Biomedical subjects

Zhinan Mei

Publications and source records attributed to Zhinan Mei.

5 recordsLinked to original sources

PubMed2026

Enzymatic innovations in Angelica pubescens reveal dual coumarin biosynthetic pathways driving metabolic diversification.

Coumarins are structurally diverse phenylpropanoid derivatives with ecological and pharmacological significance, yet the biosynthetic logic underlying their diversification remains incompletely understood in non-model medicinal plants. Angelica pubescens (Apiaceae), widely used in traditional Chinese medicine, accumulates a rich repertoire of furanocoumarins and dihydrofuranocoumarins, making it an ideal system to investigate this metabolic complexity. Here, we combined chromosome-level genome assembly, transcriptome and metabolite profiling, phylogenetics, and heterologous expression assays to dissect coumarin biosynthesis in A. pubescens. We identified two functionally specialized O-methyltransferases, ApOMT1 and ApOMT2, which catalyze regioselective methylation of xanthotoxol and bergaptol to yield the furanocoumarins xanthotoxin and bergapten. We also characterized ApCYP736A121, a cytochrome P450 enzyme that converts osthenol to the dihydrofuranocoumarin columbianetin via a previously unknown mechanism. Gene expression and metabolite accumulation patterns across tissues and developmental stages revealed functional partitioning among pathway branches. Phylogenetic and syntenic analyses indicated that ApOMT1 and ApOMT2 arose through subfunctionalization following gene duplication, whereas ApCYP736A121 evolved via neofunctionalization from a distantly related CYP736 ancestor. Together, our findings uncover dual biosynthetic routes to structurally distinct coumarins in A. pubescens and provide insights into the evolutionary mechanisms contributing to metabolic innovation in Apiaceae. This work lays a foundation for future efforts to engineer coumarin pathways and understand their ecological functions in medicinal plants.

Coumarins↗

PubMed2026

Exploring the substrate promiscuity and functional residues of UGT73 family enzymes in Entada phaseoloides.

Flavonoid glycosides and triterpenoid saponins are bioactive plant metabolites with broad applications in food, medicine, and agriculture. These compounds are typically synthesized through glycosylation catalyzed by uridine diphosphate-dependent glycosyltransferases (UGTs). In this study, phylogenetic analysis across multiple species revealed a lineage-specific expansion of the UGT73 family in legumes such as Entada phaseoloides and Glycine max. The genome of the medicinal legume E. phaseoloides was re-annotated using integrated Oxford Nanopore Technologies and Illumina transcriptomic data to identify target genes. Four expanded UGT73 family genes were selected and functionally characterized. UGT73AA6 specifically glycosylates flavonoids, while UGT73CG48 and UGT73CG49 catalyze glycosylation of both flavonoids and pentacyclic triterpenoids. UGT73CG49 exhibits higher catalytic activity for the glucosylation of flavonoids and pentacyclic triterpenes compared to its xylosylation activity. Structural modeling and molecular docking identified key active sites, and site-directed mutagenesis revealed Gly194 as a critical residue enhancing catalytic activity in UGT73CG49. This study provides new insights into the functional evolution and metabolic versatility of the UGT73 family in legumes. The identification and engineering of UGT73 genes from E. phaseoloides lay a foundation for future applications in biosynthetic pathway engineering and the industrial production of high-value glycosides.

Substrate Specificity↗

PubMed2005

The research on the anti-inflammatory activity and hepatotoxicity of triptolide-loaded solid lipid nanoparticle.

Triptolide (TP) has been shown to have anti-inflammatory, immunosuppressive, anti-fertility and anti-neoplastic activity. However, its clinical use was restricted to some extent due to its serious toxicity. The possible mechanism for triptolide-induced hepatotoxicity was related to reactive oxygen species (ROS) inducing lipid peroxidation and DNA damage. The development of controlled release delivery strategies could lead to significant advantages in the clinical use of these drugs to decreasing the toxicity. Thus, the present study was focused on the preparation and some characterization of triptolide-loaded solid lipid nanoparticle (SLN) and the measurements of anti-inflammatory activities and the hepatotoxicity of TP-SLN. The carrageenan-induced rat paw edema experiment indicated that the anti-inflammatory activities of TP-SLN were stronger than those of free triptolide. Orally administration of TP-SLN 0.2 or 0.4 mg/kg per day did not cause mortality within the period of observation. In contrast, free triptolide at different doses had caused partial death. The serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly elevated in the free triptolide-treated group whereas they did not significantly change in TP-SLN-treated mice. The free triptolide increased malondialdehyde (MDA) level and decreased activities of superoxide dismutase (SOD) and total glutathione peroxidase (GSH-Px) in the liver homogenates. However, these phenomena were not found in TP-SLN-treated mice. The results of histopathological evaluation revealed a protective effect of SLN on vacuolation, edema, inflammatory infiltration and necrosis caused by triptolide. Furthermore, TP-SLN did not change Bcl/Bax protein ratio or decrease FasL expression in liver cells. These results suggest that SLN delivery system can enhance the anti-inflammatory activity of triptolide meanwhile has a protective effect against triptolide-induced hepatotoxicity. The toxicity of TP-SLN to other tissues is under investigation.

Animals↗

PubMed2005

Triptolide loaded solid lipid nanoparticle hydrogel for topical application.

Triptolide (TP) has been shown to have anti-inflammatory, antifertility, antineoplastic, and immunosuppressive activity. However, its clinical usage is limited to some extent due to its poor water solubility and toxicity. In order to use innovative ways to administer TP and to overcome or alleviate its disadvantages, controlled-release delivery systems such as solid lipid nanoparticle(SLN(s)) have been developed. In the present paper we describe the preparation and some characterization of specialized delivery systems for TP. The transdermal delivery and anti-inflammatory activity were also evaluated. The results indicated that SLN could serve as an efficient promoter of TP penetrating into skin. Furthermore, different formulations were optimized in this study. The best formulation of SLN, consisted of tristearin glyceride, soybean lecithin, and PEG400MS, with a particle size of 123+/-0.9 nm, polydispersity index (PI) of 0.19, and zeta potential of -45 mV. When this SLN dispersion was incorporated into hydrogel, the nanoparticulate structure was maintained, and aggregation and gel phenomena of the particle could be avoided. The cumulative transdermal absorption rate in 12 h was 73.5%, whereas the conventional TP hydrogel was 45.3%. The anti-inflammatory effect is over two-fold higher than that of conventional TP hydrogel. Moreover, this SLN hydrogel consists of pharmaceutically acceptable ingredients, such as soybean lecithin and lipid, and the nanoparticle can improve safety and minimize the toxicity induced by TP.

Absorption↗

PubMed2003

Solid lipid nanoparticle and microemulsion for topical delivery of triptolide.

Triptolide (TP) has been shown to have anti-inflammatory, immunosuppressive, anti-fertility and anti-neoplastic activities. However, its clinical use is restricted to some content due to its poor water solubility and some toxic effects. In order to find innovative ways for administering TP and alleviating its disadvantages, the controlled release delivery systems such as solid lipid nanoparticle (SLN) and microemulsion have been developed. In the present paper we describe the preparation and some characterization of specialized delivery systems for TP. The transdermal delivery capacity and anti-inflammatory activity were also evaluated. The results indicated that these SLN dispersions and microemulsions could serve as efficient promoters for the TP penetrating into skin. Furthermore, different formulations were optimized in this study. The best formulation of SLN dispersion consisted of 5% tristearin glyceride, 1.20% soybean lecithin and 3.60% polyethylene glycol (400) monosterate, while the best formulation of microemulsion consisted of 40% isopropyl myristate, 50% Tween-80: 1,2-propylene glycol (5:1, v/v) and water. The steady-state flux (Js) and permeability coefficient (Kp) of triptolide for the SLN dispersion of the first 6 h were 3.1+/-0.4 microg/cm2 per h and 0.0124+/-0.001 cm/h or 6.4+/-0.7 microg/cm2 per h and 0.0256+/-0.002 cm/h for the microemulsion, which was 3.45 and 7.02 times higher than those of triptolide solution, respectively. The anti-inflammatory activity of SLN dispersion was stronger than that of microemulsion in carrageenan induced rat paw edema. However, the results were the reverse in complete Frenud's adjuvant induced paw edema. Further investigations should be carried out on the toxicity of different formulations of triptolide to tissues.

Administration, Topical↗