Clerosterol

Clerosterol from vinegar-baked radix bupleuri modifies drug transport.[Pubmed:28423482]

Oncotarget. 2017 Mar 28;8(13):21351-21361.

Vinegar-baked Radix Bupleuri (VBRB) is reportedly used to treat liver cancer when combined with traditional chemotherapy and data show that this combination may modify drug transport. We isolated Clerosterol from VBRB and studied its effect on drug transporters in normal or transporter-overexpressing cells. Transporter activity was assayed using cellular substrate concentration and transporter expression with Western blot and RT-qPCR. Clerosterol decreased cisplatin uptake in BRL cells mainly through increasing Mrp2 gene expression. Clerosterol also decreased the uptake of colchicine in HEK 293 cells by increasing both Pgp and Mrp1 activity; in detail, it could increase Pgp protein but had marginal effects on Mrp1 protein and gene expression. Further study showed Clerosterol increased OCT2 activity in HEK293-Pgp cells by increasing OCT2 protein and mRNA. Clerosterol could suppress Pgp overexpression but not by regulating protein and gene expression. And Clerosterol had marginal effects on Mrp2 and Mrp1 activity in Mrp2- and Mrp1-overexpressing HEK293 cells. Thus, Clerosterol may be an active constituent of VBRB and may work against cancer multidrug resistance by inhibiting Pgp activity.

Cytotoxic effect of clerosterol isolated from Codium fragile on A2058 human melanoma cells.[Pubmed:23389088]

Mar Drugs. 2013 Feb 6;11(2):418-30.

The cytotoxic effects and mechanism of action of Clerosterol, isolated from the marine alga Codium fragile, were investigated in A2058 human melanoma cells. Clerosterol inhibited the growth of A2058 cells with an IC(50) of 150 microM and induced apoptotic cell death, as evidenced by DNA fragmentation, an increase in the number of sub-G(1) hypodiploid cells and the presence of apoptotic bodies. Clerosterol treatment caused the loss of mitochondrial membrane potential. Alterations in the expression of apoptosis-associated proteins in response to Clerosterol treatment included upregulation of Bax, downregulation of Bcl-2 and activation of caspases 3 and 9. The pan-caspase inhibitor treatment attenuated the expression of the active form of caspases and cell death induced by Clerosterol. The present results show that Clerosterol exerts its cytotoxic effect in A2058 human melanoma cells by caspases-dependent apoptosis.

Isolation, characterization and thin-layer chromatography method development of clerosterol palmityl ester: a chemical marker for standardization of leaves of Clerodendrum phlomidis.[Pubmed:22237282]

Zhong Xi Yi Jie He Xue Bao. 2012 Jan;10(1):109-13.

OBJECTIVE: Clerosterol palmityl ester (CPE) is a unique Clerosterol derivative isolated and characterized from the leaves of Clerodendrum phlomidis. Considering the uniqueness of this compound, the present study was planned to use CPE as a specific chemical marker and develop a new validated thin-layer chromatography (TLC) method for standardisation of C. phlomidis. METHODS: Separation and quantification of CPE were achieved by TLC using a mobile phase of petroleum ether (60 to 80 degrees centigrade) and ethyl acetate (95:5, volume ratio) (Rf 0.64) on precoated silica gel 60F(254) aluminium plates. Densitometric determination was carried out after derivatization with anisaldehyde sulphuric acid reagent in absorption mode at 527 nm. RESULTS: The calibration curve was linear in the concentration range of 100 to 500 ng/spot. The method was validated for precision, repeatability and accuracy. The proposed method was found to be simple, specific, precise, accurate, rapid and cost-effective. CONCLUSION: This TLC procedure may be used effectively for quantitative determination of CPE, identification of the plant and standardization of this plant or its derived products.

Commercial peanut (Arachis hypogaea L.) cultivars in the United States: phytosterol composition.[Pubmed:20677801]

J Agric Food Chem. 2010 Aug 25;58(16):9137-46.

Phytosterols in commercially grown Runner, Virginia, and Spanish peanuts (n = 221) from 2005 and 2006 were quantified by a combination of acid hydrolysis and alkaline saponification steps followed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry analysis of the trimethylsilyl derivatives. Delta(5)-Avenasterol, which partially degrades during acid hydrolysis, was quantified after alkaline saponification plus direct analysis of the steryl glucosides isolated by solid-phase extraction. beta-Sitosterol, Delta(5)-avenasterol, campesterol, and stigmasterol were identified in peanut lipid extracts as the dominant sterols by retention time mapping and mass spectra with recoveries approximately 99%. Clerosterol, Delta(5,24(25))-stigmastadienol, Delta(7)-sitosterol + cycloartenol, and one unidentified sterol were also present but at low levels. Free and esterified phytosterols accounted for approximately 80% of the total sterols determined; the remainder was attributed to steryl glucosides. The total sterol level in Spanish market type peanuts (144.1 +/- 5.3 mg/100 g) was significantly greater than both Runners (127.5 +/- 6.3 mg/100 g) and Virginias (129.3 +/- 6.9 mg/100 g) (P < 0.05). Tamspan 90 (146.9 mg/100 g) followed by OLIN (138.5 mg/100 g) showed the highest total sterol content among the cultivars examined. Cultivar effects were strongly significant (P < 0.001) for all phytosterols, whereas production year effects were strongly significant (P < 0.001) for Delta(5)-avenasterol, Delta(5,24(25))-stigmastadienol, and the combined quantities of Delta(7)-sitosterol + cycloartenol, which coeluted. Cultivar x year interactions were strongly significant (P < 0.001) in all sterols except for Delta(7)-sitosterol + cycloartenol (P < 0.01). Total phytosterol contents were markedly higher than those reported in the existing literature for Runner and Virginia type peanuts, partially attributed to the inclusion of steryl glucosides in the analysis.