NMR chemometrics reveal bioactive compounds from propolis extracts prior to isolation

Propolis is a resinous natural product collected by honeybees from various buds and exudates, transformed and used for the protection of the colony. The chemical composition of propolis varies greatly, therefore, many different types of propolis have been identified around the world. In our previous study [1], 20 Greek methanolic propolis extracts were investigated and two separate group of samples were observed: a) propolis samples rich in terpenoids originating from Islands, and b) propolis rich in flavonoids from Mainland Greece, exhibiting strong tyrosinase and high collagenase inhibition, respectively. In this study, propolis sample (PR09) from Mainland and propolis sample (PR10) from Island group were selected for further investigation. Their methanolic extracts were fractionated by FCPC and the obtained fractions were evaluated in-vitro for their ability to inhibit tyrosinase and collagenase enzymes, subsequently. Their ¹H-NMR spectra were recorded. The biological activity was statistically correlated with spectral data through the HeteroCovariance Approach (HetCA). The analysis suggested that phenolic compounds (especially flavonoids possessing hydroxyl group at C-3’ of ring B and caffeic acid derivatives) and terpenoids (abietane type diterpenes) contribute to the anti-tyrosinase activity. Polyphenols and caffeic acid derivatives seemed to be responsible for the anti-collagenase activity.

Publication History

Article published online:
13 December 2021

• References

• 1 Stavropoulou M.I., Stathopoulou K., Cheilari A., Benaki D., Gardikis K., Chinou I., Aligiannis N. NMR metabolic profiling of Greek propolis samples: Comparative evaluation of their phytochemical compositions and investigation of their anti-ageing and antioxidant properties. Journal of Pharm. And Biomed. Anal 2021; 194