Effects of water deficit and rehydration on antioxidant and anti-inflammatory activities in methanolic root barks extracts of Rhus tripartitum and Periploca laevigata subsp. angustifolia

Rhus tripartitum (Ucria) and Periploca laevigata Aiton subsp. angustifolia (Labill.) are two medicinal plants containing several compounds with important pharmacological activities. The obtained results showed that under water deficit, the secondary metabolite levels in root bark were increased significantly for both species and decreased after rehydration for R. tripartitum but for P. laevigata, the amount of secondary metabolite increased. In addition, the quantification of phenolics and flavonoids compounds by HPLC was found to be in accordance with these results. The main compounds were catechin, cinnamic acid, epicatechin, apigenin and rutin. They also suggest that water deficit and rehydration treatments may regulate the production of phenolic compounds in Rhus and Periploca root bark. Moreover, the extracts of the root bark from Rhus and Periploca were able to scavenge DPPH and FRAP free radicals with the low IC50 and EC50 recorded for stressed plants extracts (75.66 μg/ml, 111.66 μg/ml and 118.66 μg/ml, 144.66 μg/ml, respectively for R. tripartitum and P. laevigata) and have an inhibitory effect by decreasing NO and ROS release in J774A.1 macrophages. The high antioxidant activity was detected with R. tripartitum, while anti-inflammatory activity was important with P. laevigata. The increase of these biological activities was directly proportional to the content of secondary metabolite in root bark. In general, water deficit revealed positive effects on secondary metabolites contents, hence the biological potential of R. tripartitum and P. laevigata.