Eun-Rhan Woo

HIV-1 integrase inhibitory phenylpropanoid glycosides from Clerodendron trichotomum.

Seven phenylpropanoid glycosides named acteoside (1), acteoside isomer (2), leucosceptoside A (3), plantainoside C (4), jionoside D (5), martynoside (6), and isomartynoside (7) were isolated from Clerodendron trichotomum. Compounds 1 and 2 showed potent inhibitory activities against HIV-1 integrase with IC50 values of 7.8 +/- 3.6 and 13.7 +/- 6.0 microM, respectively.

Anti-herpetic activity of various medicinal plant extracts.

In order to find antiviral compounds againstHerpes simplex virus type I (HSV-1) and II (HSV-2) from natural products, a convenient virus-induced cytopathic effect (CPE) inhibition assay was introduced. More than 300 fractions were prepared by solvent fractionation from sixty collected plants or purchased herbal medicines, and their anti-herpetic activities were evaluated. Among them, several medicinal plants showed potent anti-herpetic activity. Selective indexes (SI) of the EtOAc extract of Caraganae Radix (Caragana sinica) against HSV-1 and HSV-2 were more than 8.06 and 24.79, SI of the MeOH extract ofAcer okamotoanum leaves were 3.92 and 3.51, SI of the CH2Cl2 extract of Veratri Rhizoma et Radix (Veratrum patulum) were 5.49 and 1.31 and SI of the MeOH extract of aerial part of Osmundae Rhizoma (Osmunda japonica) were more than 3.45 and 1.25, respectively.

Bis-spirolabdane-Type Diterpenoids from Leonurus sibiricus

Six new bis-spirolabdane-type diterpenoids, leosibirinone A (1), 3alpha-acetoxyleoheteronone C (2), leosibirinone B (3), 3alpha-hydroxyleoheteronone A (4), 3alpha-acetoxyleoheteronone E (5), and 3alpha-acetoxy-15-epileoheteronone E (6), were isolated from the aerial parts of Leonurus sibiricus. Their structures were identified on the basis of 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC, and NOESY spectroscopic analyses.

SIRT1 Inhibitory Diterpenoids from the Vietnamese Medicinal Plant Croton tonkinensis

Silent information regulator two ortholog 1 (SIRT1) is a member of the sirtuin deacetylase family of enzymes that removes acetyl groups from the lysine residues in histones and other proteins. It has been suggested that SIRT1 inhibitors might be beneficial in the treatment of cancer and neurodegenerative diseases. Bioassay-guided fractionation of the MeOH extract of the leaves of CROTON TONKINENSIS resulted in the isolation of a new ENT-kaurane diterpenoid (1) along with 11 known compounds (2- 12). The structure of the new compound 1 was determined to be ENT-11 alpha-acetoxy-7 beta-hydroxykaur-16-en-15-one based on spectroscopic analyses. Compounds 3, 4, 6- 9, 11, and 12 exhibited SIRT1 inhibitory activity in an IN VITRO assay, with IC (50) values ranging from 16.08 +/- 0.11 to 44.34 +/- 2.32 microM. This is the first report showing the potential of ENT-kaurane diterpenoids as a new class of natural SIRT1 inhibitors.

Inhibition of gp 120-CD4 interaction by various plant extracts

Various assay methods have been developed to evaluate the effectiveness of substances against human immunodeficiency virus (HIV). One of them is the Syncytia formation inhibition assay, which is based on the inhibition of the interaction between the HIV-1 envelope protein gp 120 and the cellular membrane protein CD4. A variation of this assay using recombinant virus vPE 16 and CD4(+) HeLa cell was developed to find anti-HIV compounds in natural products that inhibit gp 120-CD4 binding. VPE 16 expresses glycoprotein gp 160, which is glycosylated then processed into gp 120 and gp 41 on its envelope. A total of 50 plant extracts were screened with this system. Extracts from Calicarpa japonica and Sedum sarmentosum were among those that showed strong inhibition of the gp 120-CD4 interaction.

Some sesquiterpenoids and 5α,8α-epidioxysterols fromSolanum lyratum

From the stems ofSolanum lyratum Thunb. (Solanaceae), two sesquiterpenoids together with two 5α,8α-epidioxy sterols have been isolated and identified as atractylenolide I, dehydrocarissone, ergosterol peroxide, 9,11-dehydroergosterol peroxide. These compounds never prviously isolated from this genus.

Biflavonoids isolated from Selaginella tamariscina regulate the expression of matrix metalloproteinase in human skin fibroblasts

The methanol extract from Selaginella tamariscina significantly inhibited UV irradiation induced activity of matrix metalloproteinase-1 (MMP-1) in primary fibroblasts from human skin. Using the technique of bioassay-directed chromatographic separation, five biflavonoids were isolated from the ethyl acetate soluble fraction of S. tamariscina. Here, we investigated the effect of these five biflavonoids on the regulation of MMP-1 and -2 in UV irradiated cultured dermal fibroblasts from human neonatal foreskins. Among these biflavonoids, sumaflavone and amentoflavone showed significant MMP-1 inhibitory activity in primary human dermal fibroblasts after UV irradiation. The IC(50) values of sumaflavone, amentoflavone and retinoic acid, which was used as a positive control, were 0.78, 1.8, and 10microM, respectively.