Hepatotoxicity and mechanism of Rhododendri Mollis Flos based on zebrafish model / 中国中药杂志

This study used the zebrafish model to explore the hepatotoxicity of Rhododendri Mollis Flos(RMF). The mortality was calculated according to the number of the survival of zebrafish larvae 4 days after fertilization under different concentration of RMF, and the dose-toxicity curve was fitted to preliminarily evaluate the toxicity of RMF. The liver phenotypes under the sublethal concentration of RMF in the treatment group and the blank control group were observed by hematoxylin-eosin(HE) staining and acridine orange(AO) staining. Meanwhile, the activities of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) were determined to confirm the hepatotoxicity of RMF. Real-time quantitative polymerase chain reaction(real-time PCR) and Western blot were used to determine the expressions of genes and proteins in zebrafish larvae. Gas chromatography time-of-flight mass spectrometry(GC-TOF-MS) was used to conduct untargeted metabolomics testing to explore the mechanism. The results showed that the toxicity of RMF to zebrafish larvae was dose-dependent, with 1 100 μg·mL~(-1) of the absolute lethal concentration and 448 μg·mL~(-1) of sublethal concentration. The hepatocyte apoptosis and degeneration appeared in the zebrafish larvae under the sublethal concentration of RMF. The content of ALT and AST in zebrafish larvae at the end of the experiment was significantly increased in a dose-dependent manner. Under the sublethal concentration, the expressions of genes and proteins related to apoptosis in zebrafish larvae were significantly increased as compared with the blank control group. The results of untargeted metabolomics showed that the important metabolites related to the he-patotoxicity of RMF were mainly enriched in alanine, aspartic acid, glutamic acid, and other pathways. In conclusion, it is inferred that RMF has certain hepatotoxicity to zebrafish larvae, and its mechanism may be related to apoptosis.

Toxicity mechanism of Rhododendri Mollis Flos: based on serum metabolomics and network toxicology / 中国中药杂志

This study aims to explore the toxicity mechanism of Rhododendri Mollis Flos(RMF) based on serum metabolomics and network toxicology. The toxic effect of RMF on normal rats was evaluated according to the symptoms, serum biochemical indexes, and histopathology. Serum metabolomics was combined with multivariate statistical analysis to search endogenous differential metabolites and related metabolic pathways. The toxic components, targets, and signaling pathways of RMF were screened by network toxicology technique, and the component-target-metabolite-metabolic pathway network was established with the help of serum metabolomics. The result suggested the neurotoxicity, hepatotoxicity, and cardiotoxicity of RMF. A total of 31 differential metabolites and 10 main metabolic pathways were identified by serum metabolomics, and 11 toxic components, 332 related target genes and 141 main signaling pathways were screened out by network toxicology. Further analysis yielded 7 key toxic components: grayanotoxin Ⅲ,grayanotoxinⅠ, rhodojaponin Ⅱ, rhodojaponin Ⅴ, rhodojaponin Ⅵ, rhodojaponin Ⅶ, and kalmanol, which acted on the following 12 key targets: androgen receptor(AR), albumin(ALB), estrogen receptor β(ESR2), sex-hormone binding globulin(SHBG), type 11 hydroxysteroid(17-beta) dehydrogenase(HSD17 B11), estrogen receptor α(ESR1), retinoic X receptor-gamma(RXRG), lactate dehydrogenase type C(LDHC), Aldo-keto reductase(AKR) 1 C family member 3(AKR1 C3), ATP binding cassette subfamily B member 1(ABCB1), UDP-glucuronosyltransferase 2 B7(UGT2 B7), and glutamate-ammonia ligase(GLUL). These targets interfered with the metabolism of gamma-aminobutyric acid, estriol, testosterone, retinoic acid, 2-oxobutyric acid, and affected 4 key metabolic pathways of alanine, aspartate and glutamate metabolism, cysteine and methionine metabolism, steroid hormone biosynthesis, and retinol metabolism. RMF exerts toxic effect on multiple systems through multiple components, targets, and pathways. Through the analysis of key toxic components, target genes, metabolites, and metabolic pathways, this study unveiled the mechanism of potential neurotoxicity, cardiotoxicity, and hepatotoxicity of RMF, which is expected to provide a clue for the basic research on toxic Chinese medicinals.

GC-IMS Analysis of Volatile Components in Rhododendri Mollis Flos at Different Flowering Stages / 中国实验方剂学杂志

Objective:The volatile components of Rhododendri Mollis Flos were determined and the differences of volatile components at different flowering stages were compared and analyzed. Method:Gas chromatography-ion mobility spectrometry （GC-IMS） was used to detect the volatile components in Rhododendri Mollis Flos at different flowering stages （bud stage， initial flowering stage， half-flowering stage， blooming stage and late blooming stage）. GC-IMS spectra combined with cluster analysis， principal component analysis （PCA） and orthogonal partial least squares-discriminant analysis （OPLS-DA） were used to compare the differences and similarities of volatile components in different flowering stages. Result:A total of 70 volatile components in Rhododendri Mollis Flos at different flowering stages were detected， among which 67 were common components， and 47 were identified qualitatively， mainly alcohols， esters and aldehydes. Carveol was a special component at the late blooming stage. The content of alpha-terpineol is the highest at the initial flowering stage， but not at the blooming stage and late blooming stage. The relative contents of the active ingredients ［6-methyl-5-hepten-2-one， nonanal， alpha-terpineol， 1，8-cineole， linalool oxide， 1-octen-3-ol， （<italic>E</italic>）-3-hexenol］ showed a decreasing trend during flowering stages. GC-IMS spectra showed that the samples at different flowering stages had their own characteristic peak regions， and also had common regions. The results of cluster analysis， PCA and OPLS-DA all showed that the samples at different flowering stages were distinguishable. OPLS-DA was used to screen 19 different components to distinguish different flowering stages， including <italic>γ</italic>-butyrolactone， 1，8-cineole， ethyl hexanoate， etc. Conclusion:Rhododendri Mollis Flos samples at different flowering stages can be distinguished obviously， and the active substances in the volatile components are gradually dissipated with the degree of flower opening， which can provide reference for the improvement of material basis and the study of different flowering stages of Rhododendri Mollis Flos.

Herbal Textual Research and Processing Historical Evolution of Rhododendri Mollis Flos / 中国实验方剂学杂志

In this paper， through the collection and collation of ancient materia medica， medical books and medical formulary， combining with modern literature， the historical changes of the name， origin， position， harvesting time， medicinal parts， toxicity， functions and indications， processing methods of Rhododendri Mollis Flos （RMF） were systematically combed and verified， so as to provide reference for clinical application， processing standard and basic research of RMF. According to textual research， RMF is the dried flower of Rhododendron molle. In each historical period， there are many aliases and local names， being with phenomenon of homonyms and synonyms. RMF is mostly wild and planted in a small amount， harvesting time is mostly in March to April. However， the harvesting flowering period is differently described as initial bloom， full bloom and extensive bloom. RMF was first recorded in Shennong Bencaojing (《神农本草经》)， but it did not mention its medicinal parts. Then the flowers， fruits， roots are be used as medicine， but flowers are still the main medicinal parts. RMF had a long processing history， included fried， vinegar-fried， wine-fried， steamed， wine-steamed， vinegar-steamed， and many other processing methods in ancient times. However， at present， only raw products are used in clinical practice， and only a few modern books retain the methods of stir-fried and wine-steamed， believing that the processing can reduce toxicity of RMF.