Structurally Diverse Sesquiterpenoid Glycoside Esters from Pittosporum qinlingense with Anti-neuroinflammatory Activity

Abstract

Thirteen new sesquiterpenoid glycoside esters, including 11 aromadendrane-type compounds, pitqinlingosides A–K (1–11), one cadinane-type compound, pitqinlingoside L (12), and one eudesmane-type compound, pitqinlingoside M (13), together with seven known analogues (14–20) were isolated from the twigs, fruits, and leaves of Pittosporum qinlingense. Structures were elucidated by analysis of spectroscopic data, gas chromatography mass spectrometry (GC-MS), and chemical methods. The absolute configuration was confirmed by single-crystal X-ray crystallography analysis or electronic circular dichroism spectra. Unusual glycoside esters are characterized by the presence of polyacylated β-d-fucopyranosyl, β-d-glucopyranosyl, and β-d-xylopyranosyl units. Pitqinlingosides A (1), B (2), D (4), and F (6), pittosporanoside A1 acetate (14), and pittosporanoside A1 (16) showed significant nitric oxide production inhibition in lipopolysaccharide (LPS)-induced BV-2 microglial cells with IC50 values ranging from 0.95 to 24.12 μM. Structure–activity relationships of the isolated compounds are discussed.

Pitsubcosides A–L, highly esterified eudesmane sesquiterpenoid glycosides with antibacterial activity from Pittosporum subulisepalum and their mechanism

“…Although eudesmane sesquiterpenoids have been discovered in many medicinal plants with cytotoxic, 38,39 antioxidative, 38 progesterone receptor inhibitory, 40 and other biological activities, their highly esterified glycosides representing a class of structurally distinctive metabolites have been reported mainly from the genus Pittosporum. These studies and our previous findings of sesquiterpenoid glycoside esters from P. qinlingense, 35,41,42 stimulated our curiosity to explore further bioactive sesquiterpenoid glycosides from the genus Pittosporum.…”

“…Interestingly, all compounds contain an unusual highly esterified ⊎-D-fucose, which showed metabolic similarities with other species of the genus Pittosporum. 11,18,33,35,61 The absolute configurations of compounds 1-12 were established by spectroscopic analysis, ECD calculations and single-crystal X-ray diffraction crystallography analysis.…”

“…[12][13][14][15] Sesquiterpenoids, [16][17][18][19][20] triterpenoids, 5,21-24 lignans 13 and their glycosides, carotenoids [25][26][27][28][29][30] and phthalides 31,32 have been found in Pittosporum plants. Eudesmane, 18,33,34 aromadendrane [34][35][36][37] 37 and guaiane 19 sesquiterpenoids and their glycosides are considered characteristic chemical constituents of Pittosporum. Although eudesmane sesquiterpenoids have been discovered in many medicinal plants with cytotoxic, 38,39 antioxidative, 38 progesterone receptor inhibitory, 40 and other biological activities, their highly esterified glycosides representing a class of structurally distinctive metabolites have been reported mainly from the genus Pittosporum.…”

Eremophilane and cadinane sesquiterpenoids from the fruits of Alpinia oxyphylla and their anti-inflammatory activities

“…15 As part of our ongoing investigation of more novel effective anti-inflammatory sesquiterpenoids from A. oxyphylla, a total of 38 structurally diverse sesquiterpenoids (Fig. 1), including six previously undescribed eremophilane sesquiterpenoids (1)(2)(3)(4)(5)(6), six new cadinane sesquiterpenoids (23)(24)(26)(27)(28)(29), and 26 known analogues (7-22, 25 and 31-38) were isolated and identified. Among the isolates, compound 1 possesses an unusual rearranged eremophilane skeleton, 28 and 29 are unusual rearranged cadinane sesquiterpenoids, featuring rare spiro [5.6] carbon skeletons, while 23, 24, 26, and 27 are rare nor-cadinane sesquiterpenoids.…”

Syntheses of Bufospirostenin A and Ophiopogonol A by a Conformation-Controlled Transannular Prins Cyclization

“…Consider, for example, transannular cyclizations of medium-sized rings. The transannular Prins cyclization of cyclodecenone 1 is a convenient method for synthesis of 5/7-fused hydroazulenol motifs (Figure A), which are found in many bioactive molecules . Examples of transannular Prins cyclization reactions that give trans -fused hydroazulenols such as 4 are well established and presumably proceed via “crossed” conformation 2 , in which the C5–C6 and C1–C10 bonds are oriented crosswise to each other and which is less stable than “parallel” conformation 3 .…”