Beneficial effect of Citrus limon peel aqueous methanol extract on experimentally induced urolithic rats

Himalayan Citrus jambhiri juice reduced renal crystallization in nephrolithiasis by possible inhibition of glycolate oxidase and matrix metalloproteinases

ETHNOPHARMACOLOGICAL RELEVANCE

Citrus fruits are a very rich source of electrolytes and citric acid. They have been used traditionally for treating urinary ailments and renal stones. Citrus jambhiri is indigenously used as a diuretic.

AIM OF THE STUDY

Present study aimed at establishing the antiurolithiatic potential of the juice of Citrus jambhiri fruits along with the elucidation of the mechanism involved in the urolithiasis disease defying activity.

METHODS

The antiurolithiatic activity was established by means of nucleation, growth and aggregation assay in the in vitro settings and by means of ethylene glycol mediated calcium oxalate urolithiasis in the male Wistar rats. Docking studies were performed in an attempt to determine the mechanism of the antiurolithiatic action.

RESULTS

Present study revealed the role of C. jambhiri fruit juice in reducing nucleation, growth and aggregation of calcium oxalate crystals by possible reduction in the urinary supersaturation relative to calcium oxalate and raising the zeta potential of the calcium oxalate crystals. C. jambhiri fruit juice treatment in experimental rats produced significant amelioration of hypercalciuria, hyperoxaluria, hyperphosphaturia, hyperproteinuria, hyperuricosuria, hypocitraturia and hypomagnesiuria and ion activity product of calcium oxalate. It exhibited nephroprotection against calcium oxalate crystals induced renal tubular dilation and renal tissue deterioration. Docking studies further revealed high binding potential of the phytoconstituents of C. jambhiri viz. narirutin, neohesperidin, hesperidin, rutin and citric acid with glycolate oxidase and matrix metalloproteinase-9.

CONCLUSION

C. jambhiri fruit juice possesses excellent antiurolithiatic activity. The study reveals antiurolithiatic mechanism that involves restoration of equilibrium between the promoters and inhibitors of stone formation; and inhibition of matrix metalloproteinases and glycolate oxidase.

Synthesize and characterization of CaOx crystals against various citrus waste peel extracts: an in vitro study

Citrus fruits have been consumed by world's population for several centuries. Since it's an edible source possesses various uses in treating many diseases. Among various diseases urolithiasis is one of the major issues globally demands in painless surgical treatment. Calcium Oxalate (CaOx) is found to be the most prevailing constituent of renal calculus in humans which tends to be the categories of the urolithiasis. Citric acid is commonly used in treating to dissolve them in medications. Citrate compound has the ability to bind with calcium stones to relieve oxalates in urine. The objective of the present study is to assess the efficacy of citrate compounds from waste citrate peels describing the inhibition of calcium oxalate (CaOx) crystals. Multistep extraction procedures were performed for the selected citrus peels of Citrus limon, Citrus limetta and Citrus sinensis using different solvents (hexane, aqueous and ethanol) and were tested for its inhibitory actions with different parameters against the synthesized CaOx crystals. The synthetic CaOx crystals were characterized by Microscopy, FTIR, SEM, XRD, and TGA. The structural change in the crystal was observed for inhibition at various stages like nucleation, growth and aggregation when treated with the ethanol extracts of citrus peels. Thus the present investigation concludes that the ethanol extracts of C. sinensis peels highly inhibits at a concentration of 1000 (µg/mL) in 60 min when compared to other solvents. This research would give additional information in preparation of drugs against CaOx urolithiasis in future pharmaceutical development processes.

Citrus processing by-products: an overlooked repository of bioactive compounds

Citrus fruits contain plethora of bioactive compounds stored in edible as well as inedible part. Since, citrus fruits are processed mainly for juice, the residues are disposed in wastelands, hence, plenty of nutritional potential goes in vain. But if utilized wisely, the bioactive phytochemicals in citrus by-products have the ability to revolutionize the functional food industry. In the present review, the composition of citrus by-products in terms of bioactive components and their health benefits has been reviewed. Various extraction techniques used to extract these bioactives has been discussed and a brief overview of purification and utilization of the extracted compounds, in food and nutraceutical industry is also presented. Bioactives in citrus by-products are higher than the peeled fruit, which can be extracted, isolated and incorporated into food systems for development of health foods. From the studies reviewed, it was observed that research reported on utilization of citrus by-products is limited to mainly research labs; proper scale-up process and its adequate research commercialization is the need of hour to transform these bioactives into economical functional ingredients.

Ferrotoxicity and its amelioration by endogenous vitamin D in experimental acute kidney injury

This work provides in-depth insights on catalytic iron-induced cytotoxicity and the resultant triggering of endogenous vitamin D synthesis in experimental acute kidney injury. Our results reveal significantly elevated levels of catalytic iron culminating in oxidant-mediated renal injury and a concomitant increase in 1,25-dihdyroxyvitamin D3 levels. Also, changes in other iron-related proteins including transferrin, ferritin, and hepcidin were observed both in the serum as well as in their mRNA expression. We consider all these findings vital since no connection between catalytic iron and vitamin D has been established so far. Furthermore, we believe that this work provides new and interesting results, with catalytic iron emerging as an important target in ameliorating renal cellular injury, possibly by timely administration of vitamin D. It also needs to be seen if these observations made in rats could be translated to humans by means of robust clinical trials.

Ferrotoxicity and its amelioration by endogenous vitamin D in experimental acute kidney injury

Acute kidney injury causes significant morbidity and mortality. This experimental animal study investigated the simultaneous impact of iron and vitamin D on acute kidney injury induced by iohexol, an iodinated, non-ionic monomeric radiocontrast agent in Wistar rats. Out of 36 healthy male Wistar rats, saline was injected into six control rats (group 1) and iohexol into the remaining 30 experimental rats (groups 2 to 6 comprising six rats each). Biochemical, renal histological changes, and gene expression of iron-regulating proteins and 1 α-hydroxylase were analyzed. Urinary neutrophil gelatinase-associated lipocalin (NGAL), serum creatinine, urine protein, serum and urine catalytic iron, 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and tissue lipid peroxidation were assayed. Rats injected with iohexol showed elevated urinary NGAL (11.94 ± 6.79 ng/mL), serum creatinine (2.92 ± 0.91 mg/dL), and urinary protein levels (11.03 ± 9.68 mg/mg creatinine) together with histological evidence of tubular injury and iron accumulation. Gene expression of iron-regulating proteins and 1 α-hydroxylase was altered. Serum and urine catalytic iron levels were elevated (0.57 ± 0.17; 48.95 ± 29.13 µmol/L) compared to controls (0.49 ± 0.04; 20.7 ± 2.62 µmol/L, P < 0.001). Urine catalytic iron positively correlated with tissue peroxidation (r = 0.469, CI 0.122 to 0.667, P = 0.004) and urinary NGAL (r = 0.788, CI 0.620 to 0.887, P < 0.001). 25-hydroxyvitamin D3 (61.58 ± 9.60 ng/mL) and 1,25-dihydroxyvitamin D3 (50.44 ± 19.76 pg/mL) levels increased simultaneously. In a multivariate linear regression analysis, serum iron, urine catalytic iron, and tissue lipid peroxidation independently and positively predicted urinary NGAL, an acute kidney injury biomarker. This study highlights the nephrotoxic potential of catalytic iron besides demonstrating a concurrent induction of vitamin D endogenously for possible renoprotection in acute kidney injury.

Impact statement

This work provides in-depth insights on catalytic iron-induced cytotoxicity and the resultant triggering of endogenous vitamin D synthesis in experimental acute kidney injury. Our results reveal significantly elevated levels of catalytic iron culminating in oxidant-mediated renal injury and a concomitant increase in 1,25-dihdyroxyvitamin D3 levels. Also, changes in other iron-related proteins including transferrin, ferritin, and hepcidin were observed both in the serum as well as in their mRNA expression. We consider all these findings vital since no connection between catalytic iron and vitamin D has been established so far. Furthermore, we believe that this work provides new and interesting results, with catalytic iron emerging as an important target in ameliorating renal cellular injury, possibly by timely administration of vitamin D. It also needs to be seen if these observations made in rats could be translated to humans by means of robust clinical trials.

Antiurolithiatic activity of Boldoa purpurascens aqueous extract: An in vitro and in vivo study

ETHNOPHARMACOLOGICAL RELEVANCE

Boldoa purpurascens Cav. (Nyctaginaceae) is a plant species used in traditional medicine in Cuba as antiurolithiatic.

AIM OF THE STUDY

The aim of the present investigation was to evaluate the in vitro and in vivo antiurolothiatic activity of an aqueous extract from the leaves of Boldoa purpurascens.

MATERIALS AND METHODS

The aqueous extract from leaves of Boldoa purpurascens was evaluated for antiurolithiatic activity in vitro and in vivo. In vitro crystallization of calcium oxalate (CaOx) was assessed using a nucleation, aggregation and growth assay. The effects of the extract and of Cystone®, used as a positive control, on the slope of nucleation and aggregation, as well as on the growth of CaOx crystals, were evaluated spectrophotometrically. The densities of the formed crystals were compared microscopically. In vivo activity was evaluated in an urolithiasis model in rats, in which kidney stones are induced by ethylene glycol (0.75%) and ammonium chloride (2%) in drinking water for 10 days. Three different experimental doses (100, 200 and 400 mg/kg, p.o.) of the extract and Cystone® were administered for 10 days. After 10 days, various biochemical parameters were measured in urine and serum, and histopathological analysis of the kidneys was carried out.

RESULTS

The aqueous extract of Boldoa purpurascens inhibited the slope of nucleation and aggregation of CaOx crystallization, and decreased the crystal density. It also inhibited the growth and caused the dissolution of CaOx crystals. Cystone® exhibited similar effects. At a dose of 400 mg/kg the extract reduced the concentration of uric acid in urine, as well as the serum concentration of uric acid and creatinine. Histopathologic analysis of the kidneys of the same treatment group revealed reduced tissue damage; the results were almost similar to the untreated healthy control group.

CONCLUSION

This study indicates that an aqueous leaf extract of Boldoa purpurascens may be effective in the prevention of urinary stone formation, and substantiates the traditional claim.

Antinociceptive Effect of the Citrus Flavonoid Eriocitrinon Postoperative Pain Conditions

BACKGROUND

Postoperative pain remains a major clinical problem as there are limited analgesic strategies that have been proven to be effective in preventing and relieving this type of pain. Natural products, including flavonoids, have distinct pharmacological properties and play an important role in the discovery of analgesic drugs.

MATERIALS AND METHODS

In this study, the flavonoid eriocitrin (eriodictyol 7-O-rutinoside), which is the main flavonoid in lemon fruit (Citrus limon), was mechanistically investigated for its prospective antinociceptive effect in a mouse model of postoperative pain. The antinociceptive property was evaluated by utilizing both tonic (acetic acid-induced writhing behavior) and phasic (hot-plate) nociception modalities. The hindpaw incisional surgery was performed and hyperalgesia was assessed using von Frey filaments.

RESULTS

The tested doses of eriocitrin significantly attenuated (P<0.01, P<0.001) the chemically-induced tonic visceral nociception (5, 10, 15, and 30 mg/kg) and acute phasic thermal nociception (10, 15, and 30 mg/kg). A significant dose-dependent reduction in the incisional nociceptive hyperalgesia was exhibited by eriocitrin, with a marked antinociception observed at doses of 15 mg/kg (P<0.05 during 30-60 minutes) and 30 mg/kg (P<0.05, P<0.01 during 30-120 minutes).

CONCLUSION

The antinociceptive effect of eriocitrin (30 mg/kg) was strongly blocked by the antagonists of the opioid receptor, naltrexone, and GABAA receptor, bicuculline, thereby suggesting the involvement of opioidergic and GABAergic mechanisms in the nociception, reducing proclivity of eriocitrin during transmission of incisional nociception. These results concluded that eriocitrin has a potent antinociceptive effect in postoperative pain conditions, probably mediated through opioid and GABAA receptors.

Lemon yellow #15 a new highly stable, water soluble food colorant from the peel of Citrus limon

To provide stable and low-cost naturally derived yellow pigments, a variety of food byproducts were evaluated and the constituents of lemon peel have emerged yielding a highly promising natural product with applications as a food dye. Here we report a new, highly stable and water soluble food dye called yellow #15 from the ethanol extract of the zest of Citrus limon. The structure of lemon yellow #15 was carefully assigned on the basis of spectroscopic data, including 1D and 2D NMR spectroscopy, and the absolute configuration was established by comparison of the experimental CD with calculated electronic circular dichroism (ECD) spectral data. CIELAB values and Delta CIELAB were measured and revealed this new water-soluble pigment has superior light stability relative to other natural products used as food dyes.

Extraction, characterization and biological activity of citrus flavonoids

Citrus is one of the largest and most popular fruit crops commercially grown across the globe. It is not only important in terms of economy but is also popular for its nutritional benefits to human and farm animals. Citrus is available in several varieties, all with attractive colors. It is consumed either fresh or in processed form. After processing, approximately 50% of the fruit remains unconsumed and discarded as waste. The latter includes fruit pith residue, peels and seeds. Direct disposal of these wastes to the environment causes serious problems as these contain bioactive compounds. Release of these bioactive compounds to the open landfills cause bad odor and spread of diseases, and disposal to water bodies or seepage to the underground water table deteriorates water quality and harms aquatic life. In this regard, a number of research are being focused on the development of better reuse methods to obtain value-added phytochemicals as well as for safe disposal. The important phytochemicals obtained from citrus include essential oils, flavonoids, citric acid, pectin, etc., which have now become popular topics in industrial research, food and synthetic chemistry. The present article reviews recent advances in exploring the effects of flavonoids obtained from citrus wastes, the extraction procedure and their usage in view of various health benefits.

Dietary dehydrated lemon peel improves the immune but not the antioxidant status of gilthead seabream (Sparus aurata L.)

Lemon (Citrus limon) is the third most important species of citrus in the world, while Spain is the major producer in Europe. Numerous beneficial effects of lemon are known, which explains their use in traditional medicine. The paper describes the effect of dietary dehydrated lemon peel (a sub-product of the lemon industry) on the growth, immune and antioxidant status of gilthead seabream (Sparus aurata L.) over a period of 30 days. Fish fed diets enriched with dehydrated lemon peel (1.5% and 3%) for 15 days showed improved growth and both humoral (seric immunoglobulin M) and cellular (peroxidase activity and phagocytic ability of head kidney leucocytes) immunity, as well as the expression of some immune-related genes (nkefa, il1β, igth and csfr1). However, decreases growth promotion was observed after thirty days of trial. Neither the anti-oxidant enzymes activity nor the expression of several anti-oxidants and anti-stress genes in liver was improved by the diet. The possible inclusion of dehydrated lemon peel in fish diets for its immunostimulant effects is discussed.