In Vitro Assessment of Prebiotic Potential of Culinary Spices

Abstract

BackgroundSpices are rich sources of phenolic compounds and have a number of demonstrated disease preventive activities. Diet is one of the important factors contributing to the gut microbial composition that ultimately affects human health. Several recent in vitro, in vivo and human studies showed that (poly)phenol‐rich dietary sources influence the relative abundance of different bacterial groups within the gut microbiota by reducing the numbers of potential pathogen and certain Gram‐negative Bacteroides species and enhancing beneficial bifidobacteria and lactobacilli.ObjectiveThe present study investigated chemical composition, antioxidant activity and prebiotic potential of spices using an in vitro model.MethodsSeven culinary spices including black pepper (BLP), cayenne pepper (CAP), cinnamon (CIN), ginger (GIN), Mediterranean oregano (ORE), rosemary (ROS) and turmeric (TUR) were extracted with boiling water. Major chemical constituents were characterized by UV‐HPLC method and antioxidant capacity was determined by measuring colorimetrically the extent to scavenge ABTS+ radical cations. Effects of spice extracts on the growth of 88 intestinal bacterial strains were determined by using Brucella agar plates containing serial dilutions of extracts.ResultsA total of 13 phenolic compounds, a piperine, cinnamic acid and cinnamaldehyde were identified and quantitated from 7 spices. Spice extracts exhibited high antioxidant capacity that correlated with the total amount of major chemical constituents identified. All spice extracts, with the exception of TUR, stimulated the growth of Bifidobacterium spp. and Lactobacillus spp. All spices exhibited high inhibitory activity against Ruminococcus species. CIN, ORE and ROS were active against Fusobacterium strains, and CIN, ROS and TUR were active against Clostridium spp.ConclusionsSeveral spices displayed prebiotic‐like activity by promoting the growth of beneficial bacteria and suppressing the growth of pathogenic bacteria, suggesting their potential role in the regulation of intestinal microbiota and the enhancement of gastrointestinal health. The identification and quantification of spice‐specific phytochemicals provided insight into the potential influence of these chemicals on the gut microbial communities and activities.Support or Funding InformationSupported by departmental funds from the Center for Human Nutrition, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles.