Phenolic Compounds from the Aerial Parts of Blepharis linariifolia Pers. and Their Free Radical Scavenging and Enzyme Inhibitory Activities

Abstract

Background: Blepharis linariifolia Pers. (Family: Acanthaceae) is used in traditional medicines as a general tonic and for the treatment of various health problems in Sudan. The main aim of this study was to isolate and identify the major chemical constituents from the aerial parts of B. linariifolia and evaluate their bioactivities. Methods: The dried aerial parts of the plant were extracted successively with 100% acetone and 50% acetone, and thereafter the combined extract was subjected to repeated column chromatography to isolate the main components. Free radical scavenging activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical method, and in vitro enzyme inhibitory activities against α-glucosidase, pancreatic lipase, and mushroom tyrosinase were evaluated. Results: From the detailed chemical analysis, verbascoside (1), vanillic acid (2), apigenin (3), and 6″-O-p-coumaroylprunin (4), were isolated and their structures were identified on the basis of their nuclear magnetic resonance (NMR) spectral data. Among the isolated compounds, verbascoside (1) showed the most potent free radical scavenging activity (IC50 = 22.03 ± 0.04 μM). Apigenin (3) and 6″-O-p-coumaroylprunin (4) showed promising inhibitory activities against all tested enzymes. Apigenin (3) showed the most potent inhibitory activity against α-glucosidase and tyrosinase (IC50 = 34.73 ± 1.78 μM and 23.14 ± 1.83 μM, respectively), whereas 6″-O-p-coumaroylprunin (4) showed potent inhibition for lipase (IC50 = 2.25 ± 0.17 μM). Conclusions: Four phenolic compounds were isolated and identified from B. linariifolia acetone extract, which are reported for the first time from this plant. All compounds showed good DPPH free radical scavenging activities, with verbascoside (1) being the most potent. Apigenin (3) was the most active as α-glucosidase and mushroom tyrosinase inhibitor, while 6″-O-p-coumaroylprunin (4) showed potent inhibitory activity for pancreatic lipase.

Ultrasound-Assisted Extraction of Verbascoside from Clerodendrum glandulosum Leaves for Analysis of Antioxidant and Antidiabetic Activities

“…1 H and 2D-NMR spectra of crude methanolic extract of Stachys thracica led to the unambiguous assignment of 15 individual compounds including VER . In the present study, principal signals showing the 1 H resonances and principal homonuclear correlations obtained by 2D-COSY spectra have led to the assignment of the different moieties of VER in the ethanol extract on the basis of previously published compound assignments. − …”

“… 48 In the present study, principal signals showing the 1 H resonances and principal homonuclear correlations obtained by 2D-COSY spectra have led to the assignment of the different moieties of VER in the ethanol extract on the basis of previously published compound assignments. 50 − 52 …”

Xanthine oxidase inhibition study of isolated secondary metabolites from Dolichandrone spathacea (Bignoniaceae): In vitro and in silico approach

“…The structures of all isolated compounds were elucidated based on the 1D and 2D NMR, HRESI-MS, and comparison with reference literature. Nine compounds were obtained from this species, which were previously unreported, including 5α-stigmastane-3,6-dione ( 1 ) ( Zhao et al, 2005 ); oleanolic acid ( 2 ) ( Onoja and Ndukwe, 2013 ); martynoside ( 6 ) ( Calis et al, 1984 ); cistanoside F ( 9 ) ( Kim et al, 2007 ); 1-(α-L-rhamnosyl(1–6)- β -D-glucopyranosyloxy)-3,4,5-trimethoxybenzene ( 10 ) ( Andrianaivoravelona et al, 1999 ); (+)-lyoniresinol-3α- O - β -D-glucopyranoside ( 11 ); (−)-lyoniresinol-3α- O - β -D-glucopyranoside ( 12 ); (−)-5′-methoxyisolariciresinol-3α- O - β -D-glucopyranoside ( 13 ); (−)-isolariciresinol-3α- O - β -D-glucopyranoside ( 14 ) ( Wen et al, 2012 ), and salvionoside B ( 18 ) ( Takeda et al, 1997 ), along with nine known compounds: trans -4-methoxycinnamic acid (3) ( Bylka, 2004 ); trans -3,4-dimethoxycinnamic acid (4) ( Ralph et al, 2004 ); p -coumaric acid (5) ( Rho and Yoon, 2017 ); 6- O -( p -methoxy- E -cinnamoyl)-ajugol (7 ) ( Nguyen et al, 2018 ); ixoside (8 ) ( de Santana Aquino et al, 2017 ); verbascoside (15) ( Ibrahim Dirar et al, 2019 ); isoverbascoside (16) ( Suo et al, 2013 ); scolymoside (luteolin 7- O -rutinoside) (17) ( Guvenalp et al, 2015 ), that were previously isolated from this plant. The structures of eighteen compounds isolated from D. spathacea are shown in Fig.…”

Plant Extracts as Skin Care and Therapeutic Agents

“…Orchidaceae tubers [194] Anacardium occidentale Anacardiaceae leaves [195] Anacardium occidentale Anacardiaceae fruits [196] Andropogon virginicus Poaceae aerial parts [197] Angelica keiskei Umbelliferae leaves, roots [198] Arachis hypogaea Fabaceae peanut shell [154] Areca catechu Palmaceae fruits [195] Arctium minus Asteraceae flower heads, leaves, roots [199] Artemisia verlotiorum Asteraceae whole plant [200] Atractylodis macrocephalae Asteraceae rhizomes [201] Berberis thunbergii Berberidaceae leaves [202] Bergenia pacumbis Saxifragaceae plant and its rhizomes [203] Blepharis linariifolia Acanthaceae aerial parts [204] Bletilla striata Orchidaceae tubers, fibrous roots [205] Breynia retusa Phyllanthaceae leaves [206] Bridelia ferruginea Phyllanthaceae leaves, stem bark [207] Bruguiera gymnorhiza Rhizophoraceae leaves, roots, fruits [158] Cakile maritima Brassicaceae fruits, leaves, stems [208] Cannabis sativa Cannabaceae seeds [169] Carthamus tinctorius Asteraceae seeds [209] Celastrus hindsii Celastracea leaves [210] Cercis glabra Fabaceae leaves [211] Cladium mariscus Cyperaceae seeds [212] Clausena indica Rutaceae roots [213] Combretum micranthum Combretaceae leaves [196] Crotalaria burhia Fabaceae aerial parts, roots [214] Croton hirtus Euphorbiaceae aerial parts [215] Cudrania tricuspidata Moraceae fruits [216] Cytinus hypocistis Cytinaceae aerial parts [217] Dianella ensifolia Liliaceae roots [218] Dodonaea viscosa Sapindaceae stems [219] Elaeagnus angustifolia Elaeagnaceae fruits, leaves [220] Table 4. Cont.…”