The protection of the liver as an essential organ in the body against oxidative stress and deleterious compounds has been the subject of recent investigations. Among different compounds, medicinal plants play an important role due to their hepatoprotective effects. Taraxacum officinale or “common dandelion” is a popular plant that has been traditionally used for its hepatoprotective effects. Currently, there are limited clinical studies on its hepatoprotective effects. The aim of this review article is to evaluate the hepatoprotective effects of dandelion and its mechanism of action. We reviewed literature up to July 2019 on “Taraxacum officinale” or “dandelion” and hepatoprotection. Currently available pharmacological studies indicate that dandelion extracts have hepatoprotective effects against chemical agents due to its antioxidant and anti-inflammatory activities. The anti-inflammatory effects of dandelion, the prebiotic effects of its oligofructans, inhibitory effects against the release of lipopolysaccharides and fasting induced adipose factor, digestive enzymes, and enhancing effects of lipogenesis, reduce lipid accumulation and liver inflammation, which directly or indirectly improve the liver functions. Given emerging evidence on hepatoprotective effects of dandelion, designing large human clinical studies is essential.

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Objective: To investigate the antioxidant and anti-melanogenesis activities of an ultrasonic extract of red sea cucumber, Stichopus japonicus, collected from Jeju Island. Methods: Antioxidant activity experiments were assessed by an electron spin resonance system and a cellular model of immortalized human keratinocytes (HaCaT) to determine its radical scavenging activity and protective effects against 2,2’-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress. Anti-melanogenic activity of the ultrasonic extract of red sea cucumber was also examined using the melanoma cell model B16F10 and mushroom tyrosinase. Following the induction by α-melanocyte-stimulating hormone, the effects of the ultrasonic extract of red sea cucumber on intracellular tyrosinase activity, melanin content and the melanogenic protein expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related proteins (TRP-1, and TRP-2) were examined. Results: The ultrasonic extract of red sea cucumber significantly scavenged 2,2-diphenyl-1-picrylhydrazyl and alkyl radicals [IC₅₀: (0.924±0.035) and (0.327±0.006) mg/mL, respectively], as well as showed a protective effect against oxidative stress and attenuated generation of intracellular reactive oxygen species on AAPH- induced HaCaT cells, with no cytotoxicity (12.5-400 μg/mL). The ultrasonic extract of red sea cucumber also exhibited a tyrosinase inhibitory effect [IC₅₀: (2.750±0.006) mg/mL]. On α-melanocyte-stimulating hormone-stimulated B16F10 melanoma cells, the ultrasonic extract of red sea cucumber (25-200 μg/mL) significantly inhibited not only melanin synthesis and tyrosinase activity, but also protein expressions of microphthalmia-associated transcriptional factor, tyrosinase, TRP-1, and TRP-2. Conclusions: The ultrasonic extract of red sea cucumber shows antioxidant and anti-melanogenic potential and may be a natural candidate for anti-aging as well as a whitening agent in the cosmeceuticals industry.

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Objective: To evaluate the renoprotective effect of umbelliferone in high-fat diet/streptozotocin-induced type 2 diabetic rats. Methods: We established a streptozotocin-induced type 2 diabetic model in male Wistar rats. The rats were fed with high-fat diet (45 kcal% lard fat) and injected with 35 mg/kg streptozotocin. Diabetic rats were treated with umbelliferone for 8 weeks. At the end of the experimental period, the serum and kidney were used for measuring biochemical parameters, protein expression and histological analysis. Results: After 8-week treatment, umbelliferone decreased fasting plasma glucose, concentrations of malondialdehyde and monocyte chemoattractant protein-1 in the plasma and tissues. It also significantly reduced serum creatinine, blood urea nitrogen, serum advanced glycation end products, as well as kidney weight in type 2 diabetic rats (P<0.05). Moreover, umbelliferone reduced the 24-h urine albumin, but increased 24-h urine creatinine excretion (P<0.05). In renal protein expression, umbelliferone decreased the levels of transforming growth factor-ß1 and fibronectin while increasing the levels of superoxide dismutase and catalase (P<0.05). Renal histological examination revealed an enlarged glomerular size in diabetic rats, which was smaller in umbelliferone-treated diabetic rats. Conclusions: Umbelliferone alleviates renal dysfunction in diabetes via decreasing hyperglycemia, oxidative stress, inflammation and glycation.

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Objective: To evaluate the anti-microsporidial effects of the active component of Nigella sativa seeds, thymoquinone, against Encephalitozoon intestinalis using an in vitro model. Methods: Anti-microsporidial effect of thymoquinone against Encephalitozoon intestinalis was evaluated by using various concentrations of thymoquinone (0, 1, 5, 10, 15, 20, 30, 35, and 40 μΜ) and sterile dimethyl sulfoxide. Real time PCR was used to evaluate the inhibitory effects of thymoquinone on the life cycle of Encephalitozoon intestinalis. Results: The cytotoxic effect of thymoquinone on HEK293 cell line was observed with 30, 35, and 40 μM concentrations of thymoquinone after 24, 48, and 72 hours of incubation. It was observed that 10, 15, 20, and 30 μM concentrations of thymoquinone decreased the spore density compared with the control; however, it was significant only at 30 μM. Conclusions: Thymoquinone shows potent anti-microsporidial effects against Encephalitozoon intestinalis in the in vitro model; however, the toxic concentrations of thymoquinone are also toxic to the host cells.

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Objective: To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment (SELEX) technology to identify candidates for adjunct therapy to reverse the binding of Plasmodium-infected erythrocytes. Methods: RNA aptamers were isolated using nitrocellulose membrane-based SELEX and binding analysis was screened using an electrophoretic mobility shift assay and enzyme-linked oligonucleotide assay. Results: Thirteen cycles of nitrocellulose membrane-based SELEX yielded three aptamers (RC60, RC25, RC04) exhibiting high binding against CD36 protein as shown on electrophoretic mobility shift assay. The sequence analysis revealed a G-quadruplex sequence within all the isolated aptamers that might contribute to aptamer binding and thermodynamic stability. The specificity assay further showed that RC60 and RC25 were highly specific to CD36. The competitive inhibition assay demonstrated that RC60 and RC25 shared a similar binding epitope recognized by mAb FA6-152, a specific monoclonal antibody against CD36. Conclusions: RC60 and RC25 are promising candidates as anti-cytoadherence for severe malaria adjunct therapy.

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Objective: To investigate the molecular mechanisms of the anti-obese effect of raspberry ketone against high-fat diet fed rats. Methods: Fifty adult male rats were randomly assigned to receive a standard diet, a high fat diet, and the high-fat diet and 0.5%, 1% or 2% raspberry ketone. Body weight, biochemical parameters and gene expression of CCAAT enhancer-binding protein (C/EBP)δ, fatty acid synthase (FAS), acetyl CoA carboxylase (ACC), peroxisome proliferator-activated receptor alpha (PPAR-α), hormone-sensitive lipase (HSL) and hepatic carnitine palmitoyltransferase 1 A (CPT1A) were investigated. Results: Body weight, blood glucose, insulin, total lipids, triacylglycerols, total cholesterol and low-density lipoprotein cholesterol were increased in high-fat diet fed rats. These high fat diet-induced changes were attenuated by treatment with raspberry ketone. High-density lipoprotein cholesterol was decreased in highfat diet fed rats but increased in rats treated with raspberry ketone. Molecular investigations showed induction of gene expression of C/EBP-δ, FAS, ACC, CPT1A and inhibition of gene expression of PPAR-α and HSL in high-fat diet fed rats as compared with control. Raspberry ketone treament reversed these changes except CPT1A. Conclusions: Raspberry ketone can prevent obesity induced by a high-fat diet in rats by induction of the expression of enzymes, controlling lipolysis and fatty acids β oxidation as well as inhibition of gene expressions of adipogenic factors.

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