Study On Chemical Constituents And Anti-Aging Activity Of Rhododendron Nivale

With the continuous development of economy and society,population aging has become a prominent problem.With the increase of age,the prevalence of diseases such as hypertension,Alzheimer’s disease and osteoporosis increases,which puts great pressure on the development of society.Rhododendron nivale is an evergreen shrub in the genus Rhododendron,which is mainly distributed in the alpine region above 3200m in Tibet.The flowers and leaves of Rhododendron nivale are used as different medicinal materials in Tibetan medicine.The flowers are called"Dali",which has the function of treating lung disease caused by"Bacon",while the leaves are called"Balu",which has the function of helping digestion and delaying aging.At present,the research on chemical constituents of Rhododendron nivale mainly focuses on volatile oil and polysaccharide,while the research on other compounds is relatively rare,and modern pharmacological research has found that Rhododendron nivale extract has the functions of eliminating mites and delaying aging.In this dissertation,49 compounds were isolated from the ethyl acetate parts of branches and leaves of Rhododendron nivale by using various chromatographic techniques.Their structures were determined on the basis of NMR,HRMS data,IR,CD and comparison with those in literature.The compounds were:nivalenoid A（1）,nivalenoid B（2）,1β,6α-dihydroxy-7-epi-eudesm-3-ene（3）,teucladiol（4）,4β,6β-dihydroxy-1α,5β（H）-guai-9-ene（5）,isocalammendiol（6）,（+）/（-）-nivalnoid C（7a/7b）,（+）/（-）-nivalnoid D（8a/8b）,nivalnoid E（9）,（+）/（-）-nivalone A（10a/10b）,（+）/（-）-nivalone B（11a/11b）,nivalone C（12）,nivalone D（13）,nivalone E（14）,nivalone F（15）,cannabiorcicyclolic acid（16）,rubiginosin E（17）,daurichromenic acid（18）,anthopogochromene B（19）,（+）/（-）-anthoponoid G（20a/20b）,（2R,3S）-2-（（E）-4,8-dimethylnona-3,7-dien-1-yl）-2,7-dimethylchromane-3,5-diol（21）,confluentin（22）,2,7-dimethyl-2-（4-methylpent-3-enyl）-3,4-dihydrochromen-5-ol（23）,grifolin（24）,cannabigerorcin（25）,grifolic acid（26）,（E）-3-（3,7-dimethylocta-2,6-dien-1-yl）-2,4-dihydroxy-6-methylbenzoic acid（27）,methyl（E）-3-（3,7-dimethylocta-2,6-dien-1-yl）-2,4-dihydroxy-6-methylbenzoate（28）,camarolide（29）,8,5’-dimethoxyquercetin 3-O-α–arabinofuranoside（30）,morin-3-O-α-L-lyxosid（31）,（2R,3R）-taxifolin 3-O-arabinoside（32）,epicatechin（33）,（-）-epigallocatechin（34）,（-）-catechin（35）,dihydromyricetin（36）,dihydroquercetin（37）,2,4-dihydroxy-3,6-dimethyl methylbenzoate（38）,litseachromolaevane A（39）,methyl 2,4,6-trihydroxybenzoate（40）,3-methoxy-4,5-dihydroxybenzoic acid（41）,2-O-（3,4-dihydroxybenzoyl）-2,4,6-trihydroxyphenylacetic acid（42）,atranol（43）,di-isobutyl phthalate（44）.The types of compounds include:6 sesquiterpene compounds（1-6）,of which compounds 1 and 2are new compounds;27 meroterpenoids（7a/7b-28）,of which compounds 7a/7b-15are new compounds;1 triterpenoid（29）;8 flavonoids（30-37）,of which compound 30is a new compound;4 phenolic compounds（38-41）and 3 other compounds（42-44）.The anti-aging activity of the compounds was evaluated by in vitro anti-inflammatory model and oxidative damage protection model.The results showed that seven compounds had certain anti-inflammatory activities,and their IC₅₀ ranged from 21.1 to 53.5μm;Sixteen compounds had oxidative damage protection activity at the concentration of 50μM,among which compounds 3、6、31、33 and 37 increased the cell survival rate from 44.0%±2.3%after H₂O₂ damage to 71.9%±1.1%,which significantly improved the survival rate of SH-SY5Y cells.The results showed that the compounds in Rhododendron nivale could play an anti-aging role through anti-inflammatory and oxidative damage protection.In summary,49 compounds,including 16 new compounds,were identified from the ethyl acetate parts of branches and leaves of Rhododendron nivale.The anti-aging activity of compounds was evaluated by in vitro anti-inflammatory model and oxidative damage protection model.The results of this study enriched the chemical composition library of Rhododendron nivale and the material basis of anti-aging of branches and leaves of Rhododendron nivale was partially clarified,which provided scientific basis for its further development and utilization.