Seeking the Regional Identity of Brown Propolis Produced in Southern Brazil and Linked to Total Levels of Bioactive Compounds and Biological Activity

Abstract

Total levels of caffeoylquinic, p-coumaric, and benzoic acid derivatives, flavonols, and dihydroflavonols were investigated in 44 brown propolis samples from the state of Paraná(Brazil) together with their cytotoxicity and antibacterial activities. The aim was to discover chemical and biological activity-based patterns. Great quantitative variation was found within individual samples; however, a typical extract might contain 11.14−21.45 mg of caffeoylquinic acid derivatives/g, 6.27−12.17 mg of p-coumaric acid derivatives/g, 3.18−7.45 mg of benzoic acid derivatives/g, 9.35−23.55 mg of flavonols/g, and 0.17−4.25 mg of dihydroflavonols/g. MIC values poorly correlated to the levels of p-coumaric acids, flavonols, and dihydroflavonols. Most propolis samples showed medium-to-high cytotoxic activity against at least one tumoral cell. The most susceptible cell was OVCAR-8, followed by SF-295, but no correlation was found between the inhibition of OVCAR-8 and SF-295 and levels of any chemical class investigated. The concentration of bioactive compounds in brown propolis samples together with biological activities distinguished samples produced in northern, southern, eastern, and western Parana, being characteristics associated with the geographical origin, and may help to establish a pattern for the propolis produced in the state of Parana.

Brazilian Brown Propolis: an Overview About Its Chemical Composition, Botanical Sources, Quality Control, and Pharmacological Properties

“…Forty-four samples of BP from Paraná and the Santa Catarina States were analyzed to identify the regional identity of these locations. Their compounds were identified and quantified by comparing their chemical profile with authentic standards (Machado et al 2021 ). According to this study, the BP from Southern Brazil is chemically characterized by caffeoyl-quinic acids (range, 11.14 − 21.45 mg/g), p -coumaric acid derivatives (6.27 − 12.17 mg/g), flavonols (9.35 − 23.55 mg/g), followed by benzoic acid derivatives (3.18 − 7.45 mg/g), and dihydroflavonols (0.17 − 4.25 mg/g).…”

“…Determination of total phenolic and flavonoid contents in propolis samples has been widely used to determine biological properties (Sawaya et al 2011 ), mainly using spectrophotometric assays. Usually, total phenolic content is measured by Folin–Ciocalteau’s method, and flavonoid content is measured by the AlCl 3 complexation method (Machado et al 2021 ). However, these methods do not specify each compound in the class of phenolic and flavonoids, being not selective.…”

“…It is crucial to identify the compounds responsible for the biological activities to guarantee the quality of propolis and its products. The development of validated analytical methods is mandatory to guarantee selectivity, accuracy, and precision in quantifying compounds (Machado et al 2021 ).…”

“…The method was validated based on Anvisa guidelines, and all the parameters were analyzed to guarantee the method’s reliability to identify and quantify the six diterpenes in BP samples. Machado et al ( 2021 ) analyzed 44 BBP samples from Paraná by HPLC–DAD. Analytical standards were used to quantify the total content of caffeoylquinic acid, phenylpropanoids ( p -coumaric acid derivates), benzoic acids, flavonols, and dihydroflavonols in the samples.…”

“…The cytotoxicity studies on BBP are still scarce; the literature reports especially the cytotoxicity of the ethanolic brown propolis extract from the different geographic origins of Brazil, such as the northeastern (Frota et al 2021 ), the southeastern (Ribeiro et al 2021a , b , c ), and the southern (Machado et al 2021 ) regions. As propolis activities are related to the environmental conditions prevailing in each region, the cytotoxicity reported from BP of different regions in Brazil also shows variations in the antiproliferative activities.…”