Natural and Biomimetic Antitumor Pyrazoles, A Perspective

Abstract

The present review presents an overview of antitumor pyrazoles of natural or bioinspired origins. Pyrazole compounds are relatively rare in nature, the first ones having been reported in 1966 and being essentially used as somniferous drugs. Cytotoxic pyrazoles of natural sources were first isolated in 1969, and a few others have been reported since then, most of them in the last decade. This paper presents a perspective on the current knowledge on antitumor natural pyrazoles, organized into two sections. The first focuses on the three known families of cytotoxic pyrazoles that were directly isolated from plants, for which the knowledge of the medicinal properties is in its infancy. The second section describes pyrazole derivatives of natural products, discussing their structure–activity relationships.

Preliminary Phytochemical Screening of Elytraria acaulis Roots

“…The methanolic extract of dried whole plant of Elytraria acaulis revealed two pyrazole alkaloids withasomnine and 4'-hydroxywithasomnine [24]. Withasomnine, a pyrazole alkaloid with sleepinducing properties has been first isolated in 1966 [25], is used as somniferous drugs [26]. Phytoconstituents namely, phenols, flavonoids and tannins and terpenoids possess antioxidant activity [27].…”

Styrylpyrazoles: Properties, Synthesis and Transformations

“…Although pyrazoles are rare in nature, due to the difficulty of living organisms to construct the N–N bond [ 46 , 47 ], a styrylpyrazole natural derivative, ( E )-1,5-diphenyl-3-styryl-2-pyrazoline (DSDP) 15 (also known as ( E )-1,5-diphenyl-3-styryl-4,5-dihydro-1 H -pyrazole) ( Figure 6 ), was isolated from the aerial parts of Euphorbia guyoniana [ 48 ]. In 2017, Kundu et al unveiled the binding interaction of DSDP 15 with the calf thymus DNA (ctDNA) [ 49 ].…”

Fluorinated and Non-Fluorinated 1,4-Diarylpyrazoles via MnO2-Mediated Mechanochemical Deacylative Oxidation of 5-Acylpyrazolines

“…Due to the discovery of a number of practical applications, there is increasing interest in the chemistry of pyrazole-based compounds, and fluorinated analogues are of special significance in medicine, crop protection, as well as material sciences [ 1 , 2 , 3 , 4 ]. The title heterocycle constitutes a key structural element of pharmaceuticals and agrochemicals; they exhibit a variety of biological activities such as being anti-inflammatory (e.g., Celecoxib, Lonazolac), antibacterial, anticancer (e.g., Crizotinib), anti-obesity (e.g., Rimonabant), antidepressant (e.g., Fezolamine), antiviral (e.g., Lenacapavir), and antifungal (e.g., Penthiopyrad), and have been widely applied as pesticides ( Figure 1 ) [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. In addition, some pyrazoles have been successfully applied in polymer chemistry, as well as for the preparation of advanced liquid crystalline materials [ 14 , 15 ].…”