• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.403-412
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• 2014

To develop an effective skin whitening agent for cosmetics, we isolated cucurbitacin B from Cucumis sativus L. which has been used as traditional skin lighting regimen by the bioactivity-guided fractionation, and investigated the inhibitory effects of cucurbitacin B on melanogenesis. At a non-cytotoxic concentration, cucurbitacin B reduced melanin contents of B16F1 melanoma cells in a dose-dependent manner. Cucurbitacin B did not directly inhibit mushroom tyrosinase activity, but it inhibited intracellular tyrosinase activity in a dose-dependent manner. Its inhibitory mechanism on melanin biosynthesis was further assessed, and we found that cucurbitacin B significantly decreased the protein level of tyrosinase, a major melanogenic enzymes and MITF, a master transcriptional factor of melanogenesis. In addition, cucurbitacin B increased the expression of WW domain-containing oxidoreductase (WWOX) which is known to function as tumor repressor and inhibits $Wnt/{\beta}$-catenin pathway. Collectively, these results suggest that cucuritacin B from C. sativus could be used as an active ingredient for skin whitening.

• Molecules and Cells
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• v.43 no.6
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• pp.530-538
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• 2020

The Gustatory system enables animals to detect toxic bitter chemicals, which is critical for insects to survive food induced toxicity. Cucurbitacin is widely present in plants such as cucumber and gourds that acts as an anti-herbivore chemical and an insecticide. Cucurbitacin has a harmful effect on insect larvae as well. Although various beneficial effects of cucurbitacin such as alleviating hyperglycemia have also been documented, it is not clear what kinds of molecular sensors are required to detect cucurbitacin in nature. Cucurbitacin B, a major bitter component of bitter melon, was applied to induce action potentials from sensilla of a mouth part of the fly, labellum. Here we identify that only Gr33a is required for activating bitter-sensing gustatory receptor neurons by cucurbitacin B among available 26 Grs, 23 Irs, 11 Trp mutants, and 26 Gr-RNAi lines. We further investigated the difference between control and Gr33a mutant by analyzing binary food choice assay. We also measured toxic effect of Cucurbitacin B over 0.01 mM range. Our findings uncover the molecular sensor of cucurbitacin B in Drosophila melanogaster. We propose that the discarded shell of Cucurbitaceae can be developed to make a new insecticide.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.348-353
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• 1994

The activity fractionation upon the MeOH extract of the root of trichosanthes kirilowii led to the isolation of eight cucurbitane tritepense namely cucurbitacin .betha. (I), isocucurbitacin .betha.(II), cucurbitacin D(III), isocucurbitacin D(IV), 3-epi-isocucurbitacin .betha(V), dihydrocucurbitain .betha. (VI), dihydroisocucurgbitachin .betha. (VII) and dihydrocucurbitacin E (VIII), as active principles. All isolates were shown to exhibit significant cytotoxicity against cultured human tumor cells, including A-549, Sk-OV-3, Sk-MEL-2, XF-498 and HCT 15, with an exceptionally high potency.

• Journal of Life Science
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• v.28 no.6
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• pp.733-737
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• 2018

Cucurbitacin-I, a natural triterpenoid derived from Cucurbitaceae family plants, exhibits a number of potentially useful pharmacological and biological activities. Indeed, the previous study demonstrated that cucurbitacin-I reduced the proliferation of colon cancer cells by enhancing apoptosis and causing cell cycle arrest at the G2/M phase. CD44, a type I transmembrane protein with the function of adhering to cells, mediates between the extracellular matrix and other cells through hyaluronic acid. Recent studies have demonstrated that an overexpression of the CD44 membrane receptor results in tumor initiation and growth, specific behaviors of cancer stem cells, the development of drug resistance, and metastasis. The aim was to examine the effect of cucurbitacin-I on CD44 expression human ovarian cancer cells because the effect of cucurbitacin-I on CD44 expression has not been reported. The expressions of CD44 mRNA and protein were detected using a quantitative real-time reverse-transcription polymerase chain reaction and a Western blot analysis, respectively. Treatment with cucurbitacin-I inhibited the expression of CD44 mRNA and protein. A subsequent analysis revealed that cucurbitacin-I blocked the phosphorylation of activator protein-1 (AP-1) and nuclear factor kappa-B ($NF-{\kappa}B$), which are key regulators of CD44 expression. Taken together, the data demonstrate that cucurbitacin-I regulates the AP-1 and $NF-{\kappa}B$ signaling pathways, leading to decreased CD44 expression.

• Molecules and Cells
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• v.44 no.2
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• pp.68-78
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• 2021

Secondary metabolites enable plants to protect themselves from herbivorous insects. Among these, cucurbitacin B (cuc-B) is a bitter-tasting compound with promising pharmacological potential. Dietary exposure to cuc-B lowered the hemolymph glucose levels of Drosophila melanogaster fed with a high carbohydrate diet, which is homologous to high blood glucose in humans, and its effect was comparable to that of metformin, a well-known glucose-lowering drug. Furthermore, cuc-B reduced tissue sugar levels and glycogen levels, as well as triacylglycerol levels. Our results thus highlight the potential applicability of this compound to treat chronic metabolic diseases such as diabetes and obesity. Additionally, we analyzed sleep quality and taste-associative memory enhancement after cuc-B and metformin treatment. Both supplements increased nighttime bout length and metformin increased memory consolidation. Therefore, discarded shell of Cucurbitaceae could be processed into health supplements.

• YAKHAK HOEJI
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• v.44 no.1
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• pp.87-94
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• 2000

In order to investigate the hepatoprotective constituents, Melonis Pedicellus was systematically extracted and fractionated with n-hexane, ethyl acetate, butanol and water Treatment of rats with ethyl acetate fraction reduced hepatic injuries induced by $\alpha$-naphthylisothiocyanate or D-galactosamine, whereas the components in water fraction showed protective effect only against D-galactosamine-induced hepatitis in rats. Two cucurbitacins and three sterols were isolated from ethylacetate fraction and their chemical structures were identified as cucurbitacin B, isocucurbitacin B, $\alpha$-spinasterol, stigmast-7-en-3-ol and stigmast-7-en-3-ol-0-$\beta$-D-glucopyranoside. Cucurbitacin B at the dose of 1 mg/kg (p.o.) signifcantly increased in bile flow in rats with ANIT-induced cholestasis. Isocucurbitacin B at 5 mg/hg (p.o.) showed signilicant protective effects against ANIT-induced cholestasis. These results showed that cucurbitacin B and isocucurbitacin B from Melonis Pedicellus may have hepatoprotective effect in rats with experimental cholestasis.