• Journal of fish pathology
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• v.37 no.1
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• pp.133-138
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• 2024

This study is a report on combinational effects between four sesquiterpene lactones (SLs) from bay laurel (Laurus nobilis) leaves, and oxytetracycline (OTC) or amoxicillin (AMX) against four fish pathogenic bacteria such as Vibrio anguillarum, V. harveyi, Edwardsiella tarda, and Streptococcus iniae. Individually, four SLs exerted little antibacterial activity against fish pathogenic bacteria. However, when combined with OTC or AMX, they showed synergistic interaction against pathogenic bacteria. Especailly, zaluzanin C (1) reduced the MIC of OTC (or AMX) eight-fold. Our results showed that combinations of SLs with antibiotics (ABTs) are more effective than ABTs alone to control pathogenic bacteria. The highest synergistic effect was observed when zaluzanin C (1) was combined with OTC or AMX against V. harvey or S. iniae, displaying significant reductions of MICs up to 8-fold (0.125 to 0.015 ㎍/mL and 0.0078 to 0.0009 ㎍/mL). In addition, zaluzanin C (1) improved the antibiotic potency of OTC against OTC resistant V. harveyi (250 ㎍/mL to 62.5 ㎍/mL). Synergism between ABTs and phytochemical such as SLs could be a therapeutically helpful concept to improve the efficacy of ABTs and prevent antibiotic resistance. These results suggest that SLs can be used as an alternative to reduce antibiotic resistance in aquaculture.

• Korean Journal of Pharmacognosy
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• v.27 no.1
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• pp.26-31
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• 1996

A sesquiterpene ortho-naphtpoquinone was isolated from the 80% aqueous methanolic extract of root bark of Ulmus davidiana Planch whose stem and root bark have been used as an oriental medicine for the treatment of edema, mastitis, gastric cancer and inflammation. On the basis of spectral data obtained from UV-vis, IR, HR-EIMS and NMR spectrometry, including the pulse field gradient (PFG) HMQC and HMBC techniques, the structure of this compound was determined as 2,3-dihydro-3-hydroxy-3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione which has been known as mansonone 1. This compound has been isolated only from the heart-wood of Mansonia altissima Chev, a Sterculiacea from West Africa. Thus, this compound was isolated for the second time from natural source in this study. This is the first report to present the carbon chemical shift assignment of mansonone I.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.363-367
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• 1997

From the Chinese crude drug shin-i, the flower buds of Magnolia fargesii, four sesquiterpene, oplopanoe (1), oplodiol (2), homalomenol A (3) and $1{\beta},4{\beta},7{\alpha}$-trihydroxyeudesmane (4) were isolated. These structures were elucidated and the ${13}^C-NMR$ chemical shifts of these compounds were revised by means of various 2D-NMR techniques.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.701-706
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• 2010

Two polyacetylenes (1 and 2), four coumarins (3-6), and one sesquiterpene (7) were isolated from the halophyte Glehnia littoralis. Particularly, compound 6 and 7 were isolated for the first time from Glehnia littoralis. Their chemical structures have been determined by extensive 2-D NMR experiments such as $^1H$, COSY, HMQC and HMBC and by comparison with the reported data in the literature.

• Archives of Pharmacal Research
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• v.26 no.11
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• pp.925-928
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• 2003

Four guaia-12,6-olide type sesquiterpene lactones, aguerin B (1), 8$\alpha$-acetoxyzaluzanin C (2), cynaropicrin (3), and deacylcynaropicrin (4), were isolated from the flowers of Hemisteptia Iyrata Bunge. It is the first report on the isolation of compounds 1-4 from Hemisteptia species. All the isolates (1-4) were examined for their cytotoxic activity against SK-OV-3, LOX-IMVI, A549, MCF-7, PC-3, and HCT-15 human cancer cell lines.

• Korean Journal of Medicinal Crop Science
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• v.9 no.4
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• pp.269-274
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• 2001

Two sesquiterpene lactones were isolated from the flowers of Chrysanthemum coronarium L. by silica gel chromatography and recrystalization. Their structures were determined using various spectroscopic data, and were identified as eudesmanolide derivatives douglanine and reynosin, respectively. This is reported for the first time in this plant. The cytotoxic activity of two compounds showed strong activities against human cancer cell lines such as A549, PC-3 and HCT 116.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.141-146
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• 1998

Feeding experiment of [$^3$H] 5-epi-aristolochene (5-EAS) demonstrated in suspension cultures of tobacco (Nicotiana tabacum L.) that 5-EAS hydroxylase activity was absent from control cells, but induced to a maximum level within 18 h after the addition of cellulase, and was very similar to induction pattern of sesquiterpene cyclase. This result suggest that the conversion of 5-EAS to capsidiol is catalyzed by at least one elicitor-inducible hydroxylase. Cytochrome P450 inhibitors, ancymidol and ketoconazole, suppressed the elicitor-induced capsidiol accumulation by inhibiting hydroxylase activity, suggesting that the hydroxylase may be a Cyt P450 type enzyme.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.89-94
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• 1996

Three sesquiterpene ortho-naphthoquinones were isolated from the methanolic extract of root bark of Ulmus davidiana Planch whose stem and root bark have been used as an oriental medicine for the treatment of edema, mastitis, gastric cancer and inflammation. The structures of these compounds were established on the basis of spectral data obtained from UV-vis, IR, HR-EIMS and NMR spectrometry, including the pulse field gradient (PFG)-HMQC and HMBC techniques. Their structures were determined as 2,3-dihydro-3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, 3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione and 2,3-dihydro-4-hedroxy-3,6, 9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, which were identified as mansonones E. F and H, respectively. These compounds have originally been isolated from Mansonia altissima Chev, but have never been isolated from Ulmus davidiana Planch. Especially, mansonone H was isolated for the first time from Ulmaceae. The mismatched carbon chemical shifts of mansonones E and F in the reported literature were corrected by the aid of the PFG-HMBC spectral data.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.235-239
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• 2003

Thirteen sesquiterpene lactones isolated from the flower of Chrysanthemum coronarium L., which has been widely cultivated in Korea as a vegetable for a long time, were investigated their antimicrobial activities against eight bacteria and five phytopathogenic fungi. The antimicrobial activities of dihydrochrysanolide (6) and 1-epi-dihydrochrysanolide (7) showed strong activities against all the bacteria such as Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Vibrio parahaemolyticus. Especially, Staphylococcus aureus was investigated that have very strong antibacterial activity to $1.56\;{\mu}g{\cdot}disc^{-1}$, respectively. Also, most of sesquiterpene lactones, which have ${\alpha}-methylene-{\gamma}-butyrolactone$ group, were exhibited strong activity to Gram(+) bacteria than Gram(-) bacteria. In the antifungal test, Rhizoctonia solani and Phytophthora capsici known as phytopathogenic fungi have exhibited all extensive activity about compounds that have ${\alpha}-methylene-{\gamma}-butyrolactone$ group.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.7-10
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• 2019

The whole plants of Loranthus tanakae were repeatedly extracted with 80% aqueous MeOH and the concentrate was partitioned into ethyl acetate (EtOAc), n-butyl alcohol (n-BuOH) and $H_2O$ fractions. The repeated silica gel ($SiO_2$), octadecyl $SiO_2$ (ODS), and Sephadex LH-20 column chromatographies for the n-BuOH fraction led to isolation of a cyclofarnesane sesquiterpene glucoside. The chemical structure including stereo structure was determined to be a (1'R,3'S,5'R,8'S,2E,4E)-dihydrophaseic acid $3^{\prime}-O-{\beta}-{\text\tiny{D}}$-glucopyranoside on the basis of spectroscopic analyses. This compound was isolated for the first time from L. tanakae in this study. Compound 1 showed a moderate dose-dependent cytotoxicity against human Caucasian gastric adenocarcinoma cells and human hepatocyte cari-noma cells cell lines at higher than $50{\mu}g/mL$.