The Anti-melanogenesis Activities of Some Selected Red Macroalgae from Northern Coasts of the Persian Gulf.

Tyrosinase is a key enzyme in melanin production. Therefore, tyrosinase inhibitors are used in cosmetic and medicinal industries to prevent or treat overproduction of melanin such as melasma, solar lentigo and post inflammatory melanoderma. Due to safety of natural whitening agents, in the present study, in-vitro anti-tyrosinase and in-vivo anti-melanogenesis activities of some selected red macroalgae of the Persian Gulf were investigated. The effects of various concentrations (100, 250 and 500 µg/mL) of methanolic extracts of three red macroalgae including Digenea simplex (D. simplex), Laurencia papillosa, and Laurencia paniculata on the activity of diphenolase of mushroom tyrosinase were studied by using L-Dopa as substrate. Subsequently, the activity of macroalgae with high inhibitory effect on hydroxylation of L-tyrosine was investigated by mushroom tyrosinase and zebrafish model. Anti-melanogenesis effects of algae extracts were studied on zebrafish as an alternative in-vivo model. Kojic acid was used as a positive control. All the tested macroalgae showed significantly a lower inhibitory effect on activities of diphenolase and monophenolase (of mushroom tyrosinase) compared to kojic acid. D. simplex showed the most anti-tyrosinase activity in zebrafish model among the samples. D. simplex extract and Kojic acid inhibited tyrosinase activity by 43.18% and 50.45%, and decreased total melanin content of zebrafish by 47.27% and 50.21%, respectively.

The Anti-melanogenesis Activities of Some Selected Brown Macroalgae from Northern Coasts of the Persian Gulf

Abstract Melanogenesis is a biological process which led to the synthesis of melanin pigment. Abnormal melanin production results in melasma, solar lentigo, post inflammatory melanoderma, etc. In this study, we examined the potential inhibitory effects of 17 brown macroalgae from Persian Gulf on melanogenesis. The effects of various concentrations (100, 250 and 500 µg/mL) of methanolic extracts of macroalgae belonging to four genera (including: Padina, Colpomonia, Cystoseira and Sargassum) were studied on oxidation of L-Dopa by mushroom tyrosinase. Subsequently, the activity of macroalgae with high inhibitory effect on monophenolase activity of mushroom tyrosinase and zebrafish was investigated using L-tyrosine as a substrate. Anti-melanogenesis effects of algae extracts were studied on zebrafish as an alternative in vivo model. Kojic acid was used as a positive control. All the tested macroalgae showed inhibitory effect on activities of diphenolase and monophenolase (of mushroom tyrosinase). P. boergesinii exhibited the most in vivo anti-tyrosinase activity compared with other samples. P. boergesenii inhibited zebrafish tyrosinase more potent than kojic acid (83% vs 50% inhibition for kojic acid). Moreover, it reduced melanin synthesis in zebrafish 42% (kojic acid: 50%).

Inhibitory Effects of Physalis alkekengi L., Alcea rosea L., Bunium persicum B. Fedtsch. and Marrubium vulgare L. on Mushroom Tyrosinase.

BACKGROUND: The key enzyme in the process of melanin biosynthesis is tyrosinase. Skin hyperpigmentation and browning of foods are undesirable phenomena which tyrosinase represents. Therefore, tyrosinase inhibitors have been used increasingly for medicinal and cosmetic products. OBJECTIVES: In this study, inhibitory effects of four plants including: physalis alkekengi L., Alcea rosea L., Bunium persicum B. Fedtsch. and Marrubium vulgare L. on diphenolase activity of mushroom tyrosinase were evaluated. MATERIALS AND METHODS: The inhibitory activities of hydroalcoholic extracts of plants against oxidation of L-Dopa (as a substrate) by mushroom tyrosinase were investigated. RESULTS: The hydroalcoholic extract of P. alkekengi showed the most tyrosinase inhibitory effect with IC50 of 0.09 mg/mL vs. 0.38, 0.38 and 2.82 mg/mL of B. persicum, A. rosea and M. vulgare, respectively. M. vulgare exhibited uncompetitive inhibition and other plants showed mixed type inhibition on mushroom tyrosinase. CONCLUSIONS: All plants could inhibit mushroom tyrosinase, but more investigations on human tyrosinase and clinical studies are needed.

Mercury removal from aqueous solutions with chitosan-coated magnetite nanoparticles optimized using the box-behnken design.

BACKGROUND: Nowadays, removal of heavy metals from the environment is an important problem due to their toxicity. OBJECTIVES: In this study, a modified method was used to synthesize chitosan-coated magnetite nanoparticles (CCMN) to be used as a low cost and nontoxic adsorbent. CCMN was then employed to remove Hg(2+) from water solutions. MATERIALS AND METHODS: To remove the highest percentage of mercury ions, the Box-Behnken model of response surface methodology (RSM) was applied to simultaneously optimize all parameters affecting the adsorption process. Studied parameters of the process were pH (5-8), initial metal concentration (2-8 mg/L), and the amount of damped adsorbent (0.25-0.75 g). A second-order mathematical model was developed using regression analysis of experimental data obtained from 15 batch runs. RESULTS: The optimal conditions predicted by the model were pH = 5, initial concentration of mercury ions = 6.2 mg/L, and the amount of damped adsorbent = 0.67 g. Confirmatory testing was performed and the maximum percentage of Hg(2+) removed was found to be 99.91%. Kinetic studies of the adsorption process specified the efficiency of the pseudo second-order kinetic model. The adsorption isotherm was well-fitted to both the Langmuir and Freundlich models. CONCLUSIONS: CCMN as an excellent adsorbent could remove the mercury ions from water solutions at low and moderate concentrations, which is the usual amount found in environment.

The Effect of Date Seed (Phoenix dactylifera) Extract on Paraoxonase and Arylesterase Activities in Hypercholesterolemic Rats.

BACKGROUND: Paraoxonase 1 (PON1) is a high- density lipoprotein (HDL)-associated enzyme, displaying esterase and lactonase activity. The PON1 is involved in a variety of inflammatory diseases, metabolizing toxic oxidized lipids and detoxifying of organophosphorus insecticide compounds and nerve agents. OBJECTIVES: The aim of this study was to investigate the effects of methanolic date seed extract (DSE) on paraoxonase and arylesterase activities in hypercholesterolemic rats. MATERIALS AND METHODS: Experiments were conducted in two groups of normal and hypercholesterolemic rats and continued for four weeks. Two weeks after receiving the normal and hypercholesterolemic diet, different dosages of DSE were administered during the last two weeks of the treatment. Blood samples were taken from animals before administration of DSE (at day 14) and at the end of the experimental period (at day 28). Paraoxonase and arylesterase activities of PON1 enzyme were assayed by kit using paraoxone and phenylacetate as the substrates. Relative changes in serum paraoxonase and arylesterase activities and total antioxidant capacity (TAOC) were compared between the two groups during this interval. RESULTS: Administration of DSE significantly increased serum paraoxonase and arylesterase activities in treated hypercholesterolemic groups compared to untreated ones. There was a significant difference in the TAOC of serum between the normal diet and hypercholesterolemic groups. However, DSE did not change the TAOC in hypercholesterolemic groups significantly. CONCLUSIONS: DSE increases serum paraoxonase and arylesterase activities. These beneficial effects may be subjected to the presence of natural antioxidants such as phenolic compounds in the date seed. Despite this, DSE did not increase TAOC in treated hypercholesterolemic groups compared to the untreated ones based on ABTS (2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid) radical reduction assay. This indicates that the hypercholesterolemic diet, apart from DSE and atorvastatin effects, may be responsible for the serum TAOC reduction. However, it is concluded that DSE may be useful in decreasing the symptoms of diseases resulting from the low activity of paraoxonase.

Evaluation of estimated daily intake (EDI) of cadmium and lead for rice (Oryza sativa L.) in calcareous soils.

The excessive amounts of cadmium and lead in food chain can cause health problems for humans and ecosystem. Rice is an important food in human diet. Therefore this study was conducted in order to investigate cadmium and Lead concentrations in seed rice (Oryza saliva) of paddy fields in southwest of Iran. A total of 70 rice seed samples were collected from paddy fields in five regions of Khuzestan province, Southwest Iran, during harvesting time. In the samples cadmium and Lead concentrations were measured. To assess the daily intake of Cadmium and Lead by rice, daily consumption of rice was calculated. The results showed that average concentrations of Cadmium and Lead in rice seeds were 273.6 and 121.8 µg/kg, respectively. Less than 72% of rice seed samples had Cadmium concentrations above 200 µg/kg (i.e. Guide value for cadmium); and less than 3% had Lead concentrations above 150 µg/kg (i.e. Guide value for Lead). The estimated daily intakes of cadmium by the local population was calculated to 0.59 µg/day kg bw, which corresponds to 59% of the tolerable daily intakes (i.e. 1 µg/day kg bw). Eleven out of 70 samples (15.71%) exceed the tolerable daily intakes. The dietary intakes for Lead in the local population ranged from 0.22 to 0.47 µg/day kg bw. Tolerable daily intakes for Lead is 3.6 µg/day kg bw. As a whole, long term consumption of the local rice may bear high risk of heavy metal exposure to the consumer in the study region.

Validated HPLC method for the determination of gabapentin in human plasma using pre-column derivatization with 1-fluoro-2,4-dinitrobenzene and its application to a pharmacokinetic study.

A rapid, sensitive and accurate high-performance liquid chromatographic method with UV detection was developed and validated for the quantification of gabapentin in human plasma. Gabapentin was quantified using pre-column derivatization with 1-fluoro-2,4-dinitrobenzene following protein precipitation of plasma with acetonitrile. Amlodipine was used as internal standard. The chromatographic separation was carried out on a Nova-Pak C(18) column using a mixture of 50 mM NaH(2)PO(4) (pH=2.5)-acetonitrile (30:70, v/v) as mobile phase with UV detection at 360 nm. The flow rate was set at 1.5 ml/min. The method was linear over the range of 0.05-5 microg/ml of gabapentin in plasma (r(2)>0.999). The within-day and between-day precision values were in the range of 2-5%. The limit of quantification of the method was 0.05 microg/ml. The method was successfully used to study the pharmacokinetics of gabapentin in healthy volunteers.