A comparative study between Chinese propolis
and Brazilian green propolis: metabolite profile
and bioactivity

Among different types, Chinese propolis (ChPs) and Brazilian green propolis (BrGPs) have been shown to
contain multi-functional properties. Despite extensive research in the field, reports comparing propolis
from different geographical areas are still limited, compromising our current understanding of the potential
therapeutic effect associated with propolis and its derived compounds. Herein, a comparative study
between ChPs and BrGPs including their metabolite profile and bioactivities was performed. Interestingly,
even when ChPs and BrGPs showed similar anti-inflammatory potential, our results showed that they
contained very different levels of ethanol extract, total flavonoids and total phenolic acids and in fact,
LC-MS metabolic profiling and pattern recognition could effectively distinguish ChPs and BrGPs.
Moreover, all the propolis samples tested showed good anti-oxidant activity and no significant difference
of free radical scavenging capacity existed between ChPs and BrGPs. In conclusion, ChPs and BrGPs have
a distinct chemome, but their antioxidant and anti-inflammatory activities are similar.

2 Materials and methods
2.1 Reagents and chemicals
Methanol (HPLC grade) was supplied by Merck Chemicals
(Darmstadt, Germany). Formic acid and Folin–Ciocalteu
phenol reagent were from Sigma-Aldrich (St Louis, MO, USA).
Ethanol (95%, analytical grade) was purchased from
Guangzhou Chemical Reagents Factory (Guangzhou, China).
Reference substances of chlorogenic acid, caffeic acid, isochlorogenic acid A, isochlorogenic acid C,
caffeic acid phenethyl ester, myricetin, quercetin, kaempferol, apigenin, pinocembrin and galangin
were supplied by Chengdu Alfa Biotechnology Co., Ltd (Chengdu, Sichuan, China). Artepillin
C was isolated in our lab from the ethanol soluble fraction of
Brazilian green propolis, and the purity of which was determined as 98.2% by analytical HPLC, as well as its chemical
structure was confirmed by HRMS, 1
H NMR and 13C NMR (see
Fig. S1 in the ESI†).