Santalum spicatum(R. Br.) A. DC. (Santalaceae)—nor-Helifolenal and Acorenol Isomers: Isolation and Biogenetic Considerations

Proliferacorins A-M: Thirteen undescribed acorane sesquiterpenoids isolated from the fungus Fusarium proliferatum

In this study, 13 previously undescribed acorane sesquiterpenoids, namely, proliferacorins A-M, were isolated from the solid fermentation of Fusarium proliferatum. Their structures and absolute configurations were confirmed via spectroscopic analyses, quantum-chemical NMR calculations with DP4+ probability analyses, ECD calculations and comparisons, and single-crystal X-ray diffraction techniques. Proliferacorins A-E (1-5) have a 7-oxa-tricyclo[6.3.1.01,5]tridecane decorated with a rare ether bridge between C-7 and C-11, while proliferacorin F (6) possesses a 7-oxa-tricyclic[6.4.0.01,5]dodecane skeleton with an unusual ether bond between C-6 and C-11. Proliferacorins C and D (3 and 4) are a pair of isomers at the carbon bridge between C-5 and C-7, whereas proliferacorins H and I (8 and 9) are a pair of spiro carbon isomers. All isolates were tested for their cytotoxic, anti-inflammatory, and immunosuppressive activities.

Characterization of a Sesquiterpene Synthase Catalyzing Formation of Cedrol and Two Diastereoisomers of Tricho-Acorenol from Euphorbia fischeriana

A sesquiterpene synthase gene was identified from the transcriptome of Euphorbia fischeriana Steud, and the function of its product EfTPS12 was characterized by in vitro biochemical experiments and synthetic biology approaches. EfTPS12 catalyzed conversion of farnesyl diphosphate into three products, including cedrol (1) and eupho-acorenols A (2) and B (3) (two diastereoisomers of tricho-acorenol), thereby being named EfCAS herein. The structures of 2 and 3 were determined by spectroscopic methods and comparison of experimental and calculated electronic circular dichroism spectra. EfCAS is the first example of a plant-derived sesquiterpene synthase that is capable of synthesizing acorane-type alcohols. This study also documents that synthetic biology approaches enable large-scale preparation of volatile terpenes and thereby substantially facilitate characterization of corresponding terpene synthases and elucidation of the structures of their products.

Hawaiian Sandalwood: Oil Composition of Santalum paniculatum and Comparison with Other Sandal Species

Four commercial qualities of Hawaiian sandalwood oil produced from wood of Santalum paniculatum originating from the island of Hawaii (“The Big Island”) were analyzed using GC and GC-MS. Main constituents of the oils were ( Z)-α-santalol (34.5–40.4%) and ( Z)-β-santalol (11.0–16.2%). An odor evaluation of the oils was carried out against East Indian sandalwood oil. In addition, the chemical composition of Hawaiian sandalwood oil was compared with four different Santalum species originating from East India, New Caledonia, Eastern Polynesia and Australia, respectively.

Genetic dissection of sesquiterpene biosynthesis by Fusarium fujikuroi

A treasure trove of terpenes: The products of two fungal sesquiterpene synthases from the rice pathogen Fusarium fujikuroi were identified by gene-knockout experiments, genetic engineering of the fungus for production optimization, isolation of the sesquiterpenes, and structure elucidation by spectroscopic methods.