Studies on the Chemical Constituents of the Roots of Rhododendron Molle G. Don

The compounds from the root of Rhododendron molle G.Don were isolated, purified by various chromatographic techniques, and their structures were identified according to the physical and chemical features and spectral data. Three compounds were separated from the root of Rhododendron molle G.Don and identified as Rhodojaponin-Ⅲ, taraxerol, β-sitosterol for the first time.

One New Diterpene Glucoside from the Roots of Rhododendron molle

One new grayanane diterpene glucoside, rhodomoside A 1 was isolated from the roots of Rhododendron molle G. Don (Ericaceae). Its structure was elucidated on the basis of spectral analysis.

Two New Phenolic Glycosides from the Roots of Rhododendron molle

Two new phenolic glycosides, everninic acid methyl ester-2-O-b-D- xylopyran- osyl-(16)-b-D-glucopyranoside 1 and 7-hydroxy-5-methoxyphthalide-7-b-D- xylopyranosyl- (16)-b-D-glucopyranoside 2 were isolated from the roots of Rhododendron molle G. Don. Their structures were determined by spectral evidence including 2D NMR techniques.

Antinociceptive grayanane-derived diterpenoids from flowers of Rhododendron molle

Twelve new grayanoids(1-12)along with five known compounds were isolated from flowers of Rhododendron molle.Their structures were fully characterized using a combination of spectroscopic analyses,computational calculations,and single crystal X-ray diffraction.Rhomollone A(1)possesses an unprecedented 5/6/6/5 tetra-cyclic ring system(B-nor grayanane)incorporating a cyclopentene-1,3-dione scaffold.Rhodomollein XLIII(2)is a dimeric grayanoid,containing a novel 14-membered heterocyclic ring with a C2 symmetry axis.The antinociceptive activities of compounds 3,4,6,7,and 12-17 were evaluated by an acetic acid-induced writhing test.Among them,compounds 3,7,12,15 and 16 displayed significant antinociceptive activities at a dose of 20 mg/kg with inhibition rates ranging from41.9%to 91.6%.Compounds 6 and 13 inhibited 46.0%and 39.4%of the acetic acid-induced writhes at a dose of 2 mg/kg,while compound 17 inhibited 34.3%of the writhes at a dose of 0.4 mg/kg.

Anti-rheumatoid arthritis potential of diterpenoid fraction derived from Rhododendron molle fruits

Rhododendron molle G.Don is first recorded in Shengnong’s Herbal Classic,and its fruits,which are termed as Liuzhouzi,are often used to treat rheumatoid arthritis in Chinese folk.During our ongoing investigation to develop a safer and potential new arthritis therapy,a process for the preparation of diterpenoid fraction from Rhododendron molle fruits was established.In order to evaluate the main components and the anti-rheumatoid arthritis effect of the diterpenoid fraction,phytochemical and pharmacological experiments were used.As the result,the main components of diterpenoid fraction were identified as rhodojaponinⅢ(1),rhodojaponinⅥ(2),2-O-methylrhodojaponin(3),and 5′-β-D-glucopyranosy-loxyjasmonic acid(4).These four components constitute greater than 95%of diterpenoid fraction using area normalization method of HPLC-ELSD.The results of CIA rat experiment showed that high dose of diterpenoid fraction(0.6 mg·kg^(-1)·d^(-1))significantly alleviated the symptoms of rheumatoid arthritis,similar to tripterygium polyglycosides,an effective RA therapy.Preliminary mechanism studies indicated that diterpenoid fraction significantly inhibited the abnormal proliferation of T and B lymphocytes,and remarkably reduced the levels of pro-inflammatory cytokines IL-6,IL^(-1)βand TNF-α.Overall,our findings may provide a more effective and safe alternative treatment for RA using common clinical Chinese medicines like tripterygium polyglycosides.

Highly Oxygenated Dimeric Grayanane Diterpenoids as Analgesics:TRPV1 and TRPA1 Dual Antagonists from Rhododendron molle

Six highly oxygenated dimeric grayanane diterpenoids(1—6)including three new ones,bismollethers A—C(1—3),were isolated from the flowers of Rhododendron molle collected at Qichun,Hubei,China.The structures and relative configurations of 1—6 were determined by comprehensive spectroscopic data analysis and 13C NMR calculation with DP4+analysis.The absolute configurations of bismollethers A—C(1—3)and birhodomollein B(5)were indubitably assigned by single-crystal X-ray diffraction analysis,revealing the head-to-tail linking manner of diterpenoid monomers.Bismollether A(1)is a caged dimeric grayanane diterpenoid linked through two oxygen-bridges of C-2−O−C-14′and C-14−O−C-2′,featuring a unique 1,8-dioxacyclotetradecane motif.The plausible biosynthesis pathways of 1—6 are proposed.All the isolates displayed significant analgesic activities and their structure-activity relationships were discussed.Grayanane diterpenoid dimers were found to be TRPV1 and TRPA1 dual antagonists,and docking studies provide a structural basis to design potent analgesics.

Three new dimeric diterpenes from Rhododendron molle

Birhodomolleins A-C（1-3）,three novel diterpenoids dimerized from two grayanane diterpenes through an oxygen bridge,were isolated from the flowers of Rhododendron molle.Their structures were elucidated by interpretation of their 1D and 2D NMR and other spectroscopic data.Birhodomollein A（1） contains a rare chloro-substitution on one of the grayanane moieties.These are the first examples of dimeric diterpenes from the Ericaceae family.

大别山黄杜鹃根茎叶花内参基因的表达稳定性评价

黄杜鹃(Rhododendron molle G. Don)是中国野生杜鹃花资源中极具观赏价值和药用价值的特有物种,其野生资源在大别山区零散分布,因此对其稳定内参基因的评估和筛选对黄杜鹃分子生物学和遗传学的研究至关重要。本研究以黄杜鹃根、茎、叶、花为试验材料,采用实时荧光定量PCR技术,分析RmRPL3-1、RmNAC-1、RmCOX1-4、RmPDS-1、RmUBQ-6、RmL10-4等候选内参基因在不同器官组织中的表达稳定性情况,并基于GeNorm、Normfinder和Best-Keeper软件分析荧光定量PCR的结果,筛选最优的内参基因。结果表明黄杜鹃不同组织中最稳定表达的内参基因为RmCOX1-4和RmUBQ-6的组合。本研究筛选的最稳定的内参基因将为黄杜鹃后续的基因表达研究提供校准依据。