Jung Wha Kim

Two new isochromanone derivatives, (3S,4S)-3,8-dihydroxy-6-methoxy-3,4,5-trimethylisochroman-1-one (1) and methyl (S)-8-hydroxy-6-methoxy-5-methyl-4a-(3-oxobutan-2-yl)benzoate (2), together with six known compounds (3‒8) were isolated from the cultures of an endophytic fungus Phoma sp. PF2 obtained from Artemisia princeps. The chemical structures of the isolated compounds were elucidated by interpretation of spectroscopic data (1D, 2D NMR, HRESIMS, and CD) and calculation of ECD. All the isolated compounds (1‒8) showed moderate inhibitory activities on nitric oxide levels in lipopolysaccharide-induced RAW264.7 machrophage cells.

Kim JW, et al. Nat Prod Sci. 2018 Sep;24(3):189-193. https://doi.org/10.20307/nps.2018.24.3.189

Three unprecedented ceanothane-type triterpenoids, ent-epicatechinoceanothic acid A (1), ent-epicatechinoceanothic acid B (2), and epicatechino-3-deoxyceanothetric acid A (3), containing C–C bond linkages with catechin moieties, were isolated from the roots of Zizyphus jujuba. Their chemical structures, including absolute configurations, were established by spectroscopic analysis and calculation of their ECD spectra. A possible biogenetic pathway for C–C bond formation between the catechin and the triterpenoid moieties is presented. Compound 1 was evaluated for its antiproliferative activity on HSC-T6 hepatic stellate cells.

Bioactivity-guided isolation of Opuntia ficus-indica (Cactaceae) seeds against ethanol-treated primary rat hepatocytes yielded six lignan compounds. Among the isolates, furofuran lignans 4−6, significantly protected rat hepatocytes against ethanol-induced oxidative stress by reducing intracellular reactive oxygen species levels, preserving antioxidative defense enzyme activities, and maintaining the glutathione content. Moreover, 4 dose-dependently induced the heme oxygenase-1 expression in HepG2 cells.

Background: Liver disorder was associated with alcohol consumption caused by hepatic cellular damages. Opuntia ficus-indica fruit extracts (OFIEs), which contain betalain pigments and polyphenols including flavonoids, have been introduced as reducing hangover symptoms and liver protective activity. Objective: To evaluate hepatoprotective activity of OFIEs and isolated compounds by high-speed countercurrent chromatography (HSCCC). Materials and Methods: The extract of O. ficus-indica fruits was fractionated into methylene chloride and n-butanol. The n-butanol fraction was isolated by HSCCC separation (methylene chloride-methanol-n-butanol-water, 5:4:3:5, v/v/v/v). The hepatoprotective activity of OFIEs and isolated compounds was evaluated on rat primary hepatocytes against ethanol-induced toxicity. Antioxidative parameters such as glutathione reductase and glutathione peroxidase (GSH-P_x) enzymes and the GSH content were measured. Results: Two flavonoids, quercetin 3-O-methyl ester (1) and (+)-taxifolin, and two flavonoid glycosides, isorhamnetin 3-O-β-d-glucoside (3) and narcissin (4), were isolated from the n-butanol fraction by HSCCC separation. Among them, compound 2 significantly protected rat primary hepatocytes against ethanol exposure by preserving antioxidative properties of GR and GSH-P_x. Conclusions: OFIEs and (+)-taxifolin were suggested to reduce hepatic damage by alcoholic oxidative stress.

Activated microglia are known to be a major source of cellular neuroinflammation which causes various neurodegenerative diseases, including Alzheimer’s disease. In our continuing efforts to search for new bioactive phytochemicals against neuroinflammatory diseases, the 80% methanolic extract of Pteris multifida (Pteridaceae) roots was found to exhibit significant NO inhibitory activity in lipopolysaccharide (LPS)-activated BV-2 microglia cells. Three new ent-kaurane diterpenoids, pterokaurane M₁ 2-O-β-d-glucopyranoside (4), 2β,16α-dihydroxy-ent-kaurane 2,16-di-O-β-d-glucopyranoside (10), and 2β,16α,17-trihydroxy-ent-kaurane 2-O-β-d-glucopyranoside (12), were isolated along with nine other known compounds from P. multifida roots. The chemical structures of the new compounds were determined by 1D- and 2D-NMR, HR-ESI-MS, and CD spectroscopic data analysis. Among the isolates, compounds 1 and 7 significantly inhibited NO production in LPS-stimulated BV-2 cells reducing the expression of the cyclooxygenase-2 (COX-2) protein and the level of pro-inflammatory mediators such as prostaglandin E₂ (PGE₂), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. These results suggest that ent-kaurane diterpenes from P. multifida could be potential lead compounds that act as anti-neuroinflammatory agents.

Ziziphus jujuba, a plant in the family Rhamnaceae, is used in several Asian countries as a food and traditional medicine. Fifteen new ceanothane-type (1–15) and three new lupane-type triterpenoids (16–18) were isolated from the roots of Z. jujuba, as well as 12 previously known triterpenoids (19–30). Their structures were elucidated by 1D and 2D NMR spectroscopic and HR mass spectrometric data analysis. Compounds 12 and 13 were found to possess a rare E-ring γ-lactone structure, and 14 was assigned as the first 2,28-dinorlupane derivative isolated as a natural product. Twenty-five of the isolates were examined for cytotoxicity against human hepatocellular carcinoma HepG2 cells, and compounds 6–8, 14, 17, 23, 25, 29, and 30 showed cytotoxicity with IC₅₀ values ranging from 1.9 to 5.9 μM.