Effect of phytochemicals from selected medicinal plant(s) on probiotic bacteria and their influence on gut health.

Phytochemicals such as polyphenols are plant secondary metabolites known for their bioactive properties. However, the majority of the polyphenols
(> 90%) reach the colon undigested, where they are acted upon by the colonic microflora, which plays an important role in their breakdown as well
as absorption. The activity of phytochemicals, in turn, govern the composition of the gut microbial population and/or their activity. This mutual
interaction plays a key role in maintaining gut homeostasis as well as influences host health. Reports on the effect of phytochemicals like
polyphenols on gut microbiota are scarce, and research on their mutual interactions is still in its infancy. Since probiotic bacteria are representative
gut inhabitants, initial studies were carried out to study the effect of polyphenol-rich extracts (PRE) on probiotic growth and metabolism. Extracts
of seven plants/plant parts were selected (Acacia catechu- AcE, Cyclea peltate- CpE, Holarrhena antidysentrica- HaE, Plectranthus amboinicus�PaE, Ruta graveolens- RgE, Solanum nigrum- SnE, and Woodfordia fruticosa- WfE) and studied for their antioxidant and growth stimulatory
properties on probiotic bacteria (Lactobacillus plantarum, L. casei and L. rhamnosus). Results indicated that the effect of PRE was both
concentration and plant-dependent. Based on the results, WfE which showed appreciable growth stimulation of probiotic bacteria (≈1.5 log CFU/ml
increase), enhancement in adhesion to Caco2 monolayer (≈1.5 logs CFU/ml), and good antioxidant (DPPH inhibition > 50% at 1 mg/mL) property,
in comparison to control (without extract), was selected for further studies.