Apoptosis inhibition effect of Dihydromyricetin against UVA-exposed human keratinocyte cell line

Effects of Nanoparticle-Mediated Dihydromyricetin to Diabetic Wounds: An In Vivo Study

Diabetic wound is one of the serious complications of diabetes, and the wound is persistent and easily recurring, which seriously endangers the health and life of patients. How to effectively promote the healing of diabetic wounds has been a hot spot and difficult area of clinical research. Some previous studies have shown that dihydromyricetin has the effects of regulating blood glucose, controlling the severity, and inhibiting scarring. In the present study, we used polylactic-co-glycolic acid nanoparticles as a carrier to load dihydromyricetin to make drug-loaded nanoparticles and applied them dropwise (200 µL) to diabetic mice wounds by topical application to observe the healing and scar formation of diabetic wounds. We found that the healing rate of the diabetic mice was faster and the scar formation was less obvious. In addition, the elevated blood glucose level and weight loss of the mice in the treatment group were also reduced. Therefore, nanoparticle-mediated dihydromyricetin may be an effective treatment for diabetic wounds.

Preparation, Isolation and Antioxidant Function of Peptides from a New Resource of Rumexpatientia L. ×Rumextianshanicus A. Los

Rumexpatientia L. ×Rumextianshanicus A. Los (RRL), known as "protein grass" in China, was recognized as a new food ingredient in 2021. However, the cultivation and product development of RRL are still at an early stage, and no peptide research has been reported. In this study, two novel antioxidant peptides, LKPPF and LPFRP, were purified and identified from RRL and applied to H2O2-induced HepG2 cells to investigate their antioxidant properties. It was shown that 121 peptides were identified by ultrafiltration, gel filtration chromatography, and LC-MS/MS, while computer simulation and molecular docking indicated that LKPPF and LPFRP may have strong antioxidant properties. Both peptides were not cytotoxic to HepG2 cells at low concentrations and promoted cell growth, which effectively reduced the production of intracellular ROS and MDA, and increased cell viability and the enzymatic activities of SOD, GSH-Px, and CAT. Therefore, LKPPF and LPFRP, two peptides, possess strong antioxidant activity, which provides a theoretical basis for their potential as food additives or functional food supplements, but still need to be further investigated through animal models as well as cellular pathways.

A dihydromyricetin-loaded phellinus igniarius polysaccharide/l-arginine modified chitosan-based hydrogel for promoting wound recovery in diabetic mice via JNK and TGF-β/Smad signaling pathway

The wound of diabetes has long-term excessive inflammation leading to wound fibrosis and scar formation. In the process of diabetic wound healing, good wound dressing is required for intervention. In this study, we designed a dihydromyricetin-loaded hydrogel (PCD) based on phellinus igniarius polysaccharide and l-arginine modified chitosan as an alternative material to promote diabetes wound healing. PCD had a uniform porous structure, good thermal stability, excellent mechanical properties, high water absorption, excellent antioxidant and anti-inflammatory activities and good biocompatibility and biodegradability. In addition, in the full-thickness skin trauma model of diabetes, PCD significantly inhibited the JNK signaling pathway to reduce inflammatory response, and significantly down-regulated the expression of TGF-β1, Smad2, Smad3 and Smad4 to directly inhibit the TGF-β/Smad signaling pathway to accelerate wound healing and slow down scar formation in diabetes mice. Therefore, PCD has a broad application prospect in promoting diabetes wound healing.

The role of exosomes and exosomal microRNA in diabetic cardiomyopathy

Diabetic cardiomyopathy, a formidable cardiovascular complication linked to diabetes, is witnessing a relentless surge in its incidence. Despite extensive research efforts, the primary pathogenic mechanisms underlying this condition remain elusive. Consequently, a critical research imperative lies in identifying a sensitive and dependable marker for early diagnosis and treatment, thereby mitigating the onset and progression of diabetic cardiomyopathy (DCM). Exosomes (EXOs), minute vesicles enclosed within bilayer lipid membranes, have emerged as a fascinating frontier in this quest, capable of transporting a diverse cargo that mirrors the physiological and pathological states of their parent cells. These exosomes play an active role in the intercellular communication network of the cardiovascular system. Within the realm of exosomes, MicroRNA (miRNA) stands as a pivotal molecular player, revealing its profound influence on the progression of DCM. This comprehensive review aims to offer an introductory exploration of exosome structure and function, followed by a detailed examination of the intricate role played by exosome-associated miRNA in diabetic cardiomyopathy. Our ultimate objective is to bolster our comprehension of DCM diagnosis and treatment strategies, thereby facilitating timely intervention and improved outcomes.

A comprehensive review of vine tea: Origin, research on Materia Medica, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Vine tea is a popular folk tea that has been consumed in China for more than 1200 years. It is often used in ethnic medicine by ethnic groups in southwest China with at least 35 aliases in 10 provinces. In coastal areas, vine tea is mostly used to treat heatstroke, aphtha, aphonia, toothache, etc. In contrast, in the southwest inland regions, vine tea is mostly used to clear away heat and toxic materials, antiphlogosis and relieving sore-throat, lowering blood pressure and lipid levels, and alleviating fatigue. Three main species have been used as the source of vine tea, Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla. Among them, the leaves of Nekemias grossedentata were considered as new food resource in complicance with regulations, according to the Food Safety Standards published by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China.

AIM OF THE STUDY

At present, the comprehensively summary of Materia Medica on the history and source of vine tea is currently unavailable. The current article summed up the Materia Medica, species origin and pharmacological effects of all 3 major species used in vine tea to fill the knowledge gaps. We also aim to provide a reference for future research on historical textual, resource development and medicinal utilization of vine tea.

MATERIALS AND METHODS

Adhering to the literature screening methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this review encompasses 148 scholarly research papers from three database, paper ancient books, local chronicles and folklore through field investigations. We then comprehensively summarized and discussed research progresses in scientific and application studies of vine tea.

RESULTS

The historical records indicated that vine tea could have been used as early as Southern and Northern Dynasties (AC 420-589). Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla, were used to considered as vine tea in the ethnic medicine. The main phytochemicals found in three plants are flavonoids, polyphenols and terpenoids, among which dihydromyricetin (DHM) is the most important and most studied active substance. The key words "Ampelopsis grossedentata" (Synonym of Nekemias grossedentata) and "dihydromyricetin/DHM" showed the highest frequency over the last 27 year based on the research trend analysis. And the ethnopharmacology studies drawn the main activities of vine tea are antioxidant, antibacterial, hepatoprotective, neuroprotective and anti-atherosclerosis activities.

CONCLUSIONS

This review systematically summarized and discussed vine tea from the following five aspects, history, genetic relationship, phytochemistry, research trend and ethnopharmacology. Vine tea has a long historical usage in Chinese ethnic medicine. Its outstanding therapeutic efficacies have attracted extensive attention in other places in the world at present. Nekemias cantonensis and Nekemias megalophylla are quite similar to Nekemias grossedentata in terms of many aspects. However, the current research has a narrow focus on mainly Nekemias grossedentata and DHM. We propose that future studies could be carried out to determine the synergistic effect of multi-components and multi-targets of vine tea including all 3 species to provide valuable knowledge.

Protective effect of dihydromyricetin on vascular smooth muscle cell apoptosis induced by hydrogen peroxide in rats

OBJECTIVE

Dihydromyricetin (DMY), also called Ampelopsin, which was extracted from Ampelopsis grossedentata, has been demonstrated to have a protective effect against cell oxidative injury and cell apoptosis in vitro. In the present study, we tried to study the role of DMY on apoptosis of vascular smooth muscle cells (VSMCs) induced by hydrogen peroxide (H₂O₂) and explore the underlying mechanisms.

METHODS

Apoptotic cells were detected by Hematoxylin and Eosin (H.E.) staining, Hoechst 33342 staining, and Annexin V-fluorescein isothiocyanate binding assay. The intracellular reactive oxygen species (ROS) level was estimated through fluorescence assay. The mRNA and protein expression of Caspase-3, Caspase-9, Bcl-2, and Bax were determined by reverse transcription-polymerase chain reaction (RT-PCR) and western blot.

RESULTS

The results showed that the pretreatment of VSMCs with DMY not only significantly increased cell viability, reduced intracellular ROS release, alleviated the morphological changes of apoptosis, and decreased the apoptosis rate, but also upregulated Bcl-2 expression and downregulated Caspase-3, Caspase-9, Bax expression, and ultimately attenuated the H₂O₂-stimulated apoptosis.

CONCLUSION

The inhibition of DMY on VSMC apoptosis may be mediated by ROS scavenging and the activation of the mitochondrial apoptotic signaling pathway.

Cytotoxicity and Biomineralization Potential of Flavonoids Incorporated into PNVCL Hydrogels

This study aimed to evaluate the effects of flavonoids incorporated into poly(N-vinylcaprolactam) (PNVCL) hydrogel on cell viability and mineralization markers of odontoblast-like cells. MDPC-23 cells were exposed to ampelopsin (AMP), isoquercitrin (ISO), rutin (RUT) and control calcium hydroxide (CH) for evaluation of cell viability, total protein (TP) production, alkaline phosphatase (ALP) activity and mineralized nodule deposition by colorimetric assays. Based on an initial screening, AMP and CH were loaded into PNVCL hydrogels and had their cytotoxicity and effect on mineralization markers determined. Cell viability was above 70% when MDPC-23 cells were treated with AMP, ISO and RUT. AMP showed the highest ALP activity and mineralized nodule deposition. Extracts of PNVCL+AMP and PNVCL+CH in culture medium (at the dilutions of 1/16 and 1/32) did not affect cell viability and stimulated ALP activity and mineralized nodules’ deposition, which were statistically higher than the control in osteogenic medium. In conclusion, AMP and AMP-loaded PNVCL hydrogels were cytocompatible and able to induce bio-mineralization markers in odontoblast-cells.

Hemin protects UVB-induced skin damage through inhibiting keratinocytes apoptosis and reducing neutrophil infiltration

Ultraviolet-B (UVB) exposure on the skin triggers apoptosis, oxidative stress and acute inflammatory responses, which eventually increases the risk of various skin disorders. Hemin, an iron-binding porphyrin, has been clinically used for porphyria treatment. However, whether hemin contributes to the skin protection against UVB injury remains to be elucidated. Here, we found that hemin treatment (10 and 20 mg/kg) by intraperitoneal administration could dramatically relieve UVB irradiation-induced skin damage featured by erythema, edema, epidermal hyperplasia and collagen loss in C57BL/6 J mice. Importantly, hemin treatment attenuated UVB irradiation-triggered cell apoptosis in skin epidermis. Consistently, hemin (10, 20 μM) treatment decreased Caspase-3 activation and protected against UVB-induced apoptosis in HaCaT cells. Besides, hemin treatment reduced the infiltration of neutrophils in skin under UVB irradiation, thus restrained neutrophil extracellular traps (NET) formation and myeloperoxidase (MPO) release. We further revealed that hemin inhibited the expression of inflammation associated cytokines and chemokines in UVB-induced HaCaT cells and blocked the chemotaxis of dHL-60 cells to preconditioned media from HaCaT culture upon UVB irradiation. Furthermore, hemin inhibited the excessive maturation and mobilization of bone marrow neutrophils and rectified the proportion of abnormally elevated neutrophils in the blood under UVB irradiation. In conclusion, our study showed that hemin treatment protects against UVB-induced skin damage through inhibiting keratinocytes apoptosis, and suppressing neutrophils infiltration in the skin via externally restraining the keratinocyte attraction and internally regulating bone marrow neutrophil maturation and mobilization, suggesting that hemin is an effective drug candidate for the therapy of UVB damage.

A poloxamer/hyaluronic acid/chitosan-based thermosensitive hydrogel that releases dihydromyricetin to promote wound healing

Wounds caused by accidents and surgery are inevitable, and inflammation and microbial infection during the healing process are serious clinical challenges, resulting in slow wound healing. In this study, we created a 37 °C-sensitive hydrogel using poloxamer, chitosan and hyaluronic acid, loaded with the active substance dihydromyricetin, and further evaluated its potential for wound healing. The hydrogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis for their micromorphological structure, characteristic functional groups, crystal structure and thermal stability, and in vitro drug release assays showed that the hydrogel could slowly release dihydromyricetin. In addition, the hydrogels were found to exhibit good biocompatibility and significant in vitro antioxidant and anti-inflammatory activity according to hemolysis, in vitro antioxidant and anti-inflammatory tests. Methyl thiazolyl tetrazole cytotoxicity tests verified that the film was non-toxic to human keratinocyte (HaCaT) cells, while in vivo experiments showed that this hydrogel could promote skin repair by promoting skin-associated growth factor expression and inhibiting nuclear factor kappa B-mediated cellular inflammatory factors. These results demonstrated that the temperature-sensitive hydrogels loaded with dihydromyricetin could serve as potential candidates for guided skin repair.

Role of mitochondria on UV-induced skin damage and molecular mechanisms of active chemical compounds targeting mitochondria

Mitochondria are the principal place of energy metabolism and ROS production, leading to mtDNA being especially sensitive to the impacts of oxidative stress. Our review aims to elucidate and update the mechanisms of mitochondria in UV-induced skin damage. The mitochondrial deteriorative response to UV manifests morphological and functional alterations, including mitochondrial fusion and fission, mitochondrial biogenesis, mitochondrial energy metabolism and mitophagy. Additionally, we conclude the effect and molecular mechanisms of active chemical components to protect skin from UV-induced damage via mitochondrial protection which have been described in the last five years, showing prospective prospects in cosmetics as new therapeutic targets.

UVB photoprotective capacity of hydrogels containing dihydromyricetin nanocapsules to UV-induced DNA damage

We evaluate the effect of cationic nanocapsules containing dihydromyricetin (DMY) flavonoid for safe topical use in photoprotection against UV-induced DNA damage. The stability was investigated for feasibility to produce hydrogels containing cationic nanocapsules of the flavonoid DMY (NC-DMY) for 90 days under three different storage conditions (4 ± 2 °C, 25 ± 2 °C, and 40 ± 2 °C), as well as evaluation of skin permeation and its cytotoxicity in skin cell lines. The physicochemical and rheological characteristics were maintained during the analysis period under the different aforementioned conditions. However, at 25 °C and 40 °C, the formulations indicated yellowish coloration and DMY content reduction. Therefore, the ideal storage condition of 4 °C was adopted. DMY remained in the stratum corneum and the uppermost layers of the skin. Regarding safety, all formulations demonstrated to be safe for topical application. NC-DMY exhibited a 50% Solar Protection Factor (SPF-DNA) against DNA damage caused by UVB radiation and demonstrated 99.9% protection against DNA lesion induction. These findings establish a promising formulation containing nanoencapsulated DMY flavonoids with a photoprotective and antioxidant potential of eliminating reactive oxygen species formed by solar radiation.

Ultraviolet A protective potential of plant extracts and phytochemicals

Chronic exposure to solar radiation is related to an increased incidence of various skin disorders, including premature skin aging and melanoma and non-melanoma skin cancers. Ultraviolet (UV) photons in particular are responsible for skin damage. Solar UV photons mainly belong to UVA wavebands, however UVA radiation has been mostly ignored for a long time. At the cellular level, UVA photons mainly provoke indirect oxidative damage to biomolecules via the massive generation of unstable and highly reactive compounds. Human skin has several effective mechanisms that forestall, repair and eliminate damage caused by solar radiation. Regardless, some damage persists and can accumulate with chronic exposure. Therefore, conscious protection against solar radiation (UVB+UVA) is necessary. Besides traditional types of photoprotection such as sunscreen use, new strategies are being searched for and developed. One very popular protective strategy is the application of phytochemicals as active ingredients of photoprotection preparations instead of synthetic chemicals. Phytochemicals usually possess additional biological activities besides absorbing the energy of photons, and those properties (e.g. antioxidant, anti-inflammatory) magnify the protective potential of phytochemicals and extracts. Therefore, compounds of natural origin are in the interest of researchers as well as developers. In this review, only studies on UVA protection with well-documented experimental conditions are summarized. This article includes 17 well standardized plant extracts (Camellia sinensis (L.) Kuntze, Silybum marianum L. Gaertn., Punica granatum L., Polypodium aureum L., Vaccinium myrtillus L., Lonicera caerulea L., Thymus vulgaris L., Opuntia ficus-indica (L.) Mill., Morinda citrifolia L., Aloe vera (L.) Burm.f., Oenothera paradoxa Hudziok, Galinsoga parviflora Cav., Galinsoga quadriradiata Ruiz et Pavón, Hippophae rhamnoides L., Cola acuminata Schott & Endl., Theobroma cacao L. and Amaranthus cruentus L.) and 26 phytochemicals.

Dihydromyricetin attenuates hypertrophic scar formation by targeting activin receptor-like kinase 5

Hypertrophic scar (HPS) is a manifestation of abnormal tissue repair, representing excessive extracellular matrix production and abnormal function of fibroblasts, for which no satisfactory treatment is available at present. Here we identified a natural product of flavonoid, dihydromyricetin, could effectively attenuate HPS formation. We showed that local intradermal injection of dihydromyricetin (50 μM) reduced the gross scar area, cross-sectional size of the scar and the scar elevation index in a mechanical load-induced mouse model. In addition, dihydromyricetin treatment also markedly decreased collagen density of the scar tissue. Furthermore, both in vitro and in vivo study both demonstrated that dihydromyricetin inhibited the proliferation, activation, contractile and migration abilities of hypertrophic scar-derived fibroblasts (HSFs) but did not affect HSFs apoptosis. Western blot analysis revealed that dihydromyricetin could down-regulate the phosphorylation of Smad2 and Smad3 of TGF-β signaling. Such bioactivity of dihydromyricetin may result from its selective binding to the catalytic region of activin receptor-like kinase 5 (ALK5), as suggested by the molecular docking study and kinase binding assay (12.26 μM). Above all, dihydromyricetin may prove to be a promising agent for the treatment of HPS and other fibroproliferative disorders.

Recent Update on the Pharmacological Effects and Mechanisms of Dihydromyricetin

As the most abundant natural flavonoid in rattan tea, dihydromyricetin (DMY) has shown a wide range of pharmacological effects. In addition to the general characteristics of flavonoids, DMY has the effects of cardioprotection, anti-diabetes, hepatoprotection, neuroprotection, anti-tumor, and dermatoprotection. DMY was also applied for the treatment of bacterial infection, osteoporosis, asthma, kidney injury, nephrotoxicity and so on. These effects to some extent enrich the understanding about the role of DMY in disease prevention and therapy. However, to date, we still have no outlined knowledge about the detailed mechanism of DMY, which might be related to anti-oxidation and anti-inflammation. And the detailed mechanisms may be associated with several different molecules involved in cellular apoptosis, oxidative stress, and inflammation, such as AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), protein kinase B (Akt), nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), ATP-binding cassette transporter A1 (ABCA1), peroxisome proliferator-activated receptor-γ (PPARγ) and so on. Here, we summarized the current pharmacological developments of DMY as well as possible mechanisms, aiming to push the understanding about the protective role of DMY as well as its preclinical assessment of novel application.

Protective effect of dihydromyricetin on LPS-induced acute lung injury

Dihydromyricetin (DHM), a bioactive flavonoid component isolated from Ampelopsis grossedentata, is known to have anti-inflammatory effect, but the effect of DHM on acute lung injury (ALI) is largely unknown. Here, we investigated the effect of DHM on ALI and the underlying mechanism by bioinformatic analyses and animal experiments. We found that pretreatment with DHM ameliorated lung pathological changes and suppressed the inflammation response in lung tissues after LPS challenge. The potential targets of DHM were predicted by DDI-CPI and DRAR-CPI tools and analyzed using the STRING server to predict the functionally related signaling pathways, such as MAPK signaling. Molecular docking calculations indicated that DHM could be embedded tightly into the binding pocket of ERK, JNK, and p38. Furthermore, the activation of MAPK signaling induced by LPS was inhibited by DHM. In conclusion, these findings suggest that DHM may exert its protective effect on ALI by inhibiting MAPK signaling. The present study supports a potential clinical application for DHM in treating ALI and provides a novel design that combines in silico methods with in vivo experiments for drug research.

Consumption of ellagic acid and dihydromyricetin synergistically protects against UV-B induced photoaging, possibly by activating both TGF-β1 and wnt signaling pathways

Ellagic acid (EGA) and dihydromyricetin (DHM) are both found in fruits and vegetables are used for anti-aging treatment for the skin. The anti-photoaging efficacy of EGA and DHM was investigated in UV-B irradiated skin in vivo and the involvement of transforming growth factor (TGF)-β1 and wnt signaling pathways were examined in vitro. HaCaT cells were treated with either 50μM EGA, 50μM DHM or 25μM EGA+25μM DHM before 100mJ/cm² UV-B exposure, and then oxidative stress and inflammation was measured. The involvement of TGF-β1 and wnt signaling was measured using their inhibitors, respectively, in HaCaT cells. Mice were fed a high fat diet with either 0.7% cellulose, 0.7% EGA, 0.7% DHM or 0.35% EGA+0.35% DHM for 3weeks and the dorsal skin of the mice had UV-B irradiation. 3% cellulose, 3% EGA, 3% DHM or 1.5% EGA+1.5% DHM in 1,3-buthylene glycol was applied onto the dorsal skin at 30min before 1 MED UV-B exposure. In 100mJ/cm² UVB irradiation, EGA and DHM mainly decreased oxidative stress and inflammation, respectively in HaCaT cells. Their activities were blocked by the TGF-β1 inhibitor, indicating their actions were mediated by TGF-β1 signaling (TGF-β1➔pSmad3➔Smad7). DHM enhanced wnt signaling by increasing β-catenin and decreasing Dickkopf-related protein-1. In mice, 1 MED UV-B exposure induced sunburn, redness, and blistering. EGA, DHM and especially EGA+DHM lessened their severity. UV-B increased epidermal thickness and damaged epidermal nucleus and cell structures. DHM and especially EGA+DHM prevented damage to the nucleus and cell structures. Expressions of circulating and dorsal skin IL-1β and TNF-α mRNA were lower in descending order of: control, EGA, DHM, EGA+DHM and normal-control. In conclusion, the consumption of EGA+DHM had a synergistically protective action against UV-B damage in the skin tissues of mice and HaCaT cells, and it may be associated with activating of both TGF-β1 and wnt signaling.