Chronic inflammation plays a key role in many diseases like cancer, diabetes, asthma, and arteriosclerosis.[1] Anti-inflammatory drugs are often targeting cyclooxygenase isoenzymes despite some severe side effects, like gastric ulcers, kidney damage, cardiovascular incidents, and bronchospasm, especially in long term use. Hence, there is a great interest in finding new lead compounds targeting the expression of inflammatory mediators such as COX-2 or the interleukin-group. [2]
Previous studies have shown that megastigmane derivatives have anti-inflammatory properties.[3] Therefore, five plants which are known to contain such constituents were selected as candidates for the isolation of similar and even more potent compounds. The plant material was extracted successively with solvents of different polarity, and the extracts were tested for COX-2 mRNA expression in PMA differentiated LPS stimulated THP-1 monocytes.
Among the tested plants, extracts of sweet olive flowers (Osmanthus fragrans Lour.) were found to be very active. n-Hexane and dichloromethane extracts showed 41.79 ± 4.22 % and 46.15 ± 5.31 % inhibition of COX2 mRNA expression, respectively, at concentrations of 20 µg/ml, whereas methanol extracts did not show significant effects. Active extracts were further fractionated using column chromatography. Isolation, structure elucidation and pharmacological characterization of the active compounds are in progress.
References
[1] Camps J, García-Heredia A. Introduction: oxidation and inflammation, a molecular link between non-communicable diseases. Adv Exp Med Biol 2014; 824: 1–4
[2] Conaghan PG. A turbulent decade for NSAIDs: update on current concepts of classification, epidemiology, comparative efficacy, and toxicity. Rheumatol Int 2012; 32: 1491–1502
[3] Pan SP. Phytochemical and pharmacological studies of leaves of Epipremnum pinnatum with a special focus on the inhibition of COX-2 and IL-8 expression [Disseration]. Graz; 2017