Abietane diterpenoids and iridoids from Caryopteris mongolica / 中国天然药物

Six new abietane diterpenoids (1-6) and five undescribed iridoids (7-11) have been isolated from the aerial parts of Caryopteris mongolica. The intricate structural characterization of these compounds was meticulously undertaken using an array of advanced spectroscopic techniques. This process was further enhanced by the application of DP4+ probability analyses and electronic circular dichroism (ECD) calculations. Following isolation and structural elucidation, the cytotoxicity of these compounds was evaluated. Among them, compound 3 stood out, displaying significant cytotoxic activity against HeLa cells with an IC50 value of 7.83 ± 1.28 μmol·L-1. Additionally, compounds 1, 2, 4, 9, and 10 manifested moderate cytotoxic effects on specific cell lines, with IC50 values ranging from 11.7 to 20.9 μmol·L-1.

Antimalarial and neuroprotective ent-abietane diterpenoids from the aerial parts of Phlogacanthus curviflorus / 中国天然药物

Six new ent-abietane diterpenoids, abientaphlogatones A-F (1-6), along with two undescribed ent-abietane diterpenoid glucosides, abientaphlogasides A-B (7-8) and four known analogs were isolated from the aerial parts ofPhlogacanthus curviflorus (P. curviflorus). The structures of these compounds were determined using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), one-dimensional and two-dimensional nuclear magnetic resonance (NMR) spectroscopy, electronic circular dichroism (ECD) spectra, and quantum chemical calculations. Notably, compounds 5 and 6 represented the first reported instances of ent-norabietane diterpenoids from the genus Phlogacanthus. In the β-hematin formation inhibition assay, compounds 2, 4, 7-10, and 12 displayed antimalarial activity, with IC50 values of 12.97-65.01 μmol·L-1. Furthermore, compounds 4, 5, 8, and 10 demonstrated neuroprotective activity in PC12 cell injury models induced by H2O2 and MPP+.

Diterpenoids from Rabdosia flexicaulis / 中国中药杂志

The genus Rabdosia is famous for the abundance of diverse and novel ent-kaurane diterpenoids. However, only a few ent-kauranoids have been discovered from R. flexicaulis since the investigation on its chemical constituents is not systematic. To find novel bioactive diterpenoids, the ethyl acetate extract of the above ground part of R. flexicaulis in Daofu County, Sichuan Province was obtained by column chromatography. One new compound and five known ones were identified as flexicaulin E(1), forrestin B(2), inf-lexarabdonin D(3), 7α-hydroxydehydroabietic acid(4), 15-hydroxydehydroabietic acid(5), and pomiferin F(6) by spectral techniques. Compounds 1-3 were the ent-kaurane diterpenoids isolated from this species for the first time. Compounds 4-6, aromatic abie-tanoids, were isolated from the genus Rabdosia for the first time.

Two new abietane diterpenes from Rosmarinus officinalis / 中草药

Objective: To study the chemical constituents of aerial part of Rosmarinus officinalis. Methods: Compounds were isolated and purified by repeated column chromatography on silica gel column and Sephadex LH-20 gel column. The structures of the new compounds were elucidated by analysis of their NMR and HRESIMS data. The cytotoxicity of the compounds was evaluated by SRB methods. Results: Ten compounds were obtained and identified as 7-O-isopropyl-epirosmanol (1), 7-O-isopropyl rosmaquinone (2), rosmanol (3), 7-O-methyl-rosmanol (4), epirosmanol (5), 7-methoxy-epirosmanol (6), rosmaquinone B (7), carnosol (8), galdosol (9) and pisiferal (10). Conclusion: Compounds 1 and 2 are new abietane diterpenes named 7-O-isopropyl-epirosmanol (1), 7-O-isopropyl rosmaquinone (2), and showed no cytotoxicity.

A new abietane-type diterpenoid from the twigs and leaves of Illicius majus Hoot et Thoms / 中国药学杂志

OBJECTIVE: To study chemical constituents from the twigs and leaves of Illicius majus Hoot et Thoms. METHODS: The compounds were isolated by column chromatography on silica gel, Sephadex LH-20, and flash chromatography coupled with preparative HPLC. Their structures were elucidated by spectroscopic analysis including IR, NMR, and MS. RESULTS: Six compounds, ie. majusanicol(1), angustanoic acid G(2), 4-hydroxyphenethyl alcohol(3), 4-hydroxybenzoic acid(4), 3-hydroxybenzoic acid(5), and 3, 5-dimethoxy-4-hydroxybenzoic acid(6), were isolated from the twigs and leaves of I. majus. CONCLUSION: Compound 1 is a new abietane-type diterpenoid, and compound 3-6 are isolated from this plant for the first time.

In vitro evaluation of new terpenoid derivatives against Leishmania infantum and Leishmania braziliensis

The activity of five (1-5) abietane phenol derivatives against Leishmania infantum and Leishmania braziliensis was studied using promastigotes and axenic and intracellular amastigotes. Infectivity and cytotoxicity tests were performed with J774.2 macrophage cells using Glucantime as a reference drug. The mechanisms of action were analysed by performing metabolite excretion and transmission electron microscopy ultrastructural studies. Compounds 1-5 were more active and less toxic than Glucantime. The infection rates and mean number of parasites per cell observed in amastigote experiments showed that derivatives 2, 4 and 5 were the most effective against both L. infantum and L. braziliensis. The ultrastructural changes observed in the treated promastigote forms confirmed that the greatest cell damage was caused by the most active compound (4). Only compound 5 caused changes in the nature and amounts of catabolites excreted by the parasites, as measured by ¹H nuclear magnetic resonance spectroscopy. All of the assayed compounds were active against the two Leishmania species in vitro and were less toxic in mammalian cells than the reference drug.

Cryptotanshinone but not tanshinone IIA inhibits angiogenesisin vitro

In the course of screening of angiogenesis inhibitor from natural products, cryptotanshinone from Salvia miltiorrhiza was isolated as a potent small molecule inhibitor of angiogenesis. Cryptotanshinone inhibits bFGF-induced angiogenesis of BAECs at ten micromolar ranges in vitro without cytotoxicity. Tanshinone IIA, another tanshinone isolated from S. miltiorrhiza, which is structurally very similar to cryptotanshinone except C-15 position of dihydrofuran ring does not inhibit angiogenesis induced by bFGF. These results demonstrate that cryptotanshinone is a new anti-angiogenic agent and double bond at C-15 position of the dihydrofuran ring plays a crucial role in the activity.