| General
ino
A menber of the sunflower
family, native to the lower Peruvian Andesand many many South American
forest regions, and long valued as a root crop. It was first recorded
as a native cultivated root cxrop by the Andeans in 1615. Fresh tubers
are crisp and juicy redolent of apples and melons, sometimes referred
to as "Apple of the Earth." It has a sweetness that increases
with storage. Eaten raw, baked, roasted, jammed, juiced into syrup or
drinks, or made into pudding dishes.
 Botany
Yacon is a perennial herb growing
to a height of 2 to 3 meters. Leaves are broadly ovate with widely toothed
margins and extending into the stems. Flowers are daisy-like, yellow to orange,
avidly pollicated by insects. Rootcrop is edible, fleshy, yellowish white,
sweet, with a crisp consistency of sinkamas.
Distribution
- Recently introduced and
cultivated in the Mountain Province area.
- Originally cultivated in the Andean highlights.
- Reported in China and Japan.
Constituents
• The root or tuber is a rich source of fructo-oligosaccharides
(FOS), 'prebiotics' responsible for the sweet flavor while poorly metabolized
or digested, a characteristic for a potential low calorie sweetener.
• Probiotic and antioxidant properties from protocatechuic, chlorogenic,
caffeic and ferulic acids found in the leaves.
• Inulin may be responsible for its effect on blood sugar.
• Leaves yield monoterpenes, sesquiterpenes, and diterpenes.
• Tubers yield a high content of oligofructans and polyphenols.
• Other chemicals documented in yacon include: y-cadinene, caffeic-acid,
3-caffeoylquinic-acid, chlorogenic-acid, 2,4-dicaffeoylaltraric-acid,
2,5-dicaffeoylaltraric-acid, 3,5-dicaffeoylaltraric-acid, 3,5-dicaffeoylquinic-acid,
enhydrin, ferulic-acid, fluctuanin, gallic-acid, gentisic-acid, inulin,
melampolides, oligofructans, beta-pinene, protocatechuic-acid, rosmarinic-acid,
sonchifolin, tryptophan, 2,3,5-tricaffeoylaltraric-acid, 2,4,5-tricaffeoylaltraric-acid,
and uvedalin.
• Chloroform fraction of alcohol extract of leaves yielded seven compounds: gallic acid, beta-sitosterol, behenic acid, kaempferol, quercetin, vanillic acid, hexadecanoic acid.
Properties
• Hypoglycemic,
antioxidant, antibacterial, antifungal, liver protector.
• Antibacterial, antifungal, antidiabetic.
Parts utilized
Leaves and root crop.
Uses
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, leaves are decocted 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 acitivity, highest in sweet potato, followed by taro, potato,
purple yam and lowest in the carrot.
• Phenolic
Acid / Antioxidant:
(1) 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. (2)
Study descries the antioxidant activity of SS and its phenol content
and suggests a potential of SS leaves in the human diet for prevention
of chronic radical-induced diseases.
• 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.
• 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. With
its low caloric content, it presents a potential for the treatment of
constipation in the obese and diabetic.
• 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.
• 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.
• 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.
• Antidiabetic: (1) 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. (2) Study evaluated the hypoglycemic effect of yacon tubers on alloxan-induced diabetes in mice. Results showed yacon significantly reduced blood sugar level.
Note
Although the roots
and tubers are popular marketed for its diabetic benefits, many studies report the hypoglycemic
or sugar-lowering effect only in the leaves.
Availability
Cultivated
Commercial herbal tea leaves.
Root and leaf extracts in the cybermarket. |
