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Biomedical subjects

F J Lu

Publications and source records attributed to F J Lu.

88 records · Page 5Linked to original sources
PubMed1980

Studies on patients with polychlorinated biphenyl poisoning. 2. Determination of urinary coproporphyrin, uroporphyrin, delta-aminolevulinic acid and porphobilinogen.

Urinary excretion of heme precursors were evaluated in 69 human subjects who have consumed rice oil contaminated with polychlorinated biphenyls (PCBs). Twenty four hour urinary samples were collected from 20 normal healthy volunteers and 69 PCB poisoned human subjects and assayed for the concentrations of delta-aminolevulinic acid, prophobilinogen, uroporphyrin and coproporphyrin. PCB poisoning caused an increased excretion of delta-aminolevulinic acid (from 0.72 mg/24 hours to 1.00 mg/24 hours) and uroprophyrin (from 13.6 micrograms/24 hours to 41.2 micrograms/24 hours), but not the excretion of porphobilinogen (0.34 mg/24 hours) or coproporphyrin (30 micrograms/24 hours). The excretion pattern of urinary heme precursors associated with PCB poisoning is different from those due to lead or arsenic poisoning. The analysis of urinary heme precursors may be helpful for screening patients with PCB poisoning.

Aminolevulinic Acid↗
PubMedDate not supplied

Inhibitory effects of phenolics on xanthine oxidase.

The stems of Bougainvillea spectabillis Wild (Nyctaginaceae) have been used in folk medicine against hepatitis. Spinasterol, 22, 23-dihydrospinasterol and caffeic acid were isolated from the plant stems and characterized. Caffeic acid has not been previously isolated from this plant but spinasterol has been isolated from the leaves. Caffeic acid was found to be the active principle exhibiting strong inhibition of xanthine oxidase in this study (IC50 = 39.21 microM). In order to study the structure-activity relationship of the phenolics as regards xanthine oxidase inhibition, twelve naturally occurring phenolics (esculetin, scopoletin, scoparone, barbaloin, berberine chloride, sinomenine, osthole, paeonol, honokiol, magnolol, methyleugenol and 6-gingerol) were tested for their inhibitory effects on xanthine oxidase. The results showed that esculetin displayed the strongest activity (IC50 = 28.4 microM), and induced competitive inhibition of the enzyme with respect to the substrate xanthine. The apparent inhibition constant (Ki) of esculetin was 2.369 x 10(-6) M. Since xanthine oxidase serum levels are increased in hepatic and brain tumors, caffeic acid and esculetin should be tested as anti-hepatitis or/and anticancer agents.

Anticarcinogenic Agents↗
PubMedDate not supplied

Inhibitory effects of flavonoids on xanthine oxidase.

The stems of Bougainvillea spectabillis Wild (Nyctaginaceae) have been used in folk medicine for hepatis, and spinasterol and quercetin were isolated and characterized from the plant leaves in this study. These constituents have not been previously isolated from Bougainvillea spectabillis W. Quercetin, the flavonoid, was found as active principle because it showed a strong activity on xanthine oxidase inhibition (IC50 = 7.23 microM) in this study as well as in the literature. Since xanthine oxidase serum levels are increased in hepatitis and tumoral brain tissues, quercetin may be used for remission of hepatitis or brain tumor. In order to study the structure-activity relationship of the flavonoids as regards xanthine oxidase inhibition, nine naturally occurring flavonoids have been tested the inhibitory effects on xanthine oxidase, such as baicalein, baicalin, capillarisin, d-catechin, d-epicatechin, hesperidin, liquiritin, puerarin and wogonin. The results showed that baicalein displayed the strongest activity (IC50 = 9.44 microM), followed by wogonin (IC50 = 52.46 microM) and then baicalin (IC50 = 71.73 microns). Baicalein induced uncompetitive inhibition of the enzyme with respect to xanhtine and the apparent inhibition constant (Ki) was 2.48 x 10(-6) M.

Drugs, Chinese Herbal↗