Role of Natural and Synthetic Flavonoids as Potential Aromatase Inhibitors in Breast Cancer: Structure-Activity Relationship Perspective

: World Health Organization categorized breast cancer as one of the leading cancer types in females worldwide, and its treatment remains challenging. Accumulated evidence suggested the role of estrogen and its metabolites in pre- and post-menopausal women. Upregulation of estrogen-dependent aromatase is significantly involved in the pathogenesis of breast cancer. Several aromatase inhibitors, such as exemestane, formestane, and letrozole, are being used clinically, owing to their estrogen suppression role. Apart from these drugs, several other molecules, such as natural and synthetic flavonoids, have been reported widely for a similar biological activity. However, some reasonable modifications are required for these structures to achieve desired efficacy and to alleviate toxicity. Designing a novel aromatase inhibitor will be possible if we can establish a rational correlation between the chemistry and biological features of the existing molecules. The benzopyranone-ring system, present in the flavonoid molecules, has been reported as a pharmacophore due to its inhibitory activity on aromatase, which helps repress breast cancer progression. This essential feature has been utilized to modify several natural flavonoids into 5 and 7 hydroxy/methoxy flavone, 4-imidazolyl/triazolyl flavone, 5,4’- diamino flavone, 7,8- benzo-4-imidazolyl flavone, α-naphthoflavone, and 2-azole/thiazolyl isoflavone derivatives. These scaffolds have been considered in this review for meticulous study in aspects of the structure-activity relationship for aromatase inhibitory activity, and it would likely pave the way for designing a potential lead candidate in the future.

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Isolation of Natural Compounds from Syzygium densiflorum Fruits and Exploring its Chemical Property, Therapeutic Role in Diabetic Management

The Natural Products Journal ◽

10.2174/2210315508666180622113414 ◽

2020 ◽

Vol 10 (2) ◽

pp. 168-176

Author(s):

Krishnasamy Gopinath ◽

Nagarajan Subbiah ◽

Muthusamy Karthikeyan

Keyword(s):

Density Functional ◽

Chemical Reactivity ◽

Natural Compounds ◽

Structure Activity Relationship ◽

Activity Relationship ◽

Computational Studies ◽

Therapeutic Role ◽

Relationship Analysis ◽

Structure Activity

Background: Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by the local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes. Objective: This study aimed to isolate the major phytoconstituents from the S. densiflorum fruits and to perform computational studies for chemical reactivity and biological activity of the isolated compound. Materials and Methods: Two different compounds were isolated from ethanolic extract of S. densiflorum fruits and purified using HPLC. The structures of the compounds were elucidated on the basis of their 1H NMR, 13C NMR, 1H-1H COSY, HMBC, HRESIMS, and FT-IR data. Further, the chemical reactivity of the compounds was analyzed by density functional theory calculations and its therapeutic role in diabetic management was examined by comparing the structure of isolated compounds with previously reported bioactive compounds. Results: Of the two compounds ((6,6 & 1-kestopentaose (1) and 6-(hydroxymethyl)-3-[3,4,5- trihydroxy- 6-[(3,4,5-trihydroxyoxan-2-yl)oxymethyl]oxan-2-yl]oxyoxane-2,4,5-triol)(2)). β-glucosidase, β-galactosidase, α-glucosidase and β-amylase inhibition activity of the compounds were predicted by structure activity relationship. Conclusion: Structure-activity relationship analysis was performed to predict the therapeutic role of isolated compounds. These computational studies may be performed to minimize the efforts to determine the therapeutic role of natural compounds.

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