Chemical constituents and antioxidant activity of essential oil and organic extract from the peel and kernel parts of Citrus japonica Thunb. (kumquat) from Iran

Glucosidase inhibition and compound identification of stingless bee honey and preserved fruits of Citrus japonica

Food preservation has many benefits, such as increasing shelf life, retaining nutritional values and biological activities. In the current study, total phenolic content (TCP), antioxidant and anti-glucosidase activities, and kinetic of glucose inhibition of stingless bee honey, honey mixed with fruits, and extracts of Citrus japonica were evaluated by measuring color of a reaction using a spectrophotometer. The result showed that high TPC was found in ethanol extract of C. japonica leaves and fruits (26.79 ± 6.94 and 12.79 ± 0.87 mg of gallic acid per g extract), while stingless bee honey revealed the highest antioxidant activity (1/EC50 = 0.2921) and honey mixed with fruits revealed the strongest anti-glucosidase activity (1/EC50 = 1.8181), significantly (P-value <0.05). Kinetic of glucosidase inhibition of honey were found as uncompetitive and mixed competitive inhibition, while the honey mixed with fruits showed mixed competitive inhibition. The FTIR and GC-MS analysis demonstrated the presence of several bioactive compounds. Very strong positive relationship between total phenolic content with GC-MS data was found (r = 0.926, P-value < 0.05). This knowledge confirmed that stingless bee honey and honey mixed with fruits had greater anti-diabatic potential in comparison with the extracts of C. japonica leaves and fruits.

Eating with peel or not: Investigation of the peel consumption situation and its nutrition, risk analysis, and dietary advice in China

Nutritious, balanced, tasty and easy to eat, fruit is an indispensable health food for consumers. With consumers' increasing respect for the concept of health, green and nutrition, the peel, which has higher nutritional value compared to the pulp, is gradually being emphasized in the consumption process. The suitability of fruit peels for consumption is influenced by various factors, such as the amount of pesticide residues, nutrient content, ease of peeling, and fruit texture, but there is a lack of relevant studies to guide consumers' scientific intake of fruit peels. This review first investigated chineses consumers consumption of common fruits with peels, especially eight fruits that are controversial in terms of whether to consume them with peels, and the results showed that whether people consume peels depends mainly on their nutritional value and pesticide residues. Based on this, the paper discusses the common methods of pesticide detection and removal from fruit peels, as well as the nutrients contained in different fruit peels and their physiological activities, if the peels usually have stronger antioxidant, anti-inflammatory and anti-tumor activities than the pulp. Finally, reasonable dietary recommendations are made on whether fruits should be consumed with their peels, with a view to guiding chineses consumers towards scientific consumption and provide theoretical basis for relevant research in other countries.

Chemical composition, antidiabetic, anti-inflammatory, antioxidant and toxicityactivities, of the essential oil of <em>Fortunella margarita</em> peels

The purpose of this study was to identify the principal components of the essential oil extracted from Fortunella margarita peels via hydrodistillation and to evaluate in vitro its anti-diabetic, anti-inflammatory, antioxidant, and toxicity properties. Among the detected compounds were limonene, D-germacrene, β-myrcene, and α-pinene. Method of inhibiting the denaturation of Bovine Serum Albumin (BSA) was utilized to assess the anti-inflammatory properties of Fortunella margarita. At a concentration of 400g/mL, a high anti-inflammatory effect was observed. The percentage of BSA protection against heat increased with increasing concentration. Also, the evaluation of antidiabetic activity by glucose uptake by yeast cells revealed that Fortunella margarita was more effective than the standard drug novoformine in the presence of 5 mM glucose. The antioxidant potential of the essential oil was evaluated using the DPPH free radical scavenging, reducing power and β-carotene/linoleic acid tests, where the essential oil had much lower antioxidant activity. A bioassay on the lethality of brine shrimp was conducted to determine the toxicity of the essential oil. The study reveals that the essential oil is a possible source of important bioactive compounds and that its constituents may exhibit synergistic effects. Our findings suggest that the essential oil from Fortunella margarita could be used in the future as a substitute for synthetic anti-diabetic, anti-inflammatory, and antioxidant agents with potential applications in the food and pharmaceutical industries.  

Kumquat fruit and leaves extracted with different solvents: phenolic content and antioxidant activity

Introduction. Kumquat is a good source of vitamin C, as well as phenolic and flavonoid substances. In this study, we used various solvents to obtain extracts from fresh and lyophilized dried fruits and leaves of kumquat plant, as well as six mutants, to compare their total phenolic and flavonoid contents and antioxidant activities. Study objects and methods. The total phenolic and flavonoid content was determined by the Folin-Ciocalteu method and the colorimetric method, respectively. The antioxidant capacities of the extracts were determined by commonly used antioxidant tests, such as the DPPH radical scavenging activity, reducing power, and metal chelating activity. Results and discussion. The total phenolic content of the extracts was in the range of 3705–86 329 mg GAE/g extract. The total amount of flavonoid substance ranged from 5556 to 632 222 mg QUE/g extract. The highest free radical scavenging activity was observed in the kumquat leaves. We also found that the activity of dried fruit was lower than that of fresh fruit. According to our results, the differences in the phenolic contents of the studied plants affected their antioxidant properties. We determined that the extracts with a high phenolic content showed high antioxidant activity. No significant difference was detected between the rootstock kumquat type and its mutants. Finally, we found no chelating activity in the extracts obtained from fresh and lyophilized dried fruits. Conclusion. Kumquat fruit and its leaves can be considered as functional foods due to phenolic compounds, which are able to neutralize free radicals.

Effects of ultrasound and microwave pretreatments on hydrodistillation extraction of essential oils from Kumquat peel

Main objectives of this work were to investigate the influences of ultrasound pretreatment (UP) and microwave pretreatment (MP) on extraction kinetics, chemical composition, and antioxidant activity of Kumquat peel essential oil (EO) obtained by hydrodistillation extraction (HDE). The effects of ultrasound power and processing time, and microwave power and processing time were evaluated. As compared with HDE individually, UP and MP decreased the extraction time, increased the yield and DPPH radical-scavenging activity but did not noticeably affect chemical composition of the EO. For UP and MP, the highest EO yield was obtained when the ultrasonic power and processing time, and microwave power and processing time were 210 W and 30 min, 300 W and 6 min, respectively. In comparison with MP, UP gave a higher yield and DPPH radical-scavenging activity of the EO. Overall, UP and MP are promising techniques for HDE of EO from kumquat peel.

Bioactives From Agri-Food Wastes: Present Insights and Future Challenges

Sustainable utilization of agri-food wastes and by-products for producing value-added products (for cosmetic, pharmaceutical or food industrial applications) provides an opportunity for earning additional income for the dependent industrial sector. Besides, effective valorisation of wastes/by-products can efficiently help in reducing environmental stress by decreasing unwarranted pollution. The major focus of this review is to provide comprehensive information on valorisation of agri-food wastes and by-products with focus laid on bioactive compounds and bioactivity. The review covers the bioactives identified from wastes and by-products of plants (fruits, exotic fruits, vegetables and seeds), animals (dairy and meat) and marine (fish, shellfish seaweeds) resources. Further, insights on the present status and future challenges of sustainably utilizing agri-food wastes/by-products for value addition will be highlighted.

Protective effect of Kumquat fruits and carrot seeds extracts against brain aging in rats

Introduction: Protection of brain against accelerated aging helps avoiding the occurrence of neurodegenerative diseases. So, the current work was conducted to evaluate the rescuing role of kumquat fruits crude ethanol extract, carrot seeds ethanol and petroleum ether extracts against the brain aging induced by D-galactose in rats. Methods: Forty male Sprague Dawley rats were divided equally into five groups. Group I was served as normal control, rats of group II were daily injected intraperitoneally (i.p.) with 150 mg/kg BW of D-galactose. Rats of group III, IV and V were daily injected i.p. with the same dose of D-galactose and administered orally with 250 mg/kg BW/day of kumquat fruits crude ethanol extract, carrot seeds ethanol extract and carrot seeds petroleum ether extract, respectively. After 6 weeks the rats were scarified, brain tissues were analyzed for malondialdehyde (MDA), catalase (CAT) as well as histological examination. Also, the plasma was analyzed for MDA, tumor necrosis factor-α (TNF-α), creatinine and urea levels, as well as CAT, butyrylcholinesterase (BChE), aspartate transaminase (AST) and alanine transaminase (ALT) activities. Results: From the results, it was elucidated that the tested extracts suppressed both the reduction in CAT and the elevation in MDA either in brain or plasma and the increase in plasma TNF-α, BChE as well as liver and kidney parameters. Conclusion: The tested extracts can be served as potent protective agents against the accelerated aging parameters which may be due to anti-oxidant and anti-inflammatory activities.

Biological Activities and Safety of Citrus spp. Essential Oils

Citrus fruits have been a commercially important crop for thousands of years. In addition, Citrus essential oils are valuable in the perfume, food, and beverage industries, and have also enjoyed use as aromatherapy and medicinal agents. This review summarizes the important biological activities and safety considerations of the essential oils of sweet orange (Citrus sinensis), bitter orange (Citrus aurantium), neroli (Citrus aurantium), orange petitgrain (Citrus aurantium), mandarin (Citrus reticulata), lemon (Citrus limon), lime (Citrus aurantifolia), grapefruit (Citrus × paradisi), bergamot (Citrus bergamia), Yuzu (Citrus junos), and kumquat (Citrus japonica).