Synthesis and cytotoxic evaluation of eremophilane sesquiterpene 07H239-A derivatives

Cumulative Data of 1H and 13C NMR Signals and Specific Rotations of Eremophilane Sesquiterpenoids. 2. Bicyclic Eremophilanes (2)

1H and 13C NMR signals and specific rotations of eremophilane sesquiterpenoids are cumulated as a series of review articles. In the second chapter of this review, 124 bicyclic eremophilanes without furan or lactone rings (except for epoxides) and with 3-OR functionality (some have OH) are listed in 25 tables. Those bearing long chain acyloxy groups without 3-oxygen functions and some bi- or tri-cyclic compounds are also included in this chapter. These data may help chemists working in the area of natural products chemistry as well as synthetic scientists.

Total synthesis of five natural eremophilane-type sesquiterpenoids

The first total syntheses of five natural eremophilane-type sesquiterpenoids were achieved in 4-12 steps via a common synthetic intermediate. The syntheses feature a double Michael addition, Robinson annulation, α-enolization of an unsaturated ketone, and Pd-catalyzed Suzuki coupling reaction to install the side chain. This synthetic strategy could be easily extended to other eremophilane-type sesquiterpenoids with similar bicyclic skeletons.

Eremophilane-type sesquiterpenes from fungi and their medicinal potential

Eremophilanes are sesquiterpenes with a rearranged carbon skeleton formed both by plants and fungi, however, almost no plant eremophilanes are found in fungi. These eremophilanes possess mainly phytotoxic, antimicrobial, anticancer and immunomodulatory properties and in this review fungal eremophilanes with bioactivities of potential medicinal applications are reviewed and discussed. A special focus is set on natural products bearing highly functionalized fatty acids at C-1 or C-3 position of the eremophilane backbone. Many of these fatty acids seem to contribute to the bioactivity of the metabolites enhancing the activity of the sesquiterpene moieties. Several approaches for optimization of these natural products for clinical needs and testing of the resulting derivatives are presented and discussed. The combination of identification of bioactive natural products with their subsequent improvement using a variety of genetical or chemical tools and the pharmacokinetic assessment of the products is presented here as a promising approach to new drugs.

Bioactive terpenes from marine-derived fungi

Marine-derived fungi continue to be a prolific source of secondary metabolites showing diverse bioactivities. Terpenoids from marine-derived fungi exhibit wide structural diversity including numerous compounds with pronounced biological activities. In this review, we survey the last five years’ reports on terpenoidal metabolites from marine-derived fungi with particular attention on those showing marked biological activities.

Biologically active eremophilane-type sesquiterpenes from Camarops sp., an endophytic fungus isolated from Alibertia macrophylla

Two new eremophilane-type sesquiterpenes, xylarenones F (3) and G (4), have been isolated from solid substrate cultures of a Camarops sp. endophytic fungus isolated from Alibertia macrophylla, together with the known compounds xylarenones C (1) and D (2). The structures and relative configurations of 1-4 were elucidated by extensive NMR and HRESIMS spectroscopic analysis. Due to their effects on the respiratory burst of neutrophils, which included inhibition of the reactive oxygen species production, these sesquiterpenes exhibited potential anti-inflammatory and antioxidant properties.

Four eremophilane sesquiterpenes from the mangrove endophytic fungus Xylaria sp. BL321

Three new eremophilane sesquiterpenes (1–3) were isolated from the mangrove endophytic fungus Xylaria sp. BL321 together with 07H239-A (4), a known analogue of the new compounds. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. Compound 4 showed activation activity on α-glucosidase at 0.15 μM (146%), and then, 4 gradually produced inhibitory activity on α-glucosidase with increasing concentration, and the IC₅₀ value is 6.54 μM.