Variation in bioactive compounds and bioactive principles of rosehip (Rosa rugosa Thunb.) during repening

The fruit ripening is a genetically programmed process that involves a number of biochemical and physiological processes assisted by variations in gene expression and enzyme activities. This process generally affects the phytochemical profile and the bioactive principles in fruit and vegetables. To appraise the variation in bioactive principles of rosehip from Rosa rugosa Thunb. during its ripening process, we analyzed the changes in antioxidant and anti-elastase activities and polyphenolic compounds during the four ripening stages of rosehips. Overall, an extract of unripe rosehip (stage 1) contained the highest levels of total phenolic and flavonoid contents, radical scavenging activity, reducing power, oxygen radical antioxidant capacity and elastase inhibitory activity, compared with the extracts of rosehip at other stages of ripening. In addition, we found that the reduction of flavonoid content occurs because of decreased transcriptional levels of genes involved in flavonoid biosynthesis pathway during ripning process. Based on HPLC analysis, we found that the extract of unripe fruit contained highest amount of myricetin(0.00±0.00 to1.51±0.76 μg/10 mg of extract), caffeic acid(7.18±0.20 to 39.69±2.76 μg/10 mg of extract), chlorogenic acid(6.08±0.54 to 39.69±2.76 μg/10 mg of extract), syringic acid(2.62±1.31 to 69.56±19.66 76 μg/10 mg of extract) and p-coumaric acid(0.00±0.00 to 15.68±1.69 μg/10 mg of extract), and suggested that the antioxidant and anti-elastase activities of the extract obtained from stage 1 should be mediated by the presence of these compounds. In addition, we analyzed the interaction sites and patterns between these compunds and elastase using the structure-based molecular docking approach, and suggested that Chlorogenic acid strongly interacted with elastase. Taken togather, these findings suggest that the maturity of rosehip has profound effects on the pharmaceutical value of Rosa rugosa Thunb.