Abstract

• The present work focused on the studies of chemical constituents from the leaves of Smallanthus sonchifolius (Poepp. and Endl.) H.Robinson (Yacon) and some biological activities. Yacon is one of the edible plants and it is collected from Ywar Ngan Township, Southern Shan State. Phytochemical investigation of Yacon leaves was performed and it was found that alkaloids, α-amino acids, carbohydrates, flavonoids, glycosides, phenolic compounds, reducing sugars, saponins, steroids, tannins, terpenoids, and organic acids were present, however, cyanogenic glycosides and starch were absent. Nutritional values were observed to compose by moisture (14.35 %), fiber (11.67 %), protein (11.43 %), ash (9.09 %), fat (5.31 %), carbohydrate (40.7 %) and energy value is 313.55 kcal/100 g of Yacon leaves were found to be determined by using the respective methods. In addition, the elements such as K (0.908 %), Ca (0. 801 %), S (0.120 %), Fe (0.028 %), Ba (0.008 %), Mn (0.006 %), P (0.002 %), Cu (0.002 %), Zn (0.001 %) were examined by ED XRF method. The antioxidant activities of watery and ethanol extracts of the leaves sample were determined by DPPH assay method. The IC50 value of watery and ethanol extracts were found to be 786.56 and 466.92 μg/mL, respectively. The ethanol extract is more effective than the watery extract. However, the two extracts show the mild activity when compared to the standard antioxidant ascorbic acid (IC50 = 4.57 μg/mL). In vitro screening of antimicrobial activity was examined by nutrient agar well diffusion method on eight different microorganisms (Bacillus subtilis, Staphylococcus aureus, Pseudomonas aerugino, Bacillus pumilus, Candida albicans, Escherichia coli, Aspergillus flavus and Aspergillus niger). Ethyl acetate and 95 % ethanol extracts of Yacon leaves showed antimicrobial activity on eight strains of microorganisms (inhibition zone diameter 12 mm to 30 mm). Watery extract against other strains expect A. flavus (inhibition zone diameter 13 mm to 20 mm). In addition, petroleum ether and methanol extracts against other strains except P. aeruginosa (inhibition zone diameter 11 mm to 30 mm). The cytotoxicity of methanol extract from Yacon leaf against hepatoma liver cancer cell HepG2 was evaluated by MTT assay. The IC50 value of methanol extract was found to be 53.68 µg/mL for 24 h treated time. The results of this study scientifically validate the traditional use of Yacon leaves for the treatment of liver diseases.