HPLC-DAD analysis and in vitro enzyme inhibition: An integrated approach to predict herbal binary mixture behaviour employing median effect equation

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Clara Grosso (Author) Other; Patricia Valentao (Author) FFUP; Catarina Andrade (Author) Other; Paula B Andrade (Author) FFUP

Journal

Title: Microchemical Journal

Vol. 119

Pages: 176-182

ISSN: 0026-265X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 15 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-00A-2J4

DOI: 10.1016/j.microc.2014.12.006

Abstract (EN): Many herbal teas demonstrate significantly better pharmacological effects when employed in combination rather than when used alone. In this study, four species used for depression (Trichilia catigua, Annona muricata, Cereus grandiflorus and Hyssopus officinalis), as well as their binary mixtures, were screened as MAO-A inhibitors for the first time and synergistic, antagonistic and additive interactions were evaluated using the median effect principle. All herbal teas displayed a dose-dependent inhibitory behaviour, except T. catigua for which a dual effect was observed. The IC50 values for MAO-A inhibition displayed by the four species were 7.25 mu g/mL (T. catigua), 1931 mu g/mL (A. muricata), 428.13 mu g/mL (C. grandiflorus) and 40.47 mu g/mL (H. officinalis). Concerning the mixtures, the most promising one was found to be that composed by A. muricata x C. grandiflorus, displaying a combination index close to 1 and an IC50 value of 34.37 mu g/mL. The other binary mixtures proved to be antagonist, i.e. A. muricata x H. officinalis displayed Cl between 1.79 and 3.29 and C. grandiflorus x H. officinalis from 0.96 to 7.41 (until 75% of MAO inhibition). In order to correlate the phenolic composition with the bioactivity, a dereplication strategy using high performance liquid chromatography coupled to diode array detection was adopted, fourteen compounds being identified. The best anti-MAO-A mixture composition contained 18.99 mg of phenolic compounds/g of extract (dry weight), and was composed by 5-caffeoylquinic acid, quercetin-3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-rutinoside, kaempferol-3-O-rutinoside and isorhamnetin-3-O-rutinoside. Moreover, this is the first quantification of phenolic compounds in the four aqueous extracts. These findings highlight the importance of assessing the pharmacological effect of plant mixtures, since we have shown for the first time that some of the tested mixture demonstrated antagonistic interactions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7