Bioactive terpenoids from Euonymus verrucosus var. pauciflorus showing NO inhibitory activities

Four new diterpenoids from the aerial parts of Leucas zeylanica (L.) R. Br

Four new undescribed halimane- and labdane-type diterpenoids, named zeylleucapenoids E-H (1-4), along with four known analogues (5-8), were isolated from the aerial parts of Leucas zeylanica (L.) R. Br. Their structures were determined by comprehensive spectroscopic analysis and computational calculations. Compounds 1 and 2 are the highly modified halimane diterpenoids featuring a 6/6/6-fused tricyclic system with an unusual six-membered 6,11-ether ring. Compound 8 exhibits nontoxic effects for zebrafish embryo, while it displays efficient reduction against NO production in a dose-dependent manner and strongly suppresses the secretion of LPS-induced TNF-α and IL-6 cytokines in RAW264.7 macrophages. In addition, marked reductions of iNOS and COX-2 expression were observed. Molecular docking analysis indicated that 8 has high affinities with the target amino acid residues on protein-binding sites, which may be a possible mechanism contributing to the anti-inflammatory potential of this molecule.

Zeylleucapenoids A-D, Highly Oxygenated Diterpenoids with Anti-Inflammatory Activity from Leucas zeylanica (L.) R. Br

Four previously undescribed highly oxygenated diterpenoids (1-4), zeylleucapenoids A-D, characterized by halimane and labdane skeletons, were isolated from the aerial parts of Leucas zeylanica. Their structures were elucidated primarily via NMR experiments. The absolute configuration of 1 was established using theoretical ECD calculations and X-ray crystallographic analysis, whereas those for 2-4 were assigned using theoretical ORD calculations. Zeylleucapenoids A-D were tested for anti-inflammatory activity against nitric oxide (NO) production in RAW264.7 macrophages, of which only 4 showed significant efficacy with an IC₅₀ value of 38.45 μM. Further, active compound 4 was also evaluated for the inhibition of the release of pro-inflammatory cytokines TNF-α and IL-6 and was found to have a dose-dependent inhibitory effect, while it showed nontoxic activity for zebrafish embryos. A subsequent Western blotting experiment revealed that 4 inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, molecular docking analysis indicated that the possible mechanism of action for 4 may be bind to targets via hydrogen and hydrophobic bond interactions.

Iridoids from Patrinia heterophylla and their anti-inflammatory activity

A phytochemical investigation led to the isolation of five undescribed compounds (1-5) from the methanol extract of the rhizomes and roots of Patrinia heterophylla. The structures and configurations of these compounds were characterized by HRESIMS, ECD, and NMR data analyses. These compounds were assayed for their anti-inflammatory potential using LPS-stimulated BV-2 cells, of which compound 4 showed strong nitric oxide (NO) inhibitory effects with an IC₅₀ of 6.48 μM. The potential anti-inflammatory mechanism was examined utilizing Western blotting and molecular docking. Further in vivo anti-inflammatory experiments revealed that compound 4 inhibited the production of NO and reactive oxygen species in the zebrafish model.

Subcritical Water Extraction of Onosma mutabilis: Process Optimization and Chemical Profile of the Extracts

The aboveground and root parts of Onosma mutabilis were extracted using subcritical water and the process was optimized with response surface methodology. The composition of the extracts was determined by chromatographic methods and compared to that of conventional maceration of the plant. The optimum total phenolic contents for the aboveground part and the roots were 193.9 and 174.4 μg/g, respectively. These results were achieved at a subcritical water temperature of 150 °C, an extraction time of 180 min, and a water/plant ratio of 0.1, for both parts of the plant. Principal component analysis revealed that the roots contained mainly phenols, ketones, and diols, with the aboveground part mostly alkenes and pyrazines, whereas the extract from maceration contained mainly terpenes, esters, furans, and organic acids. The quantification of selected phenolic substances showed that subcritical water extraction compared favorably to maceration, especially with respect to pyrocatechol (1062 as compared to 10.2 μg/g) and epicatechin (1109 as compared to 23.4 μg/g). Furthermore, the roots of the plant contained twice as much of these two phenolics compared to the aboveground part. Subcritical water extraction of O. mutabilis is an environmentally friendly method that can extract selected phenolics at higher concentrations compared to maceration.

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.

Supercritical carbon dioxide extraction of plant phytochemicals for biological and environmental applications - A review

Recently, supercritical fluid CO₂ extraction (SFE) has emerged as a promising and pervasive technology over conventional extraction techniques for various applications, especially for bioactive compounds extraction and environmental pollutants removal. In this context, temperature and pressure regulate the solvent density and thereby effects the yield, selectivity, and biological/therapeutic properties of the extracted components. However, the nature of plant matrices primarily determines the extraction mechanism based on either density or vapor pressure. The present review aims to cover the recent research and developments of SFE technique in the extraction of bioactive plant phytochemicals with high antioxidant, antibacterial, antimalarial, and anti-inflammatory activities, influencing parameters, process conditions, the investigations for improving the yield and selectivity. In another portion of this review focuses on the ecotoxicology and toxic metal recovery applications. Nonpolar properties of Sc-CO₂ create strong solvent strength via distinct intermolecular interaction forces with micro-pollutants and toxic metal complexes. This results in efficient removal of these contaminants and makes SFE technology as a superior alternative for conventional solvent-based treatment methods. Moreover, a compelling assessment on the therapeutic, functional, and solvent properties of SFE is rarely focused, and hence this review would add significant value to the SFE based research studies. Furthermore, we mention the limitations and potential of future perspectives related to SFE applications.

Natural iridoids from Patrinia heterophylla showing anti-inflammatory activities in vitro and in vivo

Inflammation, especially chronic inflammation, has been found to be closely related to the pathology of many diseases and the discovery of bioactive natural products to inhibit NO production is one of strategies to treat inflammation. In our continuous search for bioactive natural substances as potential anti-inflammatory agents, five new compounds (1-5) were extracted and purified from Patrinia heterophylla. The NMR and MS data analysis, along with electronic circular dichroism (ECD) calculations, led to the identification of these isolates, which were new iridoids. Using cell and zebrafish models, the in vitro and in vivo anti-inflammatory effects were conducted to evaluate the potency of anti-inflammation of these compounds. The preliminary mechanism was explored using molecular docking and Western blotting experiments.

Anti-inflammatory neo-Clerodane Diterpenoids from Ajuga pantantha

Eight new neo-clerodane diterpenoids (1-8) were acquired from the aerial parts of Ajuga pantantha. Spectroscopic data analysis permitted the definition of their structures, and experimental and calculated electronic circular dichroism data were used to define their absolute configurations. Compounds 2 and 4-8 were found to have NO inhibitory effects with IC₅₀ values of 20.2, 45.5, 34.0, 27.0, 45.0, and 25.8 μM, respectively. The more potent compounds 2, 6, and 8 were analyzed to establish their anti-inflammatory mechanism, including regulation of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins as well as their binding interactions with the two proteins.

Uncarialins A-I, Monoterpenoid Indole Alkaloids from Uncaria rhynchophylla as Natural Agonists of the 5-HT1A Receptor

Nine new monoterpenoid indole alkaloids, uncarialins A-I (1-9), were isolated from Uncaria rhynchophylla as well as 14 known analogues (10-23). Their structures were determined by HRESIMS, 1D and 2D NMR, and experimental and calculated electronic circular dichroism data. Compounds 5, 7, 15, and 22 displayed significant agonistic effects against the 5-HT_1A receptor with EC₅₀ values of 2.2 ± 0.1, 0.1 ± 0.1, 1.6 ± 0.3, and 2.0 ± 0.5 μM, respectively. The mechanisms of action of these four compounds with the 5-HT_1A receptor were investigated by molecular docking, and the results suggested that amino acid residues Asp116, Thr196, Asn386, and Tyr390 played critical roles in the observed activity of the above-mentioned compounds.