Ten lignans were isolated from the ethanol extract of stems and branches of Rhododendron ovatum through column chromatography over silica gel, ODS, Sephadex LH-20, and MCI-gel resin and semi-preparative RP-HPLC. The structures of all compounds were elucidated by extensive spectroscopic data analysis(UV, IR, HR-ESI-MS, ECD and NMR) as(-)-4-epi-lyoniresinol-9'-O-α-L-rhamnopyranoside(1),(+)-lyoniresinol-3α-O-α-L-rhamnopyranoside(2),(+)-5'-methoxyisolariciresinol-9'-O-α-L-rhamnopyranoside(3),(-)-lyoniresinol-3α-O-β-D-glucopyranoside(4),(+)-lyoniresinol-3α-O-β-D-glucopyranoside(5),(-)-4-epi-lyoniresinol-9'-O-β-D-glucopyransoide(6), racemiside(7), neociwujiaphenol(8),(+)-syringaresinol(9), and homohesperitin(10). Among them, compound 1 was a new aryltetralin-type lignan. All the isolated lignans were tested for antioxidant activities in Fe~(2+)-cysteine induced rat liver microsomal lipid peroxidation in vitro, and compounds 8 and 9 showed antioxidant activities on the formation of malondiadehyde(MDA) in rat liver microsomes at 1×10~(-5) mol·L~(-1), with significant inhibitory rates of 75.20% and 91.12%, respectively.
Animals ; Rats ; Glucosides/chemistry* ; Rhododendron ; Antioxidants/pharmacology* ; Lignans/chemistry* ; Plant Stems

This study explores the effect of total flavonoids of Rhododendra simsii(TFR) on middle cerebral artery occlusion(MCAO)-induced cerebral injury in rats and oxygen-glucose deprivation/reoxygenation(OGD/R) injury in PC12 cells and the underlying mechanism. The MCAO method was used to induce focal ischemic cerebral injury in rats. Male SD rats were randomized into sham group, model group, and TFR group. After MCAO, TFR(60 mg·kg~(-1)) was administered for 3 days. The content of tumor necrosis factor-α(TNF-α), interleukin-1(IL-1), and interleukin-6(IL-6) in serum was detected by enzyme-linked immunosorbent assay(ELISA). The pathological changes of brain tissue and cerebral infarction were observed based on hematoxylin and eosin(HE) staining and 2,3,5-triphenyltetrazolium chloride(TTC) staining. RT-qPCR and Western blot were used to detect the mRNA and protein levels of calcium release-activated calcium channel modulator 1(ORAI1), stromal interaction molecule 1(STIM1), stromal intera-ction molecule 2(STIM2), protein kinase B(PKB), and cysteinyl aspartate specific proteinase 3(caspase-3) in brain tissues. The OGD/R method was employed to induce injury in PC12 cells. Cells were randomized into the normal group, model group, gene silencing group, TFR(30 μg·mL~(-1)) group, and TFR(30 μg·mL~(-1))+gene overexpression plasmid group. Intracellular Ca~(2+) concentration and apoptosis rate of PC12 cells were measured by laser scanning confocal microscopy and flow cytometry. The effect of STIM-ORAI-regulated store-operated calcium entry(SOCE) pathway on TFR was explored based on gene silencing and gene overexpression techniques. The results showed that TFR significantly alleviated the histopathological damage of brains in MCAO rats after 3 days of admini-stration, reduced the contents of TNF-α, IL-1, and IL-6 in the serum, down-regulated the expression of ORAI1, STIM1, STIM2, and caspase-3 genes, and up-regulated the expression of PKB gene in brain tissues of MCAO rats. TFR significantly decreased OGD/R induced Ca~(2+) overload and apoptosis in PC12 cells. However, it induced TFR-like effect by ORAI1, STIM1 and STIM2 genes silencing. However, overexpression of these genes significantly blocked the effect of TFR in reducing Ca~(2+) overload and apoptosis in PC12 cells. In summary, in the early stage of focal cerebral ischemia-reperfusion injury and OGD/R-induced injury in PC12 cells TFR attenuates ischemic brain injury by inhibiting the STIM-ORAI-regulated SOCE pathway and reducing Ca~(2+) overload and inflammatory factor expression, and apoptosis.
Animals ; Male ; Rats ; Apoptosis ; Brain Ischemia/metabolism* ; Caspase 3 ; Interleukin-1 ; Interleukin-6 ; Rats, Sprague-Dawley ; Reperfusion Injury/metabolism* ; Tumor Necrosis Factor-alpha/genetics* ; Flavonoids/pharmacology* ; Rhododendron/chemistry*

To elucidate the chemical material basis of Rhododendron nivale, this study comprehensively used various chromatographic techniques to isolate and obtain five new meroterpenoid enantiomers(1a/1b-5a/5b) from the ethyl acetate extract of R. nivale. A variety of spectral analytical methods, such as high-resolution mass spectrometry(HRMS), nuclear magnetic resonance spectroscopy(NMR), and infrared(IR) spectrum, were used to evaluate the structure, combined with the measurement and calculation of electronic circular dichroism(ECD). The new compounds 1a/1b-4a/4b were named as(±)-nivalones A-B(1a/1b-2a/2b) and(±)-nivalnoids C-D(3a/3b-4a/4b), along with one known enantiomer(±)-anthoponoid G(5a/5b). Human neuroblastoma cells(SH-SY5Y cells) induced by hydrogen peroxide(H_2O_2) were used as oxidative stress models to evaluate the protective activity of the isolated compounds against oxidative damage to nerve cells. It was found that compounds 2a and 3a had a certain protective effect on nerve cells against H_2O_2-induced oxidative damage at concentrations of 50 μmol·L~(-1), which increased the cell survival rate from 44.02%±2.30% to 67.82%±1.12% and 62.20%±1.87%, respectively. Other compounds did not show a significant ability to protect cells from oxidative damage. These findings enrich the chemical constituents of R. nivale and provide valuable information for identifying the structure of its meroterpenoids.
Humans ; Rhododendron/chemistry* ; Neuroblastoma ; Oxidative Stress ; Magnetic Resonance Spectroscopy ; Stereoisomerism ; Molecular Structure

Rheumatoid arthritis(RA), as a chronic autoimmune disease, has a high incidence and disability rate, causing significant suffering to patients. Due to its complex pathogenesis, it has not been fully elucidated to date, and its treatment remains a challenging problem in the medical field. Although western medicine treatment options have certain efficacy, they require prolonged use and are expensive. Additionally, they carry risks of multiple infections and adverse reactions like malignancies. The Chinese herbal medicine Rhododendron molle is commonly used in folk medicine for its properties of dispelling wind, removing dampness, calming nerves, and alleviating pain in the treatment of diseases like rheumatic bone diseases. In recent years, modern clinical and pharmacological studies have shown that the diterpenoids in R. molle are effective components, exhibiting immune-regulatory, anti-inflammatory, and analgesic effects. This makes it a promising candidate for treating RA with a broad range of potential applications. However, R. molle has certain toxic properties that hinder its clinical application and lead to the wastage of its resources. This study reviewed recent research progress on the mechanism of R. molle in preventing and treating RA, focusing on its chemical components, anti-inflammatory and analgesic properties and summarized the adverse reactions associated with R. molle, aiming to offer new ideas for finding natural remedies for RA and methods to reduce toxicity while enhancing the effectiveness of R. molle. The study seeks to clarify the safety and efficacy of R. molle and its extracts, providing a theoretical basis for its application prospects and further promoting the development and utilization of R. molle resources.
Humans ; Rhododendron/chemistry* ; Arthritis, Rheumatoid/drug therapy* ; Anti-Inflammatory Agents ; Diterpenes/pharmacology* ; Analgesics

Rhododendron molle G. Don, belonging to the Ericaceae family, is a traditional Chinese medicinal plant with a wide spectrum of pharmacological effects. This paper aimed to review the phytochemistry, pharmacology and toxicology of R. molle, and to discuss the tendency of future investigations on this plant. A systematic review of literature about R. molle was carried out using resources including classic books about Chinese herbal medicine, and scientific data bases including CNKI, Pubmed, SciFinder, Scopus, and Web of Science. Over 67 compounds, including diterpenes, triterpenes, flavonoids, and lignans, had been extracted and identified from R. molle. The extracts/monomers isolated from the root, flower and fruits of this plant were used as effective agents for treating pains, inflammatory diseases, hypertension, and pest, etc. In addition, diterpenes, such as rhodojaponin III, were considered as the toxic agents associated with the toxicities of this plant. These findings will be significant for the discovery of new drugs from this plant and full utilization of R. molle.
Animals ; Humans ; Medicine, Chinese Traditional ; Molecular Structure ; Phytotherapy ; Plant Extracts ; chemistry ; pharmacology ; therapeutic use ; toxicity ; Plants, Medicinal ; Rhododendron ; chemistry

The present study was designed to determine the major chemical constituents of the leaves of Rhododendron dauricum L. Compounds were isolated and purified by various chromatographic methods, and their structures were elucidated by physicochemical properties and spectral data. The present study identified two new C-methyl flavanones, 5, 7, 3', 5'-tetrahydroxy-6, 8-di-C-methyl flavanone (1) and 5, 4'-dihydroxy-8-C-methylflavanone-7-O-β-D-glucopyranoside (2), and one new flavonoid glycoside, quercetin-3-O-β-D-(6"-O-cinnamoyl)-galactoside (3), along with seven known compounds, including syzalterin (4), poriolin (5), farrerol-7-O-β-D-glucopyranoside (6), myrciacetin (7), quercetin-3-O-β-D-(6-p-hydroxy-benzoyl)-galactoside (8), quercetin-3-O-β-D-(6-p-coumaroyl)-galactoside (9), and 5, 7, 3', 5'-tetrahydroxyl flavanone (10). Compounds 1-3 were determined to be new flavonoids; compounds 4-6 were isolated from this species for the first time; and compounds 7-10 were reported for the first time from this genus.
Flavanones ; chemistry ; isolation & purification ; Flavonoids ; chemistry ; isolation & purification ; Galactosides ; chemistry ; isolation & purification ; Glucosides ; chemistry ; isolation & purification ; Molecular Structure ; Plant Extracts ; chemistry ; Plant Leaves ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification ; Rhododendron ; chemistry

Eight phenolic compounds were isolated from Rhododendron phaeochrysum var. agglutinatum and their sructures were identified as phaeochrysin (1), (2R)-4-(3',4'-dihydroxyphenyl) -2-butanol (2), (-) -rhododendrol (3), rhododendrin (4), (+) -isolariciresinol (5), (-) -lyoniresinol (6), lyoniresinol-9'-O-β-D-xylopyranoside (7), and dihydrodehydrodiconiferyl-3a-O-α-L-rhamnopyranoside (8). Compound 1 is new, and compounds 2, 5-8 were isolated from this plant for the first time.
Drugs, Chinese Herbal ; chemistry ; Mass Spectrometry ; Molecular Structure ; Phenols ; chemistry ; Rhododendron ; chemistry

Thirteen compounds were isolated from the leaves of Rhododendron rubiginosum var. rubiginosum by various chromatographic techniques. On the basis of spectroscopic data, their structures were elucidated as 3,9-dihydroxy-megastigma-5-ene (1), 3 beta-hydroxy-5alpha ,6 alpha-epoxy-7-megastigmen-9-one (2), loliolide (3), ursolic acid(4), 2 alpha, 3 beta-dihydroxy-urs-12-en-28-oic acid (5), 2 alpha, 3 beta,23-trihydroxy-urs-12-en-28-oic acid (6), 7,9-dimethoxyrhododendrol (7), 7-methoxyrhododendrol (8), zingerone (9), isofraxidin (10), scopoletin (11), (+)-pinoresinol (12) and 3'-O-demethylepipinorisenol (13). All compounds were isolated from this plant for the first time, and compounds 1-3, 7-9, and 11-13 were isolated from the genus Rhododendron for the first time.
Organic Chemicals ; analysis ; chemistry ; Plant Leaves ; chemistry ; Rhododendron ; chemistry

OBJECTIVETo study the chemical constituents of Rhododendron seniavinii.

METHODCompounds were isolated from the aqueous extract of the leaves of R. seniavinii by using Sephadex LH-20, ODS open column chromatography and other means. Their structures were elucidated according to spectral data and physiochemical properties.

RESULTThirteen compounds were isolated from R. seniavinii and identified as 5-methoxydehydroconiferyl alcohol (1), dehydroconiferyl alcohol (2), (-)-syringaresinol (3), (-)-lyoniresinol (4), (+)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (5), (-)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (6), 3,4,5-trimethoxyphenyl-1-O-beta-D-glucopyranoside (7), nikoenoside (8), 3,5,7-trihydroxychromone-3-0-alpha-L-rhamnopyranoside (9), 3,4,5-trimethoxyphenol (10), scopoletin (11), scopolin (12) and quercitrin (13).

CONCLUSIONCompounds 1-12 were obtained from this plant for the first time.

Chromatography, Gel ; Coumarins ; chemistry ; isolation & purification ; Dextrans ; Glucosides ; chemistry ; isolation & purification ; Mass Spectrometry ; Plant Extracts ; chemistry ; isolation & purification ; Plant Leaves ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification ; Rhododendron ; chemistry ; Scopoletin ; chemistry ; isolation & purification

AIM: To study the chemical constituents of the flowers of Rhododendron molle. METHODS: Compounds were isolated by repeated chromatography over silica gel and Sephadex LH-20. Structures were elucidated based on spectral techniques, mainly 1D- and 2D-NMR and mass spectrometric analyses. RESULTS: Two compounds (1 and 2) were isolated. CONCLUSIONS Compounds 1 and 2 were identified as two new compounds: 2α, 10α-epoxy-3β, 5β, 6β, 14β, 16α-hexahydroxy-grayanane and benzyl 2, 6-dihydroxybenzoate-6-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranoside, respectively.
Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Flowers ; chemistry ; Magnetic Resonance Spectroscopy ; Molecular Structure ; Rhododendron ; chemistry