Seasonal variability of phenolic compounds and antioxidant activity in prickly pear cladodes of Opuntia and Nopalea genres

Abstract The prickly pear is a cactaceae that have chemical compounds that act as natural antioxidants. In addition, the prickly pear is a plant widely used in semiarid region as it’s considered very important forage for animal feed, especially in the dry season. The objectives of this research were to characterize the main classes of phytochemicals, determine the phenols content, flavonoids and anthocyanins and evaluate the antioxidant activity of the prickly pear cultivars Opuntia and Nopalea grown in the semiarid region of Pernambuco in two collection periods (dry and rainy). In the work crude ethanol extracts from cladodes of cultivars (IPA-20, Elephant Ear Mexican, F-08, V-19, Small palm, F-21 and IPA-Sertânia) were used. As for the class of phytochemical compounds from ethanol extract only the flavonoids and steroids were detected in all prickly pear cultivars, in both periods analyzed. The content of phenolic compounds ranges from 1.24 to 5.41 mg GAE g-1 DM, flavonoids 0.90 to 3.43 mg QE g-1 DM, anthocyanins from 0.05 to 0.34 µg QE 100 g-1 DM and antioxidant activity 39.59 to 217.17 µM TEAC g-1 DM. The occurrence of chemical variability and antioxidant activity were observed, both among the botanical cultivars studied and among the collection periods.

摘要 梨果仙人掌（prickly pear）隶属于仙人掌科，其所含的化学成分可作为天然抗氧化剂。此外，梨果仙人掌是半干旱地区广泛应用的植物，因其为极为重要的动物饲用草料，在旱季的饲用价值尤为突出。本研究旨在对栽培于巴西伯南布哥州半干旱地区的梨果仙人掌品种（Opuntia属与Nopalea属）的主要植物化学物类别进行表征，测定其酚类、黄酮类及花青素含量，并评估两个采集周期（旱季与雨季）下的抗氧化活性。本研究采用7个栽培品种的肉质茎（IPA-20、墨西哥象耳、F-08、V-19、小棕榈、F-21及IPA-Sertânia）的乙醇粗提物开展实验，针对乙醇提取物中的植物化学物类别，在两个分析周期的所有供试梨果仙人掌品种中，仅检出黄酮类与甾体类化合物。供试样品的酚类化合物含量范围为1.24~5.41 mg 没食子酸当量（Gall Acid Equivalent, GAE）·g⁻¹ 干物质（dry matter, DM），黄酮类化合物含量范围为0.90~3.43 mg 槲皮素当量（Quercetin Equivalent, QE）·g⁻¹ 干物质，花青素含量范围为0.05~0.34 µg QE·100 g⁻¹ 干物质，抗氧化活性范围为39.59~217.17 µM Trolox等效抗氧化容量（Trolox Equivalent Antioxidant Capacity, TEAC）·g⁻¹ 干物质。研究结果显示，在所研究的植物品种间以及不同采集周期间，均存在化学组成变异性与抗氧化活性差异。