Safety evaluation of collagenase from Streptomyces violaceoruber.

A safety assessment was conducted for microbial collagenase (COL) enzyme expressed in Streptomyces violaceoruber. The acute oral toxicity of COL was examined in Sprague-Dawley rats and the LD50 of COL via single oral administration to rats was higher than 2000 mg/kg body weight. A 13-week oral gavage study of COL showed no adverse effects due to the enzyme up to a dose of 234.9 mg total organic solids (TOS)/kg body weight per day (NOAEL). A bacterial reverse mutation test showed no mutagenic activity at the highest dose (4698 µg TOS per plate). In the mouse lymphoma TK assay, a positive result was observed at the highest dose of 4698 µg TOS/mL although it had low reproducibility. To confirm the chromosome aberration potential, an in vivo micronucleus test was conducted that demonstrated the lack of mutagenic potential on the bone marrow of rats at doses up to 1879 mg TOS/kg body weight per day. The results of the genotoxicity studies and acute and subchronic rat studies support the safe use in food production of collagenase produced from S. violaceoruber.

Addition of high load of lysophosphatidic acid to standard and high-fat chows causes no significant changes of its circulating and peripheral tissue levels but affects body weight and visceral fat mass of mice.

Oral administration of lysophosphatidic acid (LPA), a critical intercellular lipid mediator, exerts wound healing and antiulcer effects on gastrointestinal system. To evaluate effects of food-derived LPA on body homeostasis, we measured LPA levels by liquid chromatography-tandem mass spectrometry in chows, feces, plasma, liver, and visceral fat of mice fed a normal or high-fat chow supplemented with or without LPA-rich soybean phospholipids for 30 days. Reductions in daily body weight gains and visceral fat mass were mainly related to lower chow intake by mice fed the LPA-rich high-fat chow, whereas reduced body weight gains and fat mass were mainly related to decreased intestinal triacylglycerol absorption in mice fed LPA-rich chow. Our results showed no significant increase in plasma, liver, or adipose LPA levels, even if a quite high LPA concentration (2.0%) in chows was ingested daily, suggesting limited effects of food-derived LPA on the lumen side of the digestive tract. © 2018 BioFactors, 44(6):548-557, 2018.