Changes of Main Active Components in Leaf and Stem of Rosa cymosa Tratt. at Different Harvesting Periods

Objective: In order to control the herbal quality and select the optimal harvesting period of Rosa cymosa Tratt., the contents of total polysaccharide, total organic acid and ellagic acid in its leaves and stems at different harvesting periods within one year were studied in this paper. Methods: The samples of leaf or stem were collected monthly from February to December in 2021, and dried in the room temperature, then, their total polysaccharides, total organic acids, and ellagic acids were determined through UV spectrophotometry and high performance liquid chromatography (HPLC), respectively. At the same time, the quality of leaves and stems at differenet harvesting periods were comprehensively evaluated by cluster analysis and principal component analysis. Results: The contents of total polysaccharide, total organic acid and ellagic acid in its leaves and stems showed some fluctuations throughout the year. The contents of polysaccharide in leaves reached higher levels in July (22.689 mg·g⁻¹ and August (23.164 mg·g⁻¹). The content of total organic acids were highest in February (111.484 mg·g⁻¹), June (113.342 mg·g⁻¹), and August (102.425 mg·g⁻¹). The highest levels of ellagic acid were found in April (0.074 mg·g⁻¹), June (0.077 mg·g⁻¹) and August (0.074 mg·g⁻¹). The contents of total polysaccharide in the stems were higher in February (15.650 mg·g⁻¹). The content of total organic acids were highest in May (171.123 mg·g⁻¹), September (178.960 mg·g⁻¹), and February (125.393 mg·g⁻¹). The contents of ellagic acid were significantly higher in February (0.037 mg·g⁻¹) and April (0.038 mg·g⁻¹) than those in stems harvested correspondingly in other months. The leaves and stems were divided into 3 categories according to cluster analysis, which was basically consistent with principal component analysis. By principal component analysis, the cumulative contribution rates of leaves and stems reached 77.067% and 82.970%, respectively. The results showed that the comprehensive evaluation of leaves harvested in August and stems harvested in February was the highest. Conclusion: Therefore, the comprehensive analysis determined that the appropriate harvesting period for Rosa cymosa Tratt. was August for leaves and February for stems. The results of this study could provide some references for the quality evaluation and harvest research of Rosa cymosa Tratt.