Abstract

This study reports the influence of seasonality on the accumulation of verbascoside as a principal phenolic compound in Clerodendrum glandulosum Lindl. leaves along with possible alteration of antioxidant potentials. Leaves were collected during winter (December 2018), spring (February 2019), summer (May 2019), monsoon (July 2019), autumn (October 2019), and extracted with 95% aqueous methanol by cold maceration. The total phenolic content and antioxidant capacities (DPPH, ABTS and FRAP) were estimated by spectrophotometric technique, and verbascoside content was estimated by HPLC-PDA. Results indicate that the leaves collected during summer and winter both exhibited the highest total phenolic content verbascoside accumulation and antioxidant potentials which are significantly different (p < 0.05) than other seasons. Correlation studies further demonstrated that the total polyphenol and verbascoside contents were directly proportional to the antioxidant potentials. Thus, the study concludes that winter and summer are the best seasons for collecting leaves from this plant to obtain maximum antioxidant potential.

摘要

本研究报告了季节性对毛蕊花苷作为主要酚类化合物在Clerodendrum glandulosum Lindl 中积累的影响。叶以及抗氧化能力的可能改变。在冬季（2018 年 12 月）、春季（2019 年 2 月）、夏季（2019 年 5 月）、季风（2019 年 7 月）、秋季（2019 年 10 月）收集叶子，并通过冷浸渍法用 95% 甲醇水溶液提取。总酚含量和抗氧化能力（DPPH、ABTS 和 FRAP）采用分光光度法测定，毛蕊花苷含量采用 HPLC-PDA 测定。结果表明，夏季和冬季采集的叶片总酚含量最高，毛蕊花苷积累量和抗氧化能力差异显着（p < 0.05) 比其他季节。相关性研究进一步表明，总多酚和毛蕊花苷含量与抗氧化潜力成正比。因此，该研究得出结论，冬季和夏季是从这种植物中采集叶子以获得最大抗氧化潜力的最佳季节。