Vitamin P—the forgotten vitamin that seals blood vessels?

Aim of the study: Natural products, with their remarkable chemical diversity, have been widely studied for their potential to fight tumors. Quercetin (QU) and quercetin glycoside (rutin), both polyphenolic flavonoids, stand out among natural products in various studies. Rutin (RU) and its aglycone (QU) have various biological properties, including antioxidant, anti-inflammatory, and anticarcinogenic activities.

Results: There was conclusive evidence of an association between anticancer activity and treatment with RU or QU. Furthermore, studies indicated that nanoformulations of RU and QU have greater anticancer activity than either agent alone, leading to greater efficiency in cancer treatment. The results of this systematic review demonstrate the anticancer activity of RU and QU nanoformulations and their molecular mechanisms in preclinical studies. This paper also aims to support further research by addressing current limitations and challenges and proposing additional studies to realize the full potential of RU- and QU-based formulations for cancer treatment.

Aim of the study: Rutin (vitamin P or rutoside) is a citrus flavonoid glycoside that has shown beneficial effects on different organs in various conditions, including inflammation and pain. Most of rutin’s therapeutic benefits are attributed to its antioxidant and anti-inflammatory properties.

Results: This review discusses studies that investigated the pain-relieving activity of rutin and summarizes the reported mechanisms of action. Rutin’s pain-relieving effect has been studied in mice or rats with streptozotocin-induced diabetes, chronic constriction injury, and oxaliplatin-, formalin-, acetic acid-, or glutamate-induced pain responses. Based on the literature, rutin’s analgesic effects result from strengthening antioxidant defenses, lowering levels of inflammatory cytokines (e.g., tumor necrosis factor alpha (TNF-α) and interleukin-1β), suppressing the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), and modulating MAPK, NF-κB, and Nrf-2/HO-1 signaling. Preclinical findings on rutin’s pain-relieving activity are promising; however, its safety profile needs to be investigated more thoroughly, and clinical trials should be conducted to assess its analgesic effects in humans.

Aim of the study: Several lines of evidence suggest that flavonoids from vegetables and medicinal plants have beneficial effects on diabetes by improving blood glucose control, lipid profile, and antioxidant status. Rutin is a flavonoid found in many plants and has a wide range of biological activities, including anti-inflammatory, antioxidant, neuroprotective, kidney-protective, and liver-protective effects.

Results: Rutin also decreases the formation of sorbitol, reactive oxygen species, precursors of advanced glycation end products, and inflammatory cytokines. These effects are thought to account for rutin’s protective effects against kidney disease, neuropathy, liver damage, and cardiovascular disorders caused by high blood sugar and abnormal blood lipid levels. Taken together, current experimental studies support rutin’s potential to prevent or treat conditions associated with diabetes. Well-designed clinical studies are needed to evaluate the benefits and limitations of rutin in diabetes management.

Aim of the study: Revascularization therapy is the mainstay of treatment for myocardial infarction in both non-diabetic and diabetic patients. We aimed to evaluate the heart-protective effects of quercetin and rutin in myocardial infarction caused by ischemia and reperfusion in both normal and diabetic rats.

Results: The results showed that diabetic hearts subjected to ischemia and reperfusion in vivo had a larger infarct size, increased lipid peroxidation, a partial depletion of antioxidant enzymes, and a sharp drop in heart rate compared with normal rats subjected to ischemia and reperfusion. Furthermore, quercetin and rutin similarly and significantly limited infarct size in both normal and diabetic animals. However, rutin provided complete heart protection by limiting infarct size at a dose of 10 mg/kg. Both flavonoids partially but significantly reduced lipid peroxidation. Treatment also moderately improved heart rate in both normal and diabetic rats. Our data suggest that quercetin and rutin may protect against ischemia-reperfusion injury in normal and diabetic rats, partly by reducing oxidative stress and moderately increasing antioxidant reserves.

Aim of the study: Platelets play an essential role in vascular inflammation and thrombosis. Flavonoids are natural compounds used clinically to manage vascular disorders by preventing capillary permeability, acting as phlebotonics, and improving blood rheology, although their mechanism of action is still partly unknown.

Results: The effects of quercetin, rutin, diosmetin, and diosmin on platelet activation were investigated using blood from healthy, untreated volunteers. The different platelet activation states and occupancy of the GPIIb/IIIa receptor were measured by flow cytometry, using calcium ionophore as a pro-aggregating agent to trigger platelet activation and aggregation. The flavonoids studied showed notable antiplatelet activity by blocking GPIIb/IIIa receptors, suppressing platelet activation, and counteracting the pro-aggregating effect of calcium ionophore. Therefore, any of the active ingredients examined could be beneficial in preventing cardiovascular disease. This article also helps clarify a new mechanism of action for these drugs.

Aim of the study: The non-specific binding of aluminum to various substances in the body can result in toxicity. The accumulation of large amounts of aluminum can disrupt metal balance and interfere with the synthesis and release of neurotransmitters.

Results: Rats in six intervention groups were given 100 or 200 mg/kg body weight/day of three different flavonoids for four weeks after being exposed to 281.40 mg/kg body weight/day of AlCl3·6H2O for four weeks. Rats in the AlCl3-toxicity and control groups were given the vehicle after the AlCl3 exposure period. The results showed that rutin, puerarin, and silymarin could increase magnesium, iron, and zinc concentrations in the rats’ brains. Moreover, taking these three flavonoids regulated the balance of amino acid neurotransmitters and restored monoamine neurotransmitter concentrations to normal levels. Taken together, our data suggest that rutin, puerarin, and silymarin could lessen AlCl3-induced brain toxicity in rats by correcting imbalances in metal elements and neurotransmitters in the brain.

Aim of the study: Ischemia-reperfusion injury (IRI) is a common pathological process in clinical settings. Its complex causes involve interactions between oxidative stress, inflammation, mitochondrial dysfunction, and various cell death pathways. IRI is essentially a complication of reperfusion therapies aimed at restoring blood flow after ischemia.

Results: Rutin, a low-molecular-weight flavonoid glycoside found widely in vegetables, fruits, and herbal medicines, shows promising therapeutic potential because of its wide-ranging biological activities, including antioxidant, anti-inflammatory, and cell-protective effects against cell death. This review systematically explains the molecular mechanisms behind rutin’s protective effects against IRI and summarizes evidence from preclinical studies on its different modes of action. However, the clinical use of rutin is currently limited by its relatively low bioavailability. Future research should prioritize developing innovative pharmaceutical formulations to improve its bioavailability and fully realize its potential for clinical use.

Aim of the study: Diazinon is widely used as an insecticide or pesticide in agriculture. It can enter the human body through inhalation, swallowing, and skin exposure, causing poisoning.

Results: Because it has stronger antioxidant activity and higher bioavailability than rutin, quercetin effectively restored antioxidant enzyme activity (SOD, CAT, and GSH) and AChE levels in the livers of diazinon-poisoned rats to near-control values. This study suggests that quercetin is more effective than rutin in reducing diazinon-induced oxidative stress and liver toxicity by scavenging ROS, inhibiting lipid peroxidation, and restoring redox balance. Accordingly, quercetin may be considered a potential treatment for diazinon poisoning. However, more animal, cellular, and clinical studies are needed before it can be prescribed and finally approved for use in humans.