Modified Eremophilanes from Parasenecio hastatus and Their Neuroprotective Activities

Abstract

The new modified eremophilanes hastatusins A−K (1−11) and 13 known compounds (12−24) were isolated from Parasenecio hastatus. The structures of 1−24 were elucidated based on spectroscopic data analysis and comparison with literature data. The absolute configurations of compounds 1 and 2 were defined by single-crystal X-ray diffraction analysis, and the other new compounds were assigned based on ECD data. This work is the first report of the crystal structure of an 8,9-seco-eremophilanolide (1) with two lactone units. The enantiomers of 1 were separated by chiral-phase HPLC, and the absolute configurations of (−)-1 and (+)-1 were established via experimental and calculated ECD data. The new compounds represent four unusual skeletons: a modified 8,9-seco-eremophilane featuring a rare 6,9;8,12-dilactone moiety (1), a furanoeremophilane-type skeleton (2−7, 11), a rare C 14 nor-eremophilane-type skeleton (8, 9), and a modified eremophilane lactone-type skeleton (10). All isolates were assayed for their neuroprotective effects against H 2 O 2 -induced SH-SY5Y cell injury, and compounds 2−5, 12, 21, and 23 exhibited activities even at a low concentration of 1 μM.

Eremophilane Sesquiterpenoids with Antibacterial and Anti-inflammatory Activities from the Endophytic Fungus Septoria rudbeckiae

“…Using the Applied Photophysics Chirascan spectrometer (Applied Photophysics Ltd., London, U.K.), ECD spectra and UV spectra were acquired. Utilizing an Agilent DD2400-MR NMR spectrometer (Agilent Technologies Inc, Santa Clara) and a Bruker AM-400, Avance III-500 spectrometer (Bruker Corporation, Madison), 1 H, 13 C, and 2D NMR data were obtained. HRESIMS data of novel metabolites were acquired by an AB SCIEX Triple TOF 4600+ spectrometer (AB SCIEX, Boston, MA).…”

“…Eremophilane sesquiterpenes, consisting of three isoprenes, possess the identical decalin framework with the eudesmanes and probably belong to a small group of sesquiterpenes. , Eremophilane sesquiterpenoids widely existed in numerous medicinal plants, especially in the Asteraceae family. − Subsequently, the metabolites of eremophilanes produced by theendophytic and marine fungi have increased remarkably, with some exhibiting multiple bioactivities including antifungal, anti-inflammatory, antivirus, antibacterial, and insecticidal activities. − Owing to the structural diversiform and unique biological activities of eremophilane sesquiterpenes, extensive phytochemical and biological investigations have been carried out by numerous scientists. − Consequently, further studies toward the development of novel and medicinally valuable sesquiterpenoids are essential.…”

“…rudbeckiae was reinvestigated, and nine novel eremophilane sesquiterpenoids, septoreremophilanes A–I ( 1 – 9 ), together with eight known sesquiterpenoids and two known tetralones, as well as two known steroids were isolated. It should be noted that compounds 1 – 6 and 7a belong to the family of the highly oxygenated eremophilane sesquiterpenoids with a 6/6/5 tricyclic system, and bearing a hemiacetal moiety, so far, within 30 such natural compounds have been discovered. ,,− ,, Hence, the fermentation, isolation, structural elucidation, antibacterial and anti-inflammatory activity evaluation, and the possible biosynthetic pathways of septoreremophilanes A–I ( 1 – 9 ) are presented.…”

“…It should be noted that compounds 1−6 and 7a belong to the family of the highly oxygenated eremophilane sesquiterpenoids with a 6/6/5 tricyclic system, and bearing a hemiacetal moiety, so far, within 30 such natural compounds have been discovered. 1,2,[6][7][8][9]13,14 Hence, the fermentation, isolation, structural elucidation, antibacterial and anti-inflammatory activity evaluation, and the possible biosynthetic pathways of septoreremophilanes A−I (1−9) are presented.…”

Overcoming peri- and ortho-selectivity in C–H methylation of 1-naphthaldehydes by a tunable transient ligand strategy

“…In our further attempt to demonstrate the synthetic utility, several bioactive compounds 20 that bear alkyl-substituted naphthalene frameworks have been obtained efficiently ( Scheme 2 ). For example, the preparation of nordehydrocacalohastine (11), an antimicrobial eremophilane sesquiterpene first isolated from Cacalia and Senecio plants, 21 started from commercially available naphthol 5.…”