Chemical Composition, Antioxidant, and Antimicrobial Activities of Lichen Umbilicaria cylindrica (L.) Delise (Umbilicariaceae)

The phytochemical analysis of methanol and chloroform extracts of Umbilicaria cylindrica was determined by HPLC-UV method. The predominant phenolic compound in both extracts was depsidone, salazinic acid (1). Besides salazinic acid, the tested extracts of U. cylindrica contain norstictic acid (2), methyl-β-orcinol carboxylate (3), ethyl haematommate (4), atranorin (5), and usnic acid (6), in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity, and inhibitory activity towards lipid peroxidation. The lichen extracts demonstrated important antimicrobial activity against eight strains with MIC values from 15.62 to 62.50 μg/mL. This is the first report of the detail chemical composition and antioxidant activity of the lichen Umbilicaria cylindrica, and the results suggest that this lichen can be used as a new source of the natural antioxidants and the substances with antimicrobial features

Phenolic and Flavonoid Content and Antioxidant Activity of Daphne Blagayana Growing in Serbia

Cilj ovog rada je bio da se ispita fenolni i flavodnoidni sadržaj, kao i antioksidativna aktivnost metanolskih i hloroformskih ekstrakta lišća i grančica biljke Daphne blagayana. Ukupan sadržaj fenola u hloroformskom ekstraktu grančica (90.26±0.69 mg GA/g) bio je veći od sadržaja u ostalim ekstraktima (od 76.56±0.89 do 77.45±0.43 mg GA/g). U slučaju flavonoida, maksimalna vrednost je takođe zabeležena kod hloroformskog ekstrakta grančica (35.24±0.55 mg RU/g). Nekoliko različitih metoda su korišćeno za određivanje antioksidantne aktivnosti testiranih ekstrakata uključujući ukupan antioksidantni kapacitet, metal helacionu aktivnost, aktivnost hidroksi radikala i inhibitornu aktivnost prema lipidnoj peroksidaciji. Naši rezultati su pokazali da, iako sekundarni metabolite biljaka mogu značajno doprineti antioksidantnim aktivnostima, ove aktivnosti nisu bile uvek direktno povezane sa količinom fenola i flavonoida u ekstraktima. Rezultati ovih ispitivanja su pokazali, po prvi put, da grančice i lišče biljke Daphne blagayana poseduju visok sadržaj fenola i flavonoida i potencijalno antioksidantno delovanje. Ova studija je pokazala da se lišće i grančice ove biljke mogu potencijalno koristiti kao pristupačan izvor prirodnih antioksidanasa

Phytochemical and antimicrobial screening of leaves and stems of Balkan endemic species Daphne malyana Blečić

Daphne malyana Blečić (Thymelaeaceae) is an endemic species of the western part of the Balkan Peninsula. No previous detailed studies exist on D. malyana Blečić. The aim of this study was to provide information on the anatomy of the leaf and stem as well as to perform phytochemical screening and to assay the antimicrobial activity of methanol extracts of the leaves and stems of D. malyana Blečić. The phytochemical analysis showed that coumarins and flavonoids are the major classes of secondary metabolites in both leaves and stems. The antimicrobial activity of the methanol extracts from leaves and stems of D. malyana was also evaluated against six Gram-positive and six Gram-negative bacteria by employing both microdilution and disc diffusion methods. The results from the well-diffusion assay showed significant antimicrobial activity at all tested concentrations of the extracts. The results showed that methanol extracts of leaves and twigs have similar chemical compositions and similar antimicrobial activity. To our knowledge this is the first report on the phytochemistry and antimicrobial activity of this plant species. © 2012 American Scientific Publishers

HPLC Analysis, antimicrobial and antioxidant activities of Daphne cneorum L

The present study describes in vitro antimicrobial and antioxidant activities of methanol extracts obtained from the leaves and twigs of the plant Daphne cneorum L. The antimicrobial activity of these extracts was tested against human pathogenic microorganisms using a minimum inhibitory concentration (MIC) values. Total phenolics and flavonoids, as well as the antioxidant activity of the extracts were determined. The two tested extracts showed good antimicrobial and antioxidant activities. The results of a high performance liquid chromatographic (HPLC) method showed that 7,8-dihydroxycoumarin is one of the most abundant secondary metabolite in the tested extracts. The results of this study clearly indicated that the extracts of D. cneorum could be used as a potential source of natural antioxidant and antimicrobial agents

HPLC analysis, antimicrobial and antioxidant activities of Daphne cneorum L.

The present study describes in vitro antimicrobial and antioxidant activities of methanol extracts obtained from the leaves and twigs of the plant Daphne cneorum L. The antimicrobial activity of these extracts was tested against human pathogenic microorganisms using a minimum inhibitory concentration (MIC) values. Total phenolics and flavonoids, as well as the antioxidant activity of the extracts were determined. The two tested extracts showed good antimicrobial and antioxidant activities. The results of a high performance liquid chromatographic (HPLC) method showed that 7,8-dihydroxycoumarin is one of the most abundant secondary metabolite in the tested extracts. The results of this study clearly indicated that the extracts of D. cneorum could be used as a potential source of natural antioxidant and antimicrobial agents