Evaluation of Antioxidant and Antimicrobial Activities and Characterization of Bioactive Components of Two Brazilian Propolis Samples Using a pK_a-Guided Fractionation

Abstract

The ethanolic extracts of two Brazilian propolis samples were submitted to a fractionation procedure based on the pK a values of their components. The fractions obtained were evaluated for their antimicrobial activity against Staphylococcus aureus as well as for their antioxidant properties (reduction of DPPH radical). Their phenolic and flavonoid contents were measured spectrophotometrically, in order to establish the correlations between these contents and the measured activities. Further, the most active fractions of both extracts were analyzed by HRGC-MS and about twenty compounds could be characterized. Among them were 3-prenyl-4-hydroxycinnamic acid (drupanin) and 3,5-diprenyl-4-hydroxycinnamic acid (artepillin C), which seem to be the major antioxidant components of the bioactive fractions.

Chemical and Biological Analyses of Malaysian Stingless Bee Propolis Extracts

“…The composition of propolis depends on the type of plants accessible to the bees. Propolis has a wide range of biological activities, as antibacterial [1], anti-inflammatory [2], antiulcer [3], antioxidant [4], hepatoprotective [5], and tumoricidal [6] activities and high repellent index against ants [7]. It is generally accepted that bees collect resinous plant materials, produced by a variety of botanical processes, in different parts of plants.…”

Antimicrobial compounds isolated from Haematoxylon brasiletto

“…Purification of the active ethyl acetate-soluble partition of a methanol extract of the bark of Haematoxylon brasiletto (Table 1) led to the isolation of eight known compounds: hematoxylin (1), brazilin (2) (Craig et al, 1965), caffeic acid (3) (Chou et al, 2006), methyl gallate (Kubo et al, 2004) (4), gallic acid (5) (Ani et al, 2006), phloroglucinol (6) (Yamaki et al, 1994), 4-hydroxycinnamic acid (7) (van der Watt and Pretorius, 2001;Souza et al, 2007), and 5-methoxypsoralen (8) (Manderfeld et al, 1997) (Fig. 1).…”

Differences in numbers of termicins expressed in two termite species affected by fungal contamination of their environments

“…Norharmane, a β-carboline alkaloid produced by endosymbionts in termites, shows antifungal activity (Siderhurst et al, 2005a,b;Chouvenc et al, 2008). Propolis, a resinous substance collected by honeybees from various tree buds and mixed with pollen and enzymes secreted by the bees themselves, shows strong antimicrobial activity (Sforcin et al, 2000;Sawaya et al, 2002;Kartal et al, 2003;Silici and Kutluca, 2005;Souza et al, 2007). Polyandry and polygyny in social insects increase colony genetic diversity, and genetic variation within social insects can reduce parasite loads (Liersch and Schmid-Hempel, 1998;Schmid-Hempel, 1998).…”