Pharmacokinetic evaluation of the interaction between oral kaempferol and ethanol in rats

Kaempferol efficacy in metabolic diseases: Molecular mechanisms of action in diabetes mellitus, obesity, non-alcoholic fatty liver disease, steatohepatitis, and atherosclerosis

The incidence of metabolic diseases has progressively increased, which has a negative impact on human health and life safety globally. Due to the good efficacy and limited side effects, there is growing interest in developing effective drugs to treat metabolic diseases from natural compounds. Kaempferol (KMP), an important flavonoid, exists in many vegetables, fruits, and traditional medicinal plants. Recently, KMP has received widespread attention worldwide due to its good potential in the treatment of metabolic diseases. To promote the basic research and clinical application of KMP, this review provides a timely and comprehensive summary of the pharmacological advances of KMP in the treatment of four metabolic diseases and its potential molecular mechanisms of action, including diabetes mellitus, obesity, non-alcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), and atherosclerosis. According to the research, KMP shows remarkable therapeutic effects on metabolic diseases by regulating multiple signaling transduction pathways such as NF-κB, Nrf2, AMPK, PI3K/AKT, TLR4, and ER stress. In addition, the most recent literature on KMP's natural source, pharmacokinetics studies, as well as toxicity and safety are also discussed in this review, thus providing a foundation and evidence for further studies to develop novel and effective drugs from natural compounds. Collectively, our manuscript strongly suggested that KMP could be a promising candidate for the treatment of metabolic diseases.

Mulberry Leaf Compounds and Gut Microbiota in Alzheimer's Disease and Diabetes: A Study Using Network Pharmacology, Molecular Dynamics Simulation, and Cellular Assays

Recently, studies have reported a correlation that individuals with diabetes show an increased risk of developing Alzheimer's disease (AD). Mulberry leaves, serving as both a traditional medicinal herb and a food source, exhibit significant hypoglycemic and antioxidative properties. The flavonoid compounds in mulberry leaf offer therapeutic effects for relieving diabetic symptoms and providing neuroprotection. However, the mechanisms of this effect have not been fully elucidated. This investigation aimed to investigate the combined effects of specific mulberry leaf flavonoids (kaempferol, quercetin, rhamnocitrin, tetramethoxyluteolin, and norartocarpetin) on both type 2 diabetes mellitus (T2DM) and AD. Additionally, the role of the gut microbiota in these two diseases' treatment was studied. Using network pharmacology, we investigated the potential mechanisms of flavonoids in mulberry leaves, combined with gut microbiota, in combating AD and T2DM. In addition, we identified protein tyrosine phosphatase 1B (PTP1B) as a key target for kaempferol in these two diseases. Molecular docking and molecular dynamics simulations showed that kaempferol has the potential to inhibit PTP1B for indirect treatment of AD, which was proven by measuring the IC50 of kaempferol (279.23 μM). The cell experiment also confirmed the dose-dependent effect of kaempferol on the phosphorylation of total cellular protein in HepG2 cells. This research supports the concept of food-medicine homology and broadens the range of medical treatments for diabetes and AD, highlighting the prospect of integrating traditional herbal remedies with modern medical research.

Beneficial role of kaempferol and its derivatives from different plant sources on respiratory diseases in experimental models

Respiratory illnesses impose a significant health burden and cause deaths worldwide. Despite many advanced strategies to improve patient outcomes, they are often less effective. There is still considerable room for improvement in the treatment of various respiratory diseases. In recent years, alternative medicinal agents derived from food plants have shown better beneficial effects against a wide variety of disease models, including cancer. In this regard, kaempferol (KMF) and its derivatives are the most commonly found dietary flavonols. They have been found to exhibit protective effects on multiple chronic diseases like diabetes, fibrosis, and so on. A few recent articles have reviewed the pharmacological actions of KMF in cancer, central nervous system diseases, and chronic inflammatory diseases. However, there is no comprehensive review that exists regarding the beneficial effects of KMF and its derivatives on both malignant- and non-malignant respiratory diseases. Many experimental studies reveal that KMF and its derivatives are helpful in managing a wide range of respiratory diseases, including acute lung injury, fibrosis, asthma, cancer, and chronic obstructive pulmonary disease, and their underlying molecular mechanisms. In addition, we also discussed the chemistry and sources, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties, methods to enhance bioavailability, as well as our perspective on future research with KMF and its derivatives.

Ethnopharmacology of Rubus idaeus Linnaeus: A critical review on ethnobotany, processing methods, phytochemicals, pharmacology and quality control

ETHNOPHARMACOLOGICAL RELEVANCE

Rubus idaeus Linnaeus (RI) is a Chinese herbal medicine that has been widely used in China for a long time to reinforce the kidney, nourish the liver, improve vision, and arrest polyuria.

AIM OF THE STUDY

This work aims to evaluate the recent progress of the chemical composition, pharmacological activity, pharmacokinetics, metabolism, and quality control and of Rubus idaeus, which focuses on the insufficiency of existing research and will shed light on future studies of Rubus idaeus.

METHODS

Literatures about "Rubus idaeus","Red raspberry" and "Fupenzi"are retrieved by browsing the database, such as Web of Science (http://www.webofknowledge.com/wos), Pubmed (https://pubmed.ncbi.nlm.nih.gov/), CNKI (http://www.cnki.net/), and Wanfang Data (http://www.wanfangdata.com.cn). In addition, related textbooks and digital documents are interrogated to provide a holistic and critical review of the topic. The period of the literature covered from 1981 to 2022.

RESULTS

Approximately 194 compounds have been isolated from Rubus idaeus, which is rich in phenols, terpenoids, alkaloids, steroids, and fatty acids. Numerous investigations have demonstrated that Rubus idaeus exhibits many pharmacological activities, including hypoglycemic and hypolipidemic, anti-Alzheimer effect, anti-osteoporosis, hepatoprotective, anti-cancer, neuroprotective, anti-bacteria and skin care, etc. However, it is worth noting that most of the research is not associated with the conventional effect, such as reducing urination and treating opacity of the cornea.

CONCLUSION

The effectiveness of Rubus idaeus has been proved by its long-term clinical application. The research on the pharmacological activity of Rubus idaeus has flourished. In many pharmacological experiments, only the high-dose group can achieve the corresponding efficacy, so the efficacy of Rubus idaeus needs to be further interrogated. Meanwhile, the relationship between pharmacological activity and specific compounds of Rubus idaeus has not been clarified yet. Last but not least, studies involving toxicology and pharmacokinetics are very limited. Knowledge of bioavailability and toxicological behavior of Rubus idaeus can help understand the herb's pharmacodynamic and safety profile.

Response surface statistical optimization of fermentation parameters for resveratrol production by the endophytic fungus Arcopilus aureus and its tyrosinase inhibitory activity

OBJECTIVE

The present investigation primarily focusses on enhancement of resveratrol production by endophytic production from the endophytic fungus, Arcopilus aureus via one variable at a time approach (OVAT) followed by statistical approach using response surface methodology (RSM). The paper also highlights the characterization of fungal resveratrol using spectroscopic techniques. Further the tyrosinase inhibitory property was also explored in this communication for its possible use as a cosmeceutical ingredient.

RESULTS

Optimization of physicochemical and nutritional parameters using OVAT approach exhibited 1.23-fold enhancement in production of resveratrol when compared to initial yield, 89.1 ± 0.08 µg/mL. Further RSM resulted in 1.49-fold enhancement in resveratrol production i.e. 133.53 µg/ml. Further, 25 mg of fungal resveratrol in pure form was obtained from the spent broth of Arcopilus aureus by column chromatography using a mobile phase comprising of MeOH: DCM in a ratio of 1.75:98.25. Further its purity on TLC was checked using 5% MeOH: DCM as mobile phase. Symmetrical peak with R_t of 3.36 min using a C18 reverse phase column confirmed the homogeneity of the purified fungal resveratrol with standard resveratrol and further corroborated by 1H-NMR, 13C-NMR and HR-MS analysis. Fungal resveratrol exhibited a good tyrosinase inhibition with an IC₅₀ of 2.654 ± 0.432 µg/mL as compared to Kojic acid (1.329 ± 0.333).

CONCLUSIONS

The present study has provided sufficient lead that process optimization techniques can complement each other for optimized production of bioactive compounds by microorganisms apart from strain improvement techniques which are generally adopted in the industry. The enhancement of resveratrol production by Arcopilus aureus by process optimization further opens up avenues for strain improvement for commercial resveratrol production through fermentation for nutraceutical and cosmeceutical applications.

Kaempferol and Its Glycoside, Kaempferol 7-O-Rhamnoside, Inhibit PD-1/PD-L1 Interaction In Vitro

Kaempferol (KO) and kaempferol 7-O-rhamnoside (KR) are natural products from various oriental herbs such as Geranii Herba. Previous studies have reported some biological activities of KO and KR; however, their effects on PD-1/PD-L1 interaction have not been reported yet. To elucidate their inhibitory activities on PD-1/PD-L1 protein–protein interaction (PPI), biochemical assays including competitive ELISA and biolayer interferometry (BLI) systems were performed. Cellular PD-1/PD-L1 blocking activity was measured in a co-culture system with PD-1 Jurkat and PD-L1/aAPC CHO-K1 cells by T-cell receptor (TCR) activation-induced nuclear factor of activated T cells (NFAT)-luciferase reporter assay. The detailed binding mode of action was simulated by an in silico docking study and pharmacophore analysis. Competitive ELISA revealed that KO and its glycoside KR significantly inhibited PD-1/PD-L1 interaction. Cellular PD-1/PD-L1 blocking activity was monitored by KO and KR at non-cytotoxic concentration. Surface plasmon resonance (SPR) and biolayer interferometry (BLI) analysis suggested the binding affinity and direct inhibition of KR against PD-1/PD-L1. An in silico docking simulation determined the detailed mode of binding of KR to PD-1/PD-L1. Collectively, these results suggest that KR could be developed as a potent small molecule inhibitor for PD-1/PD-L1 blockade.

Pharmacokinetics and Novel Metabolite Identification of Tartary Buckwheat Extracts in Beagle Dogs Following Co-Administration with Ethanol

Alcoholic liver disease (ALD) has become a critical global public health issue worldwide. Tartary buckwheat extracts exhibit potential therapeutic effects against ALD due to its antioxidant and anti-inflammatory activities. However, in vivo pharmacokinetics and metabolite identification of tartary buckwheat extracts have not been clearly elucidated. Accordingly, the current manuscript aimed to investigate pharmacokinetics and to identify novel metabolites in beagle dogs following oral co-administration of tartary buckwheat extracts and ethanol. To support pharmacokinetic study, a simple LC-MS/MS method was developed and validated for simultaneous determination of quercetin and kaempferol in beagle dog plasma. The conjugated forms of both analytes were hydrolyzed by β-glucuronidase and sulfatase followed by liquid-liquid extraction using methyl tert-butyl ether. In addition, another effective approach was established using advanced ultrafast liquid chromatography coupled with a Q-Exactive hybrid quadrupole orbitrap high resolution mass spectrometer to identify the metabolites in beagle dog biological samples including urine, feces, and plasma. The pharmacokinetic study demonstrated that the absolute oral bioavailability for quercetin and kaempferol was determined to be 4.6% and 1.6%, respectively. Oral bioavailability of quercetin and kaempferol was limited in dogs probably due to poor absorption, significant first pass effect, and biliary elimination, etc. Using high resolution mass spectrometric analysis, a total of nine novel metabolites were identified for the first time and metabolic pathways included methylation, glucuronidation, and sulfation. In vivo pharmacokinetics and metabolite identification results provided preclinical support of co-administration of tartary buckwheat extracts and ethanol in humans.

Phenolic compounds apigenin, hesperidin and kaempferol reduce in vitro lipid accumulation in human adipocytes

BACKGROUND

Adipocytes derived from human mesenchymal stem cells (MSCs) are widely used to investigate adipogenesis. Taking into account both the novelty of these MSCs and the scarcity of studies focused on the effects of phenolic compounds, the aim of the present study was to analyze the effect of apigenin, hesperidin and kaempferol on pre-adipocyte and mature adipocytes derived from this type of cells. In addition, the expression of genes involved in TG accumulation was also measured.

METHODS

Pre-adipocytes were cultured from day 0 to day 8 and mature adipocytes for 48 h with the polyphenols at doses of 1, 10 and 25 µM.

RESULTS

Apigenin did not show an anti-adipogenic action. Pre-adipocytes treated with hesperidin and kaempferol showed reduced TG content at the three experimental doses. Apigenin did not modify the expression of the main adipogenic genes (c/ebpβ, c/ebpα, pparγ and srebp1c), hesperidin inhibited genes involved in the three phases of adipogenesis (c/ebpβ, srebp1c and perilipin) and kaempferol reduced c/ebpβ. In mature adipocytes, the three polyphenols reduced TG accumulation at the dose of 25 µM, but not at lower doses. All compounds increased mRNA levels of atgl. Apigenin and hesperidin decreased fasn expression. The present study shows the anti-adipogenic effect and delipidating effects of apigenin, hesperidin and kaempferol in human adipocytes derived from hMSCs. While hesperidin blocks all the stages of adipogenesis, kaempferol only inhibits the early stage. Regarding mature adipocytes, the three compounds reduce TG accumulation by activating, at least in part, lipolysis, and in the case of hesperidin and apigenin, also by reducing lipogenesis.

CONCLUSIONS

The present study shows for the first time the anti-adipogenic effect and delipidating effect of apigenin, hesperidin and kaempferol in human adipocytes derived from MSCs for the first time.