• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.245-248
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• 2003

The purpose of this study was to evaluate tyrosinase inhibitory activity of plant extracts, especially Korean indigenous plants, for the cosmetic use of skin whitening. When 50 plant extracts were tested, the methanol extracts of Agrimonia pilosa, Aster scaber; Dianthus sinensis, Fatsia japonica, Hemistepta lyrata, Lespedeza cuneata, Osmunda japonicum, Pyrvla japvnica, Rodgersia phodophylla and Veratrum grandiforum possessed the considerable tyrosinase inhibitory activity at 3-300 $\mu\textrm{g}$/mL. Especially, L. cuneata, aerial part of O. japonicum and V. gandiforum exhibited the strong inhibition (>50％ inhibition at 300 $\mu\textrm{g}$/mL). In particular, the methanol extract of V. grandiforum and its ethylacetate fraction showed potent inhibition ($IC_{50}$/=30 and 13$\mu\textrm{g}$/mL, respectively), while the reference compound, kojic acid, showed $IC_{50}$/ value of 26$\mu\textrm{g}$/mL. These plant extracts may be used as tyrosinase inhibitors in cosmetics.

• Natural Product Sciences
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• v.3 no.1
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• pp.19-28
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• 1997

Constitutive cyclooxygenase (COX-I) is present in cells under physiological conditions, whereas inducible cyclooxygenase (COX-II) is induced by some cytokines, mitogens, and endotoxin presumably in pathological conditions such as inflammation. We have evaluated the inhibitory effects of solvent fractionated extracts of natural products on the activities of COX-I and COX-II. Oxygen uptake COX assay was performed, as a primary screening from the tissue extracts of bovine seminal vesicles (BSV), by monitoring the initial rate of oxygen uptake using an oxygen electrode. Additionally, we evaluated plant extracts for the inhibitory effects of COX-I (in HEL cells) and COX-II (in lipopolysaccharide activated J774A.1 macrophages) using thin layer chromatography of prostanoids produced from $^{14}C-labelled$ arachidonic acid (AA). The use of such models of COX-I and COX-II assay will lead to the identification of specific inhibitors of cyclooxygenases with presumably less side effects than present therapies. Inhibitory effects of 50 kinds of plant extracts on the COX-I and COX-II activities were determined and the active fractions were found in the ethyl acetate fractions of Dryopteris crassirhizoma (roots), Amomum cardamomum (roots), Triticum aestivum (seeds), Perilla sikokiana (leaves), Anemarrhena asphodeloides (roots). Especially, the ethyl acetate fraction of Dryopteris crassirhizoma (roots), which exhibited the strong inhibition against BSV COX $(IC_{50},\;65.4\;{\mu}g/ml)$, COX-I $(IC_{50},\;8.5\;{\mu}g/ml)$, and COX-II $(IC_{50},\;17.2\;{\mu}g/ml)$, is under investigation to isolate active principles using activity-guided fractionation method.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.147-150
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• 2003

To find anticancer agents from higher plants, DNA strand-scission assay method was employed for bioassay-guided fractionation as well as for screening the crude extracts. During the screening, an ethyl acetate extracts of the heartwood of Caesalpinia sappan L. (Leguminosae) exhibited potent DNA strand-scission activity. Therefore, the ethyl acetate extracts of the dried heartwood of C. sappan was subjected to the bioassay-guided fractionation, which led to the isolation of a known compound, brazilin (1) as the active constituent. In addition, caesalpine J (2) was also isolated as an inactive constituent.

• Natural Product Sciences
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• v.9 no.4
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• pp.226-231
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• 2003

Reactive oxygen species damage biomolecules such as lipids, proteins, sugars and DNA, which can not only lead to various disease but also oxidative damage resulting aging. In order to search for antioxidants from plants, the antioxidant effects of the MeOH extracts from 182 plants were evaluated. The results showed that thirteen plant extracts exhibited antioxidant activity (>80%) in DPPH radical assay, seven plant extracts demonstrated antioxidant activity (>40%) in the hydroxyl radical assay and eighteen plant extracts were active (>80%) in the lipid peroxidation assay. In particular, the extracts of Distylium racemosum (Hamamelidaceae), Astilbe koreana (Saxifragaceae), Astilbe chinensis and Euphorbia supina (Euphorbiaceae) were identified as potent principles of antioxidant activity in all the assay systems.

• Korean Journal of Pharmacognosy
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• v.12 no.1
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• pp.55-57
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• 1981

Six medicinal plants described in Dong-Ee-Bo-Gam as to be useful for hypertension treatment were evaluated their antihypertensive activity against Okamoto-SHR, an animal model of spontaneous hypertension. Ethanol extracts of plant samples were prepared and were p.o. administered once daily for 20 days. Average blood pressures of rats were measured during two weeks periods before drug administration. Then blood pressure of each rat was measured every three days during drug administration period. As a positive control, propranolol, ${\beta}-blocker$ was used and the blood pressures of test group rats were compared with those of negative and positive control group rats. Among 6 plant extracts, Acanthopanax sessiliflorum and Atractylodes japonica (alba) extracts appeared to exhibit antihypertensive activity.

• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.355-361
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• 2013

The present study attempts to evaluate antioxidant activities of extracts from Abeliophyllum distichum. Nakai flower. The samples were collected in Jangyyeon-myeon, Goesan-gun, Korea and extracted with either hot-water or ethyl acetate (EtOAC). In DPPH, hydroxyl radical scavenging activity and $Fe^{2+}$ chelating activity of EtOAC extracts were 93.41%, 98.43%, and 7.38%, while those of hot-water extracts were 86.93%, 41.33% and 47.68% at 200 ${\mu}g/ml$, respectively. In ${\varphi}X$-174 RF I plasmid DNA cleavage assay, the protective effects of EtOAC and hot-water extracts against oxidative DNA damage were 82% and 17% at 200 ${\mu}g/ml$, respectively. Both extracts showed the protective effect of DNA migration by oxidative stress in intracellular DNA migration assay. Both extracts had no cytotoxity in NIH3T3 cells. Several polyphenolic compounds were identified such as 2-methoxy-benzoic acid, vanillic acid, phytol and pulegone by GC/MS. These results indicated that extracts of Abeliophyllum distichum Nakai flower showed antioxidant activities and protective activities against oxidative DNA damage and showed the possibility to be used as an effective natural antioxidants.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.522-528
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• 2001

Tyrosinase plays an important role in the process of melanin biosynthesis, and it is a biochemical target enzyme for skin-whitening agents and the remedy for disturbances in pigmentation. We have screened 25 natural plant extracts for inhibitory effects against DOPA oxidase activity of tyrosinase. For the inhibitory effect against DOPA oxidase activity of tyrosinase, the recombinant human tyrosinase and the purified mushroom tyrosinase were used. Each of the dried plants extracted with methanol, and then the extracts were subjected to sequential fractionations with methylene chloride, ethyl acetate, n-butanol and water, respective The methylene chloride fractions of Angelica tenuissima, Nardostachys chinensis, Bombyx mop and Saposhnikovia divaricata, and the n-butanol fraction of Bombyx mori notably inhibited the human tyrosinase activity as well as mushroom tyrosinase activity (more than 90% inhibition). This study suggests that the above extracts have a potential as whitening agents as single ingredients or in combination with other of the extracts.

• Korean Journal of Plant Resources
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• v.24 no.6
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• pp.719-723
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• 2011

Antimicrobial activities of methanol, ethanol, water, and $CH_2Cl_2$ extracts from Fritillaria unibracteata Hsiao et K.C. Hsia and F. ussuriensis Maxim. were investigated by disk-agar diffusion method. The result showed comparatively strong antimicrobial activity against several microorganisms. The extracts from F. unibracteata and F. ussuriensis dosedependently increased the activity. However, water and $CH_2Cl_2$ extracts showed no antimicrobial activity against 7 microorganisms. Especially, against the most sensitive microorganism Staphylococcus epidermidis, methanol extracts at highest concentration of 20 mg/mL exhibited the largest clear zone on plate by 6-12 mm and ethanol extracts on plate by 6-10 mm.

• Korean Journal of Medicinal Crop Science
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• v.11 no.4
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• pp.264-267
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• 2003

Korean medicinal plants were screened for their inhibitory activity against HIV-1 protease. The inhibitory activity of protease was determined by incubating the extracts in reaction mixtures containing protease and substrate $His-Lys-Ala-Arg-Val-Leu-(p-NO_{2}-Phe)-Glu-Ala-Nle-Ser-NH_{2}$ to perform proteolytic cleavage reactions. In this study the twenty six extracts from medicinal plants were investigated. Of the extracts tested, the extracts from the stem of Morus alba. exhibited the strongest activity with inhibition of 81% at a concentration of $100{\mu}g/ml$. The extracts of the flower of Saxjfraga stolonifera, and stems of Euonymus japonica and Castanea crenata showed appreciable inhibitory activity (>50%) against HIV-1 protease at same concentration.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.100-108
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• 2003

The regulation of plasma lipid level, particularly LDL cholesterol, represents the focus of current therapy for atherosclerosis. And $Lp-PLA_2$ is able to hydrolyse oxidized phosphatidylcholine within LDL into lyso-PC and oxidized fatty acids. $Lp-PLA_2$ is a potential biomarker of coronary heart disease and plays an important proinflammatory role in the progression of atherosclerosis. We investigated the inhibitory effects of methanol extracts of 224 natural plants on $Lp-PLA_2$ activity. Seven kinds of methanol extracts of tested plants showed above 50% inhibitory effect with the concentration of $100\;{\mu}g/ml$. The concentrated aqueous suspensions of each methanol extract were partitioned with n-hexane, $CHCl_3$, and EtOAc. Among them, EtOAc extracts of Astilbe chinensis var. davidii (root) and Pourthiaea villosa var. brunnea (leaf) significantly inhibited $Lp-PLA_2$ activity at the same concentration.