| Summary: | 碩士 === 中山醫學院 === 生物化學研究所 === 87 === We synthesis a compound, 2,4,5-trihydroxybenzaldehyde (2,4,5-THBA) which is a phenolic compound. It is similar in structure to phenolic protocatechuic acid that has wonderful antioxidation effect and is extracted from plant. 2,4,5-THBA is also similar in structure to catecholamine that has antitumor activity. 2,4,5-THBA possess both chemical structure of 2,5-dihydroxybenzaldehyde (2,5-DHBA) and 3,4-dihydroxybenzaldehyde (3,4-DHBA). So that we test all of their biological activity. They have ability to capture 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH) and 2,5-DHBA is the best one. 3,4-DHBA is next to 2,5-DHBA and 2,4,5-THBA is the weakest. 3,4-DHBA and 2,4,5-THBA are not toxic to rat hepatocytes but 2,5-DHBA does. They can inhibit the tert-butyl hydroperoxide (t-BHP)-induced hepatoxicity and lipid oxidation. 2,5-DHBA has the best efficiency, 2,4,5-THBA is secondary and 3,4-DHBA is the weakest. 2,4,5-THBA is little toxic to human oral fibroblast cancer cell (KB cell) and human liver cancer cell (HepG2 cell). But it is very toxic to human leukemia cancer cell (HL-60 cell) and is stronger then 2,5-DHBA and 3,4-DHBA.
In the synthesis we also get a intermediate, carpacin that is a natural product. It is extracted from the bark of Carpano tree and used in folk medicine like sedative. It has been synthesized as a possible insecticide, too. It is similar in structure to αandβ-Asarone that are genetoxic to rat hepatocytes. Carpacin's isomer, myristicin is not genetoxic to rat hepatocytes and can induce glutathion S-transferase (GST) activity that is reported to have effect in rat hepatocytes. No literature reports the biological activity of carpacin. So that we do it. Carpacin is toxic to rat hepatocytes, mouse lung cell (V79 cell), mouth embryo fibroblast (C3H10T1/2 cell) and human oral fibroblast (BF cell) at above 0.5 mM. Most cells die and LDH leakage is much when rat hepatocytes are treated with carpacin at above 0.5 mM. Carpacin can inhibit DNA synthesis and induce GST activity at no toxic doses in rat hepatocytes. The ratio of GSH/GSSG is down in rat hepatocytes when the cells treated with carpacin followed the dose is up. It has no antioxidation effect that capture little 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH) until at 1 mM.
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