Effects of Chinese medicines on monacolin K production and related genes transcription of Monascus ruber in red mold rice fermentation.

Lin Peng,Xin Che,Shuangping Liu,Aisikaer Ai-Lati,Jian Mao,Zhongwei Ji

doi:10.1002/fsn3.1511

Abstract

Monacolin K (MK) is a secondary metabolite synthesized by polyketide synthases of Monascus spp. In this study, the combined supplementation of three medicines, including Citri Reticulatae Pericarpium (CRP), Fructus crataegi (FC), and Radix Angelicae Dahuricae (RAD), were mixed with nonglutinous rice and were optimized by response surface methodology to enhance the production of MK in fermented red mold rice (RMR). Under the optimum condition, MK production achieved 3.60 mg/g, which was 41.18% higher than RMR without medicines. The improved MK production was mainly caused by the up‐regulated transcription level of mokA, mokB, mokF, mokH, mokI, and mplaeA. Meanwhile, the inhibitory effect of Poria cocos (PC) on MK production (only 0.436 mg/g) was caused by significantly down‐regulated transcription of six tested genes. Therefore, this study is beneficial for better understanding of the possible mechanism of enhanced MK production by optimization of fermentation conditions.

Highlights

Cardiovascular disease is the major factor leading mortality and morbidity of human, and hyperlipidemia is the main reason for its occurrence and development (Lewington et al, 2007)
Citri Reticulatae Pericarpium (CRP), Fructus crataegi (FC), and Radix Angelicae Dahuricae (RAD) were mixed to add into red mold rice (RMR) fermentation, and optimized addition amounts of these three medicines for Monacolin K (MK) production were further determined by response surface methodology
A MK-producing strain M. ruber M2-1 was isolated from commercial RMR, and 15 Chinese traditional medicines were mixed with nonglutinous rice to assess effects on MK production (Che et al, 2016)

Summary

| INTRODUCTION

Cardiovascular disease is the major factor leading mortality and morbidity of human, and hyperlipidemia is the main reason for its occurrence and development (Lewington et al, 2007). With the increased attention paying to functional foods, some methods are developed to improve the production of MK in RMR, which could be used to further enhance MK content in foods These methods include the optimization of culture medium (Panda, Javed, & Ali, 2010; Subhagar, Aravindan, & Viruthagiri, 2010; Suraiya et al, 2018) and the establishment of fermentation strategies in solid-state fermentation (Gum, Nguyen, Lee, Han, & Cho, 2017; Lin, Wang, Li, Wu, & Chen, 2017; Tsukahara, Shinzato, Tamaki, Namihira, & Matsui, 2009). The variety of transcription level between mixed medicines (enhanced MK production) and Poria cocos (PC) (inhibited MK production) was compared to gain better understanding of the modulation of genes related to MK synthesis

| MATERIALS AND METHODS

| RESULTS AND DISCUSSION

| CONCLUSION