Analysis of curcumin and piperine in biological samples by reversed-phase liquid chromatography with multi-wavelength detection

Synthesis, Characterization, and Evaluation of a Novel Molecularly Imprinted Polymer (MIP) for Selective Quantification of Curcumin in Real Food Sample by UV-Vis Spectrophotometry

Curcumin is the main colorant of the curcuma longa plant, a food with many benefits for human health. This work aims to synthesize a novel molecularly imprinted polymer (MIP) for the selective detection of curcumin in real samples obtained from the local market of Peru. MIPs were synthesized via bulk polymerization using curcumin, acrylamide, ethylene glycol dimethacrylate, ABCV, and acetonitrile. FTIR spectra showed equal spectra for MIP and NIP. N2 physisorption analysis presented a higher value BET surface for the MIP (28.5 m2 g-1) compared to the NIP (18.5 m2 g-1). The adsorption capacity of the MIP was evaluated using UV-vis spectrophotometry in the band around 430 nm. The adsorption kinetics found were of pseudo-second-order and a Qe value of 16.2 mg g-1. Furthermore, the adsorption process resembles the Freundlich adsorption model with a heterogeneity factor of less than 1 (0.61) and Kf greater for MIP (1.97). The selectivity test indicated that MIP is more selective for curcumin (Q = 13.20 mg g-1) than against interferents (Q = 2.19 mg g-1). The specific selectivity factor (S) obtained for the interferents was greater than 1 which indicates a good selectivity. Finally, the application of MIP in real samples using UV-vis spectrophotometry yielded a recovery value greater than 70%.

Antioxidant Nutraceutical Strategies in the Prevention of Oxidative Stress Related Eye Diseases

This review aims to discuss the delicate balance between the physiological production of reactive oxygen species and the role of antioxidant nutraceutical molecules in managing radicals in the complex anatomical structure of the eye. Many molecules and enzymes with reducing and antioxidant potential are present in different parts of the eye. Some of these, such as glutathione, N-acetylcysteine, α-lipoic acid, coenzyme Q10, and enzymatic antioxidants, are endogenously produced by the body. Others, such as plant-derived polyphenols and carotenoids, vitamins B2, C, and E, zinc and selenium, and omega-3 polyunsaturated fatty acids, must be obtained through the diet and are considered essential nutrients. When the equilibrium between the production of reactive oxygen species and their scavenging is disrupted, radical generation overwhelms the endogenous antioxidant arsenal, leading to oxidative stress-related eye disorders and aging. Therefore, the roles of antioxidants contained in dietary supplements in preventing oxidative stress-based ocular dysfunctions are also discussed. However, the results of studies investigating the efficacy of antioxidant supplementation have been mixed or inconclusive, indicating a need for future research to highlight the potential of antioxidant molecules and to develop new preventive nutritional strategies.

A Unifying Perspective in Blunting the Limited Oral Bioavailability of Curcumin: A Succinct Look

BACKGROUND

Curcumin is a polyphenolic compound derived from rhizomes of Curcuma longa, the golden spice. Curcumin has drawn much attention in recent years of biomedical research owing to its wide variety of biologic and pharmacologic actions. It exerts antiproliferative, antifibrogenic, anti-inflammatory, and antioxidative effects, among various imperative pharmacologic actions. In spite of its well-documented efficacies against numerous disease conditions, the limited systemic bioavailability of curcumin is a continuing concern. Perhaps, the poor bioavailability of curcumin may have curtailed its significant development from kitchen to clinic as a potential therapeutic agent. Subsequently, there have been a considerable number of studies over decades researching the scientific basis of curcumin's reduced bioavailability and eventually improvement of its bioavailability employing a variety of therapeutic approaches, for instance, in combination with piperine, the bio-active constituent of black pepper. Piperine has remarkable potential to modulate the functional activity of metabolic enzymes and drug transporters, and thus there has been a great interest in the therapeutic application of this widely used spice as alternative medicine and bioavailability enhancer. Growing body of evidence supports the synergistic potential of curcumin against numerous pathologic conditions when administered with piperine.

CONCLUSION

In light of current challenges, the major concern pertaining to poor systemic bioavailability of curcumin, its improvement, especially in combination with piperine, and the necessity of additional research in this setting are together described in this review. Besides, the recent advances in the potential therapeutic rationale and efficacy of curcumin-piperine combination, a promising duo, against various pathologic conditions are delineated.

Quality assessment and Analytical Quality by Design-based RP-HPLC method development for quantification of Piperine in Piper nigrum L

Background

Piper nigrum L. is one of the widely used herbs in Ayurvedic medicine. Piperine is a major phytoconstituent that is responsible for most of the activity of the herb. Quality assessment and standardization of such phytoconstituents is the need of the hour. The present study aims at developing a Quality by design (QbD)-based RP-HPLC Method for marker-based standardization of Piper nigrum L. fruits along with its quality assessment.

Results

The quality assessment of the crude sample was carried out by evaluating pharmacognostic parameters and analysis of toxic contaminants. The analytical target profile and critical quality attributes were determined and 22 factorial design was employed for optimization of the method. By performing the experiments as per the QbD concept the optimized mobile phase was identified as Acetonitrile and Water with 0.05% Acetic acid in the ratio of 70:30, with a flow rate of 1 mL/min and UV detection at 342 nm. The retention time of Piperine was found to be 5.5 min and the amount of Piperine in crude P. nigrum fruits and its extract was found to be 3.6% w/w 5.62% w/w, respectively. The Pharmacognostic parameters showed the results within specified limits and the crude drug sample showed the absence of toxic contaminants in it thus indicating the purity of the drug.

Conclusion

The utilization of the QbD approach leads to the development of a more precise and reliable method for the quantification of phytocompounds.

Validated high-performance thin-layer chromatographic analysis of curcumin in the methanolic fraction of Curcuma longa L. rhizomes

Background

In the present study, an HPTLC (high-performance thin-layer chromatography) method was developed for the quantitative determination and validation of the curcumin in the methanolic fraction of Curcuma longa L. For achieving good separation of curcumin, the mobile phase of chloroform:methanol (97:3) was used. The densitometric analysis of curcumin was performed at 420 nm in reflection/absorption mode.

Results

Linearity of the method was obtained in the range of 100‒600 ng per spot. During analysis, the methanolic fraction of the C. longa showed the presence of a quantifiable amount of curcumin. The content of curcumin was found to be 1.5% (per dry weight).

Conclusions

The method is specific, simple, precise, and accurate. The obtained data can have used for the routine analysis of the reported biomarkers in crude drugs and extracts. The quantification and the method validation of curcumin have not yet been reported in C. longa which can be utilized for the proper standardization of the plant.