Chemical constituents, antibacterial, acaricidal and anti-inflammatory activities of the essential oils from four Rhododendron species

Abstract

As the ornamental plants and traditional medicines, Rhododendron przewalskii, R. anthopogonoides, R. thymifolium, and R. capitatum are widely distributed in western China. In this paper, the essential oils from these four species were extracted by supercritical extraction and the components were analyzed using headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), the antibacterial, acaricidal and anti-inflammatory activities were investigated. Results showed that R. thymifolium (RTEO) contained the highest yield of 0.99% with 246 compounds, followed by R. capitatum (RCEO, 0.81%) with 290 chemicals, R. anthopogonoides (RAEO, 0.57%) with 302 compounds and R. przewalskii (RPEO, 0.30%) with 294 components. They also exhibited the safety at given doses and have the anti-inflammatory in vitro and in vivo tests via inhibiting the cytokines productions, the acaricidal and antibacterial activities also were found. 4-Hydroxy-3-methylacetophenone from RPEO, α-pinene and β-pinene from RAEO, β-farnesene and germacrone from RTEO, and benzylacetone from RCEO, as main and active components, inhibited the NO content in RAW 264.7 cells induced by LPS. These results indicated that four essential oils have certain medicinal value and laid the foundation for the development of these species as raw materials for the pharmaceutical and perfume industries.

Gas Chromatography–Mass Spectrometry Chemical Profiling of Commiphora myrrha Resin Extracts and Evaluation of Larvicidal, Antioxidant, and Cytotoxic Activities

“…Finally, our data and those of others support the hypothesis that the effectiveness of C. molmol resin extracts against insect pests may be explained by the presence of numerous secondary metabolites, including sesquiterpenes, phenols, aromatic terpenoids, fatty alcohol, curzerene, germacrene, and elemene [19,50,55]. Curzerene is a volatile, aromatic terpenoid found in many herbs and spices, such as Rhododendron species, which has been shown to possess anti-inflammatory, antibacterial, acaricidal, and cytotoxicity properties in vitro [56]. As per Muturi et al [40], both oleo-resin extract and essential oil derived from the genus Commiphora demonstrated toxicity against larvae of A. caspius and C. pipiens.…”

Three New Ionone Glycosides from Rhododendron capitatum Maxim

“…As a Tibetan medicine for the treatment of gastric cold, abdominal pain, pharyngalgia, cough, and inflammation [8], previous phytochemical research has shown it contains a variety of structurally diverse meroterpenoids, grayanane diterpenoids, flavonoids, and coumarins [9]. These compounds exhibit a variety of biological and pharmacological activities, including anti-inflammatory, antiviral, cytotoxic, and hypoglycaemic activities [7][8][9][10]. As part of our continuing studies on chemical components with novel structures and significant pharmacological activities from folk medicinal plants found in the Qinling region [11,12], chemical investigations of the aerial parts of R. capitatum were undertaken, leading to the isolation and identification of three new ionone glycosides (1-3) and seven known compounds (4)(5)(6)(7)(8)(9)(10).…”

“…These compounds exhibit a variety of biological and pharmacological activities, including anti-inflammatory, antiviral, cytotoxic, and hypoglycaemic activities [7][8][9][10]. As part of our continuing studies on chemical components with novel structures and significant pharmacological activities from folk medicinal plants found in the Qinling region [11,12], chemical investigations of the aerial parts of R. capitatum were undertaken, leading to the isolation and identification of three new ionone glycosides (1-3) and seven known compounds (4)(5)(6)(7)(8)(9)(10). This is the first report on the sesquiterpenoid compounds from R. capitatum (Figure 1), wherein compound 1 was a novel ionone with a 6/7 bicyclic skeleton.…”

Structural Characterization and Anti-inflammatory Activities of Anticomplementary Polysaccharides from Rhododendron principis

“…Consistent with its traditional application, “Dama” demonstrated strong anti-inflammatory activities in previous studies 13 . Essential oils 14 , flavonoids 15 , and crude polysaccharides 16 from R. arboreum and R. przewalskii have been reported to exhibit anti-inflammatory activity.…”