Two New Dichromenes from Evodia lepta

Molecular networking-based discovery of anti-inflammatory chromene dimers from Melicope pteleifolia

With the aid of a feature-based molecular networking strategy, five undescribed C₂ and C₁ symmetric chromene dimers, namely, melptelchromenes A-E, were isolated from the leaves of Melicope pteleifolia. Four asymmetric dimers were found to be racemates and were resolved by chiral phase HPLC analyses. Their structures, including absolute configurations, were elucidated by HRMS, NMR spectroscopy, and quantum mechanical calculations of ECD spectra and NMR chemical shifts. Melptelchromenes A-D possess a unique ethylidene linkage via two 2H-chromene cores, while melptelchromene E represents the first example of a dimeric chromene featuring a 1,3-diarylbutan-1-ol moiety. Of these compounds, 6,6'-linked dimeric chromenes showed nitric oxide inhibitory activities on lipopolysaccharide-induced RAW 264 cells, and (-)- and (+)-melptelchromene E were the two most potent compounds (IC₅₀, 3.0 and 5.1 μM, respectively).

The phytochemistry, pharmacology and applications of Melicope pteleifolia: A review

ETHNOPHARMACOLOGY RELEVANCE

The leaves, stems and roots of Melicope pteleifolia (Champ. ex Benth.) T.Hartley (MP; Rutaceae, called sanyaku in Chinese; syn.: Euodia lepta), have been used traditionally for the treatment of sore throat, rheumatism, eczema, dermatitis, bruises, and insect, rat, snake bites based on traditional Chinese medicine concepts.

AIM OF THIS STUDY

This paper aims to provide a comprehensive and critical analysis of studies on MP and focusing on potential relationships between traditional uses and pharmacological effects, assessing the therapeutic potential as a medicine.

MATERIALS AND METHODS

Relevant data on MP were retrieved using the keywords "Melicope pteleifolia", "pharmacology", "toxicity" and "applications" in databases including "Pubmed", "SciFinder", "Springer", "Elsevier", "Wiley", "Web of Science", "Google Scholar", "China Knowledge Resource Integrated databases (CNKI)", "PhD" and "MSc dissertations", and a hand-search.

RESULTS AND DISCUSSION

The heat-clearing, dampness-removing and gallbladder-normalizing actions of MP have been linked to biomedical concepts like anti-inflammatory, antioxidant and hepatoprotective activities. The latter is potentially based on the presence of furaquinoline alkaloids, phenylpropanoids and flavonoids. Analgesic, antimicrobial and anti-tumor effects have also been reported. Currently limited evidence is available relating to potential toxicological risks especially of aqueous extracts with so far no reports signalling specific risks. Although some studies on the pharmacodynamics of MP have been reported, studies on action mechanisms of MP are still rare.

CONCLUSIONS

In the future and prior to initiating clinical trials, the safety, in vitro and in vivo pharmacology, and mechanism of action of MP needs to be assessed, including a focus on the link between traditional uses and modern applications. In addition, phytochemical and biological studies need to conduct on flowers and fruits of MP. Furthermore, strict quality control measures are needed in the studies investigating any aspect of the pharmacology, chemistry and biology of MP.

Evodialones A and B: Polyprenylated Acylcyclopentanone Racemates with a 3-Ethyl-1,1-diisopentyl-4-methylcyclopentane Skeleton from Evodia lepta

Two polyprenylated acylcyclopentanone racemates, evodialones A (1) and B (2), featuring a 3-ethyl-1,1-diisopentyl-4-methylcyclopentane skeleton, were isolated from an extract of the aerial parts of Evodia lepta. Evodialone A (1) was resolved by chiral-phase HPLC to afford a pair of enantiomers, (+)- and (-)-evodialones A (1b/1a), while evodialone B (2) could not be resolved. Their structures were elucidated by spectroscopic analysis and a combination of computational techniques including gauge-independent atomic orbital calculation of 1D NMR data and experimental and TDDFT-calculated ECD spectra. A putative biosynthetic pathway of 1 and 2 starting from the monocyclic polyprenylated acylphloroglucinols is proposed. All the isolates were screened for the antimicrobial activity in vitro, and 1a and 1b showed moderate inhibitory activities against several pathogenic fungi with MICs values of 17.1-68.3 μM.

Pteleifolols A-E, acetophenone di-C-glycosides and a benzopyran dimer from the leaves of Melicope pteleifolia

Four new acetophenone di-C-glycosides, pteleifolols A-D (1-4) and a new dimeric benzopyran, pteleifolol E (5), were isolated from the leaves of Melicope pteleifolia. Seven known compounds, including 2,4,6-trihydroxyacetophenone-3,5-di-C-glucopyranoside (6), were also isolated. Structures of the new compounds (1-5) were established by using spectroscopic and spectrometric techniques, including 1D and 2D nuclear magnetic resonance (NMR), UV, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) data. Pteleifolols A-D (1-4) were E-p-coumaroyl, Z-p-coumaroyl, E-feruloyl, and benzoyl esters of 6, respectively. Pteleifolol E (5) was a dichromene dimerized through a C₂ unit.

(±)-Melicolones A and B, rearranged prenylated acetophenone stereoisomers with an unusual 9-oxatricyclo[3.2.1.1(3,8)]nonane core from the leaves of Melicope ptelefolia

Melicolones A (1) and B (2), a pair of rearranged prenylated acetophenone epimers with an unusual 9-oxatricyclo[3.2.1.1(3,8)]nonane core, were isolated from the leaves of Melicope ptelefolia. Further chiral high-performance liquid chromatography resolution gave enantiomers (+)- and (-)-1, as well as (+)- and (-)-2, respectively. The structures and absolute configurations of the pure enantiomers were determined by extensive spectroscopic data and single crystal X-ray diffraction. All the isolated enantiomers exhibited potent cell protecting activities against high glucose-induced oxidative stress in human vein endothelial cells.

New furoquinoline alkaloids from the leaves of Evodia lepta

Three new furoquinoline alkaloids, leptanoines A-C (1-3) along with three known compounds (4-6) were isolated from the leaves of Evodia lepta. Their structures were identified by interpretation of their spectroscopic data as well as comparison with those reported in the literature. In addition, all isolated compounds were evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities. Compound 4 showed the highest inhibitory activity towards BChE with an IC50 value of 47.9 μM. On the other hand, Compound 5 showed the highest inhibitory activity towards AChE with an IC50 value of 69.1 μM.

Methanol extract of Evodia lepta displays Syk/Src-targeted anti-inflammatory activity

ETHNOPHARMACOLOGICAL RELEVANCE

Evodia lepta (Spreng.) Merr., in the Rutaceae family, is a medicinal plant traditionally used to treat inflammatory symptoms such as in meningitis and hepatitis. However, no study has systematically investigated its anti-inflammatory activities including its molecular mechanism.

MATERIALS AND METHODS

The effects of a methanol extract from the roots Evodia lepta (El-ME) were evaluated using lipopolysaccharide (LPS)-treated RAW264.7 cells producing nitric oxide (NO) and prostaglandin E2 (PGE2), and an HCl/ethanol-induced mouse gastritis model. Target molecules were identified by analyzing the activation of transcription factors and their upstream kinases.

RESULTS

El-ME reduced the production of NO and PGE2 from LPS-activated RAW264.7 cells in a dose-dependent manner. El-ME also ameliorated the gastritis symptoms of EtOH/HCl-treated mice. The extract suppressed production of mRNA for the inducible NO synthase (iNOS) and cyclooxygenase (COX)-2; the nuclear translocation of nuclear factor (NF)-κB; the phosphorylation of upstream kinases that activate NF-κB; and the kinase activities of Syk and Src.

CONCLUSION

The anti-inflammatory effects of El-ME might be due to its suppression of Syk/Src and NF-κB. Considering the in vitro and in vivo efficacy of El-ME, Evodia lepta could be developed into an anti-inflammatory herbal remedy.

Chemical constituents and their bioactivities of "Tongling White Ginger" (Zingiber officinale)

Gingerols and their corresponding dehydration products shogaols were considered as the active principles of ginger, the rhizome of the plant Zingiber officinale, for its antioxidant, anti-inflammatory, and antitumor activities. Ginger (Z. officinale) has been cultivated for thousands of years as a spice and for medicinal purposes in China. Tongling (Anhui province, China) has traditionally been regarded as an ideal cultivation place. "Tongling White Ginger" enjoys a reputation for being one of the top gingers in China for its thin white peel, tender flesh, rich juice, and flavor. In this study, we have isolated and identified two novel gingerdione dimers, bisgingerdiones A (1) and B (2); two new gingerol derivatives, (5R)-5-acetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptan-3-one (3) and methyl (Z)-neral acetal-[6]-gingerdiol (4); and 38 known compounds (5-42) from rhizomes of Zingiber officinale collected from Tongling, China. Their structures were elucidated by means of spectroscopic methods. Compounds 1-4 showed weak cytotoxic and anti-HIV-1 activities. Compounds 6, 8, and 26 showed inhibitory activities against human and mouse 11β-HSD1 (11β-hydroxysteroid dehydrogenases) with IC(50) values between 1.09 and 1.30 μM.

Two dichromenes from Evodia lepta

Two new dichromenes, dichromene C and dichromene D, were isolated from the aerial parts of Evodia lepta. Their structures were determined by spectroscopic analysis.