Trinor- and tetranor-eremophilane sesquiterpenoids with anti-neuroinflammatory activity from cultures of the fungus Septoria rudbeckiae

Structures, Occurrences and Biosynthesis of 11,12,13-Tri-nor-Sesquiterpenes, an Intriguing Class of Bioactive Metabolites

“…Formation of the tri-nor-eremophilanes is not known, but it has been proposed that the elimination of the isopropenyl group to give tri-nor-eremophilanes might occur via oxidation and subsequent decarboxylation (Figure 15) [190]. Different authors [190,214,218] have proposed that the tri-nor-eremophilanes (59, 63-77, etc.) could originate from different precursors 105a, 105b and 105c, which, after different types of tailoring reactions, including hydroxylation, oxidation, isomerization, epoxidation, esterification and degradation, might produce diverse structures (Figure 16) [190,214].…”

“…Different authors [190,214,218] have proposed that the tri-nor-eremophilanes (59, 63-77, etc.) could originate from different precursors 105a, 105b and 105c, which, after different types of tailoring reactions, including hydroxylation, oxidation, isomerization, epoxidation, esterification and degradation, might produce diverse structures (Figure 16) [190,214]. Proposed biosynthetic pathway to tri-nor-eremophilanes (adapted from Liu et al 2016 [190]).…”

“…The indene derivative is a trinorsesquiterpene which has undergone a skeletal rearrangement, as shown in Figure 17. Hypothetical biosynthetic pathways of tri-nor-eremophilanes (adapted from Lin et al 2021 [214]).…”

“…All metabolites were tested for nitric oxide (NO) production inhibition in lipopolysaccharide (LPS)-activated BV-2 microglial cells, and dendryphiellin D ( 66 ), septeremophilane D ( 71 ) and septeremophilane E ( 72 ) were found to display significant inhibition. These results contribute to the development of more effective drugs to treat neuroinflammation [ 214 ].…”

“…Figure 16.Hypothetical biosynthetic pathways of tri-nor-eremophilanes (adapted from Lin et al 2021[214]). …”