title: Plectranthus amboinicus leaves stimulate growth of probiotic L. plantarum: evidence for ethnobotanical use in diarrhea.
abstract: BACKGROUND
  Leaves of Plectranthus amboinicus are consumed in India along with buttermilk (a probiotic source) during pathogen induced diarrhea. This treatment is known to reduce the number of episodes as well as duration of diarrhea.
  
  
  OBJECTIVE
  In the background of its ethnobotanical use, the present investigation was carried out to determine whether, apart from having an antimicrobial activity on pathogens, the leaves could possibly also have a positive effect on the beneficial microflora of the gut resulting in accelerated microbial ecological balance.
  
  
  METHODS
  The growth stimulating activity of the hot water extract (HWE) of P. amboinicus leaves on probiotic Lactobacillus plantarum was determined by microbroth dilution technique and viable plate count method in selective medium (MRS) as well as in fermented milk. The ability of the bacteria to utilize the phytoconstituents of HWE primarily phenolic acids and sugars was determined by assaying for phenolic acid decarboxylase by SDS-PAGE and β-galactosidase activity by β-gal ONPG assay.
  
  
  RESULTS
  HWE of P. amboinicus leaves inhibited growth of pathogens (Escherichia coli and Salmonella typhimurium) while stimulated the growth of L. plantarum. SDS-PAGE gel showed the presence of phenolic acid decarboxylase enzyme induced in the presence of HWE in L. plantarum indicating the utilization of polyphenols by the bacteria. Cells grown on HWE also showed β-galactosidase activity indicating their ability to utilize sugars present in HWE.
  
  
  CONCLUSIONS
  Indian borage leaves have a prebiotic effect on the probiotic bacteria (L. plantarum) which utilizes the phytoconstituents of the leaves by producing necessary metabolic enzymes. This work provides evidence in the traditional use of the leaves in the alleviation of diarrhea by accelerating microbial gut balance during infection.
authors: Fermentation Technology and Bioengineering Department, CSIR-Central Food Technological Research Institute, Mysore 570020, India.
authors: J R
authors: JR
authors: Shubha
authors: Fermentation Technology and Bioengineering Department, CSIR-Central Food Technological Research Institute, Mysore 570020, India. Electronic address: praveena@cftri.res.in.
authors: Praveena
authors: P
authors: Bhatt
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D043302:Cultured Milk Products / Q000382:microbiology; D003967:Diarrhea / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects; D020834:Ethnopharmacology / Q000379:methods; D005285:Fermentation / Q000502:physiology; D007194:India; D048191:Lactiplantibacillus plantarum / Q000187:drug effects* / Q000254:growth & development*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D031346:Plectranthus / Q000737:chemistry*; D019936:Probiotics / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D010936:Plant Extracts; D001616:beta-Galactosidase
keywords: L. plantarum; Phenolic acid decarboxylase; Plectranthus amboinicus; Polyphenols; Probiotic