• Korean Journal of Pharmacognosy
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• v.49 no.1
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• pp.15-22
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• 2018

The aim of this study was to develop a UPLC method for simultaneous analysis of 8 phenolic compounds including gallic aicd (1), protocatechuic acid (2), methyl gallate (3), ellagic acid (4), kaempferol-3-arabinofranosyl-7-rhamnoside (5), kaempferitrin (6), afzelin (7) and kaempferol-7-rhamnoside (8) isolated from Geranium thunbergii which has been traditionally used as anti-diarrheal agent. The UPLC method was optimized and validated using Halo C18 column ($4.6{\times}100mm$, $2.7{\mu}m$) consisting of MeOH and 0.1% formic acid at 260 nm in 25 minutes. In quantitative analysis of 8 compounds in MeOH extract of G. thunbergii, contents of 4-6 were 12.39, 20.52 and 21.45 mg/g, respectively. These compounds were measured as major phenolic compounds in G. thunbergii and can be useful as marker compounds for its quality control. These results suggest that the UPLC method can be contributed as basic data for quality evaluation of herbal preparations.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.62-62
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• 2018

Inhibition of aldose reductase (AR) has been shown to prevent the onset and progression of many diabetic complications wherein several AR inhibitors were isolated from plants abundant in polyphenolic compounds. Lespedeza cuneata (Fabaceae), a perennial plant indigenous in East Asian countries, is shown to be abundant in these polyphenolic substances such as flavonoids and tannins. However, there are no studies to date regarding its effects on AR. In this study, the inhibitory activity of the methanol extract and stepwise polarity fractions of Lespedeza cuneata on AR was investigated. The bioactive compounds purified from L. cuneata by repeated column chromatography were also tested for AR inhibition. Results show that the ethyl acetate and n-butanol fractions of L. cuneata exhibited potent inhibition against AR with $IC_{50}$ values of 0.57 and $0.49{\mu}g/mL$, respectively. Further analysis led to the isolation of acacetin (1), afzelin (2), astragalin (3), kaempferol (4), and scutellarein 7-O-glucoside (5). The AR inhibitory effects these five compounds were also determined in which compounds 2, 3, and 5 showed potent AR inhibitory effects with $IC_{50}$ values of 2.20, 1.91, and $12.87{\mu}M$, respectively. Quantitative analysis of astragalin (3) by HPLC-UV was also performed in the leaves and roots of L. cuneata (0.626 and 0.671 mg/g, respectively). This study reports that the flavonoids isolated from L. cuneata show promising AR inhibitory activities which can be further developed as natural therapies for treating and managing diabetic complications.

• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.449-454
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• 2023

Free-living amoebae (FLA) rarely cause human infections but can invoke fatal infections in the central nervous system (CNS). No consensus treatment has been established for FLA infections of the CNS, emphasizing the urgent need to discover or develop safe and effective drugs. Flavonoids, natural compounds from plants and plant-derived products, are known to have antiprotozoan activities against several pathogenic protozoa parasites. The anti-FLA activity of flavonoids has also been proposed, while their antiamoebic activity for FLA needs to be emperically determined. We herein evaluated the antiamoebic activities of 18 flavonoids against Naegleria fowleri and Acanthamoeba species which included A. castellanii and A. polyphaga. These flavonoids showed different profiles of antiamoebic activity against N. fowleri and Acanthamoeba species. Demethoxycurcumin, kaempferol, resveratrol, and silybin (A+B) showed in vitro antiamoebic activity against both N. fowleri and Acanthamoeba species. Apigenin, costunolide, (-)-epicatechin, (-)-epigallocatechin, rosmarinic acid, and (-)-trans-caryophyllene showed selective antiamoebic activity for Acanthamoeba species. Luteolin was more effective for N. fowleri. However, afzelin, berberine, (±)-catechin, chelerythrine, genistein, (+)-pinostrobin, and quercetin did not exhibit antiamoebic activity against the amoeba species. They neither showed selective antiamoebic activity with significant cytotoxicity to C6 glial cells. Our results provide a basis for the anti-FLA activity of flavonoids, which can be applied to develope alternative or supplemental therapeutic agents for FLA infections of the CNS.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.452-460
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• 2018

This study was conducted to investigate the physiological activities of Houttuynia cordata extracts and fractions. H. cordata extracts were extracted with 50% ethanol and the ethyl acetate fractions were obtained from the extracts. Minimum inhibitory concentration (MIC) values of the ethyl acetate fraction for S. aureus and B. subtilis were $78{\mu}g/mL$ and $312{\mu}g/mL$, respectively, indicating the high activity against gram-positive bacteria. The free radical scavenging activity ($FSC_{50}$) for 1,1-diphenyl-2-picrylhydrazyl (DPPH) was higher in the ethyl acetate fraction with $12.00{\mu}g/mL$ compared to that of $27.15{\mu}g/mL$ for 50% ethanol extract. The total antioxidant activity ($OSC_{50}$) values for reactive oxygen species (ROS) produced in $Fe^{3+}-EDTA/H_2O_2$ system by a luminol-dependent chemiluminescence method were 2.91 and $0.983{\mu}g/ml$ for the 50% ethanol extract and ethyl acetate fraction, respectively. To investigate cellular protective effects on the HaCaT cell, the intracellular ROS scavenging activity was measured after UVB irradiation and the ethyl acetate fraction of H. cordata showed the activity in a concentration-dependent from $1.6{\mu}g/mL$ and a reduction rate of 54.3% at a maximum concentration of $12.5{\mu}g/mL$. Also, HaCaT cell protective effect against $H_2O_2$-mediated decreased the cell viability of the ethyl acetate fraction of H. cordata which significantly increased the cell viability from $0.8{\mu}g/mL$ and the maximum cell viability showed 86.9%. The ethyl acetate fraction of the H. cordata extracts was analyzed by TLC and HPLC. As a result, quercitrin, isoquercitrin, hyperoside, chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, rutin and afzelin were identified. From the above results, it was suggested that the extracts and fractions of H. cordata have a potential to be applied in the field of cosmetics as a natural antioxidant/preservative capable of protecting the cell membrane from the oxidative stress by eliminating ROS and exhibiting the antimicrobial effect.