Sesquiterpenoids from the rhizomes of Atractylodes macrocephala and their protection against lipopolysaccharide-induced neuroinflammation in microglia BV-2 cells

Atramacrolodes A-D (1-4), Four Undescribed Eudesmane-Type Sesquiterpenes from the Rhizome of Atractylodes macrocephala

Four undescribed sesquiterpenes, atramacrolodes A-D (1-4), along with six known compounds 5-10 were isolated from the rhizome of Atractylodes macrocephala. Compound 3 possessed a new skeleton based on an unprecedented carton-carton connection. Their structures were determined by UV, IR, HRESIMS, NMR spectra, 13C NMR calculation with DP4+ analysis, and the comparison of experimental and calculated ECD spectra. Compounds 5 and 8 showed protective effects against paracetamol-induced liver cell injury.

Atrachinenins D-S, novel meroterpenoids with geranyl hydroquinone moiety from Atractylodes chinensis by the LC/MS-based molecular decoy and targeted isolation

To mine fascinating molecules from the rhizomes of Atractylodes chinensis, the known molecular formula of atrachinenin A was used as a bait to search LC-HRMS data in different subfractions. Sixteen new meroterpenoids, atrachinenins D-S (1-16) including three unprecedented carbon skeletons (1-5) and eleven new oxygen-bridged hybrids (6-16) were obtained by the targeted isolation. Their structures and absolute configurations were elucidated by the spectroscopic data and electronic circular dichroism (ECD) calculations. The isolated compounds were evaluated for their inhibitory activity of NO production and compounds 1, 4, 8, and 13 showed moderate anti-inflammatory activity. The proposed biosynthetic pathways of 1-5 were also discussed.

Bioactive constituents from the rhizomes of Atractylodes macrocephala

Twelve undescribed compounds including five sesquiterpenes (1-5), one monoterpene (6), and four lignans (7a/7b and 8a/8b), along with two other types (9 and 10) were isolated from the rhizomes of Atractylodes macrocephala. Among them, two pairs of enantiomers (7a/7b and 8a/8b) were successfully separated by chiral-phase HPLC, while racemate 9 could not be resolved. Their structures and absolute configurations were unambiguously elucidated by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Notably, compounds 1 and 2 are rare sesquiterpene hybrids featuring an eudesmanolactam linked to a resorcinol or methyl 2-methylpentanoat through a CN bond. Compound 3 represents the first example of eudesmanolide sesquiterpene with an oxygen-bridge between C-8 and C-14. Compounds 7a and 7b are a pair of rare enantiomeric benzodioxane norneolignans. Additionally, compound 2 exhibited weak cytotoxicity against SGC-7901 cells. Compound 4 significantly promoted the proliferation of LPS-induced IEC-6 cells with the rate of 117.2%.

Eudesmane-type sesquiterpenes from the rhizomes of Atractylodes macrocephala and their bioactivities

Fifteen undescribed eudesmane-type sesquiterpenes, named atramacronoids D-R, along with fourteen known analogues were isolated from the rhizomes of Atractylodes macrocephala. The structures of atramacronoids D-R were elucidated based on extensive spectroscopic data analysis, Snatzke's rule, electronic circular dichroism (ECD) calculations, and X-ray crystallographic analysis. Notably, of the undescribed isolates, atramacronoids D and E are the first example of eudesmanolactam-phenol and eudesmanolactam-ethyl hybrids obtained from plants, respectively. A pair of enantiomers, (+)- and (-)-atramacronoids F, were successfully resolved by chiral-phase HPLC. Atramacronoid D exhibited weak cytotoxicity against SGC-7901 cells. Atramacronoid E significantly promoted the proliferation of LPS-induced IEC-6 cells.

Sesquiterpenoids Isolated from the Rhizomes of Genus Atractylodes

Atractylodes plants have been used in traditional herbal medicine to treat gastrointestinal diseases and contain various chemical compounds. Sesquiterpenoids are the most important therapeutic compounds in Atractylodes rhizomes. Based on studies reported from 2000 to 2022, we classified sesquiterpenoids by their chemical skeletons and original resources. Moreover, we discussed their biosynthesis and physicochemical and pharmacological features. We reported sesquiterpenoids with skeletal moieties, such as monocyclic sesquiterpenes (bisabolene- and elemene-type), bicyclic sesquiterpenes (eudesmane-, isopterocarpolone-, hydroxycarissone-, eremophilane-, bisesquiterpenoid-, guaiane- and spirovetivane-type and eudesmane lactones) and tricyclic sesquiterpenes (cyperene- and patchoulene-type), with their biosynthetic pathways, chemical modifications and in vivo metabolites. The pharmacological activities of sesquiterpenoids as anti-inflammatory, anti-tumor, anti-diabetic and anti-microbial and for treating gastrointestinal disorders have been reported for this genus.

Sesquiterpene Lactams and Lactones With Antioxidant Potentials From Atractylodes macrocephala Discovered by Molecular Networking Strategy

Atractylodes macrocephala rhizome (called Bái-zhú in China) has a long history as a functional food and herbal medicine in East Asia, especially China. Sesquiterpenoids are one of the main active compounds of Atractylodes macrocephala rhizome. This study aimed to explore the unknown sesquiterpenoids of A. macrocephala rhizome using a molecular networking strategy. Two new nitrogen-containing sesquiterpenoids, atractylenolactam A (1) and atractylenolactam B (2), and 2 new sesquiterpene lactones, 8-methoxy-atractylenolide V (6) and 15-acetoxyl atractylenolide III (7), along with 12 known analogs (3-5 and 8-16) were discovered and isolated. All the structures were assigned based on detailed spectroscopic analyses. The absolute configurations of 1, 2, 6, and 7 were established by time-dependent density functional theory ECD (TDDFT-ECD) calculations. All these compounds had different degrees of concentration-dependent activating effects on nuclear-factor-E2-related factor-2 (Nrf2).