Abstract:Introduction: Lutein from Tagetes erecta L. is extracted from marigold oleoresin. It affects the pharmacokinetics of drugs which are metabolised by cytochrome P450.
The aim of the study is to find the inhibitory effect of lutein on cytochrome P450. Materials and Methods: Cytochrome P450 enzymes functions to metabolise potentially toxic compounds, including drugs and products of endogenous metabolism.Lutein at different concentrations from 5 – 100µg/ml was examined for its inhibitory property towards Cytochrome P 450 isoform CYP3A4.
Results: All the tested concentrations of Lutein showed potent inhibition against CYP3A4 in a dose – dependent manner. The IC50 value of lutein for CYP3A4 inhibitory activity was found to be 35.27µg/ml.Conclusion: The inhibitory effects of lutein indicate the possibilities of herb-drug interaction. If these extracts are co – administered with prescribed drugs that are metabolised by these CYPs and the necessity for further in vivo study.
Keywords: Lutein, cytochrome P450, inhibitory assay, marigold oleoresin, IC50.Introduction: Lutein from Tagetes erecta L. is a purified extract obtained from marigold oleoresin, which is extracted from the petals of marigold flowers with organic solvents. The final product, after saponification, contains, as a major component, lutein and a smaller proportion of zeaxanthin. Lutein (3R,3’R,6’R-??-carotene-3,3′-diol) is a member of a group of pigments known as xanthophyll and has no provitamin A activity. It is used as a food colouring agent and nutrient supplement (food additive) in a wide range of baked goods and baking mixes, beverages and beverage bases, breakfast cereals, chewing gum, dairy product analogs, egg products, fats and oils, frozen dairy desserts and mixes, gravies and sauces, soft and hard candy, infant and toddler foods, milk products, processed fruits and fruit juices, soups and soup mixes in levels ranging from 2 to 330 mg/kg.
1 Marigold flower (Tagetes erecta L.) represents a rich source of lutein. It is grown for business purposes in Mexico, Peru, Ecuador, Spain, India or China. Dried Marigold flowers contain 0.1–0.
2% dry matter (DM) of carotenoids, out of which 80% are lutein diesters. By the extraction of dried and ground flowers, a non polar oleoresin extract is acquired. 2 The recent evidence suggests that lutein is one of the abundant carotenoids in the diet and in human blood possesses strong antioxidant capabilities and may be useful in reduction of incidence of cancer.3 The purification of lutein fatty acid esters from marigold flowers was patented by Philip in 1977(U.S.Pat.No.
4,048,203).4 The xanthophylls, a major group of carotenoids, primarily include astaxanthin (AS), b-cryptoxanthin (bC), canthaxanthin (CA), lutein (LU), and zeaxanthin (ZE) (Kotake-Nara and Nagao, 2011; Zaripheh and Erdman, 2002). Unpredicted drug interactions have led to severe adverse effects or treatment failures. Many of these interactions involve the inhibition or induction of drug-metabolising cytochrome P450 (CYP) enzymes. Similarly, dietary supplements or nutrients may be inhibitors or inducers of CYP enzymes and have an effect on the pharmacokinetics of any co-medicated drugs. There are few reports about interactions between drug-metabolising enzymes and AS, bC, CA, LU, and ZE.
5 The aim of the present study was thus to investigate the reversible inhibitory or time-dependent inhibitory effects of LU affecting the pharmacokinetics of the drug, which is metabolised by cytochrome P450. Materials and methods: Lutein was extracted from marigold oleoresin, which was commercially bought. 5-100 micrograms concentrations of lutein, potassium phosphate buffer, CYP450 reagent and substrate 7-Benzyloxy-4-trifluoromethylcoumarin (BFC) were added to a 96-well plate.The mixtures were pre – incubated for 20 min at room temperature. The reaction was started by a mixture of reconstituted substrate and NADP+ and incubated at room temperature for 30-60 min. The reaction was stopped by Tris-HCl buffer, pH 10.5. The fluorescent intensities of the products were measured by Perkin Elmer Enspire fluorescence reader using an excitation and emission wavelength of 405 nm and 460 nm, respectively.
IC50 was calculated by plotting concentrations of lutein against the corresponding percent inhibition.RESULTS: Lutein at different concentrations from 5 – 100µg/ml was examined for its inhibitory property towards Cytochrome P 450 isoform CYP3A4. All the tested concentrations of Lutein showed potent inhibition against CYP3A4 in a dose – dependent manner. The IC50 value of lutein for CYP3A4 inhibitory activity was found to be 35.27µg/ml. Figure 1 shows the inhibitory potential of different concentrations of lutein on cytochrome P450.Figure 1 Table 1Effect of Lutein on Cytochrome P 450 (CYP3A4) inhibitory potentialConcentration(µg/ml) Lutein5 3.27±0.
6910 14.83±4.1620 27.24±0.1640 33.71±0.1660 45.
49100 71.54±0.49Values are expressed as Mean ± SEM (n = 3)DISCUSSION: Results from this study provide the information indicating the possibilities of herb-drug interaction if lutein extracted from marigold oleoresin aqueous extracts are co-administered with the prescribed drugs that are metabolized by CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4. Lutein extracted from Marigold oleoresin demonstrated inhibitory effects on CYP3A4.
Lutein extracted from marigold oleoresin, apart from inhibitory effects, also shows potent antioxidant activities.14 Comparing with the other studies, it was shown that inhibitory effects of lutein against cytochrome P450 was a potent inhibition in a dose-dependent manner. P. amarus and P. emblica aqueous extracts on all CYP isoforms were weaker. These weak inhibitory effects in vitro may or may not be found in vivo, however, results from these in vitro studies suggest that further confirmatory study in vivo was recommended.6 In a previous study, ECa233 demonstrated a concentration-related inhibitory effects on the activities of CYP2B6, CYP2C19 and CYP3A4 but not or very small effects on CYP1A2, CYP2C9, CYP2D6 and CYP2E1 at the range concentrations of ECa233 in the reaction mixture up to 1,000 µg/ml. No inhibitory effect of ECa233 on CYP1A2, CYP2C9, CYP2D6 and CYP2E1 rule out the potential effect of the extract to interact with various currently used medicines that are metabolized by these CYP isoforms.
7 In a study by Winitthana 16, drug – drug interactions were found out. Asiaticoside inhibited CYP2C19 (IC50 = 412.68 ± 15.44 ?M) and CYP3A4 (IC50 = 343.35 ± 29.35 ?M).
Madecassoside also inhibited CYP2C19 (IC50 = 539.04 ± 14.18 ?M) and CYP3A4 (IC50 = 453.32 ± 39.
33 ?M). Asiaticoside and madecassoside had no effect on the activities of CYP1A2, CYP2C9 and CYP2D6 and CYP2E1. Assessment of mechanism-based inhibition and the type of inhibition were performed for asiaticoside and madecassoside with CYP2C19 and CYP3A4. These results suggested that madecassoside is a mechanism-based inhibitor of CYP2C19 and CYP3A4. Asiaticoside exhibited non-competitive inhibition of CYP2C19 (Ki = 385.24 ± 8.75 ?M) and CYP3A4 (Ki = 535.
93 ± 18.99 ?M). Madecassoside also showed non-competitive inhibition of CYP2C19 (Ki = 109.62 ± 6.14 ?M) and CYP3A4 (Ki = 456.84 ± 16.43 ?M). Similar studies that were conducted are, aqueous extracts of Hibiscus on hepatic cytochrome P450 and subacute toxicity in rats.
The result was that there was no modulation.8 In a study by Teresa, inhibition of cytochrome P450 metabolism by blended herbal products and vitamins was studied. The study revealed that the extracts showed a low to moderate capacity to inhibit the cytochrome metabolism.
9 Similarly, studies on Cocktail inhibition assays for assessing the drug-drug, drug-botanical interactions and assessing the six major cytochrome P450 enzymes was conducted by Guannan and Jing Jing Wan respectively.10,11 A study by Yu Fen Zeng, reveals that although drug–drug interactions may be identified during drug development and approval, food–drug interaction and supplements–drug interaction should not be overlooked. Natural health products are being increasingly widely used.
Apart from an appraisal of product safety and effectiveness, attention should be paid to the potential that these product ingredients may interact with medications. In recent years, dietary carotenoids, especially xanthophylls, have attracted significant attention because of their activities as antioxidants and their roles in preventing cancer and age-related macular degeneration. Although no less than 40 carotenoids are ingested through the typical diet, only a few xanthophylls have been found in human tissues. There are a few reports of inducible effects on CYP activities by the xanthophylls AS, bC, CA, LU, and ZE. However, their inhibitory effects on CYPs have rarely been investigated.
5CONCLUSION: Lutein obtained from marigold petals is of major commercial interest because of its use in functional food and cosmetics, as well as in pharmaceuticals. The production yield from each marigold plant is very important for the large-scale extraction of lutein, in terms of cost efficiency. In conclusion, lutein extracted from Marigold oleoresin exhibited inhibitory effect on CYP3A4. It showed a potent inhibition against cytochrome P450. The inhibition was in a dose – dependent manner.
Results from this study provide information indicating the possibilities of herb-drug interaction if these extracts are co-administered with the prescribed drugs that are metabolized by CYP3A4. Further in vivo study is needed to investigate whether these effects are clinically significant.