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DOI: 10.1055/s-0029-1239916
An extract from purslane herb might modulate glucose metabolism through multiple mechanisms
The purslane herb (Portulaca oleracea L.) is a very common plant used worldwide as a food ingredient. It is traditionally used in folk medicine for a variety of ailments, in Near East purslane is treasured as an aid against diabetes. Animal studies confirm that purslane herb has antidiabetic properties [1, 2, 3].
To investigate the efficacy of the herb for this indication, a hydroalcoholic extract from purslane herb, PortusanaTM (EFLA®308), was tested in vitro in three different assays related to glucose metabolism. Firstly, a glucose rapid-uptake assay was performed in Caco-2 cells to model glucose uptake through the intestinal wall. The extract significantly decreased the absorption of glucose compared to the control. Reduced glucose absorption through the intestine may contribute to a hypoglycaemic effect. Secondly, to assess whether the extract could affect glucose disposal in metabolically active cells, a glucose uptake assay was conducted in differentiated 3T3-L1 adipocytes as a model for adipose tissue. Portusana dose-dependently stimulated the uptake of glucose, both in presence and absence of insulin. These results show that the extract may enhance glucose disposal in adipocytes. Thirdly, the ability to modulate the nuclear receptor PPARγ was investigated in HEC-1B cells, since PPARγ is an important molecular target for antidiabetic activity. Portusana showed agonistic as well as antagonistic activity on PPARγ, clearly suggesting that the constituents in the extract are able to bind and to activate PPARγ.
In conclusion, the findings from these in vitro studies suggest that Portusana may affect different mechanisms related to the pathophysiology of diabetes mellitus.
Acknowledgements: We would like to acknowledge these institutions for the professional conduction of the assays: Department of Clinical Pharmacology & Toxicology, University Hospital, Basel, Switzerland, Prof. Dr. J. Drewe; Vitaplant AG Swiss Research Institute for Phytopharmaceutical Products, Witterswil, Switzerland, Dr. K. Berger Büter; Technische Universität Dresden, Institut für Zoologie, Chair for molecular cell physiology and endocrinology, Germany, Prof. Dr. G. Vollmer.
References: [1] Eskander EF, Won Jun H. Egypt J Pharm Sci 1995; 36: 331–342
[2] Shen L, Lu F. CJIM 2003; 9: 289–292
[3] Sinha BP et al Seyler's Zeit 1962: 274–275