Antioxidant, antimicrobial and neutrophil-modulating activities of herb extracts.

The present study provides a comprehensive data on the antioxidant, antimicrobial and neutrophil-modulating activities of extracts from six medicinal plants--blackberry (Rubus fruticosus) leaves, chokeberry (Aronia melanocarpa) leaves, hawthorn (Crataegus monogyna) leaves, lady's mantle (Alchemilla glabra) aerial parts, meadowsweet (Filipendula ulmaria) aerial parts and raspberry (Rubus idaeus) leaves. In order to analyze the antioxidant activity of the herbs, several methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation) were used. Blackberry leaves and meadowsweet extracts revealed the highest antioxidant activities via all methods. All extracts studied blocked almost completely the opsonized zymosan particle-activated ROS production by neutrophils from human whole blood. On the other hand, the effect of extracts on phorbol myristate acetate-activated ROS production was much milder and even nonsignificant in the case of chokeberry leaves. This latter result suggests that extracts (apart from their antioxidative activity) interfere with the signaling cascade of phagocyte activation upstream of the protein kinase C activation. The antimicrobial activity of the investigated extracts against 11 human pathogens was investigated using three different methods. Meadowsweet and blackberry leaves extracts had the highest antimicrobial effect and the lowest minimal inhibiting concentrations (MICs) against the microorganisms tested.

Biological activities of selected polyphenol-rich fruits related to immunity and gastrointestinal health.

Small fruits are a rich source of bioactive substances, including polyphenols, and are therefore suitable raw materials for the production of functional foods. In the current work, we studied the antioxidative properties of six fruits: rosehip, chokeberry, hawthorn, blackcurrant, blueberry and rowanberry via different methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation). Their effect on the production of reactive oxygen species (ROS) by phagocytes, antimicrobial properties against 11 human pathogens, and mitogenic effect on hamster spleen lymphocytes were also tested. Rosehip extract showed the highest antioxidant activity via ORAC, TRAP and HORAC assays, whereas blueberry extract was the most potent inhibitor of lipid peroxidation. All extracts inhibited ROS production of opsonized zymosan-activated phagocytes, indicating that extracts interfere with the signaling cascade of phagocyte activation upstream to the protein kinase C activation. Chokeberry, blackcurrant and rowanberry extracts revealed strong antimicrobial properties against a broad spectrum of microorganisms and also had the highest mitogenic activity.