Protective Effects of Sweet Orange, Unshiu Mikan, and Mini Tomato Juice Powders on t-BHP-Induced Oxidative Stress in HepG2 Cells

Narirutin ameliorates alcohol-induced liver injury by targeting MAPK14 in zebrafish larvae

BACKGROUND

Alcohol-associated liver disease (ALD) encompasses a range of hepatic abnormalities, including isolated alcoholic steatosis, steatohepatitis, and cirrhosis. The flavanone-7-O-glycoside narirutin (NRT), the primary flavonoid in citrus peel, has antioxidant, anti-inflammatory, and lipid-lowering activity. We investigated the effects of NRT on liver injury induced by alcohol and explored the underlying mechanisms.

METHODS

Zebrafish larvae were used to investigate the effects of NRT on acute exposure to ethanol (EtOH). Liver phenotypic, morphological, and biochemical assessments were performed to evaluate the hepatoprotective effects of NRT. Network pharmacology and molecular docking analyses were conducted to identify candidate targets of NRT in EtOH-induced liver injury. A drug affinity responsive target stability (DARTS) assay was conducted to evaluate the binding of NRT to mitogen-activated protein kinase 14 (MAPK14). The mechanism of action of NRT was validated by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analysis.

RESULTS

The liver phenotypic, morphological, and biochemical assessments revealed that NRT has potential therapeutic effects against acute EtOH-induced liver injury. RT-qPCR confirmed that NRT reversed the change in the expression of genes related to oxidative stress, lipogenesis, and the endoplasmic reticulum (ER)/unfolded protein response pathway. Network pharmacology and molecular docking analyses identified potential targets of NRT's protective effects and confirmed that NRT regulates the p38 MAPK signaling pathway by targeting mitogen-activated protein kinase 14 (MAPK14).

CONCLUSIONS

NRT mitigates alcohol-induced liver injury by preventing lipid formation, protecting the antioxidant system, and suppressing ER stress-induced apoptosis through MAPK14 modulation.

Prospective multifunctional roles and pharmacological potential of dietary flavonoid narirutin

Plant-based phytochemicals are now being used to treat plenty of physiological diseases. Herbal drugs have gained popularity in recent years because of their strength, purity, and cheap cost-effectiveness. Citrus fruits contain significant amounts of flavanones, which falls to the category of polyphenols. Flavanones occupy a major fraction of the total polyphenols present in the plasma when orange juice is taken highly or in moderate states. Narirutin is a disaccharide derivative available in citrus fruits, primarily dihydroxy flavanone. From a pharmacological viewpoint, narirutin is a bioactive phytochemical with therapeutic efficacy. Many experimental researches were published on the use of narirutin. Anticancer activity, neuroprotection, stress relief, hepatoprotection, anti-allergic activity, antidiabetic activity, anti-adipogenic activity, anti-obesity action, and immunomodulation are a couple of the primary pharmacological properties. Narirutin also has antioxidant, and anti-inflammatory activities. The ultimate goal of this review is to provide the current scenario of pharmacological research with narirutin; to make a better understanding for therapeutic potential of narirutin, as well as its biosynthesis strategies and side effects. Extensive literature searches and studies were undertaken to determine the pharmacological properties of narirutin.

Aged Pericarpium Citri Reticulatae ‘Chachi’ Attenuates Oxidative Damage Induced by tert-Butyl Hydroperoxide (t-BHP) in HepG2 Cells

This study investigated the protective effects of aged Pericarpium Citri Reticulatae ‘Chachi’ (PCR-C) on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in HepG2 cells. According to HPLC analysis, PCR-C aged 10 years (PCR-C10) had the highest flavonoids content, especially polymethoxyflavones (PMFs), compared with the fresh peel of Citrus reticulata cv. ‘Chachiensis’ and PCR-C aged 1, 3, and 5 years. Then, flavonoids-rich PCR-C samples and non-flavonoids-rich PCR-C samples (NF) were prepared by extracting and purifying PCR-C of different aging periods, for further cell experiments. Pretreatment with flavonoids-rich PCR-C samples (particularly PCR-C10) considerably reversed t-BHP-induced oxidative damage in HepG2 cells by improving cell viability, increasing SOD activity and GSH levels and reducing the overproduction of ROS and MDA. Correlation analysis further indicated that the accumulation of PMFs, mainly 5,6,7,4′-tetramethoxyflavone and nobiletin, was the main reason that PCR-C10 maintained the redox balance in HepG2 cells. These findings provided direct evidence for the cellular antioxidant activity of aged PCR-C and a guide for PCR-C’s classification, authentication and rational use.

Evaluation of the Phenolic Content, Antioxidant and Antimicrobial Activities of Oil and Non-Oil Extracts of Citrus sinensis (L.) Osbeck Seeds

The seeds of Citrus sinensis (L.) Osbeck (sweet orange) are waste products usually discarded. They may however contain phytochemicals that have potent bioactivities. In this study, the phenolic content, and antioxidant and antimicrobial activities of oil and non-oil (solid) extracts of C. sinensis seeds were evaluated using standard protocols. The seed oil contained significantly (P>0.05) higher contents of total phenol and total flavonoid when compared to the solid extract. However, the non-oil extract contained significantly (P<0.05) higher tannin contents than the seed oil. Ferric reducing antioxidant potential was not significantly different between both extracts. The antimicrobial activities of both extracts revealed that the seed oil possesses better antibacterial activities compared to the non-oil extract. The antifungal test revealed that the seed oil significantly inhibited the growth of Candida albicans (20 mm zone of inhibition at a concentration of 200 μg/mL), however, it did not inhibit the growth of Aspergillus niger and Penicillum sp. The minimum inhibitory concentration values against the bacterial and fungal strains were similar for both extracts in the range of 50∼100 μg/mL. Minimum bactericidal concentration and minimum fungicidal concentration values ranged from 100∼200 μg/mL for both extracts. The results in this study indicate that C. sinensis seed oil and non-oil extracts possess antioxidant, and antibacterial and antifungal properties that may be differentially exploited in the development of antimicrobial agents.

Dietary immature Citrus unshiu alleviates UVB- induced photoaging by suppressing degradation of basement membrane in hairless mice

Ultraviolet (UV) irradiation induces physiological and morphological skin damage, resulting in skin dryness, wrinkle formation, and loss of elasticity. The basement membrane (BM) has been shown to play crucial roles in binding epidermis to dermis tightly, regulating cell differentiation and proliferation, and signaling protein production. Dietary flavonoids have been revealed to improve the damage caused by UV exposure. Immature Citrus unshiu is known to contain high concentrations of flavonoids such as hesperidin and narirutin. In this study, the effects of immature Citrus unshiu powder (ICP) on photoaged skin were demonstrated using UVB irradiated hairless mice. Oral administration of ICP improved loss of skin hydration and increase of transepidermal water loss. The histological analyses of hairless mice dorsal skin revealed that oral administration of ICP improved UVB-induced overgrowth of epidermal cell, suppressed epidermal cell mortality and BM destruction. Therefore, the administration of ICP could improve photoaging by protecting the tissues around BM.

Protective effect of bioaccessible fractions of citrus fruit pulps against H2O2-induced oxidative stress in Caco-2 cells

Fruit pulps from Navel (N) and Cara Cara (CC) oranges, and Clementine mandarin freshly harvested (M) and refrigerated stored (M12) were used to evaluate the cytoprotective effect of their bioaccessible fractions (BF) against H₂O₂-induced oxidative stress in Caco-2 cells. BF of samples preserved viability vs. H₂O₂ treated cells, reaching values similar to controls. Lipid peroxidation was reduced to levels of control cells, but M did not reach control values. ROS and mitochondrial membrane potential changes (Δψ_m) values were reduced compared with H₂O₂ treated cells, but without achieving control levels. A significant reduction in cell proportions in G1 phase and a significant increase in sub-G1 phase (apoptosis) of cell cycle was shown in H₂O₂ treated cells, and BF allowed a recovery close to control levels. Thus, BF of samples protect the cells from oxidative stress by preserving cell viability, mitochondrial membrane potential and correct cell cycle progression, and diminishing lipid peroxidation and ROS.