Agung Nugroho

Rhododendrin, an analgesic/anti-inflammatory arylbutanoid glycoside, from the leaves of Rhododendron aureum

To identify an analgesic/anti-inflammatory component from the leaves of Rhododendron aureum (Ericaceae), phytochemical isolation and pharmacological assays (writhing assays and vascular permeability assay for analgesic action in mice; carrageenan-induced paw edemaand TPA-induced ear edema assays of anti-inflammatory action in rats) were performed. Four compounds were isolated from the active fraction (BuOH fraction) by silica gel column chromatography and identified as (−)-rhododendrol, (−)-rhododendrin, avicularin and hyperoside by spectroscopic methods. Rhododendrin, the main compound of the BuOH fraction, exhibited significant analgesic actions in mice and anti-inflammatory actions in rats. This compound accounted for 3.1% of the MeOH extract and 0.48% of dried leaves, respectively, on HPLC analysis. These results suggest that rhododendrin is the major biologically active substance in the leaves of R. aureum with analgesic/anti-inflammatory activity.

Phytochemical studies of the phenolic substances in Aster glehni extract and its sedative and anticonvulsant activity

On high performance liquid chromatography, the caffeoylquinic acid (CQ) occupying the highest proportion of the water-ethanol (7:3) extract of Aster glehni (Compositae) leaves was 3-Op-coumaroylquinic acid (46.10 ± 4.22 mg/g of dried weight) among CQs tested. The IC50 of the water-ethanol (7:3) extract was 4.23 ± 0.24 μg/mL in the peroxynitrite (ONOO−)-scavenging assay. Phytochemical isolation from A. glehni extract yielded three kaempferol glycosides. The water-ethanol (7:3) extract and both p-coumaric acid and caffeic acid, phenylpropanoid moieties of CQs, had sedative effects in pentobarbital-induced sleeping time in mice and anticonvulsant effects in pentylenetetrazole-induced mice. Furthermore, the phenolic substance-rich W-E (7:3) extract of A. glehni could be used to treat anxiety or convulsion partly due to its peroxynitrite-scavenging mechanism.

Simultaneous quantification and validation of new peroxynitrite scavengers from Artemisia iwayomogi

Abstract Context: Artemisia iwayomogi Kitamura (Compositae) has been very widely used for the treatment of acute or chronic hepatitis, jaundice, and gastritis. In the course of our continuing efforts to identify and quantify peroxynitrite scavengers from Compositae plants, A. iwayomogi was used in this study. Objective: The present study was aimed to identify and quantify the peroxynitrite scavengers of A. iwayomogi. Materials and methods: Silica gel and ODS were used for column chromatography. The isolated compounds were quantified using an HPLC equipped with a Capcell Pak C18 column (5 μm, 250 mm × 4.6 mm i.d.), and the method was validated for the quality control. Peroxynitrite (ONOO−)-scavenging activities of the compounds and extracts were evaluated on the measurement of highly fluorescent rhodamine 123 converted from non-fluorescent dihydrorhodamine (DHR)-123 under the presence of peroxynitrite. Results: Based on the spectroscopic evidences, a new compound, 2″-O-caffeoylrutin (2″-O-trans-caffeic acid ester of quercetin 3-O-α-l-rhamnopyranosyl(1 → 6)-β-d-glucopyranoside) was isolated and determined together with patuletin 3-O-glucoside, scopolin, scopoletin, rutin, 3,4-dicaffeoylquinic acid, and chlorogenic acid. All of them were potent peroxynitrite scavengers (IC50 ≤ 1.88 μg/mL). Discussion and conclusion: The peroxynitrite scavengers were mainly distributed in the EtOAc fraction rather than the ether and BuOH fractions. The 70% MeOH extract exhibited a high peroxynitrite-scavenging activity. Through the validation, the present HPLC method was verified to be sufficiently sensitive, accurate, precise, and stable. Therefore, this method can be used for the quality control of A. iwayomogi.

Structure determination and quantification of a new flavone glycoside with anti-acetylcholinesterase activity from the herbs of Elsholtzia ciliata

Abstract Three acacetin triglycosides (compounds 1, 2 and 3) were isolated from the herbs of Elsholtzia ciliata (Labiatae). The structure were identified as 7-O-β-D-glucopyranosyl-(1 → 2)[α-L-rhamnopyranosyl-(1 → 6)]-β-D-glucopyranoside (compound 1), 7-O-(6-O-acetyl)-β-D-glucopyranosyl-(1 → 2)[α-L-rhamnopyranosyl-(1 → 6)]-β-D-glucopyranoside (compound 2) and 7-O-(6-O-acetyl)-β-D-glucopyranosyl-(1 → 2)[(4-O-acetyl)-α-L-rhamnopyranosyl-(1 → 6)]-β-D-glucopyranoside (compound 3) of acacetin. The structures of these compounds were determined on the basis of 2D-NMR spectroscopic data. Compound 3 has not been isolated from a natural source. In addition, the three compounds were quantitatively analysed by HPLC. Acetylcholinesterase (AChE) inhibition activity was assayed to find anti-Alzheimer’s activity, since this enzyme increases the concentration of acetylcholine (ACh), a neurotransmitter, responsible for brain’s memory. Acacetin, the aglycone of the three compounds, exhibited a potent anti-cholinesterase activity (IC50, 50.33 ± 0.87), though its glycosides (1, 2 and 3) were less active. HPLC analysis demonstrated that the three compounds were contained in the MeOH extract in the order of compounds 2 (12.63 mg/g extract) > 3 (3.10 mg/g) > 1 (2.92 mg/g).