Context: Phytochemical study and biological potential of Evax pygmaea (L.) Brot. (Asteraceae) are reported for the first time.Objective: To identify the secondary metabolites of Evax pygmaea and to determine its antioxidant, antibacterial and cytotoxic activities.Materials and methods: Dried aerial parts (1 kg) were macerated in 70% MeOH (5 L) during 72 h. The concentrated hydromethanolic extract was subjected to extractions with chloroform (3 × 300 mL), ethyl acetate (3 × 300 mL) and n-butanol (3 × 300 mL), successively. VLC of combined ethyl acetate (EAEP) and n-butanol (BEP) fractions was followed by column purifications. Antioxidant activity was investigated using DPPH, CUPRAC, and metal chelating, β-carotene/linoleic acid and ABTS assays. Agar method was used in the antibacterial study. Cytotoxic activity was determined by Brine shrimp lethality test in DMSO and ethanol, at varying concentrations (2, 1 and 0.2%) and (1, 0.2 and 0.1%) successively.Results: Quercetin (1), isorhamnetin 3-O-β-d-xyloside (2), isorhamnetin 3-O-β-d-glucoside (3), quercetin 3-O-β-d-glucoside (4), quercetin 7-O-β-D-glucoside (5), patuletin 3-O-β-d-glucoside (6) were isolated from for the first time from Evax genus. The EAEP was the most active in ABTS (IC50: <3.125 μg/mL) assay whereas the BEEP exhibited the highest activity in the β-carotene/linoleic acid assay (IC50: <3.125 μg/mL). The EAEP and BEP exhibited good antibacterial activity (MIC: 40–80 µg/mL). The plant did not show any toxicity (LD50>80 µg/mL).Discussion and conclusions: Six flavonoids were isolated for the first time from Evax pygmaea which exhibited good antioxidant and antibacterial activities.
Four new phenylethanoid glycosides (1: -4: ), 1--hydroxyphenyl-ethyl-2--acetyl-3,6-di--l-rhamnopyranosyl--d-glucopyranoside (1: ), 1---hydroxyphenyl-ethyl-3,6--di--l-rhamnopyranosyl--d-glucopyranoside (2: ), 1---hydroxyphenyl-ethyl-2--acetyl-3,6-di--l-rhamnopyranosyl-4--coumaroyl--d-glucopyranoside (3: ), and 1---hydroxyphenyl-ethyl-3,6-di--l-rhamnopyranosyl-4--coumaroyl--d-glucopyranoside (4: ), together with three known compounds, were isolated from the -butanol extract of aerial parts. The structural characterization of all compounds was performed by spectroscopic analyses, including 1D and 2D NMR, and HRESIMS experiments. The isolated compounds were assayed for their inhibitory activity on two enzymes involved in the peculiar glycolytic or lipidic metabolism of cancer cells, human lactate dehydrogenase (LDH), and monoacylglycerol lipase (MAGL), respectively. All the compounds showed negligible activity on LDH, whereas some of them displayed a certain inhibition activity on MAGL. In particular, compound 1: was the most active on MAGL, showing an IC value of 88.0 µM, and modeling studies rationalized the supposed binding mode of 1: in the MAGL active site.
A previously undescribed phenolic sulphate ester, potassium 34-dihydroxy-3-methoxybenzoic acid methyl ester-5-sulphate (1), along with nine known flavonoids, kaempferol-3-O-potassium sulphate-4',7-dimethyl ether (2), kaempferol-4',7-dimethyl ether (3), rhamnocitrin-3-O-potassium sulphate (4), rhamnocitrin (5), kaempferol (6), quercetin (7), afzelin (8), quercetin-3-O-α-l-rhamnopyranoside (9) and luteolin-3'-O-potassium sulphate (10) were isolated from the aerial parts of Tamarix balansae. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. The antibacterial assay against Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa bacteria showed a good activity for 2, 3, 7 and 9, with MICs ranging from 62.5 to 250 μg/mL. The abilities of these compounds to scavenge the DPPH were evaluated. Compounds 1, 7, 9 and 10 exhibited a good antiradical activity potential with IC values ranging from 3.0 to 115.5 μg/mL, compared with ascorbic acid (IC 7.4 μg/mL) which was used as positive control.
A pentacyclic triterpene, named salvibuchanic acid (1), together with five known compounds, were isolated from the roots of Salvia buchananii Hedge (Lamiaceae). The structural characterisation of all compounds was performed by spectroscopic analyses, including 1D and 2D NMR and HRESIMS experiments. The lupane triterpene (1) and hyptadienic acid (2) were investigated for their potential cytotoxic activity on Jurkat, HeLa and MCF7 cell lines. Both compounds showed an interesting antiproliferative activity with similar potency in all cell lines. By means of flow cytometric studies, hyptadienic acid (2) induced in HeLa cells a S cell cycle block, while 1 elicited both cytostatic and cytotoxic responses.
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