spectrometry ((-)ESI-MS(n)) was used to investigate the fragmentation pattern of C-20-nonoxygenated ent-kauranes and two subtypes of C-20-oxygenated ent-kauranes by using an ion trap instrument and accurate mass measurement on an ESI-Q-time-of-flight (TOF) mass spectrometer. The analysis revealed that loss of CH(2)O or CO(2) is the predominant process for 7, 20-epoxy and 7, 20 : 14, 20-diepoxy subgroup of C-20-oxygenated ent-kauranes. In addition, compounds of C-20-nonoxygenated ent-kauranes with a conserved core structure but different substituent groups, such as a hydroxyl, aldehyde, carboxyl, and acetyl moiety, resulted in diagnostic product ions through losses of H(2)O, CO, CO(2), and AcOH, respectively. This work clearly demonstrates the utility of tandem mass spectrometry for studies on the rationalization of the diagnostic fragmentation of a series of compounds from two main types of the ent-kaurane diterpenoids.

Cytotoxicent-Kauranoids fromIsodon parvifolius

Three new ent-kaurane diterpenoids, parvifoline Z (1), parvifoline AA (2), and parvifoline AB (3), together with 14 known compounds, were isolated from the leaves of Isodon parvifolius. The structures of the new compounds were elucidated by 1D- and 2D-NMR spectroscopy and mass spectrometry, and by comparison with known compounds. These three new diterpenoids included three types of ent-kauranoids, namely, C(20)-non-oxygenated-ent-kauranoid, 7,20-cyclo-ent-kauranoid and 6,7-seco-ent-kauranoid-7,20-olide. Compounds 1 and 2 exhibited significant cytotoxicities against A549, HT-29, and K562 cell lines.