Biological activity of SE-10, granulated powder of Sasa senanensis Rehder leaf extract.

BACKGROUND: We have previously reported that alkaline extract of Sasa senanensis leaves (SE) showed potent anti-HIV, anti-UV and radical scavenging activity. In the present study, we investigated the biological activities of SE-10, a granulated powder of SE supplemented with lactose, lactitol, trehalose and tea extract. MATERIALS AND METHODS: Cell viability of mock-infected, HIV-infected, and UV-irradiated cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Scavenging activity of superoxide anion and hydroxyl radicals was determined by electron-spin resonance spectroscopy. Cytochrome P-450 (CYP)3A4 activity was measured by ß-hydroxylation of testosterone in human recombinant CYP3A4. RESULTS: SE-10 had slightly higher anti-HIV and anti-UV activities, but slightly lower radical-scavenging and CYP3A4-inhibitory activities, as compared with SE. CONCLUSION: The present study demonstrates that the biological activities of SE were well preserved during the manufacturing process of SE-10.

Mechanism-based inhibition of recombinant human cytochrome P450 3A4 by tomato juice extract.

This study investigates whether tomato juice can inhibit cytochrome P450 (CYP) 3A4-mediated drug metabolism. Three commercially available, additive-free tomato juices, along with homogenized fresh tomato, were analyzed for their ability to inhibit testosterone 6ß-hydroxylation activity using human recombinant CYP3A4. Results were compared to that of grapefruit juice. Ethyl acetate extracts of the tomato juices moderately reduced residual activity of CYP3A4 testosterone 6ß-hydroxylation activity by 19.3-26.2% with 0-min preincubation. Residual activity was strongly reduced by 69.9-83.5% at 20-min preincubation, a reduction similar to that of grapefruit juice extract, known to contain constituents of mechanism-based inhibitors. One juice extract (tomato juice C) showed irreversible dose- and preincubation time-dependent and partial nicotinamide adenine dinucleotide phosphate (NADPH)-dependent inhibition of CYP3A4 activity. Furthermore, we examined whether the CYP3A4 inhibitory effect of tomato juice was substrate dependent by examining midazolam 1'-hydroxylation activity and nifedipine oxidation activity, in addition to testosterone 6ß-hydroxylation activity. Tomato juice showed a potent inhibitory effect on nifedipine oxidation activity, which was comparable to that on testosterone 6ß-hydroxylation activity; however, it showed a weak inhibitory effect on midazolam 1'-hydroxylation activity. We conclude that tomato juice contains one or more mechanism-based and competitive inhibitor(s) of CYP3A4. Additionally, significant CYP3A4 inhibitory activity did not result from lycopene, a major compound in tomato. Although the active compound was uncertain, a strong CYP3A4 inhibitory activity was observed in other solanaceous plants, i.e., potato, eggplant, sweet pepper, and capsicum. Therefore, responsible compounds in tomato are likely commonly shared among solanaceous vegetables.

Comparative study of biological activity of three commercial products of Sasa senanensis Rehder leaf extract.

BACKGROUND: We have previously reported that alkaline extract of Sasa senanensis leaves (SE) has several biological activities characteristic of lignin-carbohydrate complex (LCC). In the present study, we compared the biological activity of three commercially available products of SE (products A, B and C). MATERIALS AND METHODS: Cell viability of mock-infected, HIV-infected, UV-irradiated cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Radical intensity was determined by electron spin resonance spectroscopy. Cytochrome P-450 (CYP)3A4 activity was measured by ß-hydroxylation of testosterone in human recombinant CYP3A4. RESULTS: Product A is a pure SE that contains Fe(II)-chlorophyllin, whereas products B and C contain Cu(II)-chlorophyllin and less LCC. Product C is supplemented with ginseng and pine (Pinus densiflora) leaf extracts. Product A exhibited 5-fold higher anti-HIV, 4-fold higher anti-UV, 5-fold higher hydroxyl radical-scavenging, and 3-fold lower CYP3A4 inhibitory activities as compared to those of product B, and 5-fold higher, 1.5-fold higher, comparable, and 7-fold lower activities, respectively, as compared to those of product C. CONCLUSION: The present study demonstrates for the first time the superiority of product A over products B and C, suggesting the beneficial role of LCC and Fe(II)-chlorophyllin.