Antioxidant and Anticancer Activities of Strain AG12a.

Background: It has been proven that probiotic bacteria have inhibitory effects on human cancer cell lines. The aim of this study is to isolate and characterize the antioxidant probiotic and determine the possible anticancer activities of the selected strain.

Methods: One of the strain isolated from camel doogh sample showed the high antioxidant activity by using of different methods such as resistance to hydrogen peroxide, hydroxyl radical and superoxide anions. The antioxidant strain was characterized by sequencing of 16S rRNA V2-V3 regions and the 16S-23S intergenic spacer (ITS). The methanol extract of this strain supernatant was fractionated using thin layer chromatography (TLC) and antioxidant activity of fractions was detected by 0.1% of DPPH through TLC-DPPH bioautography. anticancer activity of each fraction was investigated by using MTT and flow cytometry methods.

Results: According to the phylogenetic results, the antioxidant strain was closely related to strain E91 (Accession No. EF536365). After fractionation and anti-proliferation assessments of strain AG12a extracellular materials, one of the antioxidant fraction (F4) showed maximum DPPH radical scavenging activity (IC of 535.27 μg/mL). MTT assay of the F4 fraction demonstrated cytotoxic activity against Caco-2 with the IC50 value of 299.05 μg/mL. The cell death activity of the fraction was confirmed by flow cytometry with 30.925.

Conclusions: In this study, the anticancer and apoptotic properties of against Caco-2 cell line was reported for the first time. The isolated bioactive fraction from the extracellular methanol extract needs to be further investigated in human studies of cancer therapy.