Effects of monoglucoside and diglucoside anthocyanins from Yan 73 (Vitis vinifera L.) and spine grape (Vitis davidii Foex) skin on intestinal microbiota in vitro

Yan 73 anthocyanin extracts and spine grape anthocyanin extracts, along with anthocyanin standards (malvidin-3-O-glucoside; malvidin-3,5-O-diglucoside), were used to investigate the role of anthocyanins and their structures (monoglucoside, diglucoside) on intestinal microbiota. The results showed that anthocyanins (especially monoglucoside) increased the alpha diversity and abundance of Bifidobacterium, Faecalibacterium, and Prevotella. Yan 73 anthocyanin extracts particularly promoted the growth of Lactobacillus and decreased Streptococcus abundance, while malvidin-3,5-O-diglucoside suppressed the proliferation of Escherichia-Shigella. The pH value was lower in anthocyanin extracts than in the standards. Short-chain fatty acid contents were higher in diglycososide anthocyanins than in monoglycoside. The results of scanning electron microscopic images suggested that anthocyanins might change bacterial cell morphology to exhibit antibacterial activity. Consequently, anthocyanins with different structures showed dynamic and multiple regulatory effects on intestinal microbiota for maintaining intestinal health through promoting short-chain fatty acids, lowering pH, and/or damaging bacterial cell morphology.