Phenolic compounds from Trifolium echinatum Bieb. and investigation of their tyrosinase inhibitory and antioxidant activities.
Two bischromones, 3,3'-dimethoxy-2'-oxychromone (1), 3,3'-dihydroxy-2,2'-oxychromone (2) and a biflavone, 5,7,4',5″,3'",4″″-hexahydroxy-3″-O-β-glucosyl-3',7″-O-biflavone (3) have been isolated from whole plant of Trifolium echinatum Bieb. together with five known flavonoids. The structures of the compounds were elucidated by 1D and 2D NMR analysis as well as HRESIMS. The isolated compounds were investigated for their antioxidant activity and tyrosinase inhibitory activity. Highly potent inhibition was found for compounds 1 (IC50=0.41 mM), 5 (IC50=0.47 mM) and 8 (IC50=0.45 mM) compared to those of standard tyrosinase inhibitors kojic acid (IC50=0.67 mM) and l-mimosine (IC50=0.64 mM). The antioxidative effect of the extracts was determined by using β-carotene-linoleic acid, DPPH scavenging, ABTS(+) scavenging, and CUPRAC assays. The experimental findings indicated that the compounds 2 and 8 were found to be active in radical scavenging and CUPRAC assays.
Department of Chemistry, Faculty of Science and Letters, Namik Kemal University, 59030 Tekirdag, Turkey. Electronic address: tsabudak@yahoo.com.
Temine
T
Sabudak
Ozlem
O
Demirkiran
Mehmet
M
Ozturk
Gulacti
G
Topcu
D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D044946:Biflavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002867:Chromones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology; D029921:Trifolium / Q000737:chemistry*; D014421:Turkey; D019207:beta Carotene / Q000737:chemistry
C000589069:3,3'-dihydroxy-2,2'-oxychromone; C000589068:3,3'-dimethoxy-2'-oxychromone; C000589075:5,7,4',5'',3'',4''-hexahydroxy-3'-O-beta-glucosyl-3',7'-O-biflavone; D000975:Antioxidants; D044946:Biflavonoids; D002867:Chromones; D010636:Phenols; D011753:Pyrones; D019207:beta Carotene; C011890:kojic acid; D014442:Monophenol Monooxygenase
Antioxidant activity; Biflavonoid; Bischromone; Fabaceae; Trifolium echinatum; Tyrosinase inhibition