RESULTS: The LC-MS (liquid chromatography-mass spectroscopy)-based widely targeted metabolic profiling identified 645 metabolites, of which flavonoids (22.64%), lipids (13.80%), phenolic acids (12.40%), amino acids and derivatives (10.39%), alkaloids (8.84%), and organic acids (8.37%) were dominant. Multivariate analyses unveiled that the metabolite profiles of the fruit differed regarding the altitude. Fruits from WM (highest altitude) were prime in quality, with higher levels of flavonoids, alkaloids, nucleotides and derivatives, amino acids and derivatives, and vitamins. Fruits from LD and ZN had the highest relative content of phenolic acids and terpenoids, respectively. We identified 69 significantly differentially accumulated metabolites across the pulps of the fruits from the three locations. KEGG analysis revealed that flavone and flavonol biosynthesis and isoflavonoid biosynthesis were the most differentially regulated. It was noteworthy that most active flavonoid compounds exhibited an increasing accumulation pattern along with the increase in altitude. Vitexin and isovitexin were the major differentially accumulated flavonoids. Furthermore, we identified two potential metabolic biomarkers (vitexin and kaempferol 3-O-[2-O-β-D-galactose-6-O-a-L-rhamnose]-β-D-glucoside) to discriminate between dragon fruits from different geographical origins.
CONCLUSIONS: Our findings provide insights into metabolic changes in dragon fruits grown at different altitudes. Furthermore, they show that growing pitaya at high altitudes can produce fruit with higher levels of bioactive compounds, particularly flavonoids.
结果:基于LC-MS(液相色谱-质谱)的广泛靶向代谢谱鉴定出645种代谢物,其中类黄酮(22.64%),脂质(13.80%),酚酸(12.40%),氨基酸及其衍生物(10.39%),生物碱(8.84%),有机酸占主导地位(8.37%)。多变量分析显示,水果的代谢物分布在海拔高度上有所不同。来自WM(最高海拔)的水果品质优良,黄酮类化合物含量较高,生物碱,核苷酸和衍生物,氨基酸及其衍生物,和维生素。LD和ZN的果实中酚酸和萜类化合物的相对含量最高,分别。我们从三个位置的水果果肉中鉴定出69种显着差异积累的代谢物。KEGG分析表明,黄酮和黄酮醇的生物合成以及异黄酮的生物合成受到最大的差异调节。值得注意的是,随着海拔高度的增加,大多数活性类黄酮化合物都表现出增加的积累模式。牡丹素和异牡丹素是主要的差异积累类黄酮。此外,我们确定了两种潜在的代谢生物标志物(牡蛎素和山奈酚3-O-[2-O-β-D-半乳糖-6-O-a-L-鼠李糖]-β-D-葡萄糖苷),以区分来自不同地理来源的火龙果。
结论:我们的发现提供了在不同海拔高度生长的火龙果代谢变化的见解。此外,他们表明,在高海拔地区种植火龙果可以产生具有更高水平生物活性化合物的果实,特别是类黄酮。