Green biosynthesis of gold nanoparticles using Chenopodium formosanum shell extract and analysis of the particles' antibacterial properties.

BACKGROUND: Various physical and chemical methods for synthesis of metal nanoparticles have had some drawbacks. Therefore, green synthesis of gold nanoparticles (Au NPs) has became one of the most crucial emerging areas of nanobiotechnology. In the present study, plant-mediated synthesis of Au NPs was performed using Djulis (Chenopodium formosanum) shell extract as a reducing and stabilizing agent. RESULTS: Reaction parameters were manipulated to optimize the Au NPs using a UV-visible spectrophotometer. Optimized Au NPs with a surface plasmon resonance band at 533 nm were prepared using a 744 µg mL-1 extract and a solution of pH 2.62 chloroauric acid (HAuCl4 ·3H2 O) at 40 °C. High-resolution transmission electron microscopy (HR-TEM) results indicated that most of the resultant Au NPs were spherical in shape and exhibited a mean size of 8 ± 6 nm. Energy-dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED), and X-ray diffraction (XRD) confirmed the elemental gold and crystalline nature of the resultant NPs. FTIR spectrum analysis indicated the critical role of phenolic groups in the reduction of Au3+ ions and stabilization of the formed Au NPs. Moreover, the synthesized Au NPs possessed antibacterial activity for Escherichia coli and Staphylococcus aureus. CONCLUSION: In this study, Au NPs were synthesized with high efficiency and stability using Djulis shell extract, and related antibacterial applications were demonstrated. © 2019 Society of Chemical Industry.

Antioxidation and Melanogenesis Inhibition of Various Dendrobium tosaense Extracts.

This study investigated the polyphenol content, antioxidant activity, and inhibition ability of mushroom tyrosinase and melanogenesis of Dendrobium tosaense (DT) extract. Ground DT was extracted using deionized water (W) or 50% ethanol (50E) at room temperature (RT) or 50 °C (50T) for 20 min. The 50T + 50E extract exhibited the highest total phenol content 47.0 ± 4.0 mg gallic acid equivalent/g DT extract, the highest level of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging 66.0 ± 3.0 mg Trolox equivalent/g DT extract, and the highest reducing power 12.00 ± 0.50 mg vitamin C equivalent/g DT extract. The RT + W extract had the highest total flavonoid content 110.0 ± 3.0 mg quercetin equivalent/g DT extract. The RT + 50E extract had the lowest half maximal inhibitory concentration 1.30 ± 0.00 mg/mL for 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging, and the lowest half maximal inhibitory concentration 6.40 ± 0.30 mg/mL for mushroom tyrosinase inhibition activity. DT extracts, especially RT + W and 50T + W, exhibited potent inhibitory effects on melanogenesis of B16/F10 cells. These results demonstrated the application potential of DT extract for skincare.

Novel synthetic kojic acid-methimazole derivatives inhibit mushroom tyrosinase and melanogenesis.

In this study, two kojic acid-methimazole (2-mercapto-1-methylimidazole, MMI, 1) derivatives, 5-hydroxy-2-{[(1-methyl-1H-imidazol-2-yl)thio]methyl}-4H-pyran-4-one (compound 4) and 5-methoxy-2-{[(1-methyl-1H-imidazol-2-yl)thio]methyl}-4H-pyran-4-one (compound 5), were synthesized to examine their inhibitory kinetics on mushroom tyrosinase. Compound 4 exhibited a potent inhibitory effect on monophenolase activity in a dose-dependent manner, with an IC50 value of 0.03 mM. On diphenolase activity, compound 4 exhibited a less inhibitory effect (IC50 = 1.29 mM) but was stronger than kojic acid (IC50 = 1.80 mM). Kinetic analysis indicated that compound 4 was both as a noncompetitive monophenolase and diphenolase inhibitor. By contrast, compound 5 exhibited no inhibitory effects on mushroom tyrosinase activity. The IC50 value of compound 4 for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was 4.09 mM, being much higher than the IC50 of compound 4 for inhibiting the tyrosinase activity. The results indicated that the antioxidant activity of compound 4 may be partly related to the potent inhibitory effect on mushroom tyrosinase. Compound 4 also exerted a potent inhibitory effect on intracellular melanin formation in B16/F10 murine melanoma cells, and caused no cytotoxicity. Furthermore, compound 4 induced no adverse effects on the Hen's egg test-chorioallantoic membrane (HET-CAM).

The Composition, Antioxidant and Antibacterial Activities of Cold-Pressed and Distilled Essential Oils of Citrus paradisi and Citrus grandis (L.) Osbeck.

The chemical composition and functional activities of cold-pressed and water distilled peel essential oils of Citrus paradisi (C. paradisi) and Citrus grandis (L.) Osbeck (C. grandis) were investigated in present study. Yields of cold-pressed oils were much higher than those of distilled oils. Limonene was the primary ingredient of essential oils of C. paradisi (cold 92.83%; distilled 96.06%) and C. grandis (cold 32.63%; distilled 55.74%). In addition, C. grandis oils obtained were rich in oxygenated or nitrogenated compounds which may be involved in reducing cardiovascular diseases or enhancing sleep effectiveness. The order of free radical scavenging activities of 4 citrus oils was distilled C. paradisi oil > cold-pressed C. paradisi oil > distilled C. grandis oil > cold-pressed C. grandis oil. Cold-pressed C. grandis oil exhibited the lowest activity in all antioxidative assays. The order of antimicrobial activities of 4 citrus oils was distilled C. grandis oil, cold-pressed C. paradisi oil > distilled C. paradisi oil > cold-pressed C. paradisi oil. Surprisingly, distilled C. grandis oil exhibited better antimicrobial activities than distilled C. paradisi oil, especially against Escherichia coli and Salmonella enterica subsp. The results also indicated that the antimicrobial activities of essential oils may not relate to their antioxidative activities.

Storage performance of Taiwanese sweet potato cultivars.

Three sweet potato cultivars (TNG57, TNG66, and TNG73), provided by the Taiwanese Agricultural Research Institute (TARI), were stored at either 15 °C or under ambient conditions (23.8 ~ 28.4 °C and 77.1 ~ 81.0 % of relative humidity). Sweet potato roots were randomly chosen from each replicate and evaluated for measurement of weight loss, sugar content analysis, and sprouting after 0, 14, 24, 48, 56, 70, 84, and 98 days of storage. Fresh sweet potato roots were baked at 200 °C for 60 min then samples were taken for sugar analysis. After 14 days of ambient condition storage, the sprouting percentages for TNG57, TNG66, and TNG73 were 100, 85, and 95 % respectively. When sweet potatoes were stored at 15 °C, the weight loss became less and no sweet potato root sprouted after 14 days of storage. Because manufacturers can store sweet potatoes at 15 °C for almost 2 month without other treatments, the supply capacity shortage in July and September can be reduced. The total sugar content slowly increased along with increasing the storage time. After baking, the total sugar content of sweet potatoes significantly increased due to the formation of maltose. Maltose became the major sugar of baked sweet potatoes. Raw sweet potatoes stored at 15 °C had higher total sugar contents after baking than those stored under ambient conditions. Raw sweet potatoes were recommended to be stored at 15 °C before baking.

Changes in sugar composition during baking and their effects on sensory attributes of baked sweet potatoes.

The objective of this study was to evaluate the influence of sugar composition on the sensory attributes of seven baked sweet potatoes. The sugar composition was analyzed using high performance liquid chromatography. Results showed that the total sugar content of baked sweet potatoes increased significantly because of the formation of maltose. The maltose content dramatically increased after baking, and became the major sugar component of baked sweet potatoes. On the other hand, baked sweet potatoes were evaluated on a 7-point hedonic scale for sensory analysis. Overall acceptability results showed that the panelists preferred baked CYY95-26 and TNG66 over the other baked varieties. Because the correlation between overall acceptability and sweetness was the highest (r = 0.69, p < 0.01), sweetness was determined as the most important factor determining the overall acceptability of baked sweet potatoes. Although sugar composition changed on baking, the overall acceptability of baked sweet potatoes was highly associated with the sucrose content.

Fermented broth in tyrosinase- and melanogenesis inhibition.

Fermented broth has a long history of applications in the food, pharmaceutical and cosmetic industries. Recently, the use of fermented broth in skin care products is in ascendance. This review investigates the efficacy of fermented broth in inhibiting tyrosinase and melanogenesis. Possible active ingredients and hypopigmentation mechanisms of fermented broth are discussed, and potential applications of fermented broth in the cosmetic industry are also addressed.

Kinetics of mushroom tyrosinase and melanogenesis inhibition by N-acetyl-pentapeptides.

We investigated the kinetics of 4N-acetyl-pentapeptides, Ac-P1, Ac-P2, Ac-P3, and Ac-P4, regarding inhibition of mushroom tyrosinase activity. The peptides sequences of Ac-P1, Ac-P2, Ac-P3, and Ac-P4 were Ac-RSRFK, Ac-KSRFR, Ac-KSSFR, and Ac-RSRFS, respectively. The 4N-acetyl-pentapeptides were able to reduce the oxidation of l-DOPA by tyrosinase in a dose-dependent manner. Of the 4N-acetyl-pentapeptides, only Ac-P4 exhibited lag time (80 s) at a concentration of 0.5 mg/mL. The tyrosinase inhibitory effects of Ac-P4 (IC50 0.29 mg/mL) were more effective than those of Ac-P1, Ac-P2, and Ac-P3, in which IC50s were 0.75 mg/mL, 0.78 mg/mL, and 0.81 mg/mL, respectively. Kinetic analysis demonstrated that all 4N-acetyl-pentapeptides were mixed-type tyrosinase inhibitors. Furthermore, 0.1 mg/mL of Ac-P4 exhibited significant melanogenesis inhibition on B16F10 melanoma cells and was more effective than kojic acid. The melanogenesis inhibition of Ac-P4 was dose-dependent and did not induce any cytotoxicity on B16F10 melanoma cells.

Antioxidative activity, moisture retention, film formation, and viscosity stability of Auricularia fuscosuccinea, white strain water extract.

This study showed that both water extracts (WAF-W) and ethanol extracts (EAF-W) of Auricularia fuscosuccinea (Montagne) Farlow, white strain (AF-W) demonstrated significantly stronger antioxidative effects than did commercially available Tremella fuciformis sporocarp extracts (WSK; with the exception of EAF-W in terms of superoxide radical scavenging activity levels). The moisture retention capacity of WAF-W is as potent as that of sodium hyaluronate (SHA), but less than that of WSK. No corrugation or fissures were observed in WAF-W film; only the SHA and WSK films demonstrated such effects in low-moisture conditions. The WAF-W solution also exhibited stable viscosity at high temperatures, indicating that the WAF-W film was more stable compared with the SHA and WSK films. WAF-W induced no adverse effects when a hen's egg test was performed on the chorioallantoic membrane (CAM). This study demonstrated that WAF-W exhibits excellent potential as a topical material for skin moisturizing and anti-aging effects.

Potent antioxidative and UVB protective effect of water extract of Eclipta prostrata L.

Oxidative stress, including Ultraviolet (UV) irradiation-induced skin damage, is involved in numerous diseases. This study demonstrates that water extract of Eclipta prostrata L. (WEP) has a potent effect in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide radicals, and chelating ferrous ion, exhibiting IC50 values of 0.23 mg/mL, 0.48 mg/mL, and 1.25 mg/mL, respectively. The WEP total phenol content was 176.45 mg gallic acid equivalents (GAE)/g sample. Chlorogenic acid, a component of the plant's active ingredients, was determined by HPLC and antioxidative assay. However, no caffeic acid, stigmasterol, or wedelolactone was present in WEP. WEP absorbs both UVA and UVB irradiation, and furthermore, the extract shows a dose-dependent response in the protection of HaCaT human keratinocytes and mouse fibroblasts 3T3 cells against UVB-induced cytotoxicity, which may result from a synergistic effect between chlorogenic acid and other active components present in WEP.

Inhibitory effects of novel synthetic methimazole derivatives on mushroom tyrosinase and melanogenesis.

In this study, we synthesized 4 methimazole (2-mercapto-1-methylimidazole, MMI) derivatives. The kinetics of inhibition on mushroom tyrosinase by methimazole and its derivatives were investigated. The results indicated that tert-butyl 3-methyl-2-sulfanylidene-2,3-dihydro-1H-imidazole-1-carboxylate (compound 3; 3), 2-mercaptoimidazole (MI; compound 1; 1) and MMI (compound 2; 2) significantly inhibited tyrosinase activity in a dose-dependent manner, exhibiting an IC50 value of 1.50mM, 4.11 mM, and 1.43 mM. However, compound 4 (4), compound 5 (5), and compound 6 (6) exerted no inhibitory effect on mushroom tyrosinase activity. Kinetic analysis indicated that 3 was a noncompetitive tyrosinase inhibitor, whereas both 1 and 2 were exhibited as mixed-type tyrosinase inhibitors. Furthermore, 3 exerted a potent inhibitory effect on intracellular melanin formation in the B16/F10 murine melanoma cells and did not cause cytotoxicity, as 1 and 2 did.

Tyrosinase inhibitory effect and antioxidative activities of fermented and ethanol extracts of Rhodiola rosea and Lonicera japonica.

This is the first study to investigate the biological activities of fermented extracts of Rhodiola rosea L. (Crassulaceae) and Lonicera japonica Thunb. (Caprifoliaceae). Alcaligenes piechaudii CC-ESB2 fermented and ethanol extracts of Rhodiola rosea and Lonicera japonica were prepared and the antioxidative activities of different concentrations of samples were evaluated using in vitro antioxidative assays. Tyrosinase inhibition was determined by using the dopachrome method with L-DOPA as substrate. The results demonstrated that inhibitory effects (ED50 values) on mushroom tyrosinase of fermented Rhodiola rosea, fermented Lonicera japonica, ethanol extract of Lonicera japonica, and ethanol extract of Rhodiola rosea were 0.78, 4.07, 6.93, and >10 mg/ml, respectively. The DPPH scavenging effects of fermented Rhodiola rosea (ED50 = 0.073 mg/ml) and fermented Lonicera japonica (ED50 = 0.207 mg/ml) were stronger than effects of their respective ethanol extracts. Furthermore, the scavenging effect increases with the presence of high content of total phenol. However, the superoxide scavenging effects of fermented Rhodiola rosea was less than effects of fermented Lonicera japonica. The results indicated that fermentation of Rhodiola rosea and Lonicera japonica can be considered as an effective biochemical process for application in food, drug, and cosmetics.

Applications of Lactobacillus rhamnosus spent culture supernatant in cosmetic antioxidation, whitening and moisture retention applications.

This study was aimed at investigating the antioxidant, whitening, and moisture-retention properties of Lactobacillus rhamnosus spent culture supernatant (Lr-SCS) in cosmetic applications. Results reveal that Lr-SCS effectively and gradually scavenges 1,1-diphenyl-2-picrylhydrazyl as well as 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cations, and increases reducing power in a dose-dependent manner. Additionally, Lr-SCS can also suppress tyrosinase activity in vitro and effectively promote moisture retention. Heat treatment at 100 °C for 30 min does not influence the functions of Lr-SCS. We conclude that Lr-SCS can be used effectively in skin care cosmetics.

Studies of sugar composition and starch morphology of baked sweet potatoes (Ipomoea batatas (L.) Lam).

Sugar composition of seven sweet potato cultivars was successfully analyzed. Fresh CYY95-26 sweet potatoes had the highest (8.41%) total sugar content while TNG73 had the lowest (4.5%). For these fresh sweet potatoes, maltose content was very low (0 ~ 0.39%). Because 49.92 ~ 92.43% of total sugars were sucrose, sucrose was the major sugar composition of fresh sweet potatoes. After the baking treatment, the total sugar content of baked sweet potatoes was dramatically increased due to the formation of maltose. The maltose content significantly increased from 0 ~ 0.39% to 8.81 ~ 13.97% on dry weight basis. Therefore, maltose should be included in calculating the total sugar content. Electronic micrographs of fresh sweet potato samples showed that the size of starch granules was generally less than 20 µm. After the baking treatment, starch granules completely gelatinized.

Methyl 2-[(tert-but-oxy-carbon-yl)amino]-3-(3-methyl-2-sulfanyl-idene-2,3-dihydro-1H-imidazol-1-yl)propano-ate.

In the title compound, C(13)H(21)N(3)O(4)S, the mean plane of the -N(H)-C(=O)-O- group of the carbamate unit forms a dihedral angle of 64.7 (2)° with the mean plane of the -C-C(=O)-O- group of the ester unit. In the crystal, mol-ecules are linked by N-H⋯O=C hydrogen bonds, forming chains along the c-axis direction.

Kinetics of ergothioneine inhibition of mushroom tyrosinase.

The native amino acid ergothioneine, a thiourea derivative of histidine, inhibits mushroom tyrosinase activity in a dose-dependent manner, with an IC(50) value of 1.025 mg/ml (4.47 mM). By contrast, histidine exhibited no inhibitory effect on mushroom tyrosinase activity. We characterized ergothioneine as a noncompetitive tyrosinase inhibitor using a Lineweaver-Burk plot of experimental kinetic data. The IC(50) value for ergothioneine scavenging of 2,2-diphenyl-1-picrylhydrazyl was 6.110 ± 0.305 mg/ml, much higher than the IC(50) for inhibition of tyrosinase activity which indicating ergothioneine on tyrosinase shows a weak correlation to its antioxidative activity. The results demonstrated that ergothioneine has a potent inhibition effect on tyrosinase enzyme activity, resulting from the presence of the sulfur substituted imidazole ring in ergothioneine.

Antioxidative activity of water extract of sweet potato leaves in Taiwan.

This study reports the preparation of four varieties of water extract from sweet potato leaves from Taiwan, including TNG10, TNG57, TNG66 and YSP, and evaluates their antioxidative activity. The EC50 values (scavenging DPPH radicals) of TNG10, TNG57, TNG66 and YSP were 0.27±0.01, 0.19±0.01, 0.41±0.02, and 0.31±0.02mg/ml, respectively, on a freeze-dry weight basis. The total phenolic contents of these water extracts were in the order: TNG57>TNG10>TNG66>YSP. The TNG10 and TNG57 extracts exhibited better reducing power and scavenging effects of superoxide radicals than did TNG66 and YSP. At a concentration of 1mg/ml, TNG10 and TNG57 significantly protected HaCaT cells from H2O2-induced cytotoxicity. The water extracts of YSP had more flavonoids than had those of TNG66 which may have contributed to their higher activity in many antioxidative assays. These results suggest that the water extracts of all four varieties of sweet potato leaves, and especially TNG10 and TNG57, display potent antioxidative effects.

Influence of purple sweet potato extracts on the UV absorption properties of a cosmetic cream.

Anthocyanins were added to a cosmetic cream to provide additional protection against UV radiation. The influence of anthocyanins on UV absorption ability was carefully evaluated. Anthocyanins were successfully extracted from TNG73 purple sweet potato using acidic ethanol and acidic water. Acidic ethanol-extracted anthocyanins had better radical scavenging ability, higher total phenolic content, and stronger reducing ability than acidic water-extracted anthocyanins. The cosmetic cream with 0.61 mg of total anthocyanins (per 100 g cream) absorbed approximately 46% of the incident UV radiation. Although the anthocyanins absorbed both UV-A and UV-B radiation, they were particularly effective against UV-B rays. This study demonstrates that the addition of anthocyanin extracts of purple sweet potato to a cosmetic cream improves the cream's UV absorption ability.

Dramatic synergistic anticancer effect of clinically achievable doses of lovastatin and troglitazone.

Lovastatin (an HMG-CoA reductase inhibitor) and troglitazone (a PPAR-gamma agonist) have been intensively studied prospectively for their application in cancer treatment. However, clinical trials of lovastatin or troglitazone in cancer treatment resulted in only limited responses. To improve their efficacy, lovastatin and troglitazone have, respectively, been tried to combine with other anticancer agents with varied outcomes. In our study, we found a dramatic synergism between lovastatin and troglitazone in anticancer at clinically achievable concentrations. This synergism was found in far majority of cell lines tested including DBTRG 05 MG (glioblastoma) and CL1-0 (lung). This amazing synergism was accompanied by synergistic modulation of E2F-1 and p27(Kip1), which were reported to mediate the anticancer activities of lovastatin and troglitazone, respectively, and other cell cycle regulating proteins such as CDK2, cyclin A and RB phosphorylation status. With this dramatic combination effect of lovastatin and troglitazone, a promising regimen of cancer therapy may be materialized in the future.

Differentiation of pheochromocytoma PC12 cells induced by human urine extract and the involvement of the extracellular signal-regulated kinase signaling pathway.

OBJECTIVE: The aim of this study was to investigate the effects of a human urine preparation on the differentiation of tumor cells. DESIGN: The pheochromocytoma PC12 cells were used to examine the effects of a human urine preparation, CDA-2 on the induction of differentiation markers, neurofilaments, and compared with that induced by nerve growth factor (NGF). The MAPK/ERK kinase (MEK) inhibitor U0126 was used to examine the involvement of mitogen-activated protein kinase (MAPK) signaling pathway in this differentiation inducing effect. RESULTS: We find that CDA-2 could induce differentiation of pheochromocytoma PC12 cells, as evidenced by the markedly increased expression of neurofilaments to a level comparable to those induced by NGF. This phenomenon was accompanied by the phosphorylation of extracellular-signal-regulated kinase (ERK) and could be inhibited by the MEK inhibitor, U0126. CONCLUSIONS: Our results demonstrate the presence of active components in the human urine extract that can induce differentiation of PC12 cells and may involve the ERK signaling pathway. This may provide new insights for seeking novel differentiation agents and offer hope for cancer patients.