Poster Presentation Australian Microbial Ecology 2022

In vitro simulated gastrointestinal digestion and colonic fermentation of a fixed combination of Euphorbia hirta L. extract and probiotic bacteria (#110)

Phil Aidan C. Cruz 1 , Hafiz Ansar Rasul Suleria 1 , Senaka Ranadheera 1
  1. School of Agriculture & Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia

The common spurge, Euphorbia hirta L., is an important medicinal plant used throughout parts of South and Southeast Asia for a range of indications, including diarrhoea, asthma, and dengue-induced thrombocytopenia [1,2,3]. The aqueous extracts of the plant are known to contain an abundance of glycosylated metabolites, including flavonol rhamnosides (FR) and rhamnoglucosides (FGR), such as quercitrin (Q3R), myricitrin (M3R), and rutin (R3GR) [4]. As human intestinal cytosolic β-galactosidase (CbG) and lactose phlorizin hydrolase (LPH) are unable to cleave the glycosidic L-rhamnose moiety, these compounds are subject to metabolism by gut microflora in the large intestine [5]. Because of the nature of the metabolism of compounds such as FRs and FGRs, inter-individual variability in gut microbiome composition is postulated to play a significant role in their biotransformation and conferral of pharmacological effects [6]. One of the acceptable approaches to improve the bioavailability of such compounds dependent on transformation by gut bacteria is through the co-administration of probiotic strains capable of metabolising the compounds in situ [7]. Considering this approach, we investigated the effects of combining E. hirta aqueous extracts with the probiotic strains Lactiplantibacillus plantarum MG207 and Lacticaseibacillus rhamnosus MG316 on the metabolic profiles of the extracts produced during in vitro simulated gastrointestinal digestion and colonic fermentation. From this study, we demonstrated that E. hirta extracts may be co-administered with probiotic bacteria without eliciting any significant antibiotic effect (p > .05), and that both L. plantarum MG207 and L. rhamnosus MG316 are capable of partially metabolising compounds present in E. hirta aqueous extracts such as major flavonoid glycosides in vitro. These findings provide a preliminary insight into the practicality of probiotic co-administration as a means of standardising the bioactivity of E. hirta extracts. Future studies should aim to validate these findings through in vitro intestinal cell permeability assays and in vivo methods to determine whether these metabolic changes correlate to increases in the bioavailability of bioactive compounds present in the extracts.

  1. Perera, S. D., Jayawardena, U. A., & Jayasinghe, C. D. (2018). Potential Use of Euphorbia hirta for Dengue: A Systematic Review of Scientific Evidence. Journal of tropical medicine, 2018, 2048530. https://doi.org/10.1155/2018/2048530
  2. Xia, M., Liu, L., Qiu, R., Li, M., Huang, W., Ren, G., & Zhang, J. (2018). Anti-inflammatory and anxiolytic activities of Euphorbia hirta extract in neonatal asthmatic rats. AMB Express, 8(1). https://doi.org/10.1186/s13568-018-0707-z
  3. Ali, M. Z., Mehmood, M. H., Saleem, M., & Gilani, A.-H. (2020). The use of Euphorbia hirta L. (Euphorbiaceae) in diarrhea and constipation involves calcium antagonism and cholinergic mechanisms. BMC Complementary Medicine and Therapies, 20(1). https://doi.org/10.1186/s12906-019-2793-0
  4. Mekam, P. N., Martini, S., Nguefack, J., Tagliazucchi, D., & Stefani, E. (2019). Phenolic compounds profile of water and ethanol extracts of Euphorbia hirta L. leaves showing antioxidant and antifungal properties. South African Journal of Botany, 127, 319–332. https://doi.org/10.1016/j.sajb.2019.11.001
  5. Nemeth, K., Plumb, G. W., Berrin, J.-G., Juge, N., Jacob, R., Naim, H. Y., Williamson, G., Swallow, D. M., & Kroon, P. A. (2003). Deglycosylation by small intestinal epithelial cell b-glucosidases is a critical step in the absorption and metabolism of dietary flavonoid glycosides in humans. European Journal of Nutrition, 42(1), 29–42. https://doi.org/10.1007/s00394-003-0397-3
  6. Lin, L., Luo, L., Zhong, M., Xie, T., Liu, Y., Li, H., & Ni, J. (2019). Gut microbiota: a new angle for traditional herbal medicine research. RSC Advances, 9(30), 17457–17472 https://doi.org/10.1039/c9ra01838g
  7. Vamanu, E., & Gatea, F. (2020). Correlations between Microbiota Bioactivity and Bioavailability of Functional Compounds: A Mini-Review. Biomedicines, 8(2), 39. https://doi.org/10.3390/biomedicines8020039