Effect of pretreatment with paste and sauce extract made using Tenebrio molitor larvae on ethanol‐damaged HepG2 cells

Abstract

In this study, we made koji using protein‐rich Tenebrio molitor larvae (TML) inoculated with Aspergillus oryzae, and then used the koji to prepare a paste and a sauce. The TML koji showed the highest amino nitrogen, protease activity, and free amino acids content when it was fermented for 72 h after inoculation with 0.8% A. oryzae. The koji was aged in 20% saltwater for 50 days, and then the paste and sauce were separated. To evaluate the effect of TML paste and sauce on ethanol (EtOH)‐damaged hepatocytes, aspartate aminotransferase (AST) and alanine aminotransaminase (ALT) were measured in EtOH‐treated HepG2 cells after pretreatment with TML paste and sauce extract. As a result, we confirmed that TML paste and sauce extracts lowered the AST and ALT content in the medium, compared to soybean sauce and paste extracts. TML paste and sauce extract significantly reduced the expression of tumor necrosis factor (TNF)‐α and interleukin (IL)‐6, a biomarker of inflammation, and significantly increased the activity of the antioxidants superoxide dismutase (SOD) and reduced glutathione (GSH) in proportion to the amount of TML added to the paste and sauce. These results suggest that the intake of TML paste and sauce, a new type of fermented food made from insects, may provide effective protection to the liver against hepatocyte injury by EtOH via anti‐inflammatory and antioxidative effects.

In Vitro Protective Effect of Paste and Sauce Extract Made with Protaetia brevitarsis Larvae on HepG2 Cells Damaged by Ethanol

“…As the GSH enzyme in the liver plays a significant role in liver defense, protecting against liver damage by detoxifying many toxic compounds [ 40 ], we expected that the PBL paste and sauce might have a hepatoprotective role through antioxidant activity. This antioxidant effect is similar to that of the paste and sauce extracts made of 30% (TMP30: 151.07%, 151.75%; TMS30: 148.69%, 151.37%), 50% (TMP50: 150.31%, 156.69%; TMS50: 150.63%, 151.27%), and 100% (TMP100: 152.11%, 158.30%; TMS100: 151.74%, 151.91%) TML [ 22 ].…”

“…When the amino nitrogen level and relative protease activity was compared with pastes and sauces made of GM, it was found that the proteins were further fermented in the paste and sauce made with PBL50 and PBL100 than with GM. Furthermore, when the amino nitrogen level and relative protease activity were compared with the pastes and sauces made of 30% (TMP30: 0.369 mg/mL, 96.25%; TMS30: 2.967 mg/mL, 108.03%), 50% (TMP50: 0.408 mg/mL, 19.93%; TMS50: 3.255 mg/mL, 128.21%), and 100% (TMP100: 0.437 mg/mL, 142.6%; TMS100: 3.782 mg/mL, 13.53%) of TML [ 22 ], it was found that the proteins were further fermented in the paste and sauce made with PBL than with TML. These results are inferred, because PBL (57.86%) has a higher protein content than GM (40%) and TML (50.32%) [ 6 , 11 , 22 ].…”

“…Accordingly, we expect the PBL paste and sauce to have an outstanding anti-inflammatory effect on EtOH-injured hepatocytes. In addition, the inhibition of TNF-α and IL-6 expression in this study by pretreating with PBL paste and sauce extracts was considered a similar anti-inflammatory effect to that of the pretreatment with 30% (TMP30: 0.76-fold, 0.75-fold; TMS30: 0.65-fold, 0.88-fold), 50% (TMP50: 0.73-fold, 0.59-fold; TMS50: 0.84-fold, 0.67-fold), and 100% (TMP100: 0.67-fold, 0.78-fold; TMS100: 0.59-fold, 0.75-fold) TML paste and sauce extracts [ 22 ]. These results could be attributed to the fact that PBL, an animal protein, has a higher protein content and a different amino acid composition than GM, a plant protein, and has a higher liver protective effect and anti-inflammatory effect.…”

“…In addition, an oxygen radical absorbance capacity experiment with fish sauce, which is another fermented animal protein food, showed that the sauce has more antioxidant activity than apples, limes, oranges, pears, and white grapes, which have previously been reported to have high antioxidant activity [ 19 ]. Previous studies have reported the sensory evaluation and physicochemical activities of TML sauce prepared with an inoculation of Aspergillus oryzae and Bacillus licheniformis [ 21 ] and the protective activity of TML fermented foods against ethanol (EtOH)-damaged HepG2 cells [ 22 ]. However, there have been no reports of fermented foods using PBL.…”

Tenebrio molitoras a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

“…A very particular study is the one conducted by Hwang et al. (2019), in which the authors investigated the effects on ethanol‐damaged HepG2 cells of koji, a fermented oriental food obtained by growing the filamentous fungus Aspergillus oryzae on a cereal (rice or barley) or soy prepared from TML instead from usual substrates.…”