Abstract:
To evaluate the differences in functional component contents as well as anti-inflammatory and antioxidant effects among turnip roots with different peel colors, colorimetric methods were employed to determine the contents of polysaccharides, flavonoids, saponins, glucosinolates, and polyphenols in extracts from white-, purple-, and yellow-peeled turnips. An LPS-induced inflammatory model was established using RAW264.7 cells to assess the effects of turnip extracts with different peel colors on the viability of RAW264.7 cells stimulated by lipopolysaccharide (LPS) and on the levels of inflammatory mediators (NO, IL-6, TNF-
α, IL-1
β). Meanwhile, the
in vitro antioxidant activities (DPPH· and ABTS
+· radical scavenging assays) of the three types of turnip peel extracts were preliminarily evaluated. Results showed that polysaccharide contents were 28.35, 9.97, and 7.43 g/100 g in purple-, white-, and yellow-peeled turnips, respectively. Corresponding values of 0.159, 0.156, and 0.201 g/100 g were obtained for flavonoid levels; 3.67, 3.40, and 4.50 g/100 g for saponin contents; 1.14, 2.13, and 1.54 g/100 g for glucosinolate concentrations; and 500.7, 318.05, and 313.3 g/100 g for polyphenol levels. The extracts of purple, white, and yellow-peeled turnips contributed to a significant enhancement of cell viability (
P<0.05) and effectively suppressed the levels of inflammatory factors induced by LPS, including NO, IL-6, TNF-
α, and IL-1
β. The DPPH· scavenging rates of extracts were 47.26%, 38.10%, and 63.42%, respectively, whereas those of ABTS
+· reached 81.18%, 87.30%, and 99.73%, respectively. This study provides critical experimental evidence for elucidating the anti-inflammatory mechanisms of turnips and the structure-activity relationships of their bioactive components, while also offering scientific references for the diversified development and utilization of turnip resources.