Oxidative Stress and Chemoradiation-Induced Oral Mucositis: A Scoping Review of In Vitro, In Vivo and Clinical Studies

Chemoradiation-induced mucositis is a debilitating condition of the gastrointestinal tract eventuating from antineoplastic treatment. It is believed to occur primarily due to oxidative stress mechanisms, which generate Reactive Oxygen Species (ROS). The aim of this scoping review was to assess the role of oxidative stress in the development of Oral Mucositis (OM). Studies from the literature, published in MEDLINE and SCOPUS, that evaluated the oxidative stress pathways or antioxidant interventions for OM, were retrieved to elucidate the current understanding of their relationship. Studies failing inclusion criteria were excluded, and those suitable underwent data extraction, using a predefined data extraction table. Eighty-nine articles fulfilled criteria, and these were sub-stratified into models of study (in vitro, in vivo, or clinical) for evaluation. Thirty-five clinical studies evaluated antioxidant interventions on OM's severity, duration, and pain, amongst other attributes. A number of clinical studies sought to elucidate the protective or therapeutic effects of compounds that had been pre-determined to have antioxidant properties, without directly assessing oxidative stress parameters (these were deemed "indirect evidence"). Forty-seven in vivo studies assessed the capacity of various compounds to prevent OM. Findings were mostly consistent, reporting reduced OM severity associated with a reduction in ROS, malondialdehyde (MDA), myeloperoxidase (MPO), but higher glutathione (GSH) and superoxide dismutase (SOD) activity or expression. Twenty-one in vitro studies assessed potential OM therapeutic interventions. The majority demonstrated successful a reduction in ROS, and in select studies, secondary molecules were assessed to identify the mechanism. In summary, this review highlighted numerous oxidative stress pathways involved in OM pathogenesis, which may inform the development of novel therapeutic targets.

Minor tropical fruits as a potential source of bioactive and functional foods

Tropical fruits are defined as fruits that are grown in hot and humid regions within the Tropic of Cancer and Tropic of Capricorn, covering most of the tropical and subtropical areas of Asia, Africa, Central America, South America, the Caribbean and Oceania. Depending on the cultivation area covered, economic value and popularity these tropical fruits are divided into major and minor tropical fruits. There is an annual increment of 3.8% in terms of commercialization of the tropical fruits. In total 26 minor tropical fruits (Kiwifruit, Lutqua, Carambola, Tree Tomato, Elephant apple, Rambutan, Bay berry, Mangosteen, Bhawa, Loquat, Silver berry, Durian, Persimon, Longan, Passion fruit, Water apple, Pulasan, Indian gooseberry, Guava, Lychee, Annona, Pitaya, Sapodilla, Pepino, Jaboticaba, Jackfruit) have been covered in this work. The nutritional composition, phytochemical composition, health benefits, traditional use of these minor tropical fruits and their role in food fortification have been portrayed.

Effects of GGsTop® on Collagen and Glutathione in the Oral Mucosa Using a Rat Model of 5-Fluorouracil-Induced Oral Mucositis

BACKGROUND/AIM

To evaluate the usefulness of GGsTop^® for oral mucositis, a quantitative study focusing on oral mucosal tissues is necessary. In this study, we aimed to quantify collagen and glutathione using a rat model of 5-fluorouracil-induced oral mucositis.

MATERIALS AND METHODS

Changes in ulcer area and erythrocyte count were measured to confirm the usefulness of GGsTop^® for oral mucositis. The effect of GGsTop on collagen was evaluated by observing oral mucosal tissue sections and measuring the collagen concentration in the tissues. The total glutathione concentration and the oxidized glutathione concentration were measured, and the concentration of the reduced form was calculated.

RESULTS

GGsTop^® shortened the treatment period for oral mucositis without affecting the white blood cell count. In addition, GGsTop^® promoted collagen production and alleviated oxidative stress conditions.

CONCLUSION

GGsTop affects collagen and glutathione in the treatment of oral mucositis.

Biological Activities of Extracts from Loquat (Eriobotrya japonica Lindl.): A Review

Loquat (Eriobotrya japonica Lindl.) is a subtropical fruit tree with high medicinal value native to China. Different organs of loquat have been used historically as folk medicines and this has been recorded in Chinese history for thousands of years. Research shows that loquat extracts contain many antioxidants, and different extracts exhibit bioactivity capable of counteracting inflammation, diabetes, cancer, bacterial infection, aging, pain, allergy and other health issues. Bioactive compounds such as phenolics and terpenoids have been isolated and characterized to provide a better understanding of the chemical mechanisms underlying the biological activities of loquat extracts. As the identification of compounds progresses, studies investigating the in vivo metabolism, bioavailability, and structure–activity relationships, as well as potential toxicity of loquat extracts in animal or cell models are receiving more attention. In addition, genetic studies and breeding of loquat germplasms for high contents of health-benefiting compounds may provide new insight for the loquat industry and research. This review is focused on the main medicinal properties reported and the possible pharmaceutically active compounds identified in different loquat extracts.

Phenolic composition from different loquat (Eriobotrya japonica Lindl.) cultivars grown in China and their antioxidant properties

China is one of the most important centers of diversity for Eriobotrya japonica Lindl. in the world. In this study, seven loquat cultivars grown in China were evaluated for their phenolic compounds and antioxidant activity. Eleven phenolic compounds, i.e., 3-p-coumaroylquinincacid (3-p-CoQA), 5-caffeoylquinic acid (5-CQA), 4-caffeoylquinic acid (4-CQA), 3-caffeoylquinic acid (3-CQA), 5-feruloylquinic acid (5-FQA), quercetin-3-O-galactoside (Q-3-Gal), quercetin-3-O-glucoside (Q-3-Glu), quercetin-3-O-rhamnoside (Q-3-Rha), kaempferol-3-O-galactoside (K-3-Gal), kaempferol-3-O-rhamnoside (K-3-Rha), and kaempferol-3-O-glucoside (K-3-Glu) were identified and quantified in the peel and pulp of the cultivars tested. 3-CQA and 5-CQA were the predominant components in both fruit parts. 2,2-Diphenyl-1-picrylhydrazyl radicals (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate (ABTS), and ferric reducing antioxidant power (FRAP) assays were used for the antioxidant evaluation. Results showed that peel extracts had higher antioxidant activities than their pulp counterparts in all the cultivars tested, which was correlated with their higher total phenolic contents. The antioxidant potency composite (APC) index showed obvious variations ranging from 64.15 to 100 in the peel and from 59.49 to 97.95 in the pulp of different cultivars, where "Dahongpao" (DHP) and "Luoyangqing" (LYQ) had the highest APC index in the peel and pulp, respectively. Overall, loquat cultivars rich in hydroxycinnamic acids (HCAs) such as 3-p-CoQA, 5-CQA, 4-CQA, 3-CQA and 5-FQA showed relatively higher antioxidant activities, and may be excellent sources of phytochemicals and natural antioxidants.

Newly Developed Synbiotics and the Chemotherapy-Damaged Gut

Mucositis is a common side-effect of cancer chemotherapy and radiotherapy. Features of mucositis include erythema, ulceration, and inflammation of the gastrointestinal tract accompanied by clinical symptoms of abdominal pain and digestive disturbances. New treatment strategies are required. Experimental evidence is accumulating showing therapeutic promise for new nutraceutical agents including probiotic bacteria, probiotic-derived factors, prebiotics, and plant extracts. However, the targeted development of new combinations of these agents (synbiotics) to combat mucositis remains largely unexplored. The current review addresses the potential for these nutraceutical agents to reduce the severity of chemotherapy-damaged mucositis by strategically aligning their underlying mechanism of action with features of mucositis pathogenesis. The potential for certain plant extracts to act as prebiotics, in combination with probiotics or their derived factors, is further investigated. These unique synbiotic formulations could form the basis of a new naturally sourced adjunctive approach to cancer chemotherapy.

Chan-Yu-Bao-Yuan-Tang, the water extract of a chinese medicine prescription, induces s-phase arrest and mitochondria-mediated apoptosis in human lung adenocarcinoma cells

Previous clinical studies have shown good efficacy of the traditional Chinese medicinal herbal water extract Chan-Yu-Bao-Yuan-Tang (CYBYT) in lung cancer patients. In this study, CYBYT's effects on proliferation and apoptosis of human lung adenocarcinoma cell line SPC-A-1 cultured in vitro were explored. An XTT assay, cell cycle analysis, Annexin V-FITC staining and Western blot were applied to identify the viability of cells, cell cycle arrest, stages of apoptosis, and signaling proteins, respectively. The results showed that CYBYT inhibited the growth of SPC-A-1 cells by reducing the cells in G0/G1 phase but increasing them in S phase in a concentration-dependent manner, and inducing apoptosis, whereas it had no significant inhibitory effects on the normal human IMR-90 fibroblasts. Furthermore, early and total induction of apoptosis was positively correlated with the concentration of CYBYT in SPC-A-1 cells, and the rate of total apoptosis was greater in the CYBYT 100 µg/mL and 50 µg/mL groups than that of the positive control 5-fluorouracil (5-Fu) group. Moreover, CYBYT upregulated bax, cleaved caspase-3 protein expression, downregulated bcl-2 protein expression, and released mitochondrial cytochrome c into the cytosol in a time- and concentration-dependent manner. Our findings indicated that CYBYT could significantly inhibit growth and induce apoptosis via the mitochondrial pathway in human lung adenocarcinoma cell line SPC-A-1.

Ameliorative effects of Eriobotrya japonica seed extract on cellular aging in cultured rat fibroblasts

To investigate the effects of Eriobotrya japonica seed extract (ESE) on cellular aging, intracellular calcium homeostasis in young and senescent cells was analyzed using a rat fibroblast culture as an in vitro model system and a calcium imaging technique. The application of bradykinin (BK) transiently elicited intracellular calcium ion (Ca(2+)) increased in most of the young fibroblasts, whereas these responses were scarcely observed or were significantly attenuated in senescent cells. However, the long-term treatment of senescent cells with ESE (for 7 days) dose-dependently increased the amplitude of BK-induced responses and the percentage of BK-responding cells. In particular, most senescent cells could respond to BK with long-term treatment with ESE (1.0% or 2.0%), an effect that reinstated the percentage of BK-responding cells to the same level as that in young cells. The effects of ESE on amplitude or percentage of responding cells were not observed in young cells. Moreover, the time to half decay, which was significantly longer in senescent cells than that in young cells, was shortened in senescent cells with long-term treatment with ESE. These results suggest that treatment with an adequate concentration of ESE renders BK-induced Ca(2+) dynamics in senescent cells similar to those in young cells. Therefore, ESE can retard and/or protect against cellular aging and may be useful for elucidating the antiaging processes.

Immunomodulatory effect of Eriobotrya japonica seed extract on allergic dermatitis rats

We examined the immunomodulatory effect of Eriobotrya japonica seed extract (ESE) on rat allergic dermatitis elicited by repeated dinitrofluorobenzene (DNFB) application on the ear. Oral administration of ESE significantly inhibited development of allergic dermatitis based on lower ear thickness and serum immunoglobulin E (IgE) levels. Th1 cytokine interferon-gamma (IFN-gamma) and interleukin-2 (IL-2), Th2 cytokine interleukin-4 (IL-4) and interleukin-10 (IL-10) in the lesional skin were determined. Oral administration of ESE significantly decreased IL-4 while significantly increasing IL-10 in lesional skin, and the lower levels of IFN-gamma and IL-2 were reversed by oral administration of ESE. The infiltration of eosinophils in the lesional skin was decreased by oral administration of ESE. These results suggested that ESE exerts anti-allergic actions by improving the balance of Th1/Th2 in allergic dermatitis.

Eriobotrya japonica seed extract and deep sea water protect against indomethacin-induced gastric mucosal injury in rats

We have previously reported that Eriobotrya japonica seed extract (ESE) is effective for the treatment of various gastric mucosal injuries. For the pharmaceutical preparation of ESE, we are evaluating deep sea water (DSW), which contains trace elements and has a homeostasis-enhancing effect, as the solvent. In this study, we prepared DSW containing ESE (ESE + DSW) and evaluated its usefulness for the prevention of gastric mucosal injuries using non-steroidal anti-inflammatory drug-induced acute gastric mucosal injury models in male Wistar/ST rats. Gastric mucosal injury models were prepared by administering indomethacin at 30 mg/kg orally to the rats after a 24-h fast. ESE was prepared by a routine procedure and administered at the same concentration as in the administration to humans. The rats were divided into the following 6 groups: ESE, DSW, ESE + DSW, tap water (control), rebamipide (positive control), or untreated. Gastric mucosal injuries were evaluated by measuring the injury area, lipid peroxide (LPO) level, antioxidative enzyme level, and volume of mucus. The injury area and LPO levels in plasma and gastric tissue were significantly reduced in the ESE and ESE + DSW groups compared with the control and DSW group. The plasma and gastric tissue antioxidative enzyme levels were significantly higher in the ESE and ESE + DSW groups than in the control group. These results suggest that DSW, when combined with ESE, inhibits antioxidative enzymes, and enhances the gastric mucosal protecting effect of ESE.

Effects of Eriobotrya japonica seed extract on oxidative stress in rats with non-alcoholic steatohepatitis

Objectives

Non-alcoholic steatohepatitis is associated with the deposition of lipid droplets in the liver, and is characterised histologically by the infiltration of inflammatory cells, hepatocellular degeneration and liver fibrosis. Oxidative stress may play an important role in the onset and deterioration of non-alcoholic steatohepatitis. We previously reported that an Eriobotrya japonica seed extract, extracted in 70% ethanol, exhibited antioxidant actions in vitro and in vivo. In this study, we examined the effect of this extract in a rat model of non-alcoholic steatohepatitis.

Methods

The seed extract was given in the drinking water to fats being fed a methionine-choline-deficient diet for 15 weeks.

Key findings

Increases in alanine aminotransferase and aspartate aminotransferase levels were significantly inhibited in rats fed the seed extract compared with the group on the diet alone. Formation of fatty droplets in the liver was also inhibited. Antioxidant enzyme activity in liver tissue was higher than in the diet-only group and lipid peroxidation was reduced compared with rats that also received the extract. Expression of 8-hydroxy-2′-deoxyguanosine and 4-hydroxy-2-nonenal was lower in the rats given the seed extract than in the diet-only group. In the former, liver tissue levels of transforming growth factor-β and collagen were also decreased.

Conclusions

Thus, the E. japonica seed extract inhibited fatty liver, inflammation and fibrosis, suggesting its usefulness in the treatment of non-alcoholic steatohepatitis.