PARTE UTILIZADA= Used part: Raíz, hojas, tallos. 

ACCIÓN FARMACOLÓGICA= Pharmacological action: Hipoglicemiantes. 

ZONA GEOGRÁFICA= Geografical zone: Argentina.  

DIVERSIDAD GENÉTICA Y MEJORAMIENTO DE PLANTAS MEDICINALES= Medicinal plants and improvement of medicinal herbs

 This paper focuses on the biol. and chem. variability of four yacon (Smallanthus sonchifolius) accessions cultivated under field conditions.  Significant variations in tuber shape, wt., content of oligofructans, as well as in leaf isoenzymes, phenolics, and relative DNA contents were found.  Accessions 6 and 88 were the most productive (up to 3.01 and 3.74 kg/plant); accession 48 was the most balanced from the yield aspect in three vegetative periods.  A significantly higher content of beta-(2®1) oligofructans was noted in accessions 48 and 88 as compared to 6 and 60.  No difference in sucrose, glucose, and fructose level was obsd.  Only accession 6 exhibited sep. acid phosphatase and esterase isoforms.  Accessions 6 and 60 had the highest content of phenolics, and accession 88 had the lowest relative DNA content.  Large yacon intraspecific variation may be useful in future detailed research as a good background for breeding, growing, and utilization in industrial processing.  

ÚLTIMOS AVANCES EN LA QUÍMICA Y ACTIVIDADES BACTERIOLÓGICAS EN LAS PLANTAS MEDICINALES= Medicinal plants, last advances on chemistry and bacteria activities on the medicinal herbs

1) Phytochem. investigation of the leaf of Smallanthus sonchifolius led to the isolation and identification of a new phenylpropanoid named Smallanactone A.  The structures was elucidated by anal. of spectroscopic data and it antioxidant activity was evaluated.  It showed antioxidant activity with an IC50 value of 0.46 mg/mL.

2) Prebiotics are non-digestible but fermentable oligosaccharides that can influence the compn. and the activity of some intestinal bacteria to promote the health of the host.  Smallanthus sonchifolius (yacon) contains beta-1,2-oligofructans as the main saccharides and its roots are consumed in South American countries.  The aim of the study was to evaluate the prebiotic property of yacon root flour.  Its influence on the intestinal microbiota and gut immune system were evaluated using a mice model.  The results show the prebiotic effects of yacon root flour, stimulating the growth of bifidobacteria and lactobacilli and the intestinal immune system with increases in IgA and different cytokines.  Cells from the innate response were mainly involved in the effect of yacon root flour.  T cells were also activated and able to induce IL-10 and IFNg prodn.  The long term administration of yacon root flour maintained the intestinal homeostasis without inflammatory effect regulated mainly through IL-10 and IL-4 regulatory cytokines.

3) The aim of the present study was to det. the in vivo hypoglycemic activity of five org. exts. and enhydrin obtained from yacon leaves.  The main constituents of the most active fraction were identified.  Five org. exts. and pure cryst. enhydrin were administered to normoglycemic, transiently hyperglycemic and streptozotocin (STZ)-diabetic rats.  The fasting and post-prandial blood glucose, and serum insulin levels were estd. and an oral glucose tolerance test (OGTT) was performed for the evaluation of hypoglycemic activity and dose optimization of each ext.  We found that the methanol, butanol and chloroform exts. showed effective hypoglycemic activity at min. doses of 50, 10 and 20 mg/kg body wt., resp., and were selected for further expts.  Oral administration of a single-dose of each ext. produced a slight lowering effect in the fasting blood glucose level of normal healthy rats, whereas each ext. tempered significantly the hyperglycemic peak after food ingestion.  Daily administration of each ext. for 8 wk produced an effective glycemic control in diabetic animals with an increase in the plasma insulin level.  Phytochem. anal. of the most active fraction, the butanol ext., showed that caffeic, chlorogenic and three dicaffeoilquinic acids were significant components.  Addnl., enhydrin, the major sesquiterpene lactone of yacon leaves, was also effective to reduce post-prandial glucose and useful in the treatment of diabetic animals (min. dose: 0.8 mg/kg body wt.).  The results presented here strongly support the notion that the phenolic compds. above as well as enhydrin are important hypoglycemic principles of yacon leaves that could ameliorate the diabetic state.

Summary
Yacon (Smallanthus sonchifolius – Asteraceae) is a species native to the Andean regions of Southern Peru, Northern Bolivia, and Northwestern Argentina (Salta and Jujuy). Although the importance of yacon is mainly in the nutritional field (the fresh or desiccated tubers are edible), some medicinal uses have also been reported for this plant. Recent pharmacological studies in animals and plants have shown the benefits of yacon and of the fructose-oligosaccharides in nutrition in general, and to the digestive system in particular, mainly due to their behavior as probiotics and dietary fibres. Hypoglycemic, hypocholesterolemic, and colon cancer preventive properties have also been described for these compounds.

1) ALONSO, Jorge ; DESMARCHELIER, Cristian. Plantas medicinales autóctonas de la Argentina : bases científicas para su aplicación en atención primaria de la salud.  Buenos Aires: L.O.L.A, 2005, p. 567.

2) VALENTOVA, Katerina, et al. The Biological and Chemical Variability of Yacon.  Journal of Agricultural and Food Chemistry . 2006, vol.54, nº4, p.1347-1352.
 
3) RUAN, Shucheng, et al. A new phenylpropanoids from the leaf of Smallanthus sonchifolius and its antioxidant activity.  Asian Journal of Chemistry . 2010, vol.22, nº7, p.5776-5778.
 
4) BIBAS BONET, M. E., et al. Prebiotic effect of yacon (Smallanthus sonchifolius) on intestinal mucosa using a mouse model. Food and Agricultural Immunology . 2010, vol.21, nº2, p.175-189.
 
5) GENTA, Susana B., et al. Hypoglycemic activity of leaf organic extracts from Smallanthus sonchifolius: Constituents of the most active fractions. Chemico-Biological Interactions . 2010, vol.185, nº2, p.143-152.

6) Plantas medicinales autóctonas de la Argentina. Bases científicas para su aplicación en atención primaria de la salud / Jorge Alonso y Cristian Jorge Desmarchelier. - 1a ed. - Ciudad Autónoma de Buenos Aires: Corpus Libros Médicos y Científicos, 2015.