Increased Intestinal Absorption of Vitamin U in Steamed Graviola Leaf Extract Activates Nicotine Detoxification

Graviola leaves contain much vitamin U (vit U), but their sensory quality is not good enough for them to be developed as food ingredients. Addition of excipient natural ingredients formulated alongside vit U as active ingredients could enhance not only its sensory quality but also its bioavailability. The objectives of this study were to measure the bioaccessibility and intestinal cellular uptake of bioactive components, including rutin, kaempferol-rutinoside, and vit U, from steamed extract of graviola leaves (SGV) and SGV enriched with kale extract (SGK), and to examine how much they can detoxify nicotine in HepG2 cells. The bioaccessibility of vit U from SGV and SGK was 82.40% and 68.03%, respectively. The cellular uptake of vit U in SGK by Caco-2 cells was higher than that in SGV. Cotinine content converted from nicotine in HepG2 cells for 120 min was 0.22 and 0.25 μg/mg protein in 50 μg/mL of SGV and SGK, respectively, which were 2.86 and 3.57 times higher than the no-treatment control. SGK treatment of HepG2 cells upregulated CYP2A6 three times as much as did that of SGV. Our results suggest that graviola leaf extract enriched with excipient ingredients such as kale could improve vit U absorption and provide a natural therapy for detoxifying nicotine.

Digestive recovery of sulfur-methyl-L-methionine and its bioaccessibility in Kimchi cabbages using a simulated in vitro digestion model system

BACKGROUND

Sulfur-methyl-L-methionine (SMM) has been known to provide various biological functions such as radical scavenging effect, inhibition of adipocyte differentiation, and prevention of gastric mucosal damage. Kimchi cabbages are known to be a major food source providing SMM but its bioaccessibility has not been studied. The objective of current study was to determine both the digestive stability of SMM and the amount released from Kimchi cabbages under a simulated in vitro digestion model system.

RESULTS

The in vitro digestion model system simulating a human gastrointestinal tract was carried out for measuring digestive recovery and bioaccessibility of SMM. SMM was quantified by using high-performance liquid chromatography with a fluorescence detector. Recovery of an SMM standard after digestion was 0.68 and 0.65% for fasted and fed conditions, respectively, indicating that the digestive stability of the SMM standard was not affected by dietary energy or co-ingested food matrix. The SMM standard was also significantly stable in acidic pH (P < 0.05). The bioaccessibility of SMM from Kimchi cabbages was measured under a fasted condition, resulted in 8.83, 14.71 and 10.88%, for salivary, gastric and small intestinal phases, respectively.

CONCLUSION

Results from our study suggest that SMM from Kimchi cabbages, a component of food sources, is more bioavailable than SMM by itself.

[Positron emission tomography with L-[S-methyl-11C]-methioine and its biodistribution]

OBJECTIVE

To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection.

METHODS

Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas.

RESULTS AND CONCLUSION

(11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.

Differential labelling of sphingolipids by [3H]serine and ([3H]methyl)-methionine in fish leukocytes

Long chain bases are constituents of all sphingolipids and their biosynthesis is presumed to occur via the initial condensation of serine with palmitoyl-CoA. The biosynthesis of phytosphingosine, a long chain base containing three hydroxyl groups, has been less studied than sphingosine but is assumed to occur by hydroxylation of sphinganine. We report in this paper that the label from ([3H]methyl)-methionine is preferentially incorporated into phytosphingosine bases of neutral glycosphingolipids, whereas the label from [3H]serine is mainly incorporated into the sphingoid base of sphingomyelin. These results show that in fish leukocytes the biosynthesis of individual sphingoid bases and their downstream sphingolipid products follow different pathways of metabolism. Our observations suggest that in fish leukocytes the synthesis of the constitutive long chain bases of sphingomyelin and complex glycosphingolipids is coordinately regulated and may be localized in separate compartments.

[Metabolism of S-methylmethionine (vitamin U) in animals]

Metabolism of S-methylmethionine (vitamin U) has been studied in rats. Biotransformation of this compound actively proceeds in the liver, kidneys, and digestive tract. Metabolism of S-methylmethionine in the liver and kidneys was found to proceed both via methylation of homocysteine with the formation of methionine and via enzymatic hydrolysis to dimethylsulfide and homoserine. In the digestive tract, only the activity of S-methylmethionine-sulphonium hydrolase was found. The physiological role of the metabolic routes under study is discussed.

[S-methyl methionine (vitamin U) pharmacokinetics in rat and man]

S-methyl methionine was shown to be rapidly absorbed, accumulated in the liver and kidneys and actively assimilated by the organisms of rats and man. Some constants of pharmacokinetics of different optical forms of S-methyl methionine were determined. The predominant use of L-form was found. The concurrent administration of D- and L-forms stimulates processes of D-form assimilation.