Temperature and storage periods on the maintenance of chemical composition of medicinal plants

Resumo

Determining the chemical composition of medicinal plants used for therapeutic purposes is of fundamental importance. These plants must meet quality standards for commercialization by ensuring pharmacological properties and efficacy. However, for the maintenance of their active compounds, it is very important to store them at a suitable temperature and ensure the safety of these compounds. The objective of this work was to evaluate the effect of different temperatures and storage periods in the maintenance of chemical composition of bushy lippia (Lippia alba), crajiru (Arrabidaea chica), eucalyptus (Eucalyptus grandis), lemon grass (Cymbopogon citratus), citronella (Cymbopogon nardus) and sage (Lippia microphylla) leaves. Leaves of these medicinal plants were stored for different periods (30, 60 and 90 days) at different temperatures (0, 17 and 24 °C). A complete randomized design was used with five replications, each one with 150g of leaves. For each combination of temperature and storage period, different variables were evaluated such as phenolic compounds, total anthocyanins, antioxidant activity (ORAC and DPPH), carotenoids and chlorophyll contents. Leaves stored at 0°C resulted in the most efficient preservation of chemical compounds at 30, 60 and 90 days. However, this temperature causes physiological damage to the leaves. Therefore, for commercial use, dried or crushed leaves in the form of powder is recommended. Storage at 17 °C keeps the chemical composition of the leaves at satisfactory levels, while at 24 °C there is a significant decrease over the periods of cold storage.