Flavonoid Derivatives from the Aerial Parts of Trifolium trichocephalum M. Bieb. and Their Antioxidant and Cytotoxic Activity

Abstract

Trifolium L. species with a rich isoflavone content have been used as expectorant, analgesic, antiseptic, tonic, and wound-healer in folk medicine. The aim of the study is to evaluate pharmacological properties of the extracts and isolated compounds of T. tricocephalum. Phytochemical investigation of the aerial parts of T. trichocephalum led to the isolation of daidzein, genistein, quercetin, and daidzein 4'-O-β-glucoside for the first time from this species. Isolated compounds along with the methanol extract, water, ethyl acetate and chloroform subextracts were tested for their radical scavenging and cytotoxic activity which was evaluated by MTT assay. According to the results of activity tests, extracts showed a concentration-dependent radical scavenging activity as well as cytotoxic effect on HepG2 cells at 400 μg/mL, whereas the compounds did not exert any obvious cytotoxic effect at tested concentrations.

Metabolite variations and antioxidant activity of Muntingia calabura leaves in response to different drying methods and ethanol ratios elucidated by NMR‐based metabolomics

“…The 1 H‐ 1 H correlation via the spin system also showed the coupling network between δ H 6.95 (s), 7.57 (d, J = 8.6 Hz) and 7.99 (d, J = 7.7 Hz). Meanwhile, the resonating signal at δ H 6.85 from ring A at position H‐6 shows similar spin system with daidzein ( 22 ), 3′‐hydroxydaidzein ( 25 ) and a daidzein derivatives ( 43 ) 26 . The TOCSY correlation of compound 43 was also exhibited at δ H 7.15 (m) and 7.83 (d, J = 8.5 Hz) 26 .…”

“…Meanwhile, the resonating signal at δ H 6.85 from ring A at position H‐6 shows similar spin system with daidzein ( 22 ), 3′‐hydroxydaidzein ( 25 ) and a daidzein derivatives ( 43 ) 26 . The TOCSY correlation of compound 43 was also exhibited at δ H 7.15 (m) and 7.83 (d, J = 8.5 Hz) 26 . However, due to lack of information, these derivatives have yet to be confirmed.…”

“…Formononetin ( 29 ) was detected with signals located at δ H 3.82 (s), 6.49 (d, J = 1.9 Hz), 7.92 (d, J = 8.5 Hz) and 8.02 (s) 33 . Compound 43 was detected as a daidzein derivatives based on the signals resonating at δ H 6.85 (m), 7.15 (m) and 7.83 (d, J = 8.5 Hz) 26 . The flavanones group includes 7,4′‐dimethoxy‐5‐hydroxyflavanone ( 24 ), which was identified based on the signals at δ H 3.12 (m), 6.08 (s), 6.70 (d, J = 1.7 Hz), 6.83 (d, J = 2.2 Hz) and 7.52 (s); 28 6‐hydroxyflavanone ( 27 ), which was detected based on the signals at δ H 2.54 (dd, J = 3.8, 15.8 Hz) and 7.43 (d, J = 2.1 Hz); 31 and hiravanone ( 38 ) with signals resonating at δ H 2.82 (dd, J = 4.1, 12.4 Hz), 5.25 (t, J = 6.5 Hz) and 5.39 (dd, J = 3.5, 13.2 Hz) 38 .…”

“…The signals resonating at δ H 5.96 (d, J = 2.3 Hz) and 6.81 (d, J = 10.1 Hz) was identify as kaempferol 7‐(6″‐ p ‐coumarylglucoside) ( 35 ) 37 . As for the isoflavones group, daidzein ( 22 ) was identify based on the signals at δ H 7.95 (d, J = 8.1 Hz), 7.32 (d, J = 7.4 Hz) and 6.85 (m), 26 while the signals at δ H 6.85 (m), 6.88 (d, J = 2.0 Hz) and 7.04 (d, J = 1.6 Hz) were assigned for 3′‐hydroxydaidzein ( 25 ) 29 . The signals corresponding to 2′,4′,7‐trihydroxy‐3′,8‐diprenylisoflavan ( 28 ) were detected at δ H 1.75 (s), 2.54 (dd, J = 3.8, 15.8 Hz), 3.19 (d, J = 8.9 Hz) and 5.25 (t, J = 6.5 Hz) 32 .…”

Rumex dentatus L. phenolics ameliorate hyperglycemia by modulating hepatic key enzymes of carbohydrate metabolism, oxidative stress and PPARγ in diabetic rats

“…The structure of the compounds was confirmed by 1 H-, 13 C-and 2D-NMR and spectroscopic tools (UV, MS and IR). The isolated compounds were identified as quercetin (2) (Renda et al, 2017), emodin-1-O-β-Dglucopyranoside (3) (El-Toumy et al, 2012), kaempferol-3-O-β-D-glucuronide (4) (Yang et al, 2010), querectin-3-O-β-D-glucuronide (5) (M. Soliman et al, 2002), querectin-3-O-β-Dglucopyranoside (6) (Islam et al, 2012), kaempferol (7) and resveratrol 3-glucoside (8) (Vastano et al, 2000). The OH groups in positions 5, 7 and 4′ are common in these compounds.…”