Yacon leaf aqueous extract: Effects on diabetic oxidative stress and its therapeutic implications

Abstract

Oxidative stress, resulting from an imbalance between free radical production and antioxidant defenses, plays a key role in the pathogenesis of various diseases, including diabetes mellitus. In recent times, the search for safer natural antioxidants has intensified. Smallanthus sonchifolius [Poepp. & Endl.] H. Robinson (yacon) is a traditional Andean crop recognized for its pharmacological properties. We have previously demonstrated the efficacy and safety of aqueous extract of yacon leaves for treating hyperglycemia in rodents. This study aimed to analyze the major chemical components of a 10% yacon leaf decoction and evaluate its antioxidant capacity in a streptozotocin-induced diabetes model in Wistar rats. The decoction was found to contain 77.47 ± 1.23 mg GAE/g of total phenolic compounds, with caffeic and chlorogenic acids identified as constituents by TLC and HPLC. Antioxidant activity was initially assessed in vitro using DPPH and β-carotene/linoleic acid assays, which revealed moderate radical scavenging activity. Streptozotocin-induced diabetic Wistar rats treated with the decoction (140 mg /kg/day) for 30 days exhibited a significant reduction in malondialdehyde levels and decreased activities of superoxide dismutase and catalase in liver and kidney homogenates, compared with untreated diabetic animals. In contrast, glutathione peroxidase activity and reduced glutathione levels were significantly increased. These findings show that yacon leaf decoction could be helpful in reducing problems related to oxidative stress in diabetes.