Phytochemical profile and pharmacological properties of Trifolium repens

Investigating the involvement of the NLRP3/ASC/caspase-1 and NF-κb/MAPK pathways in the pathogenesis of gouty arthritis: Insights from irradiated and non-irradiated Trifolium alexandrium L. extracts and some metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

Trifolium alexandrinum L. (TA), has traditionally been used in folk medicine for its anti-inflammatory properties against hyperuricemia and gout. However, the specific mechanisms of action of TA have not been thoroughly studied.

AIM OF THE WORK

This study aimed to evaluate the protective effects of irradiated (TR25) and non-irradiated (TR0) Trifolium alexandrinum L. aqueous extract (TAAE), along with two isolated compounds, caffeine (CAF) and saponin (SAP), in a rat model of acute gouty arthritis (GA).

MATERIALS AND METHODS

The GA model was established by injecting a monosodium urate (MSU) suspension into the knee joint. Synovial tissue pathology was assessed, and levels of TNF-α, IL-6, IL-1β, NF-κB, mTOR, AKT1, PI3K, NLRP3, and ASC were measured by ELISA. mRNA expression of ERK1, JNK, and p-38 MAPK was detected using qRT-PCR, and Caspase-1 protein expression was assessed by immunohistochemical analysis. Knee swelling, uric acid levels, liver and kidney function, and oxidative stress markers were also evaluated.

RESULTS

TAAE analysis identified 170 compounds, with 73 successfully identified using LC-HR-MS/MS, including caffeine citrate and theasapogenol B glycoside as the main constituents. The studied materials demonstrated significant protective effects against GA. TR25 administration significantly mitigated knee joint circumference compared to other treatments. It demonstrated potential in alleviating hyperuricemia, renal and hepatic impairments induced by MSU crystals. TR25 also alleviated oxidative stress and reduced levels of IL1β, IL-6, TNF-α, and NF-κB. Weak Caspase-1 immune-positive staining was observed in the TR25 group. TR25 decreased NLRP3 and ASC expression, reducing inflammatory cytokine levels in GA. It effectively inhibited the PI3K, AKT, and mTOR signaling pathways, promoting autophagy. Additionally, TR25 suppressed ERK1, JNK, and p-38 MAPK gene expression in synovial tissue. These effects were attributed to various components in TAAE, such as flavonoids, phenolic acids, tannins, alkaloids, and triterpenes.

CONCLUSION

Importantly, irradiation (25 KGy) enhanced the antioxidant effects and phtchemical contents of TAAE. Additionally, TR0, TR25, CAF, and SAP exhibited promising protective effects against GA, suggesting their therapeutic potential for managing this condition. These effects were likely mediated through modulation of the NLRP3/ASC/Caspase-1 and ERK/JNK/p-38 MAPK signaling pathways, as well as regulation of the PI3K/AKT/mTOR pathway. Further research is warranted to fully elucidate the underlying mechanisms and optimize their clinical applications.

Potential Antidiabetic, Antioxidative and Antiproliferative Properties of Functional Wheat Flour Muffins Enriched with White Clover Flowers (Trifolium repens L.)

The aim of the study was to evaluate the functional properties of muffins fortified with white clover flowers (Trifolium repens L.), which were added to the dough in the following amounts: (i) 0% (control); (ii) 2.5%; (iii) 5.5%; (iv) 7.5%; and (v) 10%. The organoleptic properties were assessed by a panel of consumers. Additionally, the following parameters were also tested: basic chemical composition, total polyphenols, the antioxidant activity together with antiproliferative effects on the A375 melanoma cell line, starch nutritional fractions and the in vitro glycemic index. As a result, replacing wheat flour with white clover flour significantly affected the color, aroma and taste of the muffins. The content of proteins, fats, total ash, dietary fiber, resistant starch (RS), slowly digestible starch (SDS),total polyphenols and antioxidant activity increased statistically significantly with the elevated amount of white clover flour added to the dough. At the same time, the content of free glucose (FG), rapidly available glucose (RAG) and rapidly digestible starch (RDS), the value of the in vitro glycemic index and the viability of melanoma cancer cells decreased significantly. The muffins enriched with white clover flowers might constitute an interesting proposition and extension of the existing assortment of confectionery products.

High-Altitude Medicinal Plants as Promising Source of Phytochemical Antioxidants to Combat Lifestyle-Associated Oxidative Stress-Induced Disorders

Oxidative stress, driven by reactive oxygen, nitrogen, and sulphur species (ROS, RNS, RSS), poses a significant threat to cellular integrity and human health. Generated during mitochondrial respiration, inflammation, UV exposure and pollution, these species damage cells and contribute to pathologies like cardiovascular issues, neurodegeneration, cancer, and metabolic syndromes. Lifestyle factors exert a substantial influence on oxidative stress levels, with mitochondria emerging as pivotal players in ROS generation and cellular equilibrium. Phytochemicals, abundant in plants, such as carotenoids, ascorbic acid, tocopherols and polyphenols, offer diverse antioxidant mechanisms. They scavenge free radicals, chelate metal ions, and modulate cellular signalling pathways to mitigate oxidative damage. Furthermore, plants thriving in high-altitude regions are adapted to extreme conditions, and synthesize secondary metabolites, like flavonoids and phenolic compounds in bulk quantities, which act to form a robust antioxidant defence against oxidative stress, including UV radiation and temperature fluctuations. These plants are promising sources for drug development, offering innovative strategies by which to manage oxidative stress-related ailments and enhance human health. Understanding and harnessing the antioxidant potential of phytochemicals from high-altitude plants represent crucial steps in combating oxidative stress-induced disorders and promoting overall wellbeing. This study offers a comprehensive summary of the production and physio-pathological aspects of lifestyle-induced oxidative stress disorders and explores the potential of phytochemicals as promising antioxidants. Additionally, it presents an appraisal of high-altitude medicinal plants as significant sources of antioxidants, highlighting their potential for drug development and the creation of innovative antioxidant therapeutic approaches.

Detection of isoflavones and phytoestrogen-rich plant extracts binding to estrogen receptor β using a yeast-based fluorescent assay

Alchemilla vulgaris L., Trifolium pratense L. and Glycyrrhiza glabra L. are important remedies in traditional medicine, known for many usages, including treating gynecological diseases. Despite folkloric use of the plant materials, there is a lack of scientific data to support their therapeutic application. The aims of the present study were to evaluate the relative binding affinities (RBAs) of plant-derived phytoestrogens for estrogen receptor β (ERβ) using fluorescent biosensor in yeast and to apply this assay for the assessment of the potential of plant materials towards ERs and treatment of estrogen-related disorders. Ligand-binding domain of ERβ fused with yellow fluorescent protein (ERβ LBD-YFP) was expressed in S. cerevisiae and fluorescence was detected by fluorimetry and fluorescence microscopy. Structural basis for experimental results was explored by molecular docking. Yeast-based fluorescent assay was successfully optimized and applied for identification of natural phenolic compounds and phytoestrogen-rich plant extracts that interact with ERβ-LBD, making this biosensor a valuable tool for screening estrogenic potential of a variety of plant extracts. This assay can be used for preliminary testing of plant-derived or fungal extracts, but also other sources of environmental substances with ER-modulating activity in order to assess their possible effects on the female reproductive system.

Allelopathic effect of the methanol extract of the weed species-red sorrel (Rumex acetosella L.) on the growth, phytohormone content and antioxidant activity of the cover crop - white clover (Trifolium repens L.)

Allelopathy is a biological process in which one organism releases biochemicals that affect the growth and development of other organisms. The current investigation sought to determine the allelopathic effect of Rumex acetosella on white clover (Trifolium repens) growth and development by using its shoot extract (lower IC50 value) as a foliar treatment. Here, different concentrations (25, 50, 100, and 200 g/L) of shoot extract from Rumex acetosella were used as treatments. With increasing concentrations of shoot extract, the plant growth parameters, chlorophyll and total protein content of Trifolium repens decreased. On the other hand, ROS, such as O2.- and H2O2, and antioxidant enzymes, including SOD, CAT, and POD, increased with increasing shoot extract concentration. A phytohormonal study indicated that increased treatment concentrations increased ABA and SA levels while JA levels were reduced. For the identification of allelochemicals, liquid‒liquid extraction, thin-layer chromatography, and open-column chromatography were conducted using R. acetosella shoot extracts, followed by a seed bioassay on the separated layer. A lower IC50 value was obtained through GC/MS analysis. gammaSitosterol was identified as the most abundant component. The shoot extract of Rumex acetosella has strong allelochemical properties that may significantly impede the growth and development of Trifolium repens. This approach could help to understand the competitive abilities of this weed species and in further research provide an alternate weed management strategy.

Physiological characteristics, rhizosphere soil properties, and root-related microbial communities of Trifolium repens L. in response to Pb toxicity

Trifolium repens L. (T. repens) is considered a potential phytoremediation species due to its large biomass and ability to accumulate and tolerate heavy metals. Lead (Pb) is an important heavy metal pollutant that can affect plant growth, photosynthesis, and enzyme activity. However, response mechanism of microorganisms in three root niches of metal tolerant plants to Pb is not completely understood. Therefore, in this study, a Pb poisoning model of T. repens was established with a Pb gradient (0, 1000 mg/kg, 2000 mg/kg, and 3000 mg/kg), and was used to evaluate growth and physiological responses, as well as enrichment and transport coefficients in T. repens, and explore the characteristics of rhizosphere soil and microbial composition of three root niches. We found that Pb stress caused oxidative injury, and inhibited photosynthesis in T. repens. 16S rDNA sequencing analysis showed that the richness of microbial communities in bulk soil was higher than that in rhizosphere soil both under Pb stress and Pb nonstress conditions. Moreover, Proteobacteria was dominant phylum in bulk and rhizosphere soils, and Proteobacteria and Cyanobacteria were dominant phylum in endophytic bacteria. For the first time, we systematically investigated the response of Pb from bulk soil to plant leaves. The results showed that microbial interaction existed between bulk and rhizosphere soil. Rhizosphere bacterium Haliangium was positively correlated with urease activity and soil nutrients. Endophytic bacterium Pseudomonas was positively correlated with plant biomass and played an important role in Pb tolerance of T. repens. In addition, endophytic bacteria formed complex correlation networks with growth and physiological indexes of both root and shoot, moreover the network in root was more complicated. Taken together, Pb stress dose-dependently inhibited the growth of plants. This study provided a theoretical basis for the further development of microbial cooperation with plant remediation of heavy metal contaminated soil.

Investigation of Trifolium repens L. from the Indian Himalayan region as a phyto-therapeutic agent

Trifolium repens is a well-known herbaceous, perennial herb and has been extensively used in the traditional medicine system over the years. Various parts of the plant are traditionally used as a curative agent against several health ailments such as skin problems, wound healing, stomach disorders, sedative, fever, antiseptic, analgesic, expectorant, psoriasis and eczema. To maximise the plant's potential for usage in the future, the review also aims to update information about its significant pharmacological properties. The ethnomedicinal benefits of T. repens have been well studied; however, the facets of the plant have not been explored yet. The current review outlines several bioactive compounds quantified from T. repens and a few of them namely quercetin, kaempferol, myricetin, acacetin and linamarin, have been reported to have biological activities such as antibacterial, antifungal, antileishmanial, anti-inflammatory, antiaging and anti-hepatotoxic activities. A significant number of in vitro studies have been done on the plant extract, but little is known about the isolation and efficacy of the potent natural bioactive compounds of T. repens. The bioactive compounds in T. repens can be used for advanced drug development against various health disorders.

The potential role of formononetin in cancer treatment: An updated review

Currently, cancer is one of the main research topics, due to its high incidence and drug resistance to existing anti-cancer drugs. Formononetin, a natural product with phytoestrogenic properties and diverse biological functions, has attracted the attention of researchers working on anticancer drugs. Formononetin emerges as an intriguing bioactive substance compared to other isoflavones as it exhibits potent chemotherapeutic activity with less toxicity. Formononetin effectively plays a significant role in inhibiting cell proliferation, invasion, and metastatic abilities of cancer cells by targeting major signaling pathways at the junction of interconnected pathways. It also induces apoptosis and cell cycle arrest by modulating mediator proteins. It causes upregulation of key factors such as p-AKT, p38, p21, and p53 and downregulation of NF-κB. Furthermore, formononetin regulates the neoplastic microenvironment by inactivating the ERK1/2 pathway and lamin A/C signaling and has been reported to inactivate JAK/STAT, PKB or AKT, and mitogen-activated protein kinase pathways and to suppress cell migration, invasion, and angiogenesis in human cancer cells. To assist researchers in further exploring formononetin as a potential anticancer therapeutic candidate, this review focuses on both in vitro and in vivo proof of concept studies, patents, and clinical trials pertinent to formononetin's anticancer properties. Overall, this review discusses formononetin from a comprehensive perspective to highlight its potential benefits as an anticancer agent.

Polyphenols in Agricultural Grassland Crops and Their Health-Promoting Activities-A Review

Grassland crops are emerging reservoirs of undisturbed, natural antioxidants and phytochemicals, such as phenolic acids and flavonoids. The present review will focus on the most commonly cultivated crops, namely Lolium perenne L, Cichorium intybus L, Plantago lanceolata L. and Trifolium pratense L, which have been recognized for their polyphenolic composition. However, these crops are often undervalued and underutilized, yet have the means of potentially creating novel, value-added food and nutraceutical products. Previous studies relating to these crops have identified them as rich sources of caffeic acid, chlorogenic acid, daidzein, kaempferol, luteolin, and quercetin. The key to harnessing the hidden potential of these species is the recovery, identification, and characterization of the phytochemicals they contain. Considering the upsurge of research studies on alternative plant-based diets for the health of humans and the planet earth, there is a necessity to understand the phytochemical composition and the bioactivity that they possess. This review summarizes recovery methods of phytochemicals from the aforementioned grassland crops and their compositional and functional (antioxidant, anti-cancer, and anti-diabetic) characterization and discusses the potential for grassland crops as an abundant reservoir of health-promoting ingredients which can increase the nutritional composition within novel food innovations or within nutraceuticals.

White clover from the exclusion zone of the Chernobyl NPP: Morphological, biochemical, and genetic characteristics

A comprehensive study of the biological effects of chronic radiation exposure (8 μGy/h) in populations of white clover (Trifolium repens L.) from the Chernobyl exclusion zone was carried out. White clover is one of the most important pasture legumes, having many agricultural applications. Studies at two reference and three radioactively contaminated plots showed no stable morphological effects in white clover at this level of radiation exposure. Increased activities of catalase and peroxidases were found in some impacted plots. Auxin concentration was enhanced in the radioactively contaminated plots. Genes involved in the maintenance of water homeostasis and photosynthetic processes (TIP1 and CAB1) were upregulated at radioactively contaminated plots.

Antioxidant and Anti-Inflammatory Effects of 6,3',4´- and 7,3´,4´-Trihydroxyflavone on 2D and 3D RAW264.7 Models

Dietary flavones 6,3´,4´-trihydroxyflavone (6,3´,4´-HOFL) and 7,3´,4´-trihydroxyflavone (7,3´,4´-HOFL) showed preliminary antioxidant and anti-inflammatory activities in a two-dimensional (2D) cell culture model. However, their action mechanisms remain unclear, and the anti-inflammatory activities have not been studied in a reliable three-dimensional (3D) cell model. Therefore, in the current study, the antioxidant potency was examined by their scavenging ability of cellular reactive oxygen species. Anti-inflammatory activities were examined via their inhibitory effects on inflammatory mediators in vitro on 2D and 3D macrophage models, and their mechanisms were determined through transcriptome. In the 3D macrophages, two flavones were less bioactive than they were in 2D macrophages, but they both significantly suppressed the overexpression of proinflammatory mediators in two cell models. The divergent position of the hydroxyl group on the A ring resulted in activity differences. Compared to 6,3´,4´-HOFL, 7,3´,4´-HOFL showed lower activity on NO, IL-1β suppression, and c-Src binding (IC₅₀: 12.0 and 20.9 µM) but higher ROS-scavenging capacity (IC₅₀: 3.20 and 2.71 µM) and less cytotoxicity. In addition to the IL-17 and TNF pathways of 6,3´,4´-HOFL, 7,3´,4´-HOFL also exerted anti-inflammatory activity through JAK-STAT, as indicated by the RNA-sequencing results. Two flavones showed prominent antioxidant and anti-inflammatory activities on 2D and 3D models.

Evaluation of Wound Healing Potential of Novel Hydrogel Based on Ocimum basilicum and Trifolium pratense Extracts

Plants are an inexhaustible source of compounds with different medicinal properties, suitable as alternative options for the prevention and treatment of various pathologies. They are safe, effective and economical. In this paper, a combined extract made of Ocimum basilicum and Trifolium pratense extracts (EOT) was used for the first time to demonstrate its healing effect on dermal pathologies. To evaluate the wound healing effect of EOT, a novel gel formulation was prepared and subsequently tested in vitro (using the scratch test assay) and in vivo (on an animal model). The in vitro tests demonstrated the complete recovery of the dermal fibroblast monolayer when treated with EOT in a concentration of 50 µg/mL. In vivo results using a hydrogel formulation based on EOT demonstrated improved wound contraction time and complete healing after 13 days of treatment. Moreover, a clinical case of Psoriasis vulgaris was presented, in which one week of treatment led to the significant improvement of the patient’s health. In conclusion, the topical use of the novel gel formulation containing EOT is a successful therapeutic alternative in the treatment of dermal diseases.

Perspectives on the Combined Effects of Ocimum basilicum and Trifolium pratense Extracts in Terms of Phytochemical Profile and Pharmacological Effects

Nowadays, the tendency in pharmaceutical and food industries is to replace synthetic antioxidants with the natural ones. For this reason, there is a growing interest in analyzing natural, healthy and non-toxic additives as potential antioxidants. Some plants, which contain high levels of phenolic compounds, present an increasing interest for medicine due to their ability to scavenge free radicals, along with other pharmacological activities, such as antibacterial activity, wound healing and anti-inflammatory effect, to mention only a few. The aim of this review is to explore the therapeutic potential of Ocimum basilicum and Trifolium pratense in relation with their phytochemical profile and to highlight the pharmacological activity of aqueous or ethanol extracts. Special attention was devoted to the dermal pathology and wound healing effects, in the context of multiple skin conditions such as acne, eczema boils, psoriasis and rashes. Additionally, both extracts (Trifolium sp. and Ocimum sp.) are characterized by high content of antioxidant compounds, which are responsible for the radiance and resistance of the skin and slowing down of the aging process by maintaining estrogen levels. Moreover, the potential combined effect of the mixed extract is pointed out in terms of future applications for wound healing, based on some preliminary results obtained from a “scratch tests” assay performed with respect to human dermal fibroblasts.

Nephroprotective property of Trifolium repens leaf extract against paracetamol-induced kidney damage in mice

Paracetamol-induced toxicity is one of the major drawbacks in the treatment of inflammatory conditions. The present study was performed to find out the impacts of phenolic compounds in the Trifolium repens (white clover) leaves (TR) against the paracetamol-induced nephrotoxicity in mice. The extract was administered orally to mice in different doses (1, 2, and 3 mL having a dry mass of 11.0 mg/mL) along with paracetamol (300 mg/kg) alone or in combination. Kidney histology, serum renal function tests, serum electrolytes, reduced glutathione, and lipid peroxidation were evaluated. Paracetamol significantly affected kidney weight, renal profile biochemistry, serum electrolytes, reduced glutathione, and thiobarbituric acid reactive substances (as lipid peroxidation) in mice. The amount of total phenolic compounds identified in the extract was 8.89 mg/g, representing 80.8% of the extract. The simultaneous administration of the TR extract leads to the normalization of all those parameters, which were deviated due to paracetamol ingestion. Kidney histological examination showed that nephrotoxicity was induced due to paracetamol, while the extract rich in phenolic compounds acts as therapeutic agents. The administration of extract also normalized the reduced glutathione from 0.837 to 2.21 of the paracetamol and paracetamol with 3-mL extract, respectively. Lipid peroxidation in the kidney was significantly (p < 0.05) declined by the extract (0.435 µmol/g) as compared to PC (3.96 µmol/g). In conclusion, TR extract possesses active beneficial phenolic compounds with nephroprotective function.