Q43, a new triterpenoid extracted from Chinese acorn, exhibits pronounced anti-neuroinflammatory activity through the MAPK and NF-κB pathways

Six new phenylpropanoids from Kaempferia galanga L. and their anti-inflammatory activity

Kaempferia galanga L. is an aromatic medicinal plant belonging to the Zingiberaceae family. Its rhizome has been widely used as traditional Chinese medicine and a flavor spice for a long time. In this study, six previously undescribed phenylpropanoids, including four [2+2]-cycloaddition-derived cyclobutane natural products (1-4), and two phenylpropanoids (5-6) were isolated from the rhizomes of K. galanga L. Their structures were elucidated by spectroscopic methods, single-crystal X-ray diffraction, NMR calculation, and ECD spectra calculation. These cyclobutane derivatives were isolated from K. galanga for the first time. Furthermore, compounds 1-6 were evaluated for the potential inhibitory activities on NO production and NF-κB nuclear translocation in LPS-triggered RAW 264.7 macrophages. The results showed that the isolated compounds have a moderate anti-inflammatory activity measured on their potency to inhibit NO production and the expression of iNOS and COX-2. Additionally, compound 2 effectively suppressed NF-κB nuclear translocation at a concentration of 40 μM.

Ilexchinene, a new seco-ursane triterpenoid from the leaves of Ilex chinensis with therapeutic effect on neuroinflammation by attenuating the MAPK/NF-κB signaling pathway

BACKGROUND

Neuroinflammation is a vital factor participating in the whole pathogenetic process of diverse neurodegenerative disorders, but accessible clinical drugs are still insufficient due to their inefficacy and side effects. Triterpenoids are reported to possess potential anti-neuroinflammatory activities, and the leaves of Ilex chinensis are a commonly used herbal medicine containing many ursane-type and oleanane-type triterpenoids. However, the novel triterpenoids from I. chinensis and their underlying mechanisms are still elusive.

PURPOSE

To isolate novel seco-ursane triterpenoids with anti-neuroinflammatory effects from the leaves of I. chinensis and reveal their underlying mechanisms.

STUDY DESIGN AND METHODS

The novel compound was purified by column chromatography and identified by comprehensive spectroscopic experiments. The LPS-induced BV-2 cell model and LPS-induced acute murine brain inflammation model were used to assess the anti-neuroinflammatory effect of the structure and further understand its underlying mechanisms by cell viability, ELISA, Western blot analysis, qRT‒PCR analysis, behavior analysis, H&E staining, and immunofluorescence staining experiments.

RESULTS

Ilexchinene is a novel ursane-type triterpenoid with a rare 18,19-seco-ring skeleton that was first isolated and identified from I. chinensis. Ilexchinene evidently reduced the overexpression of inflammatory substances in vitro. A mechanistic study suggested that ilexchinene could decrease NF-κB activation to prevent the formation of the NLRP3 inflammasome in the early neuroinflammatory response; in addition, it could prevent the phosphorylation of ERK and JNK. In vivo, ilexchinene remarkably improved LPS-induced mouse behavioral deficits and diminished the number of overactivated microglial cells. Furthermore, ilexchinene evidently diminished the overexpression of inflammatory substances in mouse brains. A mechanistic study confirmed that ilexchinene markedly suppressed the MAPK/NF-κB pathway to relieve the neuroinflammatory response.

CONCLUSION

We identified a novel 18,19-seco-ursane triterpenoid from the leaves of I. chinensis and revealed its underlying mechanism of neuroinflammation for the first time. These findings suggest that ilexchinene might possess promising therapeutic effects in neuroinflammation.

Anti-Inflammatory Benzofuran Neolignans from the Fruits of Canarium album (Chinese Olive)

Chinese olive is a well-known fruit in China. In this study, we explored anti-inflammatory phytochemicals of Chinese olive fruit, which led to the isolation of nine pairs of new enantiomers of benzofuran neolignans (1a/1b-9a/9b). Among them, the planar structures of compounds 1-3 were undescribed previously, and the absolute configurations of all compounds were reported first. Their stereostructures were elucidated on the basis of the interpretation of NMR, HRESIMS, and electronic circular dichroism (ECD) data, as well as ECD calculation. All compounds exhibited pronounced inhibitory effects on lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 macrophages with IC₅₀ values ranging from 6.0 to 30.2 μM. Furthermore, compounds 6a and 6b exert anti-inflammatory effects by blocking the nuclear translocation of NF-κB, thereby reducing the expression of pro-inflammatory mediators COX-2, iNOS, IL-1β, and IL-6. This study could provide some guidance and evidence to the further development and utilization of the Chinese olive.

UV-guided isolation of enantiomeric polyacetylenes from Bupleurum scorzonerifolium Willd. with inhibitory effects against LPS-induced NO release in BV-2 microglial cells

UV-guided fractionation led to the isolation of thirteen new polyacetylenes (1-13) from the roots of Bupleurum scorzonerifolium Willd. All polyacetylenes were analyzed as racemates since the lack of optical activity and Cotton effects in the ECD spectra. The sequent chiral-phase HPLC resolution successfully gave twelve pairs of enantiomers 1a/1b and 3a/3b-13a/13b. Their structures were elucidated based on the HRESIMS and NMR data analyses. The absolute configurations were determined by the combination of Snatzke's method, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Using Griess methods and MTT assays, polyacetylenes 1a, 3a, 4a/4b-12a/12b, and 13a displayed inhibitory activities against LPS-induced NO release in BV-2 microglial cells.