Antimicrobial effects of a compound solution of three medicine food homology plants

Siraitia grosvenorii is a perennial herb endemic to Guangxi province of China. Its fruit, commonly known as Luo hanguo, and has been used for hundreds of years as a natural sweetener and as a traditional medicine for the treatment of pharyngitis, pharyngeal pain, as well as an anti-tussive remedy in China. Based on ninety-three literary sources, this review summarized the advances in chemistry, biological effects, and toxicity research of S. grosvenorii during the past 30 years. Several different classes of compounds have been isolated or detected from various parts of S. grosvenorii, mainly triterpenoids, flavonoids, polysaccharides, amino acids, and essential oils. Various types of extracts or individual compounds derived from this species exhibited a wide array of biological effects e.g. anti-tussive, phlegm-relieving, anti-oxidant, immunomodulatory, liver-protecting, glucose-lowering, and anti-microbial. The existing research has shown that extracts and individual compounds from S. grosvenorii are basically non-toxic. Finally, some suggestions for further research on specific chemical and pharmacological properties of S. grosvenorii are proposed in this review.

Lactobacillus casei AST18 was screened as an antifungal lactic acid bacteria which we have reported before. In this research, the antifungal properties of cell-free culture filtrate (CCF) from L. casei AST18 were detected, and the antifungal compounds of CCF were prepared by ultrafiltration, and semi-preparative HPLC, and then determined by GC-MS. CCF was sensitive to pH and heat treatment but it was not affected by the treatment of trypsin and pepsin. Through the treatment of ultrafiltration and semi-preparative HPLC there were two parts of CCF which showed antifungal activities: part 1 and part 4. Lactic acid was identified as the main antifungal compound in part 1. In part 4, three small molecular substances were detected with GC-MS. The three potential antifungal substances were cyclo-(Leu-Pro), 2,6-diphenyl-piperidine, and 5,10-diethoxy-2,3,7,8-tetrahydro-1H,6H-dipyrrolo[1,2-a;1',2'-d]pyrazine. The antifungal activity of L. casei AST18 was a synergistic effect of lactic acid and cyclopeptides.