Antioxidants in aerial parts of Hypericum sampsonii, Hypericum japonicum and Hypericum perforatum

Abstract

Antioxidants contents and antioxidative enzymes and their activities in fresh aerial tissues of Hypericum sampsonii (Sampson's St John's Wort), Hypericum japonicum (Japanese St John's Wort) and Hypericum perforatum were investigated. Hypericum sampsonii contained more total ascorbate [34.33 lmol g )1 fresh weight (FW)] than H. perforatum (57% less) and H. japonicum (82% less). It also contained more thiol and phenolics than two other species. Hypericum japonicum had highest superoxide dismutase (SOD) activity (8.74 mmol min )1 g )1 FW), followed by H. sampsonii (2% less) and H. perforatum (37% less). Hot-air dried H. perforatum materials contained more thiol [208.7 lmol g )1 dry weight (DW)] and phenolics (352.82 mg g )1 DW) than freeze-dried and fresh materials. Both drying treatments decreased the activities of antioxidative enzymes in aerial tissues of H. perforatum. However, freeze-dried H. perforatum contained the highest SOD activity (5.42 mmol min )1 g )1 DW) among the antioxidative enzymes measured from both freeze-dried and hot-air dried tissues (ranged from 0.02 to 2.65 lmol min )1 g )1 DW).

Harvest time affects antioxidant capacity, total polyphenol and flavonoid content of Polish St John’s wort’s (Hypericum perforatum L.) flowers

“…air-drying and lyophilization (freeze-drying), despite the application of both in Hypericum studies. To the best of our knowledge, only one such study is available, comparing the hot-air and freeze drying approach in relation to antioxidant properties 21 .…”

Influence of postharvest processing and storage conditions on key antioxidants in pūhā (S onchus oleraceus L.)

“…Medicinal herbs are often dried to less than 15% moisture content before being manufactured into nutraceutical products [8]. The drying process is complex and could affect the quality attributes of dried medicinal plant materials.…”

“…The drying process is complex and could affect the quality attributes of dried medicinal plant materials. Several drying methods, including freeze‐drying, microwave‐drying, hot‐air‐drying and cool wind‐drying, are reported to affect the concentration of antioxidants and their activity in many plant materials [5,6,8,12,13,27]. Previously, we reported three caffeic acid derivatives – caftaric, chlorogenic and chicoric acids – as the major antioxidants in methanolic extracts of S. oleraceus leaves [21].…”

“…Drying can cause deterioration of nutritional substances and degradation of compounds, such as antioxidants, that contribute to the medicinal effects, thus reducing the final product quality. Open air‐drying, oven‐drying and freeze‐drying are widely used methods in the food and pharmaceutical industry [6–8]. One of the disadvantages of open air‐drying is the difficulty in achieving consistent quality because of variability in drying process parameters such as temperature and humidity [7].…”

Avaliação da capacidade antioxidante de variedades de melão (Cucumis melo L.) comercializadas no Brasil e determinação do teor de glutationa reduzida (GSH)

“…A liofilização da amostra foi realizada com objetivo de concentrar a GSH, além de preservá-la, pois segundo dados da literatura (CHEN at al., 2009), o teor de GSH em produtos in natura pode ser afetado pela sua degradação. Consequentemente, produtos desidratados (liofilizados) são mais estáveis, uma vez que diminuem as possibilidades de ocorrência de reações enzimáticas e crescimento de microrganismos.…”