Protective effects of anthocyanins from purple sweet potato on acute carbon tetrachloride-induced oxidative hepatotoxicity fibrosis in mice

Effects of Foods of Mesoamerican Origin in Adipose Tissue and Liver-Related Metabolism

Adipose tissue and liver metabolism play a key role in maintaining body homeostasis; therefore, their impairment conduces a pathological state. Nowadays, occidental lifestyle is a common etiological issue among a variety of chronic diseases, while diet is a unique strategy to prevent obesity and liver metabolism impairment and is a powerful player in the treatment of metabolic-related diseases. Mesoamerican foods are rich in bioactive molecules that enhance and improve adipose tissue and liver performance and represent a prophylactic and therapeutic alternative for disorders related to the loss of homeostasis in the metabolism of these two important tissues.

Anthocyanin-Containing Purple Sweet Potato (Ipomoea batatas L.) Synbiotic Yogurt Inhibited 3T3-L1 Adipogenesis by Suppressing White Adipocyte-Specific Genes

Purpose

We unravel the effect of anthocyanin-containing purple sweet potato synbiotic yogurt (PSPY) on 3T3-L1 adipocyte differentiation and its fundamental molecular mechanisms.

Methods

Molecular docking simulation was performed to observe and identify the affinity and interaction between bioactive compounds and targeted proteins. MDI (isobutylmethylxanthine, dexamethasone, and insulin)-containing medium, a cocktail that stimulates adipogenesis, was used in this study. The toxic effect possibility of the yogurt product was evaluated using 3-[4, 5-dimethylthiazol-2-yl]-2.5 diphenyl tetrazolium bromide (MTT) assay. A 0.25%, 0.5%, 1%, and 5% (v/v) plain or purple sweet potato yogurt supernatant was given to 3T3-L1 preadipocyte culture medium from 24 h after seeding until day 11 of MDI-induced differentiation. The mRNA expression and lipid accumulation were analyzed using RT-qPCR and Oil red O staining, respectively, on day 11 after differentiation induction.

Results

In silico study suggested that anthocyanin-derived compounds have the potential to inhibit peroxisome proliferator activated receptor gamma (PPAR-γ), a master regulator for white adipogenesis. Anthocyanin-containing PSPY significantly suppressed the expression of Pparg, Adipoq, Slc2a4, and Pgc1a. PSPY significantly suppressed Pparg with 1% and 5% concentrations, while with a concentration of 0.25%, PSPY significantly suppressed Adipoq expression as compared to control. Significant inhibition of Slc2a4 and Pgc1a was observed starting from a 0.25% concentration of PSPY. The suppression of adipogenic genes was also observed with the treatment of plain yogurt; however, the effects were relatively lower than the PSPY. The group treated with 1% and 5% of PSPY also showed inhibition effects on lipid accumulation.

Conclusion

This study demonstrated PSPY inhibition effect on white adipocyte differentiation through suppression of Pparg and its downstream genes, Adipoq and Slc2a4, indicating the potential of this yogurt as a functional food for obesity management and prevention.

Acute and sub-chronic oral toxicity study of purple sweet potato (Ipomoea batatas [L.] Lam) yogurt in mice (Mus musculus)

Background and Aim:

Food safety is an important aspect to be evaluated in preventing any potentially harmful side effects of food product such as yogurt. The purple sweet potato yogurt product was developed to combine the benefits of probiotic activities in yogurt and the bioactive effects of anthocyanin in purple sweet potato. This study was performed to investigate acute and sub-chronic oral toxicity of purple sweet potato yogurt (PSPY) in mice.

Materials and Methods:

Acute oral toxicity was evaluated by a 14-day observation for any clinical sign of toxicity on fifteen female balb/c mice following a single dosage of PSPY (nil, 2 or 5 g/kg body weight). The sub-chronic oral toxicity study was conducted by feeding PSPY to four groups of mice with the dose of 0, 12, 20, and 40 g/kg body weight for 28 days, and another group of mice receiving 40 g/kg body weight purple sweet potato for 14 days longer to observe any delayed toxicity effect. Body weight and clinical signs of toxicity were observed daily. Liver and kidney macroscopy and relative organ weight, liver histology, liver enzyme, and hematology profile analyses were done at the end of the study.

Results:

There were no signs of toxicity observed from the acute toxicity study and no abnormality in body weight, relative organ weight, and gross organ examination. In the sub-chronic toxicity study, there were no clinical signs of toxicity, no significant differences in body weight, relative liver weight, liver enzymes, hematology profile, or abnormality in gross and histological examination of the liver.

Conclusion:

This study shows that oral administration of PSPY in mice up to 5 g/kg body weight did not result in acute toxicity, while the dosage up to 40 g/kg body weight did not lead to sub-chronic toxicity.

Enhancing the In Vitro Biological Activity of Degraded Silk Sericin and Its Analog Metabolites

Two sericins of high and low molecular weight (HS and LS) were prepared from commercial silkworm cocoon silk with a boiling water and Ca(OH)₂ solution with ultrasonic treatments, respectively. This study first investigated the release concentration of the two abovementioned sericins in simulated saliva, gastric juice, and intestinal juice (pH 6.8, 2.0, and 7.4, respectively) within 10 h. The results showed that the order of sericin release rate and its amount in the simulated environment was gastric juice > saliva > intestinal juice. Second, the molecular weights of both sericin metabolites formed by in vitro enzymatic degradation were lower than 15 kDa. The α-glucosidase inhibitory activities of both sericins and their analog metabolites were positively correlated with their concentrations. The IC₅₀ values of the HS- and LS-derived metabolites were 1.02 ± 0.12 mg/mL and 0.91 ± 0.15 mg/mL, respectively, which were five to seven times lower than those of both original sericins. The total antioxidant capacities and hydroxyl radical scavenging capacities of both metabolites were enhanced by one- to three-fold compared with HS and LS. These results indicate that both sericins, regardless of molecular size, have significantly enhanced antioxidant, superoxide free radical scavenging, and glycosidase inhibitory activities after simulated metabolism, and that LS is better than HS regardless of simulated digestion. These results confirm that sericin is important in the sustainable development and utilization of silk resources, especially the reduction in environmental pollution, and provides new ideas for the development of adjuvant treatments for diabetes and the development of foods with anti-hyperglycemic functions.

The flavonoid-rich ethanolic extract from the green cocoon shell of silkworm has excellent antioxidation, glucosidase inhibition, and cell protective effects in vitro

The green cocoon shell of a novel variety of silkworm, Bombyx mori, is rich in two types of quercetin and kaempferol flavonoids. The aim of this study was to identify these flavonoids in the ethanolic extract (EE) from green cocoons and develop EE applications in healthy foods. The experimental results indicated that the amount of total amino acids in EE was 27.06%. The flavonoids in EE are presented in quercetin and kaempferol glycosides. The total amount of the two aglycones was 33.42 ± 0.08 mg/g. The IC50 values of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 1,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonicacid) (ABTS), and hydroxyl radical scavenging abilities were 296.95 ± 13.24 μg/mL, 94.31 ± 9.13 μg/mL, and 9.21 ± 0.15 mg/mL, respectively. The IC50 values of the inhibitory activities of α-amylase and α-glucosidase were 37.57 ± 6.45 μg/mL and 212.69 ± 22.94 μg/mL, respectively. EE also reduced the level of reactive oxygen species (ROS) and oxidative stress in L02 cells induced by high glucose levels. It also effectively decreased the content of 8-hydroxyl deoxyguanosine (8-OHdG), nuclear factor κB (NF-κB), and tumour necrosis factor alpha (TNF-α) in cells with a good dose effect. These results clearly indicated that the flavonoid-rich EE with excellent antioxidant and glucosidase inhibition abilities significantly reduced the damage to cells caused by oxidative stress and inflammatory reactions. It is suggested that EE might serve as useful functional foods for the treatment of related diseases induced by oxidative stress such as diabetes mellitus.

Purple sweet potato color protects against hepatocyte apoptosis through Sirt1 activation in high-fat-diet-treated mice

Background

Recent evidence indicates that the inhibition of hepatocyte apoptosis is possible to develop a potential therapeutic strategy for nonalcoholic fatty liver disease (NAFLD). Our previous work suggested that purple sweet potato color (PSPC), a class of naturally occurring anthocyanins, effectively improved many features of high-fat diet (HFD)-induced NAFLD. However, whether PSPC ameliorates HFD-induced hepatocyte apoptosis has never been investigated.

Objective

Here we investigated the effects of PSPC on HFD-induced hepatic apoptosis and the mechanisms underlying these effects.

Design

Mice were divided into four groups: Control group, HFD group, HFD + PSPC group and PSPC group. PSPC was administered by daily oral gavage at doses of 700 mg/kg/day for 20 weeks. EX-527 (a SirT1-selective inhibitor) and Sirt1 siRNA were used to demonstrate the Sirt1 dependence of PSPC-mediated effects on apoptotic and survival signaling pathways in vivo and in vitro.

Results

Our results showed that PSPC reduced body weights, hepatic triglyceride contents, histopathological lesions and serum ALT levels in a mouse model of NAFLD induced by HFD. Furthermore, PSPC attenuated HFD-induced hepatocyte apoptosis ratio from 7.27 ± 0.92% to 1.79 ± 0.27% in mouse livers, which is insignificant compared with that of controls. Moreover, PSPC activated Sirt1 by boosting NAD⁺ level in HFD-treated mouse livers. Furthermore, PSPC promoted Sirt1-dependent suppression of P53-mediated apoptotic signaling and activation of Akt survival signaling pathway in HFD-treated mouse livers, which was confirmed by EX527 treatment. Moreover, Sirt1 knockdown abolished these ameliorative effects of PSPC on apoptosis and P53 acetylation and protein expression in PA-treated L02 cells. Ultimately, PSPC reduced Caspase-3 activation and Bax level, and elevated the Bcl-2 level in HFD-treated mouse livers.

Conclusion

PSPC protected against HFD-induced hepatic apoptosis by promoting Sirt1- dependent inhibition of p53-apoptotic pathway and facilitation of Akt survival pathway. This study indicates that PSPC is a candidate for nutritional intervention of NAFLD.

Protective effect of Letinous edodes foot peptides against ethanol‑induced liver injury in L02 cells

The aim of the present study was to evaluate the protective effect and mechanism of Letinous edodes foot peptides on ethanol‑induced L02 cells. A cell model of ethanol‑induced damage was established in vitro to study the effects of the Letinous edodes foot peptides on human L02 hepatocytes. The expression and activity of superoxide dismutase (SOD), malondialdehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH), following treatment were examined to determine the anti‑alcoholism and hepatoprotective functions of Letinous edodes foot peptides. Taking Letinous edodes foot peptides prior to ethanol exposure was more beneficial, which significantly increased SOD activity and the mRNA expression of ADH and ALDH suppressed by ethanol. In addition, the intracellular MDA content, and AST and ALT activity decreased in ethanol‑induced L02 cells pretreated with the peptides, when compared with the control. Furthermore, Letinous edodes foot peptides inhibited the ethanol‑induced activation of the proinflammatory cytokines, interleukin‑6 and tumor necrosis factor‑α, and promoted the metabolic regulation factors, AMP‑activated protein kinase‑α2 and peroxisome proliferator‑activated receptor‑α.

Hepatoprotective and antioxidant activities of Spondias mombin leaf and stem extracts against carbon tetrachloride-induced hepatotoxicity

Objective

Spondias mombin L. is a tree used in folk medicine in Nigeria for the treatment of hepatitis. This study was carried out to comparatively evaluate the hepatoprotective and antioxidant effects of S. mombin leaf and stem (SML and SMS) methanolic extracts in a rat model of carbon tetrachloride (CCl₄)-induced hepatotoxicity.

Methods

Forty-two rats were distributed into seven groups. Groups A and B received water; groups C and D received 500 and 1000 mg/kg SML extract, respectively; groups E and F received 500 and 1000 mg/kg SMS extract, respectively; and group G received 100 mg/kg silymarin. Water, the two extracts, and silymarin were administered daily by oral gavage for 7 days. Hepatotoxicity was induced in groups B to G by the administration of CCl₄ once on the seventh day. After 48 h, rats were sacrificed, and tissues and serum samples were examined for histological and biochemical indices of hepatotoxicity.

Results

Administration of CCl₄ resulted in liver injury with significant elevation in the hepatocellular injury markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), and conjugated bilirubin (CBIL), associated with a significant reduction in total circulatory protein. Pretreatment with SML and SMS extracts at both doses significantly ameliorated liver injury; lowered ALT, AST, ALP, TBIL, and CBIL levels; elevated cellular glutathione levels as well as catalase and superoxide dismutase activities; and decreased the levels of thiobarbituric acid reactive substances.

Conclusion

This study provides preliminary evidence supporting the potential therapeutic benefit of S. mombin in xenobiotic-induced hepatotoxicity.

Chemical constituents and health effects of sweet potato

Sweet potatoes are becoming a research focus in recent years due to their unique nutritional and functional properties. Bioactive carbohydrates, proteins, lipids, carotenoids, anthocyanins, conjugated phenolic acids, and minerals represent versatile nutrients in different parts (tubers, leaves, stems, and stalks) of sweet potato. The unique composition of sweet potato contributes to their various health benefits, such as antioxidative, hepatoprotective, antiinflammatory, antitumor, antidiabetic, antimicrobial, antiobesity, antiaging effects. Factors affecting the nutritional composition and bio-functions of sweet potato include the varieties, plant parts, extraction time and solvents, postharvest storage, and processing. The assays for bio-function evaluation also contribute to the variations among different studies. This review summarizes the current knowledge of the chemical composition of sweet potato, and their bio-functions studied in vitro and in vivo. Leaves, stems, and stalks of sweet potato remain much underutilized on commercial levels. Sweet potato can be further developed as a sustainable crop for diverse nutritionally enhanced and value-added food products to promote human health.

A new estimation of the total flavonoids in silkworm cocoon sericin layer through aglycone determination by hydrolysis-assisted extraction and HPLC-DAD analysis

BACKGROUND

Silk sericin and a few non-protein components isolated from the cocoon layer including two silk proteins in silkworm Bombyx mori has many bioactivities. The dietary sericin possess antinatural oxidation, anticancer, antihyperlipidemic, and antidiabetic activities. The non-protein components surrounding the sericin layer involve in wax, pigments mainly meaning flavonoids, sugars, and other impurities. However, very few investigations have reported the estimation of the total flavonoids derived from the cocoon layer. The flavonoids are commonly present in their glycosylated forms and mostly exist as quercetin glycosides in the sericin layers of silkworm cocoons.

OBJECTIVE

The aim of this study was to find a more accurate method to estimate the level of the total flavonoids in silkworm cocoons.

DESIGN

An efficient procedure of hydrolysis-assisted extraction (HAE) was first established to estimate the level of the total flavonoids through the determination of their aglycones, quercetin, and kaempferol. Then, a comparison was made between traditional colorimetric method and our method. In addition, the antioxidant activities of hydrolysis-assisted extract sample were determined.

RESULTS

The average contents of quercetin and kaempferol were 1.98 and 0.42 mg/g in Daizo cocoon. Their recoveries were 99.56 and 99.17%. The total sum of quercetin and kaempferol was detected to be 2.40±0.07 mg/g by HAE-HPLC, while the total flavonoids (2.59±0.48 mg/g) estimated by the traditional colorimetric method were only equivalent to 1.28±0.04 mg/g of quercetin. The HAE sample also exhibits that IC50 values of scavenging ability of diphenyl picryl hydrazinyl (DPPH) radical and hydroxyl radical (HO·) are 243.63 µg/mL and 4.89 mg/mL, respectively.

CONCLUSIONS

These results show that the HAE-HPLC method is specificity of cocoon and far superior to the colorimetric method. Therefore, this study has profound significance for the comprehensive utilization of silkworm cocoon and also may be applied to the estimation of total flavonoids in other functional foods.