Hepatoprotective coumarins and secoiridoids from Hydrangea paniculata

Coumarins as versatile therapeutic phytomolecules: A systematic review

BACKGROUND

Coumarins, abundantly distributed in a plethora of biologically active compounds, serve as a fundamental motif in numerous natural products, drugs, and therapeutic leads. Despite their small size, they exhibit a diverse range of biological activities, intriguing researchers with their immense pharmacological potential.

PURPOSE

This study consolidates the evidence regarding the essential role of coumarins in modern drug discovery, exploring their broad-spectrum pharmaceutical effects, structural versatility, and mechanisms of action across various domains.

METHODS

For literature search, we utilized PubMed, Google scholar, and SciFinder databases. Keyword and keyword combinations such as "coumarins", "natural coumarins", "specific natural coumarins for particular diseases", and "therapeutic effects" were employed to retrieve relevant studies. The search encompassed articles published between 2005 and 2023. Selection criteria included studies reporting on the pharmacological activities of natural coumarins against various diseases.

RESULTS

The results highlight the therapeutic potential of natural coumarins against various diseases, demonstrating anti-cancer, anti-oxidant, and anti-inflammatory activities. They also act as monoamine oxidase inhibitors and phosphodiesterase inhibitors, and as anti-thrombotic, anti-diabetic, and hepatoprotective agents. They also show efficacy against diabetic nephropathy, neurodegenerative diseases, microbial infections and many other diseases.

CONCLUSION

This review underscores the significant role of natural coumarins in medicinal chemistry and drug discovery. Their diverse biological activities and structural versatility make them promising therapeutic agents. This study serves as a catalyst for further research in the field, aiming to address emerging challenges and opportunities in drug development.

Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar 'Yae-no-amacha' using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.

Versatile approach for the synthesis of furo-coumarin derivatives

Abstract:

Owing to useful physio-chemical properties of furo-coumarin derivatives, their synthetic and mechanistic investigation has been reported here. We have demonstrated a range of synthetic approach to access furan-fused coumarin derivatives. Many metal mediated, base and acid catalyzed approach have been revealed for the construction of thiscoumarin based fused heterocycles of biological importance. In addition to this, microwave assisted synthetic routes have been also revealed. The last and useful approach for the synthesis of these heterocycles includes use of purely solvent as a reaction media for synthesizing these interesting classes of heterocycles.

Total Coumarins from Hydrangea paniculata Show Renal Protective Effects in Lipopolysaccharide-Induced Acute Kidney Injury via Anti-inflammatory and Antioxidant Activities

Background: Septic acute kidney injury (AKI) causes high mortality in critical care units, and no effective therapy exists in clinical treatment. In the current study, water and ethanol extracts of Hydrangea paniculata (HP), a traditional Chinese medicinal plant, were used to test its renoprotective effects in a lipopolysaccharide (LPS)-induced murine model of septic AKI.

Methods: C57BL/6 mice were orally pretreated with HP three times, and then intraperitoneal LPS injection was used to induce septic AKI. Blood from animals was collected for biochemical analysis and kidneys were obtained for pathological analysis. Kidney tissue homogenates were used to investigate the effect of HP on inflammation and oxidative stress. Immunohistochemistry was used to investigate tubular cell apoptosis. Flow cytometry was conducted to analyze leukocyte infiltration into the kidneys. Blood cell counts were used to analyze changes in peripheral leukocytes. In vitro studies with Ana1 and HK-2 cells stimulated by LPS were used to investigate the anti-inflammatory effects and inhibition of signaling pathways by HP.

Results: HP significantly decreased blood urea nitrogen and plasma neutrophil gelatinase-associated lipocalin concentrations, as well as tubulointerstitium injuries in septic AKI mice. Moreover, HP administration improved animal survival following lethal LPS injections. HP ameliorated apoptosis of tubular cells by inhibiting the cleavage of caspase 3 and caspase 7. HP also showed pronounced antioxidant activity in AKI kidneys. HP showed anti-inflammatory effects by inhibiting the infiltration of neutrophils and macrophages into kidney tissues induced by LPS, as well as inhibiting the production of cytokines and chemokines. Possible molecular mechanisms included HP inhibition of NF-κB nuclear translocation in LPS-induced macrophages and tubular cells, and reduction of STAT3, STAT1, and ERK1/2 phosphorylation stimulated by LPS in vitro. Single acute toxicity tests confirmed that HP, even at 5 g/kg dosage, does not cause animal death. Pharmacokinetics also showed that coumarins from HP could be metabolized into two bioactive compounds, umbelliferone, and esculetin.

Conclusions: HP extract may protect renal function in LPS-induced AKI by anti-inflammatory and antioxidant activities, and has potential in the critical care of AKI.

Effect of pre-treatment of blue honeysuckle berries on bioactive iridoid content

The aim of the study was to evaluate the effect of the different methods of preparation of the blue honeysuckle (Lonicera caerulea L. var. Kamtschatica) cv. 'Wojtek' and their influence on the iridoid content of fruit juices and fresh and freeze-dried pomaces. Compounds were identified by UPLC-ESI-qTOF-MS/MS in negative ion mode. Five iridoids - loganic acid, 7-epi-loganic acid 7-O-pentoside, loganin, sweroside, and secologanin - were determined in blue honeysuckle fruits and products. The results revealed no differences in iridoid content between the fresh pomace from skin and flesh, or between the juice from skin and flesh. A higher content of iridoids was obtained in juice from crushed than from whole berries, and in freeze-dried pomace from whole than from crushed berries. Freeze-dried pomace from blue honeysuckle can be an excellent source of bioactive iridoids.

Three new coumarin glycosides from the stems of Hydrangea paniculata

Three new coumarin glycosides (1-3), together with three known compounds (4-6), have been obtained from the stems of Hydrangea paniculata Sieb. Their structures were elucidated based on spectroscopic data and chemical evidence. In addition, compounds 1-3 were screened for their neuroprotective effects against serum deprivation-induced PC12 cell damage, hepatoprotective activities against DL-galactosamine-induced toxicity in HL-7702 cells and their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line, but they were inactive.

Total Coumarins from Hydrangea paniculata Protect against Cisplatin-Induced Acute Kidney Damage in Mice by Suppressing Renal Inflammation and Apoptosis

Aim. Hydrangea paniculata (HP) Sieb. is a medical herb which is widely distributed in southern China, and current study is to evaluate renal protective effect of aqueous extract of HP by cisplatin-induced acute kidney injury (AKI) in animal model and its underlying mechanisms. Materials and Methods. HP extract was prepared and the major ingredients were coumarin glycosides. AKI mouse models were established by single i.p. injection of 20 mg/kg cisplatin, and HP was orally administrated for total five times. The renal biochemical functions, pathological staining, kidney oxidative stress, and inflammatory status were measured. Apoptosis of tubular cells and infiltration of macrophages and neutrophils were also tested. Results. HP administration could improve the renal function by decreasing concentration of blood urea nitrogen (BUN) and creatinine and attenuates renal oxidative stress and tubular pathological injury and apoptosis; further research demonstrated that HP could inhibit the overproduction of proinflammatory cytokines and regulate caspase and BCL-2 family proteins. HP also reduced renal infiltration of macrophages and neutrophils, and its effect might be by downregulating phosphorylation of ERK1/2 and stat3 signaling pathway. Conclusions. This present study suggests that HP could ameliorate cisplatin induced kidney damage by antioxidation and suppressing renal inflammation and tubular cell apoptosis.

New Phenylpropanoid and Coumarin Glycosides from the Stems of Hydrangea paniculata Sieb

A new phenylpropanoid glycoside (1), and two new coumarin glycosides (2, 3), together with two known compounds (4, 5), have been isolated from the stems of Hydrangea paniculata Sieb. Their structures have been determined by spectroscopic and chemical methods. Furthermore, compound 1 (50 μM) exhibited significant hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage in vitro assays.

Bioactive alkaloids from the aerial parts of Houttuynia cordata

ETHNOPHARMACOLOGICAL RELEVANCE

Houttuynia cordata is an important traditional Chinese medicine used in heat-clearing and detoxifying, swelling and discharging pus, promoting diuresis and relieving stranguria which recorded in Pharmacopoeia of the people's Republic of China (2015 Edition). H. cordata has been recorded in the book Bencaogangmu which was written by Shizhen Li for the treatment of pyretic toxicity, carbuncle swelling, haemorrhoids, and rectocele diseases.

AIM OF THE STUDY

Phytochemical investigation of the aerial parts of H. cordata and evaluation of their PTP1B inhibitory activities and hepatoprotective activities.

MATERIALS AND METHODS

The dried aerial parts of H. cordata were fractionated by liquid-liquid extraction to obtain CHCl₃, ethyl acetate, and n-butanolic fractions. The CHCl₃ fraction was confirmed active fraction by the bioactivity-guided investigation, which was isolated and purified by chromatographing over silica gel, Sephadex LH-20, MPLC, and preparative HPLC. The chemical structures of the purified compounds were identified by their spectroscopic data and references.

RESULTS

Eight new compounds (1-8), together with fourteen known compounds (9-22) were isolated from the aerial parts of H. cordata. The known compounds (9-22) were obtained from this plant for the first time. Among them, some compounds exhibited moderate bioactivities.

CONCLUSION

Compounds (1-8) were identified as new alkaloids, and the known alkaloids (9-22) were isolated from this plant for the first time. Compounds 1, 4, 14, and 19 showed significant PTP1B inhibitory activities with IC₅₀ values of 1.254, 2.016, 2.672, and 1.862µm, respectively. Compounds 1, 3, 6, 11, 17, and 20 (10µm) exhibited moderate hepatoprotective activities against D-galactosamine-induced WB-F344 cells damage.

Capparis spinosa leaves extract: Source of bioantioxidants with nephroprotective and hepatoprotective effects

Capparis spinosa, Capparidaceae, is largely distributed all over the Mediterranean Basin and is traditionally used to treat many illnesses, such as liver and kidney diseases. The aim of the current study was to explore the antioxidant, nephroprotective and hepatoprotective effects of methanolic extract of Capparis spinosa leaves (MECS) associated with its phytochemical content. The levels of total phenolics, flavonoids and condensed tannins were 23.37mgGAE/g, 9.05mgQE/g and 9.35mgTAE/g, respectively. HPLC analysis revealed nine compounds, namely rutin, resveratrol, coumarin, epicatechin, luteolin, catechin, kaempferol, vanillic acid and gallic acid. The MECS showed interesting antioxidant capacity. The MECS-treatment significantly reduced the increased plasma levels of creatinine, urea and uric acid, reduced the elevated MDA levels, significantly reduced the antioxidant enzyme activities and restored the kidney damage, provoked by cisplatin-treatment. Furthermore, MECS-treatment significantly prevented the increase in serum ALT, AST and LDH levels in acute liver damage induced by CCl₄, decreased the amount of hepatic malondialdehyde (MDA) formation and elevated the activities of SOD, CAT and GPx, and restored liver injury. This study supports the traditionally use of C. spinosa to cure kidney and liver diseases. The obtained results highlighted the possible use of C. spinosa as a source of phytochemical with important biological advantages.

Progress in the Chemistry of Naturally Occurring Coumarins

Coumarins are the largest group of 1-benzopyran derivatives found in plants. The initial member of this group of compounds, coumarin (2H-1-benzopyran-2-one), a fragrant colorless compound, was first isolated from the Tonka bean (Dipteryx odorata, family Fabaceae) in 1820. The name coumarin comes from a French term for the tonka bean, coumarou. Since the discovery of coumarin, several of its derivatives, with umbelliferone (7-hydroxycoumarin) being the most common one, have been reported from various natural sources. The families Apiaceae, Asteraceae, and Rutaceae are the three major plant sources of coumarins.Generally, these plant secondary metabolites may be classified into simple, simple prenylated, simple geranylated, furano, pyrano, sesquiterpenyl and oligomeric coumarins. Using this standard classification, this chapter aims to present an account on the advances of the chemistry of naturally occurring coumarins, as reported in the literature during the period 2013-2015.In Sect. 1, the coumarins are introduced and their generic biosynthetic route discussed briefly. In Sect. 2, the largest of the three sections, various classes of natural coumarins are detailed, with their relevant structures and the citation of appropriate references. In a concluding section, it is highlighted that during the last 3 years, more than 400 coumarins have been reported in the literature. Many of these coumarins have been re-isolations of known compounds from known or new sources, most often associated with various biological activities. However, a substantial number of coumarins bearing new skeletons, especially dimers, prenylated furanocoumarins, sesquiterpenyl, and some unusual coumarins were also reported during the period of 2013-2015.Coumarin chemistry remains one of the major interest areas of phytochemists, especially because of their structural diversity and medicinal properties, along with the wide-ranging bioactivities of these compounds, inclusive of analgesic, anticoagulant anti-HIV, anti-inflammatory, antimicrobial, antineoplastic, antioxidant, and immunomodulatory effects. Despite significant advancements in the extraction, isolation, structure elucidation and bioactivity testing of naturally occurring coumarins, only a marginal advancement has been observed recently in relation to the study of their biosynthesis.

Hepatoprotective pyranocoumarins from the stems of Clausena emarginata

Seven pyranocoumarins, clauemarmarins A-G, along with 6 known analogues were isolated from the stems of Clausena emarginata. Their structures were elucidated by extensive spectroscopic analyses, and the absolute stereochemistries at C-6″ of clauemarmarin B, C and D and the absolute configurations of clauemarmarin E, F and G were determined by ECD experiments. Compounds clauemarmarin C, D and two known analogues exhibited hepatoprotective activities against DL-galactosamine-induced damage in WB-F344 cells at the concentration of 10 μM.

Hepatoprotective standardized EtOH-water extract from the seeds of Fraxinus rhynchophylla Hance

Fraxinus rhynchophylla Hance (Oleaceae), its stem barks are known as Cortex fraxini (秦皮 qín pí) listed in Chinese Pharmacopoeia. Phytochemical study has indicated that methanol extracts from Qinpi has protective effect on acute liver injury. The present study investigates the hepatoprotective activity of EtOH–water extract from the seeds of F. rhynchophylla Hance against carbon tetrachloride-induced liver injury in mice. The EtOH–water extract significantly alleviated liver damage as indicated by the decreased levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the malondialdehyde (MDA) content, and increased the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px), and reduced the pathological tissue injury induced by CCl₄. Quantitative analysis of seven major constituents (1–7) in EtOH–water extract (EWE) was developed by high performance liquid chromatography-diode-array detector (HPLC-DAD). The current research indicates that the EWE from the seeds of F. rhynchophylla Hance decreased liver index, inhibited the increase of serum aminotransferase induced by CCl₄, and decreased hepatic MDA content, SOD and GSH-Px activities. These results suggested that the pretreatment with EWE protected mice against CCl₄-induced liver injuries. Based on the results, the EtOH–water extract from the seeds of F. rhynchophylla Hance is efficacious for prevention and treatment of CCl₄-induced hepatic injury in mice. Secoiridoid and tyrosol glucosides might be the active ingredients responsible for the biological and pharmacological activities of hepatoprotection.

Extraction, identification, fractionation and isolation of phenolic compounds in plants with hepatoprotective effects

The liver is one of the most important organs of human body, being involved in several vital functions and regulation of physiological processes. Given its pivotal role in the excretion of waste metabolites and drugs detoxification, the liver is often subjected to oxidative stress that leads to lipid peroxidation and severe cellular damage. The conventional treatments of liver diseases such as cirrhosis, fatty liver and chronic hepatitis are frequently inadequate due to side effects caused by hepatotoxic chemical drugs. To overcome this problematic paradox, medicinal plants, owing to their natural richness in phenolic compounds, have been intensively exploited concerning their extracts and fraction composition in order to find bioactive compounds that could be isolated and applied in the treatment of liver ailments. The present review aimed to collect the main results of recent studies carried out in this field and systematize the information for a better understanding of the hepatoprotective capacity of medicinal plants in in vitro and in vivo systems. Generally, the assessed plant extracts revealed good hepatoprotective properties, justifying the fractionation and further isolation of phenolic compounds from different parts of the plant. Twenty-five phenolic compounds, including flavonoids, lignan compounds, phenolic acids and other phenolic compounds, have been isolated and identified, and proved to be effective in the prevention and/or treatment of chemically induced liver damage. In this perspective, the use of medicinal plant extracts, fractions and phenolic compounds seems to be a promising strategy to avoid side effects caused by hepatotoxic chemicals.

Monoterpenes from the leaves of Hydrangea paniculata and their hepatoprotective activities

Three new monoterpenes, hydrangines A-C (1-3), together with four known compounds, were isolated from the ethanol extract of the leaves of Hydrangea paniculata. The structures of new isolates were elucidated on the basis of extensive 1D and 2D NMR analyses, and their absolute configurations were determined by comparison of experimental and calculated electronic circular dichroism spectra. In in vitro bioassays at 10 μM, compounds 1-6 showed hepatoprotective activities against dl-galactosamine-induced toxicity in HL-7702 cells.

Anti-inflammatory lignanamides from the roots of Solanum melongena L

Four new lignanamides, melongenamides A-D (1-4), together with six known ones (5-10), were isolated from the roots of Solanum melongena L. Their structures were elucidated on the basis of 1D and 2D NMR experiments and by comparison of their spectroscopic and physical data with the literature values. Compounds 2-8 exhibited inhibitions of nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages with IC50 values ranging from 16.2 to 58.5 μM.