Total Peroxynitrite Scavenging Capacity of Phenylethanoid and Flavonoid Glycosides from the Flowers of Buddleja officinalis

Abstract

The flowers of Buddleja officinalis MAXIM. (Buddlejaceae) are used in traditional medicine in several parts of the world where it is indigenous. In folk medicine remedies, it is used for the treatment of stroke, headache, neurological disorders, conjunctival congestion, clustered nebulae, removal of heat, replenishment of the liver, and clearing the corneal opacity.1-3) Besides its uses in traditional medicine, the B. officinalis plant has also been cultured and its flowers used as a yellow natural food colorant. 1,4) Phytochemical studies of the flower have yielded isolation of flavonoids, 5) saponins, 6) and several phenylethanoid glycosides. 7)Pharmacognosy and usage of B. officinalis in traditional recipes have been widely reported by Chinese and Korean scientists. Flavonoids from the flowers have shown weakly antioxidative and antifungal activities.5) The aqueous extract of B. officinalis inhibits highly glucose-induced matrix metalloproteinase activity.3) However, the antioxidant activities of constituents from the flower have been not extensively studied.5) As part of our investigations of bioactive compounds from Vietnamese medicinal plants, the flowers of B. officinalis were found to possess high antioxidant activity using the total oxidant scavenging capacity (TOSC) assay. The TOSC assay developed by the Winston and collaborators is a method for evaluating antioxidant activity based on the inhibition of oxy-radical-induced production of ethylene gas from a-keto-g-methiolbutyric acid (KMBA). 8,9) The advantages of this method are that it is simple, rapid, and applicable for either biological tissues as well as pure antioxidants. Furthermore, unlike 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, this assay can evaluate antioxidant capacity against physiological oxidants including peroxynitrite.In this paper, the isolation of nine compounds, including six phenylethanoid glycosides (1-6) and three flavones (7-9) from EtOAc and n-BuOH extracts of the flowers of B. officinalis are reported. Of these, bioside (2) was isolated for the first time from the Buddleja genus. Antioxidant activities against peroxynitrite were then evaluated using TOSC assay. MATERIALS AND METHODS General Experimental ProceduresThe nuclear magnetic resonance ( 1 H-NMR, 400 MHz and 13 C-NMR, 100 MHz) spectra were recorded on a Bruker DRX-NMR spectrometer (Germany) using Bruker's standard pulse program. Chemical shifts were reported in ppm downfield from tetramethylsilan (TMS), with J in Hz. The electronspray ionization (ESI) mass spectra were recorded on an AGILENT 1100 LC-MSD trap spectrometer. Silica gel (70-230, 230-400 mesh, Merck), YMC RP-18 resins (30-50 mm, Fuji Silysia Chemical Ltd.) were used as absorbents in the column chromatography. Thin layer chromatography (TLC) plates (Silica gel 60 F 254 and RP-18 F 254 , 0.25 mm, Merck) were purchased from Merck KGaA (Darmstadt, Germany). Spots were detected under UV radiation (254, 365 nm) and by spraying the plates with 10% H 2 SO 4 followed by heating with a heat gun. Chemistry, VAST...

Evaluation of the total oxy-radical scavenging capacity of catechins isolated from green tea

“…These results indicated that the antioxidant activities of sugar alcohols are mediated by their aliphatic hydroxyl groups and that the TOSC assay is a reliable tool for quantitatively assessing the antioxidant potency of chemical substances. We have successfully evaluated the antioxidant capacities of plant extracts (Tai et al, 2009), isolated or synthetic compounds (Tung et al, 2008), and biological samples (Kim, Woodcroft, Oh, Abdelmegeed, & Novak, 2005;Kim et al, 2009) using the TOSC assay. In the present study, all samples including catechins and GA were analysed for at least five concentrations, and ethylene production was reduced in the presence of each sample in a concentration-dependent manner (data not shown).…”

Activation of AMPK by Buddleja officinalis Maxim. Flower Extract Contributes to Protecting Hepatocytes from Oxidative Stress

“…BFE is an aqueous extract from the flowers of B. officinalis that contains numerous bioactive compounds, including acteoside, apigenin, buddlejasaponin I, echinacoside, isorhoifolin, linarin, methylcatalpol, mimengoside B, 6-O-vanilloyl ajugol, and salidroside [1, 3–7]. Our results of the chromatographic analysis revealed that the main compounds in BFE were acacetin, apigenin, and luteolin.…”

“…In traditional Oriental medicine, BFE is used as a folk remedy to treat inflammation, vascular diseases, conjunctivitis, clustered nebulae, headache, and stroke, as well as enhance liver function [1–3]. However, there is little scientific data to support the effects of BFE.…”

“…B. officinalis is a flowering shrub in the family Scrophulariaceae that is widely distributed in America, Africa, and Asia. It is used in China and Korea to treat inflammation, vascular diseases, conjunctivitis, headache, and stroke, as well as enhance liver function [1–3]. B. officinalis reportedly contains iridoids (e.g., methylcatalpol and 6-O-vanilloyl ajugol), monoterpenoids (e.g., betulalbusides A), flavonoids (e.g., apigenin, isorhoifolin, and linarin), triterpenoids (e.g., acteoside, salidroside, and echinacoside), and phenylethanoids (e.g., buddlejasaponin I and mimengoside B) [1, 3–7].…”

Chemical Constituents fromBuddleja officinalisand Their Inhibitory Effects on Nitric Oxide Production

“…[1][2][3][4][5][6][7] In the course of an investigation for the isolation of plantderived nitric oxide (NO) production inhibitors, a MeOH extract of the flower buds of B. officinalis showed inhibitory effects on LPS-induced NO production. The dried flower buds of B. officinalis were extracted with MeOH, and the resultant extract was partitioned successively with n-hexane, CH 2 Cl 2 , and water.…”