Potential of Lactococcus lactis strain LAC3 isolated from Indonesian traditional fermented buffalo milk (Dadih) as antioxidant and antidiabetic agents

Abstract

Dadih is one of Indonesia indigenous traditional fermented foods made from buffalo milk originating from West Sumatera. Dadih is traditionally made by keeping buffalo milk in a covered bamboo tube for two hours. The goal of this study as to discover secondary metabolites generated by Lactococcus lactis subsp. Lactis strain LAC3 (isolated from Dadih) proceed with bioactivity assay as an antidiabetic and antioxidant agent. The secondary metabolites were isolated then partially purified by ammonium sulfate precipitation followed by gel filtration chromatography. The DPPH technique was used to test antioxidant activity, whereas the α-glucosidase inhibition assay was used to determine antidiabetic activity. The potential fraction was then examined by LC-MS to identify structural information of secondary metabolites. Collected protein fraction (no. 2-12) showed antioxidant activity (39-90%) and exhibited antidiabetic activity around 82-95%. LC-MS results revealed several compounds related to antioxidant and antidiabetic activity such as hydrazine carboxamide derivatives and metformin hydrochloride. Our results indicated that secondary metabolites generated by lactic acid bacteria isolated from dadih have activity as antioxidant and antidiabetic agents and potential for further development as antioxidant and antidiabetic sources.