Solid state fermentation process with Aspergillus kawachii enhances the cancer-suppressive potential of silkworm larva in hepatocellular carcinoma cells

Abstract

Background Mulberry silkworm larvae ( Bombyx mori ) are known as the oldest resource of food and traditional medicine. Although silkworm larvae have been reported to treat various chronic diseases, the effect of fermentation by microorganisms improving the biological activities of silkworm larvae was not reported. In the present study, fermented silkworm larvae was developed via solid-state fermentation with Aspergillus kawachii and investigated its anti-cancer activity in human hepatocellular carcinoma cells. Methods We investigated the anti-cancer effects of unfermented (SEE) and fermented silkworm larva ethanol extract (FSEE) on HepG2 human hepatocellular carcinoma cells as well as compared changes in free amino acid, fatty acid, and mineral contents. Anti-cancer activities were evaluated by SRB staining, cell cycle analysis, Annexin V staining, Hoechst staining, DNA fragmentation analysis and western blot analysis. Fatty acid, free amino acid and mineral contents of SEE and FSEE were determined by gas chromatography, amino acid analyzer and flame atomic absorption spectrophotometer, respectively. Results Compared with SEE, treatment with FSEE resulted in apoptotic cell death in HepG2 cells characterized by G0/G1 phase cell cycle arrest, DNA fragmentation, and formation of apoptotic bodies. Furthermore, FSEE significantly up-regulated pro-apoptotic as well as down-regulated anti-apoptotic proteins in HepG2 cells. However, an equivalent concentration of SEE did not induce cell cycle arrest or apoptosis in HepG2 cells. Moreover, fermentation process by Aspergillus kawachii resulted in enhancement of fatty acid contents in silkworm larvae, whereas amino acid and mineral contents were decreased. Conclusion Collectively, this study demonstrates that silkworm larvae solid state-fermented by Aspergillus kawachii strongly potentiates caspase-dependent and -independent apoptosis pathways in human hepatocellular carcinoma cells by regulating secondary metabolites. Electronic supplementary material The online version of this article (10.1186/s12906-019-2649-7) contains supplementary material, which is available to authorized users.

Fermented Edible Insects for Promoting Food Security in Africa

“…Available studies have employed starter cultures (mainly bacteria and fungi culture) in either submerged or solid-state fermentation at varying conditions to enable bio-modification of inherent components of edible insects. Among the few experimental studies, solid state fermentation of dried Bombyx mori larvae using Aspergillus kawachii as starter culture was reported to show higher fatty acid and lower amino acid and mineral contents [66]. Ethanol extracts from the resultant sample was therapeutically demonstrated to induce improved cancer inhibitory effects in human hepatocellular carcinoma cells through modification of secondary metabolites.…”

Potential of edible insects as source of functional foods: biotechnological approaches for improving functionality

“…Plant-based fermented foods are produced using substrates like cereals, legumes, fruits and vegetables, whereas dairy, meat and fishes are applied for production of animal-based fermented products [83]. Attempt on fermentation of certain edible insects shows increased shelf life [84], enhanced nutrition content [85][86][87][88][89] improved taste [90,91] and reduction of microbial contamination risk [92]. The fermentation process of edible insects and its benefits are presented Fig.…”

Trends in functional food development with three-dimensional (3D) food printing technology: prospects for value-added traditionally processed food products

“…Enriched, printed, and baked snacks with ground insects were reported with a corresponding significant increase in the total essential amino acid, protein digestibility, and corrected amino acid score (Severini, Azzollini, et al 2018). Edible insects as novel and affordable sources of proteins in food have been reported and are known to contain appreciable bio-components with nutritional and therapeutic properties (Cho et al 2018;Cho et al 2019;Kewuyemi, Kesa, et al 2020). In light of the above reported studies on the printed food structures suggested being rich in healthpromoting components could, therefore, be potentially appreciated or improved through the bio-modification processes of fermentation or malting techniques (Adebo 2020;Ohanenye et al 2020).…”