Amplifying therapeutic potential through optimization of bioavailability of poorly soluble flavonols via albumin-based nanoparticles

OBJECTIVE

Flavonols have different pharmacological actions that render them highly promising therapeutic targets. However, their water solubility and bioavailability are low, which restricts their therapeutic potential. ABNPs, albumin-based nanoparticles, are potential nanocarriers that enhance flavonol solubility, stability, and targeted delivery. By utilizing ABNPs, in this work we provide a detailed overview of strategies employed to attain maximum bioavailability of poorly water-soluble flavonols. The review critically evaluates ABNP-mediated delivery's pharmacokinetic advantage, physicochemical properties, and formulation principles. We also highlight existing gaps in research, such as the need for stringent in vivo validity tests, standardized formulation procedures, and in-depth mechanistic understanding of flavonol-albumin interactions.

SIGNIFICANCE

Despite having potential therapeutic activities, the utilization of flavonoids in the form of medication is limited. Some recent studies have shown that flavonoids exhibit low solubility, low permeability and chemical instability, thereby limiting their bioavailability and therapeutic responses.

METHODS

To overcome these drawbacks, multiple novel drug delivery approaches have emerged in the pharmaceutical research.

RESULTS

These novel approaches seem to offer a viable foundation for improving the bioavailability of the flavonoids and positioning them as viable therapeutic options. Out of all the polymers implemented in enhancing the solubility and bioavailability of the flavonoids, albumin-based nanomaterials have been the most efficacious one.

CONCLUSION

Compared to all other polymeric nano-carriers, albumin nano-carriers offer a greater scale of drug entrapment and drug loading because of their capacity for surface modification, crosslinking, conjugation, coupling, and characteristics including biodegradability and biocompatibility.

Anticancer Activity and Molecular Mechanisms of Acetylated and Methylated Quercetin in Human Breast Cancer Cells

Quercetin, a flavonoid polyphenol found in many plants, has garnered significant attention due to its potential cancer chemoprevention. Our previous studies have shown that acetyl modification of the hydroxyl group of quercetin altered its antitumor effects in HepG2 cells. However, the antitumor effect in other cancer cells with different gene mutants remains unknown. In this study, we investigated the antitumor effect of quercetin and its methylated derivative 3,3',4',7-O-tetramethylquercetin (4Me-Q) and acetylated derivative 3,3',4',7-O-tetraacetylquercetin (4Ac-Q) on two human breast cancer cells, MCF-7 (wt-p53, caspase-3-ve) and MDA-MB-231 (mt-p53, caspase-3+ve). The results demonstrated that 4Ac-Q exhibited significant cell proliferation inhibition and apoptosis induction in both MCF-7 and MDA-MB-231 cells. Conversely, methylation of quercetin was found to lose the activity. The human apoptosis antibody array revealed that 4Ac-Q might induce apoptosis in MCF-7 cells via a p53-dependent pathway, while in MDA-MB-231 cells, it was induced via a caspase-3-dependent pathway. Furthermore, an evaluation using a superoxide inhibitor, MnTBAP, revealed 4Ac-Q-induced apoptosis in MCF-7 cells in a superoxide-independent manner. These findings provide valuable insights into the potential of acetylated quercetin as a new approach in cancer chemoprevention and offer new avenues for health product development.

Quercetin: Its Antioxidant Mechanism, Antibacterial Properties and Potential Application in Prevention and Control of Toxipathy

Quercetin, as a flavonol compound found in plants, has a variety of biological activities. It is widely present in nature and the human diet, with powerful oxidative properties and biological activities. In this review, the antioxidant mechanism and broad-spectrum antibacterial properties of quercetin are revealed; the intervention effects of quercetin on pesticide poisoning and the pathway of action are investigated; the toxic effects of main mycotoxins on the collection and the detoxification process of quercetin are summarized; whether it is able to reduce the toxicity of mycotoxins is proved; and the harmful effects of heavy metal poisoning on the collection, the prevention, and control of quercetin are evaluated. This review is expected to enrich the understanding of the properties of quercetin and promote its better application in clinical practice.

New insights for the use of quercetin analogs in cancer treatment

AIM

Quercetin (Q1) is a flavonoid widely present in plants and endowed with several pharmacological properties mostly due to its antioxidant potential. Q1 shows anticancer activity and could be useful in cancer prevention. On the other hand, Q1 is poorly soluble in water and unstable in physiological systems, and its bioavailability is very low.

METHODS

A small set of Q1 derivatives (Q2-Q9) has been synthesized following opportunely modified chemical procedures previously reported. Anticancer activity has been evaluated by MTT assay. Human Topoisomerases inhibition has been performed by direct enzymatic assays. Apoptosis has been evaluated by TUNEL assay. ROS production and scavenging activity have been determined by immunofluorescence.

RESULTS

The anticancer profile of a small library of Q1 analogues, in which the OH groups were all or partially replaced with hydrophobic functional groups, has been evaluated. Two of the studied compounds demonstrated an interesting cytotoxic profile in two breast cancer models showing the capability to inhibit human Topoisomerases.

CONCLUSION

The studied compounds represent suitable leads for the development of innovative anticancer drugs. [Formula: see text].

Research Progress in the Modification of Quercetin Leading to Anticancer Agents

The flavonoid quercetin (3,3′,4′,5,7-pentahydroxyflavone) is widely distributed in plants, foods, and beverages. This polyphenol compound exhibits varied biological actions such as antioxidant, radical-scavenging, anti-inflammatory, antibacterial, antiviral, gastroprotective, immune-modulator, and finds also application in the treatment of obesity, cardiovascular diseases and diabetes. Besides, quercetin can prevent neurological disorders and exerts protection against mitochondrial damages. Various in vitro studies have assessed the anticancer effects of quercetin, although there are no conclusive data regarding its mode of action. However, low bioavailability, poor aqueous solubility as well as rapid body clearance, fast metabolism and enzymatic degradation hamper the use of quercetin as therapeutic agent, so intense research efforts have been focused on the modification of the quercetin scaffold to obtain analogs with potentially improved properties for clinical applications. This review gives an overview of the developments in the synthesis and anticancer-related activities of quercetin derivatives reported from 2012 to 2016.

Aspirination of α-Aminoalcohol (Sarpogrelate M1)

Aspirination of α-aminoalcohol (sarpogrelate M1) has been performed under various general esterification conditions. In most cases, the desired aspirinate ester was obtained at a low yield with unexpected byproducts, the formation of which was mostly derived from the chemical properties of the tertiary α-amino group. After systematic analysis of those methods, the aspirinated sarpogrelate M1 was prepared using a two-step approach combining salicylate ester formation and acetylation.

Quercetin derivatives as novel antihypertensive agents: Synthesis and physiological characterization

The antihypertensive flavonol quercetin (Q1) is endowed with a cardioprotective effect against myocardial ischemic damage. Q1 inhibits angiotensin converting enzyme activity, improves vascular relaxation, and decreases oxidative stress and gene expression. However, the clinical application of this flavonol is limited by its poor bioavailability and low stability in aqueous medium. In the aim to overcome these drawbacks and preserve the cardioprotective effects of quercetin, the present study reports on the preparation of five different Q1 analogs, in which all OH groups were replaced by hydrophobic functional moieties. Q1 derivatives have been synthesized by optimizing previously reported procedures and analyzed by spectroscopic analysis. The cardiovascular properties of the obtained compounds were also investigated in order to evaluate whether chemical modification affects their biological efficacy. The interaction with β-adrenergic receptors was evaluated by molecular docking and the cardiovascular efficacy was investigated on the ex vivo Langendorff perfused rat heart. Furthermore, the bioavailability and the antihypertensive properties of the most active derivative were evaluated by in vitro studies and in vivo administration (1month) on spontaneously hypertensive rats (SHRs), respectively. Among all studied Q1 derivatives, only the ethyl derivative reduced left ventricular pressure (at 10(-8)M÷10(-6)M doses) and improved relaxation and coronary dilation. NOSs inhibition by L-NAME abolished inotropism, lusitropism and coronary effects. Chronic administration of high doses of this compound on SHR reduced systolic and diastolic pressure. Differently, the acetyl derivative induced negative inotropism and lusitropism (at 10(-10)M and 10(-8)÷10(-6)M doses), without affecting coronary pressure. Accordingly, docking studies suggested that these compounds bind both β1/β2-adrenergic receptors. Taking into consideration all the obtained results, the replacement of OH with ethyl groups seems to improve Q1 bioavailability and stability; therefore, the ethyl derivative could represent a good candidate for clinical use in hypertension.