Antinociceptive and anti-inflammatory potential of Rhododendron arboreum bark

Abstract

Rhododendron arboreum Smith. (Ericaceae), an evergreen small tree, is one of the 1000 species that belongs to genus Rhododendron distributed worldwide. In folk medicine, as various parts of this plant exhibit medicinal properties, it is used in the treatment of different ailments.The present study was designed to evaluate the potential anti-inflammatory and antinociceptive effects of methanolic extract of R. arboreum bark, followed by activity-guided fractionation of n-hexane, n-butanol, chloroform, ethyl acetate and aqueous fractions.The ethyl acetate fraction (200 mg/kg i.p.) showed the maximum analgesic effect (82%) in acetic acid-induced writhing, followed, to a less extent, by crude extract and chloroform fraction both at a dose of 200 mg/kg i.p. (65.09% and 67.89%, respectively). In carrageenan-induced mouse paw oedema, the crude extract and its related fractions displayed in a dose-dependent manner (50-200 mg/kg i.p.) an anti-inflammatory activity for all time-courses (1-5 hrs). For the active extract/fractions (200 mg/kg i.p.), the maximum effect was observed 5 h after carrageenan injection. These evidences were also supported by in vitro lipoxygenase inhibitory properties. In conclusion, R. arboreum crude methanolic extract and its fractions exhibited anti-inflammatory and antinociceptive effects. For these reasons, this plant could be a promising source of new compounds for the management of pain and inflammatory diseases.

LC-ESI-MS/MS Characterization of Concentrated Polyphenolic Fractions from Rhododendron luteum and Their Anti-Inflammatory and Antioxidant Activities

“…It is interesting to note that our results are in agreement with data showing a correlation between the total phenolic content and the ability to inhibit lipoxygenase [ 34 ]. Similar results to those for RL-M in the anti-LOX assay were obtained in the case of the R. arboreum methanolic extract [ 36 ].…”

Influence of Accelerated Solvent Extraction Conditions on the LC-ESI-MS/MS Polyphenolic Profile, Triterpenoid Content, and Antioxidant and Anti-lipoxygenase Activity of Rhododendron luteum Sweet Leaves

“…As shown by our findings, the aqueous RL samples (67.50–90.13% of LOX inhibition) had higher anti-LOX activity than R. arboreum aqueous extracts (48.35% of LOX-inhibition) [ 57 ]. The enzyme-inhibition grade of our most active sample—RL80C-W—is comparable to that of the most active ethyl-acetate extract of R. arboreum [ 57 ]. The water and hydro-methanolic extracts prepared at 80 °C inhibited LOX most effectively.…”

Phytochemical Analysis and Evaluation of in Vitro Immunomodulatory Activity of Rhododendron Arboreum Leaves

“…Methanolic extract of R. arboreum leaves through gas chromatographymass spectrometry (GC-MS) analysis confirms the presence of main phytoconstituents, i.e., 22-stigmasten-3-one (14.59%) with highest area percentage, followed by 1, 1, 6-trimethyl-3-methylene-2-(3, 6, 10, 13,14-pentamethyl-3-ethenyl-pentadec-4-enye) cyclohexane (12.26%), beta-amyrin (7.62%), and linoleyl alcohol (6.50%) having antimicrobial, anticancer, antiarthritic, anti-inflammatory, and antiviral properties [20]. This plant is reported to possess several medicinal and pharmacological properties such as hepatoprotective, antioxidant, immunomodulatory, anti-inflammatory, anti-diabetic, anticancer, antinociceptive, adaptogenic, and antidiarrheal, oxytocic, estrogenic, prostragl, synthetase inhibitory activity, and central nervous system depressant activity [17,[21][22][23][24][25][26][27][28][29][30][31]. In the present study, ursolic acid and kaempferol were quantitatively estimated from the R. arboreum leaves collected from Himachal Pradesh and its immunomodulatory properties were determined.…”