Antioxidant activity evaluation of dried herbal extracts: an electroanalytical approach

ABSTRACT The prevention of chronic and degenerative diseases, is a health concern deeply associated with oxidative stress. Such progressive phenomena can be avoided through exogenous antioxidant intake, which set up a reductant cascade, mopping up damaging free radicals. Medicinal herbs are commonly associated with high antioxidant potential, and hence their health benefits. The commerce of dried herbal extracts movements a big portion of developing countries economy. The determination of medicinal herbs the antioxidant activity capacity is of utmost importance. The assessment of antioxidant activity in phytotherapics is mostly achieved by spectrophotometric assays, however colored substances can produce interferences that do not occur in electroanalytical methods. Therefore, the aim of this paper is to compare spectrophotometric and voltammetric techniques to evaluate antioxidant activity in herbal drugs such as: Ginkgo biloba L., Camellia sinensis (L.) Kuntze, Theaceae; Hypericum perforatum L., Hypericaceae; Aesculus hippocastanum L., Sapindaceae; Rosmarinus officinalis L., Lamiaceae; Morinda citrifolia L., Rubiaceae; Centella asiatica (L.) Urb., Apiaceae; Trifolium pratense L., Fabaceae; Crataegus oxyacantha L., Rosaceae; and Vaccinium macrocarpon Aiton, Ericaceae. The spectrophotometric methods employed were DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and the Folin-Ciocalteu assays. The electroanalytical method used was voltammetry and it was developed a phenoloxidase based biosensor. The redox behavior observed for each herbal sample resulted in distinguishable voltammetric profiles. The highest electrochemical indexes were found to G. biloba and H. perforatum, corroborating to traditional spectrophotometric methods. Thus, the electroanalysis of herbal drugs, may be a promising tool for antioxidant potential assessment.

Pharmacological evaluation and molecular docking of new di-tert-butylphenol compound, LQFM-091, a new dual 5-LOX/COX inhibitor.

Dual 5-LOX/COX inhibitors are potential new dual drugs to treat inflammatory conditions. This research aimed to design, synthesis and to evaluate the anti-inflammatory and antinociceptive effects of the new compound, which is derived from nimesulide and darbufelone lead compounds. The new dual inhibitor 5-LOX/COX has the possible advantage of gastrointestinal safety. A voltammetric experiment was conducted to observe the drug's antioxidative effect. A formalin test, a hot plate test and carrageenan-induced mechanical hyperalgesia were employed to evaluate the analgesic nature of LQFM-091. To evaluate anti-inflammatory activity, we measured edema, leukocyte count, myeloperoxidase activity and cytokines levels in carrageenan-induced inflammation tests. We elucidated the underlying mechanisms by assessing the interaction the with COXs and LOX enzymes by colorimetric screening assay and molecular docking. The lethal dose (LD50) was estimated using 3T3 Neutral Red Uptake assay. Our results indicate that the LQFM-091 prototype is a powerful antioxidant, as well as able to inhibit COX-1, COX-2 and LOX activities. LQFM091 was classified in GHS category 4 (300