(Linn.) Lam.
Habitat: Native to tropical America; cultivated throughout India for edible tubers.
English: Sweet potato.Ayurvedic: Mukhaaluka, Rataalu, Raktaalu, Raktapindaka, Raktakan- da.Siddha/Tamil: Sakkareivelleikulan- gu.Unani: Shakarkand, Rataalu.Action: Root—used in strangury, urinary discharges, burning sensation, thirst. Whole plant—used in low fever and skin diseases.
Cooked tubers contain reducing sugars 6.45, sucrose 2.23, maltose 864, dextrins 0.51 and polysaccharides 14-13%. Cooking increases the sweetness as a result of the hydrolysis of starch to maltose and dextrins through the action of beta-amylase.Sweet potatoes are rich in starch content. During the storage a part of starch content is converted into reducing sugars and subsequently into sucrose. In a sample stored for 5 months, the starch content was reduced from 19.1% to 14.1% while the percentage of reducing sugars (as dextrose) and sucrose increased from 0.9 to 1.7 and 1.9 to 6.1% respectively.Indian types with white flesh contain little or no carotene, while American types with pink flesh contain as high as 5.4-7.2 mg/100 g of carotene. Vitamins present in the tubers are : thiamine 0.09-0.14, riboflavin 0.05-0.10 and vitamin C 16-22 mg/100 g.The hot aqueous extract of leaves exhibits significant inhibitory activity of rat lens aldose reductase (AR). Ellagic and 3,5-dicaffoylquinic acids have been isolated as potent inhibitors.The leaves also contain polysaccha- rides which increase the platelet count in experimental animals due to enhanced production ofthrombopoietin.From the stem and root, hexadecyl, octadecyl and eicosyl p-coumarates have been isolated.The tubers show significant lectin activity and exhibit haemagglutinating activity in trypsinized rabbit erythro- cytes.
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