Chemical profile and toxicogenetic safety assessment of Smallanthus sonchifolius (yacon) organic extracts.

The interest in Smallanthus sonchifolius (yacon) has strongly resurfaced due to its multiple beneficial effects on human health. This study aimed at determining the toxicity and the chemical profile of an ethanol extract (EE) and a crude lactone mixture (CLM) of yacon leaves. Cytotoxicity and genotoxicity tests were performed by the MTT assay and the alkaline version of the comet assay respectively. The phytochemical analysis, performed by chromatographic and spectroscopy techniques, revealed the presence of nine sesquiterpene lactones (STLs) and two acyclic diterpene acids. In all cases, cell viability was inversely proportional to the extract concentration employed. The effects obtained with the highest dose of EE were significantly different from those obtained with the negative and solvent controls. Conversely, no significant differences were observed between the lowest doses of EE and controls. As for CLM, all tested doses showed statistically significant increases, as compared to negative and solvent controls.

Toxicogenetic evaluation of Smallanthus sonchifolius (yacon) as a herbal medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson, commonly known as yacon, is a medicinal plant belonging to the Asteraceae family used in traditional folk medicine. Its roots and leaves have been used by people suffering from diabetes or from various digestive or renal disorders. AIM OF THE STUDY: This study aimed at evaluating the in vitro potential genotoxic effects of the aqueous extract of yacon in order to determine its safety and at characterizing its phytochemical composition. MATERIALS AND METHODS: The aqueous extract of S. sonchifolius was prepared in a similar way to that commonly used in popular medicine as tea bags. Thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC-MS/MS) were used to identify the main compounds. The MTT test was performed to determine the range of doses and the Cytochalasine B-blocked micronucleus (Cytome assay) was used to assess geneotoxicity. RESULTS: The chemical analysis of the aqueous extract revealed the presence of the sesquiterpene lactones (STLs) enhydrin and the dimer enhydrofolin, as the main compounds together with phenolic compounds. Increasing concentrations of the extract induced a cytotoxic effect on CHO-K1 and HepG2 cells. A statistically significant increase in the frequency of MNi, NBUDs and NPBs was observed in CHO-K1 cells, while in HepG2 cells a statistically significant frequency increase was observed with three of the four tested doses for MNi and only with the highest dose for NPBs and NBUs (genotoxic effect). CONCLUSION: 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 in quantities of up to 250 mL/day.

The Role of Endothelin System in Renal Structure and Function during the Postnatal Development of the Rat Kidney.

Renal development in rodents, unlike in humans, continues during early postnatal period. We aimed to evaluate whether the pharmacological inhibition of Endothelin system during this period affects renal development, both at structural and functional level in male and female rats. Newborn rats were treated orally from postnatal day 1 to 20 with vehicle or bosentan (Actelion, 20 mg/kg/day), a dual endothelin receptor antagonist (ERA). The animals were divided in 4 groups: control males, control females, ERA males and ERA females. At day 21, we evaluated renal function, determined the glomerular number by a maceration method and by morphometric analysis and evaluated possible structural renal alterations by three methods: 〈alpha〉-Smooth muscle actin (α-SMA) immunohistochemistry, Masson's trichrome and Sirius red staining. The pharmacological inhibition of Endothelin system with a dual ERA during the early postnatal period of the rat did not leads to renal damage in the kidneys of male and female rats. However, ERA administration decreased the number of glomeruli, the juxtamedullary filtration surface area and the glomerular filtration rate and increased the proteinuria. These effects could predispose to hypertension or renal diseases in the adulthood. On the other hand, these effects were more pronounced in male rats, suggesting that there are sex differences that could be greater later in life. These results provide evidence that Endothelin has an important role in rat renal postnatal development. However these results do not imply that the same could happen in humans, since human renal development is complete at birth.