Description:Field of Invention:
The present invention discloses the DNA protection ability of newly synthesized thiazoly pyrazoles under UV-irradiations. All compounds (1a-m) effectively protected DNA supercoiled form of DNA as compared to control (C) in which DNA is converted into open circular form from the supercoiled form.
Background of the invention:
Heterocycles have diversified physical, chemical and biological properties. Among all known organic compounds more than half account for heterocyclic compounds, which possess various properties (New J. Chem. 2017, 41, 16-41). Incorporation of N atom in five-membered heterocyclic rings, such as thiazole, pyrazole, imidazole, tetrazole, oxazole, and triazole represents a series of compounds having broad spectrum of pharmaceutical properties (Bioorg. Chem. 2016, 69, 77-90; J. Med. Chem. 1989, 32, 1673-1681). Nowadays, from medicinal chemist point of view, clubbed heterocyclic motifs are considered as powerful tools to design new potential drug candidates (J. Med. Chem. 2017, 60, 7108-7122). Therefore, thiazole clubbed pyrazoles i.e. Thiazol-2-yl-1H-pyrazol-5(4H)-ones are considered as suitable lead candidates due to their DNA protective and divergent biological potency (BMC Chem. 2019, 13, 116). Moreover, it has been already reported that arylazo group linked pyrazole derivatives have UV induced DNA protective potential (Med. Chem. Res. 2015, 24, 3863-3875). As DNA is a prime molecule, therefore, stability of DNA plays crucial role for existence and proper functioning of living systems. DNA functionality altered by various factors such as genetic defects, UV rays and environmental (Chem. Biol. Interact. 2018, 279, 73–83). Among them, exposure to radiations (mainly UV-B: 280-315 nm) directly or indirectly have deteriorating effects like DNA damage, early aging, hyperpigmentation, skin cancer, cataract formation, edema, erythema, cellular death and induces mutagenic and cytotoxic DNA lesions like 6-4 photoproducts (6-4PPs), cyclobutane-pyrimidine dimers (CPDs) as well as genomic integrity altered by DNA strand breaks (Radiat. Res. Appl. Sci. 2015, 8, 247–254; J. Nucleic Acids 2010, 32, 592980). Nowadays, radiations are being used for treatment of various diseases for betterment of human life (Br. Med. Bull. 2003, 68, 259–275). For betterment of living beings, therefore, it is essential to design such compounds which have potential to protect DNA under UV- irradiations. Therefore, it is always worthwhile to design such molecules which have good capability to protect UV-induced DNA.
Keeping in mind, the aforementioned facts, pharmacological importance of thiazolyl-pyrazolones and in continuation of our ongoing work to synthesize biologically active heterocyclic scaffolds, it was planned to synthesize new thiazole linked pyrazolone derivatives with expectation as potential DNA protective agents against UV-irradiations.
Summary of the invention:
The present invention discloses the DNA protective screening of new thiazolyl-pyrazole derivatives under the exposure of UV-irradiation. Form the experimental results, it was evident that at concentration (50 µg) all compounds protected the supercoiled form of DNA under UV-irradiation.
Detailed description of the invention:
To explore the versatility of the synthesized compounds (1a-m, Fig. 1), DNA protecting potential against pBR322 DNA has been evaluated.

Fig. 1 Different substitution patterns on the thiazolyl-pyrazole moiety of the
compounds (1a-m)
DNA protecting activity
In the field of medicinal and chemical sciences, DNA protecting agents play an eminent role for betterment of human life. Therefore, biochemists as well as chemists have keenly focused to design biologically active motifs which have higher efficacy to protect nucleic acid strands. Mainly, from therapeutic point of view, researchers focused on those compounds that have potential to protect DNA under UV-irradiation. DNA protecting activity generally related to efficiency to protect relaxation of super coiled (SC) DNA into open circular (OC) DNA.
Agarose gel electrophoresis technique was used to evaluate the DNA protecting activity of synthesized compounds. Bands were analyzed in control (C) and test compounds in presence and absence of UV-irradiations with respect to control and test samples. In absence of UV-irradiation no degradation was observed when bands appeared in test samples were compared with control, intensity of both forms were found to be same.
In the present investigation, all the synthesized compounds (1a-m) at 50 µg concentration have higher efficacy to protect supercoiled form of DNA under UV-irradiations when compared to control (C) which is unable to protect the initial supercoiled form and converted it into more relaxed open circular form. Apart from this, band intensity of compound 1f increased followed by 1a and 1b whereas band intensity of 1c, 1d, 1e, 1g and 1h was comparable to control (A) whereas band intensity was decreased for (1i-m). Moreover, none of the investigated compounds exhibited conversion of supercoiled form into open circular form when compared to control (C). Among all of the screened compounds 1i and 1k converted into open circular form but conversion is not prominent as compared to control (C). Therefore, compounds 1a-h act as potent DNA protective agents (Fig. 2).

Fig. 2 Effects of compounds 1a–j (50 µg) on plasmid DNA under UV-irradiation: lane 1 DNA + DMSO without UV, lane 2 DNA + DMSO + UV, lane 3 DNA + 1a + UV, lane 4 DNA + 1b + UV, lane 5 DNA + 1c + UV, lane 6 DNA + 1d + UV, lane 7 DNA + 1e + UV, lane 8 DNA + 1f + UV, lane 9 DNA + 1g + UV, lane 10 DNA + 1h + UV, lane 11 DNA + 1i + UV, lane 12 DNA + 1j + UV, lane 13 DNA + 1k + UV, lane 14 DNA + 1l + UV, lane 15 DNA + 1m + UV
Outcome of the Invention:
All synthesized compounds act as DNA protective agents at 50 µg concentration and out of them 1a-h were more effective in DNA protection under UV-irradiations. Effectiveness of the compounds is concentration dependent and considered as suitable DNA protecting agents under UV-irradiation in near future and used as main ingredient for sunscreen which protects skin from sunburns and skin cancer. Toxicology study of compounds is under examination.
Highlights of the Invention:
? Explored new thiazoly-pyrazole derivatives as new DNA protective agents.
Experimental:
Treatment of DNA with the samples
The synthesized chemical compounds (1a-m) were dissolved in DMSO to prepare a stock solution of 10 mg/ml. Different concentrations of each compound (50 µg) from the above stock solutions were mixed with plasmid DNA and treated with UV using UV-illuminator at 360 nm for 30 minutes at room temperature. Two controls were maintained; Plasmid (A): plasmid in Tris EDTA buffer, and DMSO + UV control (C): plasmid mixed with DMSO followed by UV treatment, to clearly observe the effects of different compounds on plasmid DNA under UV treatment. After UV treatment, the treated plasmid DNA and the controls were incubated at 37? for 1 hour.
Agarose gel electrophoresis
Agarose gel (1% wt./vol.) was prepared by mixing 1 g agarose in 100 mL of 1X Tris-acetate EDTA (TAE) buffer and heated to dissolve the agarose. After cooling down to 55?, ethidium bromide with a final concentration of .5µg/ml was mixed and gel was cast in a tray fitted with a comb. After gel solidification, gel was placed in electrophoresis chamber and flooded with 1X TAE buffer followed by careful removal of the comb. Treated plasmid DNA and controls were mixed with loading dye (0.25% bromothymol blue and 30% glycerol). Each well was loaded with 9 µL of the above mixture and gel electrophoresis was carried out at 90 mV for 1 hour. The gel was visualized using InGenius3 Gel Documentation System (Syngene, UK).
, Claims:Claims:
I/We claim
1. The compounds of the formula I, where Ar is C6H5, 4-F-C6H4, 4-Cl-C6H4, 4-Br-C6H4, 4-CH3-C6H4, 4-CH3O-C6H4, 4-NO2-C6H4, 4-CF3-C6H4, 4-CF3O-C6H4, 4-C6H5-C6H4, 4-CN-C6H4, Chromenyl, Naphthyl as DNA protective agents.

2. The compounds as claimed in claim 1, wherein the said compounds as claimed in claim 1, acted as DNA protecting agents at 50 µg concentration for effective protecting of supercoiled form of DNA under UV-irradiation.