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Family • Asteraceae
Yacon
Smallanthus sonchifolius (Poepp.) H.Robinson
POTATO BEAN
Ya gen
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| Scientific names | Common names |
| Helianthus esculentus Warsz. ex Otto & Dietr. | Yacon (Tag.) |
| Polymnia edulis Wedd. | Earth apple (Engl.) |
| Smallanthus sonchifolius (Poepp.) H.Robinson | Ground apple (Engl.) |
| Peruvian ground apple (Engl._ | |
| Potato bean (Engl.) | |
| Yacon strawberry (Eng.) | |
| Smallanthus sonchifolius (Poepp.) H.Rob. is an accepted name The Plant List | |
| Other vernacular names |
| AMARA: Aricona, Aricoma (Bolivia), Aricuma (Bolivia). |
| FRENCH: Poire de terre. |
| JAPANESE: Yaakon. |
| QUECHUA: Llacjon, Llacoma, Llacón (Peru, Bolivia), Llacum, Llacuma, Llakuma (Peru, Bolivia), Llamón, Llaqon, Yacumpi. |
| SPANISH: Arboloco (Colombia), Chicama, Colla, Jacón, Jícama, Jíquima (Venezuela, Colombia, Ecuador), Jíkima, Jiquimilla (Venezuela, Colombia), Polaco, Puhe, Racón, Shicama, Taraca, Yacón (Bolivia, Peru). |
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Distribution Constituents
Properties Parts utilized Edibility / Nutrition - Fresh tubers are crisp and juicy when eaten raw; sweetness increases with storage. - The root looks likes a sweet potato, but with a completely different taste, texture, and nutrient profile. The taste is that of apple, watermelon, and celery combined. (59) - Yacon root syrup can be prepared by reducing yacon juice, which yields thick, dark, and sweet syrup. While touting many health benefits, over-consumption ,may cause digestive upsets, bloating, discomfort, nausea and diarrhea. (59) - Tubers also steamed, baked, or roasted. Also, processed into jams, juice, cereals, etc. (2) - In Japan and Brazil, aerial parts used as components of medicinal tea. (See caution below) (25) - Rich in potassium, calcium, and phosphorus. Folkloric - Decoction of leaves used as tea for diabetics. - In South America, the raw tubers as a diuretic for kidney and bladder problems. - In Bolivia, decoction of leaves used for cystitis, hepatosis and nephrosis. - In Peru, warm poultice of leaves used for myalgias and rheumatism. - In Brazil, leaves decocted for diabetes. Studies • Local Root Crops as Antioxidant: A 2006 study of commonly consumed roots crops in the Philippines (Kamote, Ipomoea batata; ubi, purple yam, Dioscorea alata; cassava, Manihot esculenta; taro or gabi, Colocasia esculenta; carrot, Daucus carota; yacon (Smallanthus sonchifolius) showed them to be rich sources of phenolic compounds with antioxidant activity, highest in sweet potato, followed by taro, potato, purple yam and lowest in the carrot. (1) • Phenolic Acid / Antioxidant: A study of the crude extracts of dried leaves and tubers of yacon yielded phenolic acids – chlorogenic, caffeic and ferulic acids – contributing to the radical scavenging activity detected. (4) • Cytoprotective / Anti-hyperglycemic: Report suggests the anti-hyperglycemic activity of tubers and cytoprotective activity of its leaves are probably due to the oligofructan and phenolic content, respectively. • Prebiotic: Inulin and oligofructose from the extracts of yacon roots known for its prebiotic properties presents a potential use in treating certain types of colitis by stimulating growth of Lactobacillus and Bifidogacterium microflora. (6) • Constipation / Colonic Transit Time: Yacon syrup's effect on colon-transit time was studied in healthy volunteers. Results showed an softer stools and acceleration of colonic transit time. Transit time through the gastrointestinal tract was significant decreased from 59.7 ± 4.3 to 38.4 ± 4.2 h (p<0.001). It was well tolerated with an excellent side effect profile. With its low caloric content, it presents a potential treatment of constipation in the obese and diabetic. (8) • Subchronic Toxicity Studies: A 4-month oral consumption of dried yacon root flour and diet supplement on normal Wistar rats showed to be well tolerated with no negative responses, toxicity, or adverse nutritional effects. It showed significantly reduced serum triglyceride levels. (9) • Antioxidant / Cytoprotective/ Antihyperglycemic: All extracts exhibited strong protective activity against oxidative damage to rat hepatocyte cultures, reduced hepatic glucose production via gluconeogenesis and glycogenolysis. The combination of radical scavenging, cytoprotective and antihyperglycemic activities presents a potential use in the prevention and treatment of chronic diseases involving oxidative stress, especially diabetes. • Antibacterial: Study showed the enhancement and antimicrobial activity of yacon leaves against methicillin-resistant Staphylococcus aureus in the presence of light. (10) • Antiteratogenic Potential: Extracts from the leaf of P. laevigata and yacon tubers (Smallanthus sonchifolius) were studied for antiteratogenic potential using duck embryos. Extracts administered with retinoic acid had antiteratogenic properties. (11) • Antidiabetic / Alpha-Glucosidase Inhibition: Study evaluated the inhibitory effect of smallanthaditerpenic acids A, B, C and D on alpha-glucosidases. Their IC50 were determined to be 0.48 mg/mL, 0.59 mg/mL, 1.00 mg/mL, and 1.17 mg/mL respectively. (13) • Antidiabetic / Tubers: Study evaluated the hypoglycemic effect of yacon tubers on alloxan-induced diabetes in mice. Results showed yacon significantly reduced blood sugar level. (14) • Decreased Hepatic Insulin Resistance: Study evaluated the effect of a yacon diet on blood glucose. Results showed reduction of blood glucose likely due to its beneficial effects on hepatic insulin sensitivity in the insulin resistance state. (16) • Yacon FOS (Fructo-Oligosaccharides) / Prebiotic: Study have shown the benefits of prebiotics like inulin and FOS in health and nutrition. This study showed yacon can prevent enteric infection caused by S. typhimurium, the effect mediated by enhancing non-specific immunity, such as total S-IgA, that improves the immunological intestinal barrier. (17) • Antibacterial Activity of Leaf Constituents / Enhydrin: Study investigated the antibacterial activity of leaf constituents enhydrin, polymatin B, alloschkuhriolide. Results showed only enhydrin showed antibacterial activity against MRSA (methicillin resistant Staphylococcus aureus). (18) • Yacon Fructans Effect on Maintenance of Healthy Bones: Yacon flour consumption significantly resulted in a positive Ca and Mg balance leading to higher bone mineral retention and biomechanical properties. The positive effects on mineral intestinal absorption, bone mass, and biomechanical properties showed yacon's important role in the maintenance of healthy bones. (19) • Trypanocidal / Chagas Disease: Study isolated sesquiterpene lactones enhydrin, uvedalin, and polymatin B from an organic extract of S. sonchifolius. The compounds were tested for trypanocidal activity against Trypanosoma cruzi. Results suggest enhydrin and uvedalin might have potential as agents against Chagas disease. (20) • Antioxidant / Leaves: Study evaluated various extracts of leaves for antioxidant activity and phenolic content. Study yielded protocatechuic, chlorogenic, caffeic and ferulic acids from two fractions. Both fractions showed potent antioxidant activity in the DPPH and xanthine/XOD superoxide radical scavenging tests. Results suggest the use of leaves in human diet may be a potential remedy for the prevention of chronic diseases cause by radicals, e.g., arteriosclerosis. (21) • Constituents and Activities: Study evaluated the botany, composition, and main constituents of Smallanthus sonchifolius (yacon) and Lepidium meyeni (maca). The potential of yacon tubers to treat hyperglycemia, kidney problems and skin rejuvenation and the antihyperglycemic and cytoprotective activity of leaves seem mostly related to its oligofructan and phenolic content. (22) • Glycemic Effect in Diabetic Rats: Study of crude extracts of leaves showed on STZ induced glycemia in rats showed the effectiveness of yacon extracts is related to the method of preparation and time of treatment. The hydroalcoholic extract significantly reduced the levels of glucose in the diabetic rats. (24) • Caution / Renal Toxicity Report / Leaves: Study evaluated the repeated-dose toxicity of three extracts of yacon leaves. Results showed renal damage associated with increased blood glucose levels after prolonged oral administration of aqueous extract. Evidence suggests the terpenoids were the main toxic compounds. Based on the results, the study did not recommend the oral use of yacon leaves to treat diabetes. (25) (also read, study below: 50) • Effect of Hepatic Metabolism: Study of extracts and fractions of leaves extracts showed strong protective effect against oxidative damage to rat hepatocyte cultures, reduced glucose production via gluconeogenesis and glycogenolysis. The combination of radical scavenging, cytoprotective and anti-hyperglycemic activity of leaves suggest potential for use in prevention and treatment of chronic diseases involving oxidative stress, particularly diabetes. (26) • Prebiotic Effect on Intestinal Mucosa / Yacon Root Flour: Study evaluated the prebiotic property of yacon root flour and its influence on the intestinal microbiota and gut immune system using a mice model. Results showed long term administration of yacon root flour maintained the intestinal homeostasis without inflammatory effect regulated through IL-10 and IL-4 regulatory cytokines. (27) • Protective Effect / Colon Carcinogenesis: Study investigated the potential benefit of yacon intake on colon carcinogenesis induced by DMH in male Wistar rats. Results showed a significant reduction in number of aberrant crypt foci and number of invasive adenocarcinomas. Results suggest dried extract of yacon root or a symbiotic formulation of yacon plus Lactobacillus casei intake may reduce the development of chemically-induced colon cancer. Study suggests yacon root intake may have a potential as chemopreventive agent against colon carcinogenesis. (28) • Topical Anti-Inflammatory / Effect on Neutrophil Migration: Study evaluated the in vivo topical anti-inflammatory potential of a leaf-rinse extract from dried leaves of yacon on croton oil ear edema assay in mice. Results showed topical anti-inflammatory effect with anti-oedematogenic activity followed by inhibition of neutrophil migration. (29) • Colonic Health Maintenance: Study in rats showed consuming 10% yacon tuber powder and cookies containing 14.75% yacon tuber (equivalent to 5% and 9.5% of FOS, respectively) for 28 days resulted in changes in bowel habit, cecum size, SCFAs production and intestinal microbial community significantly different from consumption of commercialized FOS and placebo cookies. Results suggests yacon tuber consumption may play an important and slightly different role in colonic health. (31) • Improved Antioxidant Activity: Study evaluated the effects of different forms of yacon extracts on the lipid oxidation and color of emulsion-type sausage. Study reported significant decrease in pH and residual nitrite values, increased thiobarbituric and reactive substances. Results suggest the addition of 20% yacon extract to emulsion-type sausages was most effective in improving lipid oxidative stability. (32) • Comparative Hypoglycemic Activity of Yacon and Stevia: Study evaluated ethanolic leaf extracts of Yacon and Stevia for hypoglycemic action in streptozotocin induced diabetic mice. Results showed Stevia rebaudiana exhibited hypoglycemic activity comparable to the drug metformin while the leaf extract of Smallanthus sonchifolius showed no hypoglycemic action. (33) • Hypoglycemic / Hypolipidemic / Tuber Extract and Chlorogenic Acid Constituent: Study evaluated the hypoglycemic effect of Yacon tuber extract and its constituent, chlorogenic acid (CGA), in streptozotocin induced diabetic rats. Results showed a significant hypoglycemic effect, together with significant decreases in total cholesterol and triglycerides. Radical scavenging activity of CGA was similar to vitamin E control. Results suggest a potential in the management of hyperglycemia and diabetic nephropathy. (34) • Hypolipidemic / Roots: Frutooligosaccharides (FOS) are sugars naturally found at high concentrations in storage roots of yacon. Study evaluated the effects of subchronic oral consumption of yacon root flour as diet supplement in STZ-induced diabetic Wistar rats. The FOS-rich yacon flour did not significantly alter the weight of test animals. There was a significant decrease in fasting plasma triacylglycerol and VLDL. An identified incretin could be an effective mediator of the lipid lowering effects of FOS present in the yacon flour. Results suggest yacon root flour, a natural product rich in FOS, has potential as a nutraceutical product with beneficial effects in diabetes-associated hyperlipidemia. (36) • Caffeic Acid / Roots: Study of a phenolic fraction of yacon roots yielded major water-soluble phenolic compounds: two of these were chlorogenic acid (3-caffeoylquinic acid) and 3,5-dicaffeoylquinic acid; three were novel caffeic acid esters of altraric acid, viz. 2,4- or 3,5-dicaffeoylaltraric acid, 2,5-dicaffeoylaltraric acid, and 2,3,5- or 2,4,5- tricaffeoylaltraric acid. (35) • Effect of Aging on Fermented Yacon and Sensory Profile: Perishability and low production volume is a problem. Study analyzed the changes in aging during one year of storage and sensory analysis of fermented yacon. At the end of the one-year aging, total and volatile acidity increased significantly (p<0.05), together with a decrease in FOS (fructooligosaccharide). The product showed good antioxidant capacity with acceptable sensory profiles. Results suggest alternatives in the industrial sector and potential for farmers to do large-scale production. (37) • Effect on Pancreatic Fibrosis: Study in rats suggests 1% yacon extract has an inhibitory effect on DBTC-induced pancreatic fibrosis. (39) • Prebiotic and Immunomodulatory Effect: Yacon tubers contain frutooligosaccharides (FOS), known as prebiotics, beneficial in improving the host's intestinal flora balance and enhance immunomodulatory potential. This study investigated the effect of FOS-rich yacon extract on intestinal flora and immune system of BABL/c mice sensitized and challenged with ovalbumin. Study showed improvement in intestinal flora. Results suggest yacon-derived FOS can epidemiologically improve Th1/Th2 cytokine balance through its prebiotic effect on the number of beneficial bacterial in the animal gut. (40) • Effect in an Intestinal Infection Model of Salmonella typhimurium: Study analyzed the preventive effects of yacon on enteric infection caused by a strain of Salmonella enteritidis serovar typhimurium in a mouse model. Results suggest yacon can prevent enteric S. typhimurium infection given up to 30 days, mediated by enhancing non-specific immunity such as total S-IgA which improved the immunological intestinal barrier. (41) • Comparative Antioxidant Effect of Leaves and Roots: Study compared the in vivo hepatic antioxidant activity of hydroalcoholic extracts of yacon leaves and roots in rats with STZ-induced diabetes in terms of in vitro antioxidant capacity. Both roots and leaves extract restored the increased protein carbonyl levels to normality, while the roots extract restored ROS levels to normality. The in vivo action of the root extract was more effective than the leaf extract in reducing hepatic oxidative stress that accompanies diabetes. (42) • Invention / Buccal Tablet Formulation: An invention reports on the use of dried power of Smallanthus sonchifolius as the main drug component in buccal tablet formulation, as well as fermented S. sonchifolius leaves, chrysanthemum and liquorice extracts as adjuvant components together with auxillary ingredients. The resulting buccal tablet has the characteristic of diminishing inflammation, inhibiting bacteria, as well as a pleasant mouth-feel and easy absorption property. (43) • Bioactivities of Phenolic Compounds / Antioxidant: Phenolic extracts were found to have significant DPPH radical scavenging activity and significant anti-lipoperoxidativve activity on rat liver microsomes comparable to commercial supplement containing silymarin. On CAM vascular irritation assay, the phenolic extract exhibited an anti-inflammatory activity comparable to hydrocortisone. (see constituents above) (44) • Attenuation of Hyperglycemia and Skeletal Muscle Oxidative Stress in Diabetes: Study evaluated the effect of a hydroalcoholic extract of Yacon leaves on antioxidant, glycemic, and anti-inflammatory biomarkers in diabetic rats. Results showed improvement in the biomarkers which may be mediated via improvement of glucoregulation and amelioration of oxidative stress and inflammation, particularly in diabetic rats. (46) • Antioxidant Effects of Herbal Tea Leaves: Study evaluated the potent antioxidative effects of herbal tea leaves from yacon using different free radical models and a ferric reducing model. A hot water extract exhibited the highest yield of total polyphenol and scavenging eff3ect on DPPH assay. Results support the potential of yacon tea leave as a good source of natural antioxidants for preventing O2-radical mediated disorders. (48) • Cytotoxic Potential / Anticancer Cell Lines / Leaves: Study evaluated the cytotoxic potential of various extracts of yacon leaves against MCF-7 (breast cancer), HT-29 (colon cancer), and HDFn (normal human dermal fibroblast) cell lines. Results showed significant reduction in cellular viability of MCF-7 cells lines in a dose-dependent manner. DCM extract showed most potency against MCF-7 and significant cytotoxicty against HT-29 cells, with IC50 lower than 5-FU. (49) • Safety and Toxicity Studies: Review reports on safety and toxicity studies. In an acute toxicity study of normal healthy rats treated with 2, 5, 10 times greater than effective dose of different organic extracts of yacon leaves or isolated compound enhydrin, there were no deaths or signs of acute toxicity (Genta et al, 2010; 2012). Administration of yacon extracts for two generations showed no effects on reproductive functions or development of live-born pups (Ogose et al., 2009). A toxicity study of various doses of 10% yacon leaves decoction (25, 50, and 100 times) and enhydrin (100, 200, and 400 times) for effective hypoglycemic doses for up to 14 days, showed no signs of toxicity or deaths, suggesting an LD50 of about 14.0 and 0.32 g/kbw, respectively (Serra Barcellona et al, 2001; Honore et al; 2012). (50) • Improvement of Gut Health in a Model of Colon Cancer: Study evaluated the intestinal effects of YF (yacon flour) supplementation in an animal model of induced colon cancer. Results showed YF was effective in the modulation of gut health in the animal model of colon cancer. (51) • Sesquiterpene Lactones / Leishmanicidal and Trypanocidal: Study evaluated the activity of enhydrin, uvedalin, and polymatin B, three sesquiterpene lactones (STLs) isolated from S. sonchifolius, on Leishmania mexicana (MNYC/BZ/62/M) and Trypanosoma cruzi (Dm28c). intracellular amastigotes. In in vivo study, enhydrin and uvedalin displayed a significant decrease in circulating parasites (50-71%) and no signs of hepatotoxicity. The three compounds showed leishmanicidal and trypanocidal activity on different parasite stages. (52) • Health-Promoting Benefits of Fructooligosaccharides / Yacon as Food Supplement: Review addresses the role of yacon supplementation in promoting health and reducing risk of chronic diseases. Several pre-clinical and clinical trials have suggested suggested the growth of health promoting bacteria while reducing pathogenic bacteria populations. The end products of FOS fermentation by the intestinal microbiota, short chain fatty acids, act as substrates or signaling molecules in the regulation of immune response, glucose homeostasis, and lipid metabolism. Most studies have concluded that due to its functional properties, yacon roots can be used as a dietary supplement to prevent and treat chronic diseases. (53) • Toxiogenetic Study / Safety Profile: Study evaluated the in vitro potential genotoxic effects of the aqueous extract of yacon to determine its safety and phytochemical composition. The aqueous extract was prepared in the popular formulation of tea bags. MTT test determined the range of doses and Cytome assay assessed genotoicity. Chemical analysis revealed the presence of sesquiterpene lactones (STLs) enhydrin and the dimer enhydrofolin, as main compounds, along with phenolic compounds. Increasing concentration of the extract induced a cytotoxic effect on CHO-K1 and HepG2 cells. Results demonstrated the inability of the metabolic system to counteract the genetic instability, allowing the safe consumption of the leaves as a 2% tea infusion of up to 250 mL/day. (54) • Renal Toxicity Concern with Leaves: Studies on the safety of prolonged oral consumption of yacon leaf extracts are lacking. Study evaluated the repeated-dose toxicity of three extracts of yacon leaves i.e. aqueous extract (AE) prepared as tea infusion, a leaf-rinse extract (LRE) which is rich in sesquiterpene lactones (STLs), and a polar extract from leaves without trichomes, or polar extract (PE) which lacks STLs but is rich in chlorogenic acid. The toxicity of each extract was evaluated in a repeated-dose toxicity study in Wistar rats for 90 days. Alterations of specific biochemical parameters in the blood (creatinine, glucose and albumin of rats treated with AE pointed to renal damage, which was confirmed by histological analysis of the kidneys. The renal damage as associated with increased blood glucose levels after prolonged administration of the AE, which suggested that the hypoglycemic effect seen in an earlier study after 30 days treatment is reversible and likely caused by renal injury from yacon toxicity. Because of STLs detected in both AE and LRE, evidence suggests the terpenoids are the main toxic compounds in leaves. Based on the results, the authors do not recommend the oral use of yacon leaves to treat diabetes. (56) • Antihyperglycemic / Diabetic Wound Healing / Leaves: Study evaluated the antihyperglycemic and diabetic wound healing activity of yacon leaves extract. Diabetic condition was induced by streptozotocin and nicotinamide in rats. Wound was induced by punch biopsy. Yacon leaves extract was administered both orally and topically. Results showed antihyperglycemic and diabetic wound healing activities comparable to reference drugs glibenclamide and nebacetin cream. (59) Note Availability |
© Godofredo U. Stuart Jr., M.D. / StuartXchange |
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| PHOTOS / ILLUSTRATIONS |
| Photo © Godofredo Stuart / StuartXchange |
| OTHER IMAGE SOURCE / Flower / Public Domain / File:Smallanthus sonchifolius .p.jpg/ Bob Hille / Nederlands: Smallanthus sonchifolius yacon Wikipedia |
| OTHER IMAGE SOURCE / TUBERS / File:Yacon.jpg / Phote by Fk. 2005 / GNU Free Documentation License / click on image to go to source page / Wikimedia Commons |
Additional
Sources and Suggested Readings |
DOI |
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| List of Understudied Philippine Medicinal Plants |
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General
info 
Botany
• Major portion of tuberous root biomass is water (>70% of fresh weight), saccharides, especially oligofructans (70-80% of dry weight), protein content (0.3% to 3.7%). (
