Analysis of bioactive compounds in cinnamon leaves and preparation of nanoemulsion and byproducts for improving Parkinson's disease in rats

Introduction

Cinnamomum osmophloeum Kanehira (C. osmophloeum), a broad-leaved tree species of Taiwan, contains phenolic acids, flavonoids, and phenylpropanoids such as cinnamaldehyde and cinnamic acid in leaves. Many reports have shown that the cinnamon leaf extract possesses anti-inflammatory, hypoglycemic, hypolipidemic and neuroprotective functions. This study aims to analyze bioactive compounds in C. osmophloeum (cinnamon leaves) by UPLC-MS/MS and prepare hydrosol, cinnamon leaf extract and cinnamon leaf nanoemulsion for comparison in improving Parkinson's disease (PD) in rats.

Methods

After extraction and determination of total phenolic and total flavonoid contents, cinnamaldehyde and the other bioactive compounds were analyzed in cinnamon leaves and hydrosol by UPLC-MS/MS. Cinnamon leaf nanoemulsion was prepared by mixing a suitable proportion of cinnamon leaf extract, soybean oil, lecithin, Tween 80 and deionized water, followed by characterization of particle size and polydispersity index by dynamic light scattering analyzer, particle size and shape by transmission electron microscope, encapsulation efficiency, as well as storage and heating stability. Fifty-six male Sprague-Dawley rats aged 8 weeks were divided into seven groups with group 1 as control (sunflower oil) and group 2 as induction (2 mg/kg bw rotenone in sunflower oil plus 10 mL/kg bw saline), while the other groups including rotenone injection (2 mg/kg bw) followed by high-dose of 60 mg/kg bw (group 3) or low-dose of 20 mg/kg bw (group 4) for tube feeding of cinnamon leaf extract or cinnamon leaf nanoemulsion at the same doses (groups 5 and 6) every day for 5 weeks as well as group 7 with rotenone plus hydrosol containing 0.5 g cinnamon leaf powder at a dose of 10 mL/kg bw. Biochemical analysis of brain tissue (striatum and midbrain) was done to determine dopamine, α-synuclein, tyrosine hydroxylase, superoxide dismutase, catalase, glutathione peroxidase and malondialdehyde contents by using commercial kits, while catalepsy performed by bar test.

Results and discussion

An extraction solvent of 80% ethanol was found to be the most optimal with a high yield of 15 bioactive compounds being obtained following UPLC analysis. A triple quadrupole tandem mass spectrometer with electrospray ionization mode was used for identification and quantitation, with cinnamaldehyde present at the highest amount (17985.2 µg/g). The cinnamon leaf nanoemulsion was successfully prepared with the mean particle size, zeta potential, polydispersity index and encapsulation efficiency being 30.1 nm, -43.1 mV, 0.149 and 91.6%, respectively. A high stability of cinnamon leaf nanoemulsion was shown over a 90-day storage period at 4 and heating at 100 for 2 h. Animal experiments revealed that the treatments of cinnamon leaf extract, nanoemulsion and hydrosol increased the dopamine contents from 17.08% to 49.39% and tyrosine hydroxylase levels from 17.07% to 25.59%, while reduced the α-synuclein levels from 17.56% to 15.95% in the striatum of rats. Additionally, in the midbrain of rats, an elevation of activities of superoxide dismutase (6.69-16.82%), catalase (8.56-16.94%), and glutathione peroxidase (2.09-16.94%) was shown, while the malondialdehyde content declined by 15.47-22.47%. Comparatively, the high-dose nanoemulsion exerted the most pronounced effect in improving PD in rats and may be a promising candidate for the development of health food or botanic drug.

Analysis of Phenolic Acids and Flavonoids in Rabbiteye Blueberry Leaves by UPLC-MS/MS and Preparation of Nanoemulsions and Extracts for Improving Antiaging Effects in Mice

Rabbiteye blueberry leaves, a waste produced after harvest of blueberry, are rich in polyphenols. This study aims to analyze phenolic acids and flavonoids in blueberry leaves by UPLC-MS/MS and prepare nanoemulsions for determining anti-aging activity in mice. Overall, 30% ethanol was the most suitable extraction solvent for total phenolic acids and total flavonoids. A total of four phenolic acids and four flavonoids were separated within seven minutes for further identification and quantitation by UPLC-MS/MS in selective reaction monitoring (SRM) mode, with 3-O-caffeoylquinic acid being present in the highest amount (6474.2 μg/g), followed by quercetin-3-O-galactoside (1943.9 μg/g), quercetin-3-O-rutinoside (1036.6 μg/g), quercetin-3-O-glucoside (867.2 μg/g), 5-O-caffeoylquinic acid (815.8 μg/g), kaempferol-3-O-glucoside (309.7 μg/g), 3,5-dicaffeoylquinic acid (195.3 μg/g), and 4,5-dicaffeoylquinic acid (60.8 μg/g). The blueberry nanoemulsion was prepared by using an appropriate ratio of soybean oil, Tween 80, glycerol, ethanol, and water at 1.2%, 8%, 2%, 2%, and 86.8%, respectively, and mixing with dried blueberry extract, with the mean particle size and zeta potential being 16 nm and -54 mV, respectively. A high stability was observed during storage of nanoemulsion for 90 days at 4 °C and heated at 100 °C for 2 h. An animal study revealed that this nanoemulsion could elevate dopamine content in mice brain as well as superoxide dismutase, glutathione peroxidase, and catalase activities in mice liver while reducing the contents of malondialdehyde and protein carbonyl in mice brains. Collectively, the high-dose nanoemulsion possessed the highest efficiency in improving mice aging with a promising potential for development into a health food.

Quantification of Xanthone and Anthocyanin in Mangosteen Peel by UPLC-MS/MS and Preparation of Nanoemulsions for Studying Their Inhibition Effects on Liver Cancer Cells

Mangosteen peel, a waste produced during mangosteen processing, has been reported to be rich in xanthone and anthocyanin, both of which possess vital biological activities such as anti-cancer properties. The objectives of this study were to analyze various xanthones and anthocyanins in mangosteen peel by UPLC-MS/MS for the subsequent preparation of both xanthone and anthocyanin nanoemulsions to study their inhibition effects on liver cancer cells HepG2. Results showed that methanol was the optimal solvent for the extraction of xanthones and anthocyanins, with a total amount of 68,543.39 and 2909.57 μg/g, respectively. A total of seven xanthones, including garcinone C (513.06 μg/g), garcinone D (469.82 μg/g), γ-mangostin (11,100.72 μg/g), 8-desoxygartanin (1490.61 μg/g), gartanin (2398.96 μg/g), α-mangostin (51,062.21 μg/g) and β-mangostin (1508.01 μg/g), as well as two anthocyanins including cyanidin-3-sophoroside (2889.95 μg/g) and cyanidin-3-glucoside (19.72 μg/g), were present in mangosteen peel. The xanthone nanoemulsion was prepared by mixing an appropriate portion of soybean oil, CITREM, Tween 80 and deionized water, while the anthocyanin nanoemulsion composed of soybean oil, ethanol, PEG400, lecithin, Tween 80, glycerol and deionized water was prepared as well. The mean particle size of the xanthone extract and nanoemulsion were, respectively, 22.1 and 14.0 nm as determined by DLS, while the zeta potential was -87.7 and -61.5 mV. Comparatively, xanthone nanoemulsion was more effective than xanthone extract in inhibiting the growth of HepG2 cells, with the IC₅₀ being 5.78 μg/mL for the former and 6.23 μg/mL for the latter. However, the anthocyanin nanoemulsion failed to inhibit growth of HepG2 cells. Cell cycle analysis revealed that the proportion of the sub-G1 phase followed a dose-dependent increase, while that of the G0/G1 phase showed a dose-dependent decline for both xanthone extracts and nanoemulsions, with the cell cycle being possibly arrested at the S phase. The proportion of late apoptosis cells also followed a dose-dependent rise for both xanthone extracts and nanoemulsions, with the latter resulting in a much higher proportion at the same dose. Similarly, the activities of caspase-3, caspase-8 and caspase-9 followed a dose-dependent increase for both xanthone extracts and nanoemulsions, with the latter exhibiting a higher activity at the same dose. Collectively, xanthone nanoemulsion was more effective than xanthone extract in inhibiting the growth of HepG2 cells. Further research is needed to study the anti-tumor effect in vivo.

A Comparative Study on Improving Streptozotocin-Induced Type 2 Diabetes in Rats by Hydrosol, Extract and Nanoemulsion Prepared from Cinnamon Leaves

Cinnamomoum osmophloeum Kanehira (C. osmophloeum) contains various biologically active antioxidant compounds such as flavonoids, phenolic acids and cinnamaldehyde. Type 2 diabetes mellitus is a chronic disease of metabolic abnormality caused by insulin deficiency or resistance. The objectives of this study were to analyze various bioactive compounds in C. osmophloeum leaves by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and compare the effects of hydrosol, extract and nanoemulsion prepared from C. osmophloeum leaves on improving type 2 diabetes in rats. Our results show that a total of 15 bioactive compounds in C. osmophloeum leaves, including quercetin, quercetin-3-O-galactoside, quercetin-3-O-glucoside, rutin, caffeic acid, benzoic acid, 5-O-caffeoylquinic acid, kaempferol 3-β-D-glucopyranoside, trans-cinnamic acid, coumarin, cinnamyl alcohol, p-coumaric acid, eugenol, kaempferol and cinnamaldehyde, were separated within 14 min for subsequent identification and quantitation by UPLC-MS/MS. The nanoemulsion was successfully prepared by mixing C. osmophloeum leaf extract, soybean oil, lecithin, Tween 80 and deionized water in an appropriate proportion with a mean particle size, polydispersity index, zeta potential and encapsulation efficiency of 36.58 nm, 0.222, -42.6 mV and 91.22%, respectively, while a high storage and heating stability was obtained. The animal experiment results reveal that the high-dose nanoemulsion was the most effective in reducing both fasting blood glucose and oral glucose tolerance test value, followed by low-dose nanoemulsion, high-dose extract, low-dose extract and leaf powder in hydrosol. A similar trend was shown in reducing serum insulin and the homeostatic model assessment of insulin resistance index. In addition, the contents of serum biochemical parameters, including total cholesterol, triglyceride, aspartate aminotransferase, alanine aminotransferase, uric acid, urea nitrogen and creatinine, were reduced, with the high-dose nanoemulsion showing the most pronounced effect. Collectively, the high-dose nanoemulsion may possess great potential to be developed into a hypoglycemic health food or botanic drug.

Formation and Inhibition of Heterocyclic Amines and Polycyclic Aromatic Hydrocarbons in Ground Pork during Marinating

This study aims to simultaneously extract heterocyclic amines (HAs) and polycyclic aromatic hydrocarbons (PAHs) from ground pork for respective analysis by UPLC-MS/MS and GC-MS/MS, and study the effects of different flavorings and marinating time length on their formation and inhibition. Results showed that both HA and PAH contents followed a time-dependent increase during marinating, with HAs being more susceptible to formation than PAHs. The total HA contents in unmarinated pork and juice was, respectively, 61.58 and 139.26 ng/g, and rose to 2986.46 and 1792.07 ng/g after 24-h marinating, which can be attributed to the elevation of reducing sugar and creatinine contents. The total PAH contents in unmarinated pork and juice were, respectively, 34.56 and 26.84 ng/g, and increased to 55.93 and 44.16 ng/g after 24-h marinating, which can be due to the increment of PAH precursors such as benzaldehyde, 2-cyclohexene-1-one and trans,trans-2,4-decadienal. Incorporation of 0.5% (w/v) cinnamon powder or 0.5% (w/v) green tea powder was effective in inhibiting HA formation with the former showing a more pronounced effect for marinated pork, while the latter was for marinated juice. However, their addition was only effective in inhibiting PAH formation in marinated pork. Principle component analysis revealed the relationship between HA and PAH formation in ground pork and juice during marinating.

An improved surface enhanced Raman spectroscopic method using a paper-based grape skin-gold nanoparticles/graphene oxide substrate for detection of rhodamine 6G in water and food

Organic toxins are persistent chemicals of global concern capable of accumulating in environment and food. Surface enhanced Raman spectroscopy (SERS) is a promising technique that facilitates onsite detection of organic toxins. However, the fabrication of a SERS substrate is complicated and difficult to provide flexibility, fastness and cost-effectiveness. This study aims to develop a paper-based SERS method using grape skin-gold nanoparticles/graphene oxide (GE-AuNPs/GO) as SERS substrate and evaluate its efficiency with rhodamine 6G (Rh6G) as a model organic toxin and a real water and food contaminant. GE-AuNPs synthesized by green method using grape skin waste extract and GE-AuNPs/GO showed a surface plasmon resonance at 536 and 539 nm, particle size 18.6 and 19.5 nm, and zeta potential -44.6 and -59.7 mV, respectively. Paper-based SERS substrates were prepared by coating a hydrophobic thin-film of 30% polydimethylsiloxane solution in hexane on Whatman no. 1 filter paper, followed by drop-casting GE-AuNPs or GE-AuNPs/GO and drying. The SERS signals of Rh6G showed an enhancement factor of 5.8 × 10⁴ for GE-AuNPs and 1.92 × 10⁹ for GE-AuNPs/GO, implying that a combination of electromagnetic surface plasmon, charge transfer and molecular resonances may be responsible for a higher enhancement of signal by the latter. A low detection limit of 7.33 × 10^-11 M in the linear range of 10^-11-10^-5 M was obtained for GE-AuNPs/GO, while the relative standard deviation of repeatability and reproducibility was 9.6 and 12.6%, respectively. Paper-based GE-AuNPs/GO SERS substrate was highly stable as <20% loss in efficiency was shown over a 60-day storage period. Application to real samples showed a high recovery of Rh6G from tap water (93.9-100.8%) as well as food samples such as red chilli powder (91.0-95.4%), red glutinous rice ball (96.6-98.3%) and tomato ketchup (98.9-102.3%) after QuEChERS extraction. Collectively, the developed paper-based GE-AuNPs/GO can be a potential substrate for sensitive onsite detection of rhodamine 6G by SERS method.

A Comparative Study on Analysis of Ginsenosides in American Ginseng Root Residue by HPLC-DAD-ESI-MS and UPLC-HRMS-MS/MS

Ginseng (Panax quinquefolius), a popular herbal and nutritional supplement consumed worldwide, has been demonstrated to possess vital biological activities, which can be attributed to the presence of ginsenosides. However, the presence of ginsenosides in ginseng root residue, a by-product obtained during processing of ginseng beverage, remains unexplored. The objectives of this study were to develop a high-performance liquid chromatography-photodiode array detection-mass spectrometry (HPLC-DAD-ESI-MS) and an ultra-high-performance-liquid-chromatography-tandem mass spectrometry (UPLC-HRMS-MS/MS) method for the comparison of ginsenoside analysis in ginseng root residue. Results showed that by employing a Supelco Ascentis Express C18 column (150 × 4.6 mm ID, particle size 2.7 μm) and a gradient mobile phase of deionized water and acetonitrile with a flow rate at 1 mL/min and detection at 205 nm, a total of 10 ginsenosides, including internal standard saikosaponin A, were separated within 18 min and detected by HPLC-DAD-ESI-MS. Whereas with UPLC-HRMS-MS/MS, all the 10 ginsenosides were separated within six minutes by using an Acquity UPLC BEH C18 column (50 × 2.1 mm ID, particle size 1.7 μm, 130 Å) and a gradient mobile phase of ammonium acetate and acetonitrile with column temperature at 50 °C, flow rate at 0.4 mL/min and detection by selected reaction monitoring (SRM) mode. High accuracy and precision was shown, with limit of quantitation (LOQ) ranging from 0.2−1.9 μg/g for HPLC-DAD-ESI-MS and 0.269−6.640 ng/g for UPLC-HRMS-MS/MS. The contents of nine ginsenosides in the ginseng root residue ranged from <LOQ-26.39 mg/g by HPLC-DAD-ESI-MS and <LOQ-21.25 mg/g by UPLC-HRMS-MS/MS, with a total amount of 38.37 and 34.71 mg/g, respectively.

A Comparative Study on Inhibition of Breast Cancer Cells and Tumors in Mice by Carotenoid Extract and Nanoemulsion Prepared from Sweet Potato (Ipomoea batatas L.) Peel

The objectives of this study were to determine carotenoid composition in sweet potato (TNG66) peel and prepare carotenoid nanoemulsion to study its inhibition effect on breast cancer cells MCF-7 and tumors in mice. Results showed that a total of 10 carotenoids were separated within 30 min by employing a YMC C30 column and a gradient mobile phase of methanol/acetonitrile/water (74:14:12, v/v/v) and dichloromethane (B) with a flow rate of 1 mL/min, column temperature of 25 °C, and detection wavelength of 450 nm. Following quantitation, all-trans-β-carotene was present in the highest amount (663.8 μg/g). The method validation data demonstrated a high accuracy and precision of this method. The carotenoid nanoemulsion was prepared by mixing an appropriate proportion of carotenoid extract, Tween 80, PEG 400, soybean oil and deionized water with the mean particle size being 15.7 nm (transmission electron microscope (TEM)), polydispersity index 0.238, encapsulation efficiency 97% and zeta potential −69.8 mV. A high stability of carotenoid nanoemulsion was shown over a 90-day storage period at 25 °C and during heating at 100 °C for 2 h. The release percentage of total carotenoids from carotenoid nanoemulsion under gastric and intestinal condition was 18.3% and 49.1%, respectively. An antiproliferation study revealed that carotenoid nanoemulsion was more effective than carotenoid extract in inhibiting the growth of human breast cancer cells MCF-7. Following treatments of paclitaxel (10 μg/mL), carotenoid nanoemulsion (20 and 10 μg/mL) and carotenoid extract (20 and 10 μg/mL), the tumor weight of mice respectively decreased by 77.4, 56.2, 40.3, 36.1 and 18.7%, as well as tumor volume of mice by 75.4, 65.0, 49.7, 46.7 and 26.5%. Also, both carotenoid extract and nanoemulsion could reduce the levels of epidermal growth factor (EGF) and (vascular endothelial growth factor (VEGF) in serum, with the latter being more effective. This finding suggested that carotenoid nanoemulsion was more effective than carotenoid extract in inhibiting tumor growth in mice.

Comparative Study on Inhibition of Pancreatic Cancer Cells by Resveratrol Gold Nanoparticles and a Resveratrol Nanoemulsion Prepared from Grape Skin

Resveratrol, a phenolic compound possessing vital biological activities such as anti-cancer, is present abundantly in grape skin, a waste produced during the processing of grape juice. The objectives of this study were to prepare resveratrol-gold nanoparticles and a resveratrol nanoemulsion from grape skin and study their inhibition effects on pancreatic cancer cells BxPC-3. The spherical-shaped citrate gold nanoparticles (GNPs) and resveratrol-gold nanoparticles (R-GNPs) were, respectively, prepared with a surface plasmon resonance peak at 528 and 538 nm, mean particle size of 20.8 and 11.9 nm, and zeta-potential at −32.7 and −66.7 mV, by controlling an appropriate concentration of citrate/resveratrol and gold chloride as well as stirring time and temperature. The resveratrol nanoemulsion, composed of soybean oil, Tween 80, and sucrose fatty acid ester in glycerol and water, possessed a high storage stability with a mean particle size of 14.1 nm, zeta-potential of −49.7 mV, and encapsulation efficiency of 95.5%. An antiproliferation study revealed that both R-GNPs and resveratrol nanoemulsion could effectively inhibit the growth of pancreatic cancer cells BxPC-3, with the latter showing a higher inhibition effect. Western blot analysis implied that both can down-regulate expressions of cyclin A, cyclin B, CDK1, and CDK2 and up-regulate expressions of p53 and p21, accompanied by enhancing cytochrome C expression, decreasing BcL-2 expression, increasing Bax expression, and leading to the elevation of caspase-8, caspase-9, and caspase-3 activities for cell apoptosis execution. Future research is needed to study the inhibition of pancreatic tumors in vivo by R-GNPs and resveratrol nanoemulsions.

Effects of Black Garlic Extract and Nanoemulsion on the Deoxy Corticosterone Acetate-Salt Induced Hypertension and Its Associated Mild Cognitive Impairment in Rats

Organosulfur compounds, phenolic acids and flavonoids in raw and black garlic were determined, and followed by preparation of black garlic nanoemulsion for studying their effects on deoxycorticosterone acetate-salt-induced hypertension and associated mild cognitive impairment in rats. Three organosulfur compounds, including diallyl sulfide (87.8 μg/g), diallyl disulfide (203.9 μg/g) and diallyl trisulfide (282.6 μg/g) were detected in black garlic by GC-MS, while gallic acid (19.19 μg/g), p-coumaric acid (27.03 μg/g) and quercetin (22.77 μg/g) were detected by UPLC-MS/MS. High doses of both black garlic extract and nanoemulsion prepared using Tween-80, glycerol, grapeseed oil and water could decrease systolic blood pressure through the elevation of bradykinin and nitric oxide levels as well as diminish aldosterone and angiotensin II levels in rats. In Morris water maze test, they could significantly decrease escape latency and swimming distance and increase the time spent in the target quadrant, accompanied by a decline of acetylcholinesterase activity and malondialdehyde level in the hippocampus as well as a rise in glutathione level and activities of superoxide dismutase, catalase and glutathione peroxidase. In addition, the levels of tumor necrosis factor, interleukin-6 and interleukin-1β were reduced. Effects of lowering blood pressure and improving learning/memory ability in rats followed the order: lisinopril > black garlic nanoemulsion > black garlic extract.

Inhibition of Melanoma Cells A375 by Carotenoid Extract and Nanoemulsion Prepared from Pomelo Leaves

This study aims to determine carotenoids in pomelo leaves (Citrus grandis Osbeck), a rich source of nutrients and phytochemicals, by high-performance liquid chromatography-mass spectrometry and prepare carotenoid nanoemulsions for the study of its inhibitory mechanism on melanoma cells A375. Fourteen carotenoids were separated within 27 min by using a YMC-C30 column and a gradient mobile phase of methanol-acetonitrile-water (84:14:2, v/v/v) and methylene chloride with a flow rate of 1 mL/min and detection wavelength of 450 nm. All-trans-lutein plus its cis-isomers were present in the largest amount (3012.97 μg/g), followed by all-trans-neoxanthin (309.2 μg/g), all-trans-violaxanthin (208.5 μg/g), all-trans-β-carotene plus its cis-isomers (203.17 μg/g), all-trans-α-carotene plus its cis-isomers (152.5 μg/g), all-trans-zeaxanthin (54.67 μg/g), and all-trans-β-cryptoxanthin plus its cis-isomers (24.56 μg/g). A stable carotenoid nanoemulsion was prepared with a mean particle size of 13.3 nm, zeta-potential of −66.6 mV, a polydispersity index of 0.132 and an encapsulation efficiency of 99%. Both the carotenoid extract and nanoemulsion could upregulate p53, p21, cyclin B and cyclin A expressions in melanoma A375 cells and downregulate CDK1 and CDK2 in a concentration-dependent manner. Also, they could upregulate Bax and cytochrome-C and downregulate Bcl-2, leading to cell apoptosis through activation of caspase-9, caspase-8 and caspase-3. Compared to extract, carotenoid nanoemulsion was shown to be more effective in inhibiting the growth of melanoma cells A375. This finding further demonstrated that a carotenoid nanoemulsion prepared from pomelo leaves possessed a great potential to be developed into functional foods or even botanic drugs.

Preparation of Chlorophyll Nanoemulsion from Pomelo Leaves and Its Inhibition Effect on Melanoma Cells A375

Pomelo (Citrus grandis), an important fruit crop grown in tropical and subtropical areas, is cultivated mainly in Asian countries. The dominant pigment in pomelo leaves, chlorophyll, has been reported to possess many biological activities such as antioxidant, anti-inflammation and anticancer. The objectives of this study were to determine chlorophylls in Pomelo leaves by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and to encapsulate the isolated chlorophylls from preparative column chromatography into a nanoemulsion system for elucidating the inhibition mechanism on the growth of melanoma cells A375. The results showed that chlorophyll a and chlorophyll b could be separated within 25 min by using a C18 column and a gradient ternary mobile phase of acetone, acetonitrile and methanol. Pomelo leaves mainly contained chlorophyll a (2278.3 μg/g) and chlorophyll b (785.8 μg/g). A highly stable chlorophyll nanoemulsion was prepared with the mean particle size being 13.2 nm as determined by a dynamic light scattering (DLS) method. The encapsulation efficiency of chlorophyll nanoemulsion was 99%, while the zeta potential was −64.4 mV. In addition, the chlorophyll nanoemulsion possessed high thermal stability up to 100 °C and remained stable over a 90-day storage period at 4 °C. Western blot analysis revealed that chlorophyll nanoemulsion and extract could upregulate p53, p21, cyclin B and cyclin A as well as downregulate CDK1 and CDK2 in a concentration-dependent manner for inhibition of melanoma cells A375. Furthermore, chlorophyll nanoemulsion and extract could upregulate Bax and cytochrome C and downregulate Bcl-2, leading to activation of caspase-9, caspase-8 and caspase-3 for the induction of cell apoptosis. Compared to chlorophyll extract, chlorophyll nanoemulsion was more effective in inhibiting the growth of melanoma cells A375.

Removal of polycyclic aromatic hydrocarbons from water by magnetic activated carbon nanocomposite from green tea waste

This study aims to synthesize a magnetic activated carbon nanocomposite from green tea leaf waste (MNPs-GTAC) for evaluation of adsorption efficiency of 4 priority polycyclic aromatic hydrocarbons (PAHs). MNPs-GTAC contained spherically-shaped MNPs with cubic spinel structure, surface area at 118.8 m²/g, particle size at 8.6 nm and saturation magnetization at 34.2 emu/g. PAH adsorption reached a plateau at an MNPs-GTAC dose of 50 or 60 mg/L, pH of 2-4 and ionic strength of 0.1-10%, with PAH reduction in the presence of humic acid being compensated by addition of 0.1% sodium chloride. Kinetics was rapid attaining 80% removal within 5 min and the pseudo-second-order rate decreased in this order: Benzo[a]anthracene>Chrysene>Benzo[b]fluoranthene>Benzo[a]pyrene. Isotherm modeling revealed a Langmuir type-2 shape with the maximum adsorption capacity being 28.08, 22.75, 19.14 and 15.86 mg/g for Benzo[b]fluoranthene, Benzo[a]pyrene, Chrysene and Benzo[a]anthracene, respectively. Temperature study showed the PAH adsorption to be an endothermic and spontaneous process with increased randomness at solid-solution interface. Acetonitrile could completely recover the adsorbed PAH and MNPs-GTAC was successfully recycled 5 times with a minimum loss. Application to mineral water showed 86-98% and 72-89% removal for PAHs spiked respectively at 0.1 and 1 mg/L, while a complete removal was attained in tap and river waters.

Preparation of Catechin Nanoemulsion from Oolong Tea Leaf Waste and Its Inhibition of Prostate Cancer Cells DU-145 and Tumors in Mice

Anti-cancer activity of catechin nanoemulsions prepared from Oolong tea leaf waste was studied on prostate cancer cells DU-145 and DU-145-induced tumors in mice. Catechin nanoemulsions composed of lecithin, Tween-80 and water in an appropriate proportion was prepared with high stability, particle size of 11.3 nm, zeta potential of -67.2 mV and encapsulation efficiency of 83.4%. Catechin nanoemulsions were more effective than extracts in inhibiting DU-145 cell growth, with the IC50 being 13.52 and 214.6 μg/mL, respectively, after 48 h incubation. Furthermore, both catechin nanoemulsions and extracts could raise caspase-8, caspase-9 and caspase-3 activities for DU-145 cell apoptosis, arresting the cell cycle at S and G2/M phases. Compared to control, catechin nanoemulsion at 20 μg/mL and paclitaxel at 10 μg/mL were the most effective in reducing tumor volume by 41.3% and 52.5% and tumor weight by 77.5% and 90.6% in mice, respectively, through a decrease in EGF and VEGF levels in serum.

Analysis and formation of polycyclic aromatic hydrocarbons and cholesterol oxidation products in thin slices of dried pork during processing

This study aims to determine toxic compounds polycyclic aromatic hydrocarbons (PAHs) and cholesterol oxidation products (COPs) in thin slices of dried pork as affected by different flavorings and roasting temperature treatments through employing a QuEChERS method coupled with gas chromatograph-tandem mass spectrometer (GC-MS/MS) and gas chromatograph-mass spectrometer (GC-MS), respectively. By employing this method, high accuracy and precision was attained for freeze-dried pork hind leg sample. Following addition of 8 different flavorings with roasting temperature at 120, 160, and 200 °C, the levels of total COPs and PAHs in thin slices of dried pork followed a temperature-dependent increase during roasting, which was further confirmed by principle component analysis. High level of soy sauce or sugar inhibited COP formation, while the low-level minimized PAH formation in thin slices of dried pork during roasting. Sugar was more effective in inhibiting COP formation while soy sauce was more efficient in reducing PAH formation.

Understanding of Colistin Usage in Food Animals and Available Detection Techniques: A Review

Progress in the medical profession is determined by the achievements and effectiveness of new antibiotics in the treatment of microbial infections. However, the development of multiple-drug resistance in numerous bacteria, especially Gram-negative bacteria, has limited the treatment options. Due to this resistance, the resurgence of cyclic polypeptide drugs like colistin remains the only option. The drug, colistin, is a well-known growth inhibitor of Gram-negative bacteria like Acinetobacter baumanni, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Technological advancements have uncovered the role of the mcr-1(mobilized colistin resistance) gene, which is responsible for the development of resistance in Gram-negative bacteria, which make them distinct from other bacteria without this gene. Additionally, food animals have been determined to be the reservoir for colistin resistance microbes, from which they spread to other hosts. Due to the adverse effects of colistin, many developed countries have prohibited its usage in animal foods, but developing countries are still using colistin in animal food production, thereby imposing a major risk to the public health. Therefore, there is a need for implementation of sustainable measures in livestock farms to prevent microbial infection. This review highlights the negative effects (increased resistance) of colistin consumption and emphasizes the different approaches used for detecting colistin in animal-based foods as well as the challenges associated with its detection.

An overview on recent in vivo biological application of cerium oxide nanoparticles

Cerium oxide nanoparticles (CNPs) possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences +3 and +4. This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer's disease, obesity, liver inflammation, cancer, sepsis, amyotrophic lateral sclerosis, acute kidney injury, radiation-induced tissue damage, hepatic ischemia reperfusion injury, retinal diseases and constipation. In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma, ovarian, breast and retinoblastoma cancer cell-induced mice, with their conjugation with folic acid, doxorubicin, CPM, or CXC receptor-4 antagonist ligand eliciting higher efficiency. After conjugation with triphenylphosphonium or magnetite nanoparticles, CNPs were shown to combat Alzheimer's disease by reducing amyloid-β, glial fibrillary acidic protein, inflammatory and oxidative stress markers in mice. By improving muscle function and longevity, the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis. Also, they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis, triglyceride synthesis, GAPDH enzyme activity, leptin and insulin levels. In CCl4-induced rats, stress signaling pathways due to inflammatory cytokines, liver enzymes, oxidative and endoplasmic reticulum messengers could be attenuated by CNPs. Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation. The same CNPs could improve kidney function by diminishing renal superoxide, hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats. Radiation-induced lung and testicular tissue damage could be alleviated in mice, with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number. Through enhancement of gastrointestinal motility, the CNPs could alleviate constipation in both young and old rats. They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.

Nanoemulsion and Nanoliposome Based Strategies for Improving Anthocyanin Stability and Bioavailability

BACKGROUND

Anthocyanins, a flavonoid class of water-soluble pigments, are reported to possess several biological activities, including antioxidant, anti-inflammatory, and anti-cancer. However, anthocyanins are highly susceptible to degradation in high pH, light, heat, and oxygen during processing and storage. Conventional microencapsulation techniques fail to provide stability to anthocyanins under physiological environments mainly because of their large particle size as well as low zeta potential and encapsulation efficiency.

METHODS

Nanotechnology provides novel strategies for preparing nanoformulations to enhance the physicochemical stability of anthocyanins. Nanoemulsion and nanoliposome are the two most commonly used nanosystems in pharmaceutical and food-related fields. In this review, an overview of various nanoemulsion and nanoliposome systems reported recently for enhancing stability, bioavailability, and bioactivity of anthocyanins is presented.

RESULTS

Anthocyanin nanoemulsions with different oil, water, surfactant, and cosurfactant ratios were prepared from extracts of mangosteen peel, purple sweet potato, cranberry, red cabbage, blueberry, jaboticaba peel, and acai berry and evaluated for their antioxidant activity, enhancement of physicochemical stability, topical skin application, and urinary tract infection. Likewise, unilamellar and multilamellar nanoliposomes were prepared using different types and levels of lecithin without or with cholesterol from anthocyanin standards and extracts of Hibiscus sabdariffa, mulberry, elderberry, black carrot, and pistachio green hull for the evaluation of physicochemical and oxidative stability, in vitro bioaccessibility, and melanogenic activity, as well as protective effects against diabetes mellitus and cataract.

CONCLUSION

This review provides an insight into the current nanotechnology updates on enhancement of anthocyanin stability and biological activity.

Preparation of coffee oil-algae oil-based nanoemulsions and the study of their inhibition effect on UVA-induced skin damage in mice and melanoma cell growth

Coffee grounds, a waste by-product generated after making coffee, contains approximately 15% coffee oil which can be used as a raw material in cosmetics. Algae oil rich in docosahexaenoic acid (DHA) has been demonstrated to possess anticancer and anti-inflammation functions. The objectives of this study were to develop a gas chromatography-mass spectrometry (GC-MS) method for the determination of fatty acids in coffee oil and algae oil and prepare a nanoemulsion for studying its inhibition effect on ultraviolet A-induced skin damage in mice and growth of melanoma cells B16-F10. A total of 8 and 5 fatty acids were separated and quantified in coffee oil and algae oil by GC-MS, respectively, with linoleic acid (39.8%) dominating in the former and DHA (33.9%) in the latter. A nanoemulsion with a particle size of 30 nm, zeta potential -72.72 mV, and DHA encapsulation efficiency 100% was prepared by using coffee oil, algae oil, surfactant (20% Span 80 and 80% Tween 80), and deionized water. Differential scanning calorimetry (DSC) analysis revealed a high stability of nanoemulsion when heated up to 110°C at a pH 6, whereas no significant changes in particle size distribution and pH occurred over a 90-day storage period at 4°C. Animal experiments showed that a dose of 0.1% coffee oil-algae oil nanoemulsion was effective in mitigating trans-epidermal water loss, skin erythema, melanin formation, and subcutaneous blood flow. Cytotoxicity test implied effective inhibition of melanoma cell growth by nanoemulsion with an IC50 value of 26.5 µg/mL and the cell cycle arrested at G2/M phase. A dose-dependent upregulation of p53, p21, cyclin B, and cyclin A expressions and downregulation of CDK1 and CDK2 occurred. Also, both Bax and cytochrome c expressions were upregulated and bcl-2 expression downregulated, accompanied by a rise in caspase-3, caspase-8, and caspase-9 activities for apoptosis execution. Collectively, the apoptosis pathway of melanoma cells B16-F10 may involve both mitochondria and death receptor.

Preparation of catechin extracts and nanoemulsions from green tea leaf waste and their inhibition effect on prostate cancer cell PC-3

Green tea is one of the most commonly consumed natural health beverages in Taiwan’s market, with the major functional component catechin being shown to possess several biological activities such as antioxidation, anticancer, and prevention of cardiovascular disease. The objectives of this study were to develop a high-performance liquid chromatography–mass spectrometry method to determine the variety and content of catechins in green tea leaf waste, a by-product obtained during processing of tea beverage. In addition, catechin nanoemulsion was prepared to study its inhibition effect on prostate cancer cell PC-3. Results showed that a total of eight catechin standards were separated within 25 minutes by using a Gemini C18 column and a gradient mobile phase of 0.1% formic acid (A) and acetonitrile (B) with flow rate at 1 mL/min, column temperature at 30°C, and detection wavelength at 280 nm. Among various extraction solvents, 50% ethanol generated the highest yield of total catechins from tea leaf waste, of which five catechins were identified and quantified. The catechin nanoemulsion was composed of catechin extract, lecithin, Tween 80, and deionized water in an appropriate proportion, with the mean particle size being 11.45 nm, encapsulation efficiency 88.1%, and zeta potential −66.3 mV. A high stability of catechin nanoemulsion was shown over a storage period of 120 days at 4°C. Both catechin extract and nanoemulsion could inhibit growth of PC-3 tumor cells, with the half maximal inhibitory concentration being 15.4 μg/mL and 8.5 μg/mL, respectively. The PC-3 cell cycle was arrested at S phase through elevation of P27 expression and decline of cyclin A, cyclin B, cyclin-dependent kinase 2, and cyclin-dependent kinase 1 expression. In addition, both catechin extract and nanoemulsion could induce apoptosis of PC-3 cells through decrease in B-cell lymphoma 2 (bcl-2) expression and increase in cytochrome c expression for activation of caspase-3, caspase-8, and caspase-9. Taken together, both caspase-dependent and caspase-independent pathways may be involved in apoptosis of PC-3 cells.

Optimizing a Male Reproductive Aging Mouse Model by D-Galactose Injection

The d-galactose (d-gal)-injected animal model, which is typically established by administering consecutive subcutaneous d-gal injections to animals for approximately six or eight weeks, has been frequently used for aging research. In addition, this animal model has been demonstrated to accelerate aging in the brain, kidneys, liver and blood cells. However, studies on aging in male reproductive organs that have used this animal model remain few. Therefore, the current study aimed to optimize a model of male reproductive aging by administering d-gal injections to male mice and to determine the possible mechanism expediting senescence processes during spermatogenesis. In this study, C57Bl/6 mice were randomized into five groups (each containing 8–10 mice according to the daily intraperitoneal injection of vehicle control or 100 or 200 mg/kg dosages of d-gal for a period of six or eight weeks). First, mice subjected to d-gal injections for six or eight weeks demonstrated considerably decreased superoxide dismutase activity in the serum and testis lysates compared to those in the control group. The lipid peroxidation in testis also increased in the d-gal-injected groups. Furthermore, the d-gal-injected groups exhibited a decreased ratio of testis weight/body weight and sperm count compared to the control group. The percentages of both immotile sperm and abnormal sperm increased considerably in the d-gal-injected groups compared to those of the control group. To determine the genes influenced by the d-gal injection during murine spermatogenesis, a c-DNA microarray was conducted to compare testicular RNA samples between the treated groups and the control group. The d-gal-injected groups exhibited RNA transcripts of nine spermatogenesis-related genes (Cycl2, Hk1, Pltp, Utp3, Cabyr, Zpbp2, Speer2, Csnka2ip and Katnb1) that were up- or down-regulated by at least two-fold compared to the control group. Several of these genes are critical for forming sperm-head morphologies or maintaining nuclear integration (e.g., cylicin, basic protein of sperm head cytoskeleton 2 (Cylc2), casein kinase 2, alpha prime interacting protein (Csnka2ip) and katanin p80 (WD40-containing) subunit B1 (Katnb1)). These results indicate that d-gal-injected mice are suitable for investigating male reproductive aging.

Inhibition of lung cancer cells A549 and H460 by curcuminoid extracts and nanoemulsions prepared from Curcuma longa Linnaeus

The objectives of this study were to explore the inhibition mechanism of lung cancer cells A549 and H460 by curcuminoid extracts and nanoemulsions prepared from Curcuma longa Linnaeus. In addition, human bronchus epithelial cell line BEAS-2B (normal cell) was selected for comparison. A high-performance liquid chromatography (HPLC) method was developed to separate and quantify the various curcuminoids in C. longa extract, including curcumin (1,714.5 μg/mL), demethoxycurcumin (1,147.4 μg/mL), and bisdemethoxycurcumin (190.2 μg/mL). A high-stability nanoemulsion composed of Tween 80, water, and curcuminoid extract was prepared, with mean particle size being 12.6 nm. The cell cycle was retarded at G2/M for both the curcuminoid extract and nanoemulsion treatments; however, the inhibition pathway may be different. H460 cells were more susceptible to apoptosis than A549 cells for both curcuminoid extract and nanoemulsion treatments. Growth of BEAS-2B remained unaffected for both the curcuminoid extract and nanoemulsion treatments, with a concentration range from 1 to 4 μg/mL. Also, the activities of caspase-3, caspase-8, and caspase-9 followed a dose-dependent increase for both A549 and H460 cells for both the treatments, accompanied by a dose-dependent increase in cytochrome C expression and a dose-dependent decrease in CDK1 expression. Interestingly, a dose-dependent increase in cyclin B expression was shown for A549 cells for both the treatments, while a reversed trend was found for H460 cells. Both mitochondria and death receptor pathways may be responsible for apoptosis of both A549 and H460 cells.

Inhibition of colon cancer cell growth by nanoemulsion carrying gold nanoparticles and lycopene

Lycopene (LP), an important functional compound in tomatoes, and gold nanoparticles (AN), have received considerable attention as potential candidates for cancer therapy. However, the extreme instability and poor bioavailability of LP limits its in vivo application. This study intends to develop a nanoemulsion system incorporating both LP and AN, and to study the possible synergistic effects on the inhibition of the HT-29 colon cancer cell line. LP-nanogold nanoemulsion containing Tween 80 as an emulsifier was prepared, followed by characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS) analysis, ultraviolet spectroscopy, and zeta potential analysis. The particle size as determined by TEM and DLS was 21.3±3.7 nm and 25.0±4.2 nm for nanoemulsion and 4.7±1.1 nm and 3.3±0.6 nm for AN, while the zeta potential of nanoemulsion and AN was -32.2±1.8 mV and -48.5±2.7 mV, respectively. Compared with the control treatment, both the combo (AN 10 ppm plus LP 12 μM) and nanoemulsion (AN 0.16 ppm plus LP 0.4 μM) treatments resulted in a five- and 15-fold rise in early apoptotic cells of HT-29, respectively. Also, the nanoemulsion significantly reduced the expressions of procaspases 8, 3, and 9, as well as PARP-1 and Bcl-2, while Bax expression was enhanced. A fivefold decline in the migration capability of HT-29 cells was observed for this nanoemulsion when compared to control, with the invasion-associated markers being significantly reversed through the upregulation of the epithelial marker E-cadherin and downregulation of Akt, nuclear factor kappa B, pro-matrix metalloproteinase (MMP)-2, and active MMP-9 expressions. The TEM images revealed that numerous nanoemulsion-filled vacuoles invaded cytosol and converged into the mitochondria, resulting in an abnormally elongated morphology with reduced cristae and matrix contents, demonstrating a possible passive targeting effect. The nanoemulsion containing vacuoles were engulfed and internalized by the nuclear membrane envelop for subsequent invasion into the nucleoli. Taken together, LP-nanogold nanoemulsion could provide synergistic effects at AN and LP doses 250 and 120 times lower than that in the combo treatment, respectively, demonstrating the potential of nanoemulsion developed in this study for a possible application in colon cancer therapy.

Cytotoxicity and antibacterial activity of gold-supported cerium oxide nanoparticles

BACKGROUND

Cerium oxide nanoparticles (CeO2) have been shown to be a novel therapeutic in many biomedical applications. Gold (Au) nanoparticles have also attracted widespread interest due to their chemical stability and unique optical properties. Thus, decorating Au on CeO2 nanoparticles would have potential for exploitation in the biomedical field.

METHODS

In the present work, CeO2 nanoparticles synthesized by a chemical combustion method were supported with 3.5% Au (Au/CeO2) by a deposition-precipitation method. The as-synthesized Au, CeO2, and Au/CeO2 nanoparticles were evaluated for antibacterial activity and cytotoxicity in RAW 264.7 normal cells and A549 lung cancer cells.

RESULTS

The as-synthesized nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy, and ultraviolet-visible measurements. The X-ray diffraction study confirmed the formation of cubic fluorite-structured CeO2 nanoparticles with a size of 10 nm. All synthesized nanoparticles were nontoxic towards RAW 264.7 cells at doses of 0-1,000 μM except for Au at >100 μM. For A549 cancer cells, Au/CeO2 had the highest inhibitory effect, followed by both Au and CeO2 which showed a similar effect at 500 and 1,000 μM. Initial binding of nanoparticles occurred through localized positively charged sites in A549 cells as shown by a shift in zeta potential from positive to negative after 24 hours of incubation. A dose-dependent elevation in reactive oxygen species indicated that the pro-oxidant activity of the nanoparticles was responsible for their cytotoxicity towards A549 cells. In addition, cellular uptake seen on transmission electron microscopic images indicated predominant localization of nanoparticles in the cytoplasmic matrix and mitochondrial damage due to oxidative stress. With regard to antibacterial activity, both types of nanoparticles had the strongest inhibitory effect on Bacillus subtilis in monoculture systems, followed by Salmonella enteritidis, Escherichia coli, and Staphylococcus aureus, while, in coculture tests with Lactobacillus plantarum, S. aureus was inhibited to a greater extent than the other bacteria.

CONCLUSION

Gold-supported CeO2 nanoparticles may be a potential nanomaterial for in vivo application owing to their biocompatible and antibacterial properties.