Anti-inflammatory activities of gentiopicroside against iNOS and COX-2 targets

Gentiopicroside-An Insight into Its Pharmacological Significance and Future Perspectives

Gentiopicroside (GPS) is a leading component of several plant species from the Gentianaceae botanical family. As a compound with plenty of biological activities and a component of herbal drugs, GPS has an important role in the regulation of physiological processes in humans. The results of recently published scientific studies underline a meaningful role of this molecule as an active factor in metabolic pathways and mechanisms, which may have an influence in the treatment of different diseases, including digestive tract disorders, malignant changes, neurological disorders, microbial infections, bone formation disorders, inflammatory conditions, and others. This review aims to collect previously published reports on the biological properties of GPS as a single compound that were confirmed by in vitro and in vivo studies, and to draw attention to the newly discovered role of this bitter-tasting secoiridoid. Thanks to these properties, the research on this substance could be revisited.

Dual-target inhibitors based on COX-2: a review from medicinal chemistry perspectives

Inhibitors of COX-2 constitute a class of anti-inflammatory analgesics, showing potential against certain types of cancer. However, such inhibitors are associated with cardiovascular toxicity. Moreover, although single-target molecules possess specificity for particular targets, they often lead to poor safety, low efficacy and drug resistance due to compensatory mechanisms. A new generation of dual-target drugs that simultaneously inhibit COX-2 and another target is showing strong potential to treat cancer or reduce adverse cardiac effects. The present perspective focuses on the structure and functions of COX-2, and its role as a therapeutic target. It also explores the current state and future possibilities for dual-target strategies from a medicinal chemistry perspective.

Secondary metabolites from Gentiana cruciata L. and their anti-inflammatory and analgesic activities

A previously unreported secoiridoid glycoside, cruciatoside (1) was isolated from the aerial parts of Gentiana cruciata L. along with ten known compounds eustomoside (2), eustomorusside (3), gentiopicroside (4), 6'-O-β-D-glucopyranosyl gentiopicroside (5), loganic acid (6), isoorientin (7), isovitexin (8), isovitexin 2''-(E)-ferulate (9), mangiferin (10), and 2-methyl-inositol (11). The chemical structures of the isolates were elucidated based on extensive 1 D and 2 D NMR experiments as well as HRMS analysis. All isolates were evaluated for their in vitro anti-inflammatory and analgesic activities. Compounds 9, 4, and 7 (200 µM) showed moderate anti-inflammatory activity by inhibiting nitrite production from LPS-induced RAW 264.7 macrophage cells, with the inhibition rates of 39.5%, 25.8% and 22.9% respectively without exhibiting substantial cytotoxicity. Besides, 1, 2, 4, and 7 exerted the highest decrease in IL-6 levels. Moreover, compound 4 showed in vitro analgesic activity by decreasing the PGE2 level comparable to the reference drugs.

Preparation, Characterization, and In Vivo Evaluation of Gentiopicroside-Phospholipid Complex (GTP-PC) and Its Self-Nanoemulsion Drug Delivery System (GTP-PC-SNEDDS)

The objective of the present study was to develop a gentiopicroside-phospholipid complex (GTP-PC) and its self-nanoemulsion drug delivery system (GTP-PC-SNEDDS) to increase the oral bioavailability of gentiopicroside (GTP). The factors affecting the formation of GTP-PC were studied with the complexation efficiency and dissociation rate. The properties of the complex were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), dissolution, etc. Then, GTP-PC was loaded into SNEDDS by investigating the effects of weight ratios of GTP-PC to blank SNEDDS, preparation technology, dilution media, and dilution multi, based on the screening results of oils, surfactants, and cosurfactants. In rats, GTP, GTP-PC, and GTP-PC-SNEDDS were orally administered at different times, and GTP concentrations were determined using RP-HPLC. The optimal GTP-PC was prepared with tetrahydrofuran as the reaction solvent, GTP:phospholipid = 1:2, and stirring for 4 h. The optimal prescription for GTP-PC-SNEDDS was as follows: Maisin 35-1:Miglycol = 30%, Labrasol:Cremophor EL = 1:4 = 40%, Transcutol P = 30%; Maisin 35-1:Miglycol = 12, and the ratio of GTP-PC to blank was 1:10-then the mixture was stirred at 37 °C for 1 d and then placed for 2 d to form stable GTP-PC-SNEDDS. After oral administration of GTP, GTP-PC and GTP-PC-SNEDDS, and mean plasma GTP concentration-time curves were all in accordance with the single-compartment model. The C_max, AUC_0-∞, and Fr of the three formulations were significantly higher than that of GTP, demonstrating that GTP was metabolized rapidly, and its higher bioavailability could be achieved by the formation of GTP-PC and GTP-PC-SNEDDS. Among the three formations, the bioavailability of GTP-PC-SNEDDS was highest, with approximately 2.6-fold and 1.3-fold of Fr value, compared with GTP-PC (suspension) and GTP-PC (oil solution), respectively. Compared with GTP, GTP-PC and GTP-PC-SNEDDS enhanced the bioavailability of GTP significantly. In the future, this study could serve as a reference for clinical trials using GTP-PC and GTP-PC-SNEDDS.

Polyphenol-Polysaccharide Complex: Preparation, Characterization and Potential Utilization in Food and Health

Polysaccharides and polyphenols coexist in many plant-based food products. Polyphenol-polysaccharide interactions may affect the physicochemical, functional, and physiological properties, such as digestibility, bioavailability, and stability, of plant-based foods. In this review, the interactions (physically or covalently linked) between the selected polysaccharides and polyphenols are summarized. The preparation and structural characterization of the polyphenol-polysaccharide conjugates, their structural-interaction relationships, and the effects of the interactions on functional and physiological properties of the polyphenol and polysaccharide molecules are reviewed. Moreover, potential applications of polyphenol-polysaccharide conjugates are discussed. This review aids in a comprehensive understanding of the synthetic strategy, beneficial bioactivity, and potential application of polyphenol-polysaccharide complexes. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A Review on the Ethnomedicinal Usage, Phytochemistry, and Pharmacological Properties of Gentianeae (Gentianaceae) in Tibetan Medicine

Gentianaceae is a large plant family and is distributed worldwide. As the largest tribe in Gentianaceae, Gentianeae contains 939-968 species, and the Qinghai-Tibet Plateau and adjacent areas are the main centers of diversity for Gentianeae. Species from the Gentianeae are widely used in traditional Tibetan medicine. In this review, a systematic and constructive overview of the information on botany, ethnomedicinal usage, phytochemistry, and pharmacological properties of Gentianeae in Tibetan medicine is provided. The results of this study are based on a literature search, including electronic databases, books, websites, papers, and conference proceedings. Botanical studies showed that Gentianeae includes the subtribe Gentianeae and Swertiinae, and several new genera and taxa have been identified. Approximately 83 species from Gentianeae were used in Tibetan medicine, among which Gentiana and Swertia constituted the largest number of species with 42 and 24 species, respectively. The species from Gentianeae are mainly used as Bangjian (སྤང་རྒྱན།), Jieji (ཀྱི་ལྕེ།), Dida (ཏིག་ཏ།), and Ganggaqiong (གང་གྰཆུང་།) in Tibetan medicine with different clinical applications. More than 240 formulas were found containing Gentianeae species with different attending functions. Phytochemical studies showed that the main active components of Gentianeae species are iridoids, xanthones, flavonoids, and triterpenoids. The bioactivities of plants from Gentianeae include hepatic protection, upper respiratory tract protection, joint and bone protection, glucose regulation, antibacterial, antioxidant, anticancer, and antiviral effects. This review will provide a reference for future research on natural resource protection, plant-based drug development, and further clinical investigation.

Gentiopicroside prevents alcoholic liver damage by improving mitochondrial dysfunction in the rat model

Gentianae Radix et Rhizoma is a medical plant that is widely cultivated in China, North Korea, Japan, and Russia, and gentiopicroside is one of its major active compounds. In this study, the hepatoprotective activity of gentiopicroside on rats with alcoholic liver damage (ALD) was evaluated using the transaminase and blood lipid levels and antioxidant capacity. The potential mechanism of hepatoprotective effect of gentiopicroside was evaluated by mitochondrial function detection, gas chromatography-mass spectrometry (GC-MS) metabolomic analysis, and anti-apoptosis analysis. Results showed that the gentiopicroside exhibited good hepatoprotective activity on rats with ALD by decreasing the transaminase levels, regulating the blood lipid levels, and increasing the antioxidant capacity. The potential mechanisms were related to regulating mitochondrial dysfunction by recovering mitochondrial membrane potential level, adenosine triphosphate concentration, activities of key enzymes in tricarboxylic acid cycle, and activities of complex I-V, regulating micromolecular metabolism and anti-apoptosis. These findings supported the further exploration of Gentianae Radix et Rhizoma as effective phytotherapy to prevent and treat ALD.

The extract from the roots of Rose odorata sweet var. gigantean (Coll. et Hemsl.) Rehd. et Wils attenuates DSS-induced ulcerative colitis by regulating the Nrf2/NF-κB signaling pathways

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease. Many natural medicines or ethnic drugs have been proven to be effective and beneficial in the treatment of UC. Among these, the root of Rose odorata sweet var. gigantean (Coll. et Hemsl.) Rehd. et Wils. (ROS), a kind of Yi nationality medicine called “GU-GONG-GUO,” has been shown to be useful as a therapeutic agent for sputum and diarrhea. However, the effects and mechanisms of ROS extract (ROE) on UC remain relatively unknown. The aim of this study was to explore the protective effects and the underlying mechanisms of ROE on UC. First, we established a dextran sulfate sodium (DSS)-induced experimental colitis mouse model and then evaluated the anti-inflammatory effects of ROE in vivo. Then, RAW264.7 cells were stimulated with lipopolysaccharide (LPS) in the presence or absence of ROE to explore its mechanisms in vitro. It was found that ROE attenuated DSS-induced colon length shortening, body weight loss, and colonic pathological damage. Furthermore, ROE inhibited the activity of nitric oxide synthase (NOS), myeloperoxidase (MPO), and malondialdehyde (MDA). Also, ROE decreased several LPS-induced inflammatory cytokines including TNF-α, IL-6, and IL-1β in RAW264.7. In addition, ROE inhibited the expression of p-NF-κB, p-IKKα/β, and Keap1 proteins and increased the expression of Nrf2 and HO-1 proteins. Our study suggested that ROE prevented DSS-induced colitis though the Nrf2/NF-κB pathway. Overall, it can be concluded that ROE may be a promising and effective agent for UC.

To evaluated the anti-inflammatory effects of ROE in vivo and in vivo by activating Nrf2/Nf-κB pathway.

Inducible nitric oxide synthase inhibitors: A comprehensive update

Inducible nitric oxide synthase (iNOS), which is expressed in response to bacterial/proinflammatory stimuli, generates nitric oxide (NO) that provides cytoprotection. Overexpression of iNOS increases the levels of NO, and this increased NO level is implicated in pathophysiology of complex multifactorial diseases like Parkinson's disease, Alzheimer's disease, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Selective inhibition of iNOS is an effective approach in treatment of such complex diseases. l-Arginine, being a substrate for iNOS, is the natural lead to develop iNOS inhibitors. More than 200 research reports on development of nitric oxide synthase inhibitors by different research groups across the globe have appeared in literature so far. The first review on iNOS, in 2002, discussed the iNOS inhibitors under two classes that is, amino acid and non-amino acid derivatives. Other review articles discussing specific chemical classes of iNOS inhibitors also appeared during last decade. In the present review, all reports on both natural and synthetic iNOS inhibitors, published 2002 onwards, are studied, classified, and discussed to provide comprehensive information on iNOS inhibitors. The synthetic inhibitors are broadly classified into two categories that is, arginine and non-arginine analogs. The latter are further classified into amidines, five- or six-membered heterocyclics, fused cyclics, steroidal type, and chalcones analogs. Structures of the most/significantly potent compounds from each report are provided to know the functional groups important for incurring iNOS inhibitory activity and selectivity. This review is aimed to provide a comprehensive view to the medicinal chemists for rational designing of novel and potent iNOS inhibitors.