Evaluation of Diarylheptanoid–Terpene Adduct Enantiomers from Alpinia officinarum for Neuroprotective Activities

Abstract

Two pairs of new diarylheptanoid-monoterpene adduct enantiomers, (±)-alpininoids A and B [(±)-1 and (±)-2], as well as three pairs of new diarylheptanoid-sesquiterpene adduct enantiomers, (±)-alpininoids C-E [(±)-3-(±)-5], together with four known diarylheptanoids (6-9) were isolated from the rhizomes of Alpinia officinarum. Their structures with absolute configurations were elucidated on the basis of comprehensive spectroscopic analyses and computational calculation methods. The skeletons of these cyclohexene-containing hybrid natural products were hypothesized to be generated via a crucial Diels-Alder cycloaddition between the diarylheptanoids (7 and 8) and terpenes, of which 1 represents a new carbon skeleton. All isolated compounds were evaluated for their neuroprotective effects against MPP (1-methyl-4-phenylpyridinium)-induced cortical neuron injury. At a concentration of 16 μM, (+)-1 significantly increased cell viability when compared with MPP treatment alone.

Three Pairs of New Spirocyclic Alkaloid Enantiomers From the Marine-Derived Fungus Eurotium sp. SCSIO F452

“…With the advancements in whole-genome sequencing and searching tools of biosynthetic gene clusters of secondary metabolites, some Diels-Alderases, such as SpnF, PyrE3, Pyrl4, AbyU, and PvhB, have been identified and substantiated to be of great importance in the biosynthesis of NPs (Takao et al, 2005; Kim et al, 2011; Fage et al, 2015; Tian et al, 2015; Byrne et al, 2016; Tan et al, 2019). Besides, some NPs like spirotriscoumarins A and B (Tang et al, 2016), artemisians A–D (Xue et al, 2017), and alpininoids A–E (Liu et al, 2018) are proposed to be biosynthesized by spontaneous DA cycloaddition. A plausible biogenetic route of 1 – 4 is proposed in Scheme 1.…”

Sekgranaticin, a SEK34b-Granaticin Hybrid Polyketide from Streptomyces sp. 166#

“…To solve this problem, δ C values of two plausible epimers, 1 and iso - 1 (Figures and S1), were calculated at the B3LYP/6-311++G­(2d,p) level (Figures S2 and S3, Tables S4–S7). The DP4 probability analysis (Figure and Table S2) allowed the determination of the relative configuration of sekgranaticin as 1 instead of iso - 1 . This deduction could be evidenced from the possible biosynthetic pathway of 1 (Scheme ), which was postulated to be biogenetically derived from two known microbial polyketides, granaticin A ( 2 ) and SEK34b.…”

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

“…configs. via the TDDFT-ECD method [206]. Compounds 438−441 are four pairs of diarylheptanoid enantiomers acquired from Dioscorea villosa in 2012, with the abs.…”

“…Two pairs of acetophenone enantiomers 423a/423b and 426a/426b exerted excellent protection on human vein endothelial cells (HUVEC) against extreme glucose-induced oxidative stress at 1 µM [200], with both dextrorotary enantiomers being much more active than their levorotary counterparts and showing complete cell protection. The (+)-enantiomer of diarylheptanoids (±)-433 significantly increased the cell viability of cortical neurons compared with the control group (MPP + treatment alone), while its (−)-enantiomer was inactive [206]. (−)-433b inactive [206] a Positive controls.…”

“…The (+)-enantiomer of diarylheptanoids (±)-433 significantly increased the cell viability of cortical neurons compared with the control group (MPP + treatment alone), while its (−)-enantiomer was inactive [206]. (−)-433b inactive [206] a Positive controls.…”