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

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

A phytochemical investigation of the leaves of Rhododendron anthopogon revealed the presence of five known monoterpenes: ranhuadujuanine A (1), cannabiorcicyclolic acid (2), ranhuadujuanine B (3), ranhuadujuanine C (4) and ranhuadujuanine D (5). All compounds are firstly reported as natural products. The assignments of some 13C-signals of ranhuadujuanine A reported in the literature were revised on the basis of 2D-NMR spectra.
Biological Products ; isolation & purification ; Magnetic Resonance Spectroscopy ; Monoterpenes ; chemistry ; Plant Leaves ; chemistry ; Rhododendron ; chemistry

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

An unusual natural product named 2,4,6-trihydroxacetophenone-3, 5-di-C-beta-D-glucoside (18) were isolated from aerial parts of Rhododendron lepidotum grows in Tibet, along with other 17 known compounds: hopenol-B (1), lupeol (2), ursolic acid (3), avicularin (4), quercetin (5), myricetin (6), hyperoside (7), myricetin-3'-O-beta-D-xyloside (8), (+)-taxifolin-3-O-alpha-L-arabinopyranoside (9), (+)-taxifolin-3-O-beta-D-glucopyranoside (10), lyoniside (11), confluentin (12), 2-(4-hydroxyphenyl)-ethyltriacontanoate (13), 2, 6-dimethoxy-4-hydroxyphenyl-1-O-beta-D-glucopyranoside (14), (-)-2-hydroxy-5-(2-hydroxyethyl) phenyl-O-beta-D-glucopyranoside (15), (-)-isola-riciresinol (16) and isofraxoside (17). All the compounds were firstly isolated from this plant as well as compounds 1, 13-18 were reported occurrence in R. spp. for the first time. The structures were identified based on analyses of spectroscopic data and physico-chemical evidences.
Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; chemistry ; Organic Chemicals ; analysis ; isolation & purification ; Rhododendron ; chemistry

OBJECTIVETo investigate the flavonoids in Rhododendron mariae.

METHODThe constituents in R. mariae were determined by UPLC/Q-TOF-MS. The chromatographic separation was performed on a C18 column (2.1 mm x 50 mm, 1.7 microm) with a gradient elufion of methanol-water containing 0.1% formic acid. The mass specfrometer eqaipped with elecfrospay ionizafion source was usedas defecfor and operated in data was collected under the positive and negative ion modes.

RESULTSeven constituents were identified as myricetin-3-O-beta-D-gluconside (1), myricetin-3'-O-beta-D-xylopyraoside (2), hyperoside (3), isoquercitrin (4), avicularin (5), quercitroside (6) and quercetin (7).

CONCLUSIONIn this study, the main flavonoids in R. mariae were separated by UPLC, and identified through the information of positive ion and negative ion and relative molecular mass which were determined by Q-TOF-MS. It is an accurate and effective method which can be applied for the constituent identification of R. mariae.

Chromatography, High Pressure Liquid ; Flavonoids ; analysis ; chemistry ; Mass Spectrometry ; Rhododendron ; chemistry

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

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

OBJECTIVETo investigate the flavonoid constituents of the Rhododendron anthopogonoides systematically.

METHODThe chemical components were isolated by sephadex LH-20, polyamide and silica gel column chromatography. The chemical structures were elucidated on the basis of physic-chemical properties and spectral data.

RESULTEight compounds were isolated and identified as: Quercetin (I), isorhamnetin (II), hyperoside (III), cacticin (IV), hirsutine (V), kaemferol-3-beta-D-galactoside (VI) myricetin-3-beta-D-Xyloside (VII), (6''-O-(4-Hydroxybenzoyl) hyperoside (VIII).

CONCLUSIONCompounds II, IV, V, VI, VII, and VIII were obtained from this plant for the first time. Compounds VII and VIII were separated from the Ericaceae plant for the first time.

Alkaloids ; chemistry ; isolation & purification ; Flavonols ; chemistry ; isolation & purification ; Plant Leaves ; chemistry ; Plant Stems ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; Rhododendron ; chemistry