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The effects of pH, surfactant, ion concentration, coformer, and molecular arrangement on the solubility behavior of myricetin cocrystals

Shuzhen Ren,Mingyu Liu,Chao Hong,Guowen Li,Jiabin Sun,Jianying Wang,Lei Zhang,Yan Xie

Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin (MYR) cocrystals, including their kinetic solubility, thermodynamic solubility, and intrinsic dissolution rate (IDR). The effects of pH, surfactant, ion concentration, and coformers on the cocrystal solubility were evaluated. Furthermore, single crystal structures of MYR, myricetin–isonicotinamide (MYR–INM) and myricetin–caffeine (MYR–CAF) cocrystals were analyzed to discuss the possible reasons for the enhancement of cocrystal solubility from the perspective of the spatial structure. The results indicated that the kinetic solubility of MYR cocrystals was modulated by pH and cocrystal coformer (CCF) ionization in buffer solution, while it primarily depended on the CCF solubility in pure water. In addition, the solubility of MYR cocrystals was increased in a concentration dependent fashion by the surfactant or ion concentration. The thermodynamic solubility of MYR–INM (1:3) cocrystals decreased with the increases of the pH value of the dissolution media. The IDR of MYR cocrystals was faster than that of MYR in the same medium and extremely fast in pH 4.5 buffer. The improved solubility of MYR cocrystals was probably related to the alternate arrangements of MYR and INM/CAF molecules and increased intermolecular distance. The present study provides some references to investigate the solubility behavior of pharmaceutical cocrystals.

Nitrite Scavenging and Inhibition of N-Nitrosamines Formation by Phenolic Extracts From Diospyros lotus L. Leaves and Active Ingredients

YanHua Tian,HuiZhi Du,Li Wang,ShiFei Li,Lu Zhang,LiWei Zhang

Diospyros lotus L. leaves are used as a functional tea and folk medicine in several Asian countries. This study aimed to evaluate the effects of phenolic extracts of the leaves on scavenging nitrite and inhibiting N-nitrosamines (NAs) formation and to determine the active ingredients responsible for these effects. Of the 7 fractions (Fr1-Fr7) prepared from the extract of D. lotus leaves, Fr5 contained the highest phenolic content and exhibited the strongest activity. Five active ingredients of Fr5 were discovered, and 4 of them were identified as myricitrin (Mytr), myricetin (Myt), myricetin-3-O-β-d-glucoside (Myt-Glc), and myricetin-3-O-β-d-galactoside (Myt-Gal). The content of Mytr was much higher than those of the other 3 ingredients, both in Fr5 and extracts of D. lotus leaves. Finally, Mytr and Myt were proved to have stronger activities by the 1,1-diphenyl-2-trinitrophenyl hydrazine scavenging, nitrite scavenging, and inhibition of NAs formation assays. These results indicated that Mytr was the main active ingredient of D. lotus leaves. Myt, Mytr, and Fr5 from the leaves could be used as natural agents for antioxidant, nitrite scavenging, and inhibition of NAs formation in food and the human body.

Method for enhancing bioavailability of myricetin based on self-assembly of casein–myricetin nanomicelles

Hui Guo,Yun Fei Chen,Yi Tang,Jun Qing Qian

In order to expand the application in the medical field and enhance pharmacological effects, casein–myricetin nanomicelles were prepared by the self-assembly method and characterised by ultraviolet–visible spectroscopy and Fourier transform infrared spectroscopy. The parameters in self-assembly were optimised according to the factors of particle size, encapsulation yield, and drug loading. The result showed a pH of 5.5, a casein concentration of 2 mg/ml, a mass ratio of casein to myricetin of 8:1, ultrasonic power of 300 W, ultrasonic time of 5 min and ethanol volume of 7 ml were the optimal conditions. The situ cycle intestinal perfusion methods indicated that casein–myricetin nanomicelles can be more easily absorbed by small intestine than myricetin standard sample. Therefore, casein micelles are effective for improving the water solubility of myricetin.

Comparative Analysis of Radical Adduct Formation (RAF) Products and Antioxidant Pathways between Myricetin-3-O-Galactoside and Myricetin Aglycone

Xican Li,Xiaojian Ouyang,Minshi Liang,Dongfeng Chen

The biological process, 3-O-galactosylation, is important in plant cells. To understand the mechanism of the reduction of flavonol antioxidative activity by 3-O-galactosylation, myricetin-3-O-galactoside (M3OGa) and myricetin aglycone were each incubated with 2 mol α,α-diphenyl-β-picrylhydrazyl radical (DPPH•) and subsequently comparatively analyzed for radical adduct formation (RAF) products using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS) technology. The analyses revealed that M3OGa afforded an M3OGa–DPPH adduct (m/z873.1573) and an M3OGa–M3OGa dimer (m/z958.1620). Similarly, myricetin yielded a myricetin–DPPH adduct (m/z711.1039) and a myricetin–myricetin dimer (m/z634.0544). Subsequently, M3OGa and myricetin were compared using three redox-dependent antioxidant analyses, including DPPH•-trapping analysis, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-trapping analysis, and•O2inhibition analysis. In the three analyses, M3OGa always possessed higher IC50values than those of myricetin. Conclusively, M3OGa and its myricetin aglycone could trap the free radical via a chain reaction comprising of a propagation step and a termination step. At the propagation step, both M3OGa and myricetin could trap radicals through redox-dependent antioxidant pathways. The 3-O-galactosylation process, however, could limit these pathways; thus, M3OGa is an inferior antioxidant compared to its myricetin aglycone. Nevertheless, 3-O-galactosylation has a negligible effect on the termination step. This 3-O-galactosylation effect has provided novel evidence that the difference in the antioxidative activities of phytophenols exists at the propagation step rather than the termination step.

Thermal degradation mechanism of myricetin in palmitic acid

Shengxiong Chen,Fan Zhang,Randolph R.J. Arroo,Jesus Simal-Gandara,Hui Cao,Jianbo Xiao

Lipid oxidation governs myricetin degradation in heated palmitic acid. • o-Quinone formation triggers B-ring cleavage and oxidative dimerization. • Carbonyl addition and lipid-derived ester conjugates were detected. • Vitamin C suppresses radical-driven pathways and improves myricetin retention. Dietary polyphenols are susceptible to degradation during high-temperature cooking, yet their transformation behavior in lipid-rich frying systems remains poorly understood. The thermal stability and degradation of myricetin in a simplified palmitic acid model under frying-relevant conditions was investigated. Myricetin degraded rapidly at 180 °C but remained relatively stable at 120 °C. UPLC–QTOF–MS/MS, supported by density functional theory calculations, suggested that myricetin transformation is temperature-dependent but primarily governed by lipid oxidation–derived radical and carbonyl chemistry. Vitamin C markedly delayed myricetin degradation by suppressing radical initiation and limiting o -quinone–centered downstream reactions. These findings highlight lipid oxidation as a key determinant of polyphenol stability during frying and clarify the protective role of antioxidants in lipid-rich thermal processing systems. Download: Download high-res image (202KB) Download: Download full-size image

Mechanistic studies of inhibition on acrolein by myricetin

Dingmin Zhang,Xiaoyun Jiang,Liubang Xiao,Yongling Lu,Shengmin Sang,Lishuang Lv,Wenjiang Dong

Acrolein (ACR) is an unsaturated aldehyde with high activity and toxicity and is produced in vivo and in food. This study investigated the impact of B-ring structure on the trapping of ACR by flavonols and the trapping mechanism and efficacy of ACR by myricetin. Galangin, kaempferol, quercetin, and myricetin, which possess the same A- and C-ring but different numbers of –OH groups on the B-ring, were selected for this study. Our results suggested that increasing the number of –OH groups on the B-ring can enhance the ACR trapping efficacy of flavonol and myrectin was identified as the most active flavonol. The adducts of myricetin with ACR under different ratios and incubation times were analyzed using LC-MS/MS. We also purified and identified the major mono- and di-ACR-myricetin adducts. Furthermore, myricetin could dose-dependently inhibit the formation of ACR in cookies through the formation of mono- and di-ACR adducts.

Deep eutectic solvent extraction of myricetin and antioxidant properties

Junhai Liu,Xiaosha Guo,Qiaowei Miao,Xiaohui Ji,Yinku Liang,Tianjiao Tong

In this study, a response surface method (RSM) was used to optimise the ultrasonic-assisted deep eutectic solvent (DES) extraction of myricetin from myricetin leaves. The results demonstrated that the DES-5 (choline chloride–oxalic acid) system exhibited better extraction results than the other seven DESs prepared. The optimum extraction conditions for myricetin were a DES-5 system with 19% water content of DES, a liquid-to-solid ratio of 37 : 1 mL g−1, an extraction time of 45 min, and an extraction temperature of 72 °C. Under these conditions, the extraction amount of myricetin was 22.47 mg g−1. To optimise the extraction process, the crude myricetin extract was purified, and the optimal conditions were as follows: an AB-8 macroporous adsorption resin was used with an anhydrous ethanol desorption agent. The adsorption rate was 1 BV per h (bed volume per hour), the desorption rate was 1 BV per h, and the desorption capacity was 2 BV (bed volume). The antioxidant properties of the myricetin were also investigated. The results demonstrated that, with an increase in concentration, the scavenging rates of DPPH and ˙OH free radicals increased. Compared to Vc, myricetin had a better scavenging ability for DPPH free radicals, whereas purified myricetin had a better antioxidant effect. At the same concentration, the radical-scavenging rate of the ˙OH radical was slightly higher in myricetin purified by the macroporous adsorption resin than in Vc, and that of the unpurified myricetin was the smallest. Myricetin was purified using a macroporous adsorption resin to improve its antioxidant properties.

HPLC Fingerprint Analysis with the Antioxidant Potential of Polygonatum sibiricum Combined with the Chemometric Calculations

Li-Wen Zhang,Jin Wang,Ye Ge,Zhe-Lin Kuang,Ying-Qing Zhang

Polygonatum sibiricum(P. sibiricum) is a significantly health-promoting plant unique in medicine and food. Currently, research on the bioactive components ofP. sibiricumprimarily focuses on polysaccharides. According to theChinese Pharmacopoeia, the polysaccharide content inP. sibiricummust be at least 7.0%, which is the only criterion used for determining its content. In contrast, this study aims to thoroughly investigate and clarify the various components that contribute to the therapeutic and functional properties ofP. sibiricum. We seek to broaden the focus beyond polysaccharides to identify other potentially significant bioactive substances. We established High-Performance Liquid Chromatograph (HPLC) fingerprints for wine-processedP. sibiricumfrom various regions and identified 17 common peaks. The antioxidant activities of these components were assessed using ABTS and DPPH methods. The spectrum–effect relationship was elucidated through partial least squares regression and grey relational analysis. The results revealed that the antioxidant active components in wine-processedP. sibiricuminclude 5-hydroxymethylfurfural,p-hydroxycinnamic acid, myricetin, caffeic acid, vanillic acid, and adenosine. This research not only clarifies the antioxidant material basis of wine-processedP. sibiricumbut also establishes a scientific foundation for enhanced quality control in future applications.

Myricetin ameliorates glucocorticoid-induced osteoporosis through the ERK signaling pathway

Shuli Fan,Xiang Gao,Peng Chen,Xu Li

Myricetin has been reported to promote osteogenic differentiation and inhibit osteoclastogenesis. The aim of this study was to investigate the potential effects of myricetin on glucocorticoid-induced osteoporosis (GIOP) both in vivo and in vitro . Male Sprague-Dawley (SD) rats were given dexamethasone (DEX, 0.1 mg/kg, s.c.) once daily and myricetin (1 mg/kg or 2.5 mg/kg, i.p.) once every other day for a total of five weeks. Body weight was recorded once a week. Bone mineral density (BMD), the activities or levels of bone turnover markers, and histological changes were assessed. MC3T3-E1 cells were incubated with DEX (1 μM) and myricetin (20 μM). Osteoblast proliferation, differentiation and mineralization were evaluated. U0126 was added to evaluate the involvement of the ERK signaling pathway. The results showed that myricetin increased body weight gain and inhibited DEX-induced reduction in BMD, enhanced alkaline phosphatase (ALP) activity, and upregulated osteocalcin (OCN), bone morphogenetic protein 2 (BMP2) and runt-related transcription factor 2 (Runx2) levels, whereas reduced tartrate-resistant acid phosphatase (TRAP) activity and C-terminal telopeptide of type I collagen (CTx) level. In addition, myricetin ameliorated histological changes in the femurs. In our in vitro studies, myricetin promoted osteoblast differentiation and mineralization in DEX-treated MC3T3-E1 cells, accompanied by increases in BMP2, Runx2, ALP, OCN, collagen type I alpha 1 (COL1A1) and osteopontin (OPN) levels. The promotion effects of myricetin on osteogenic differentiation and matrix mineralization were reversed by U0126. These results suggest that myricetin may alleviate DEX-induced osteoporosis by promoting osteogenic differentiation and matrix mineralization via the ERK signaling pathway.

Preparation, characterisation, and pharmacodynamic study of myricetin pH-sensitive liposomes

Chenlu Li,Mengzhe Du,Lingzhi Meng,Michael Adu-Frimpong,Caizhi Gong,Sile Zheng,Wentao Shi,Qilong Wang,Elmurat Toreniyazov,Hao Ji,Xia Cao,Jiangnan Yu,Ximing Xu

Aims Myricetin (MYR) was incorporated into pH-sensitive liposomes in order to improve its bioavailability and anti-hyperuricemic activity.Methods The MYR pH-sensitive liposomes (MYR liposomes) were prepared using thin film dispersion method, and assessed by particle size (PS), polydispersed index (PDI), zeta potential (ZP), encapsulation efficiency, drug loading, and in vitro release rate. Pharmacokinetics and anti-hyperuricemic activities were also evaluated.Results The PS, PDI, ZP, encapsulation efficiency, and drug loading of MYR liposomes were 184.34 ± 1.05 nm, 0.215 ± 0.005, −38.46 ± 0.30 mV, 83.42 ± 1.07%w/w, and 6.20 ± 0.31%w/w, respectively. The release rate of MYR liposomes was higher than free MYR, wherein the cumulative value responded to pH. Besides, the Cmax of MYR liposomes was 4.92 ± 0.20 μg/mL. The level of uric acid in the M-L-H group (200 mg/kg) was reduced by 54.74%w/v in comparison with the model group.Conclusion MYR liposomes exhibited pH sensitivity and could potentially enhance the oral bioavailability and anti-hyperuricemic efficacy of MYR.

Myricetin Inhibits Photodegradation of Profenofos in Water: Pathways and Mechanisms

Nan Zhang,Yawei Yang,Xin Wang,Taozhong Shi,Pei Lv,Qing X. Li,Rimao Hua

Profenofos is a detectable insecticide in the environment with strong toxicity to non-targeted organisms. Photodegradation is a main transformation of profenofos in the environment. Myricetin is a flavonoid that strongly scavenges free radicals. The effect of myricetin on the photodegradation of profenofos was studied. The half-lives (T1/2) of profenofos were 1.7–7.0 and 90 h under artificial light and sunlight. The photolysis rate of profenofos decreased by 1.87–4.72 and 7.62 times with the addition of 20 ratios of myricetin. Free radicals reacting with profenofos were •OH and1O2, and the key free radical was •OH. Myricetin strongly scavenged •OH and1O2which rapidly reacted with profenofos.O-(2-Chlorophenyl)-O-ethyl-S-propyl phosphorothioate (M3) andO-(2-chlorophenyl)-O-ethyl phosphorothioate (M4) were major and new photoproducts of profenofos. According to the Ecological Structure Activity Relationships, photodegradation of profenofos was a detoxification process, but myricetin inhibited the photodegradation of profenofos and its photoproducts. These results highlight the implication of myricetin on the fate and potential risk of profenofos in the environment.

Fast Detection of Myricetin With the Use of Dedicated Microdroplets

Zuoren Xiong,Hai Zhang,Yuelan Lu,Lingli Zhang,Weimin Sun,Yongjun Liu