Phytochemical study and pharmacological activity of Terminalia chebula fruit extracts activity as Dihydrofolate Reductase enzyme inhibitors associated with antioxidant effect: In vitro study

Dihydrofolate reductase (DHFR) is a fundamental enzyme in producing the precursor of purines and pyrimidines for biosynthesis of DNA, RNA and amino acids at various stages. It is considered the key target for both anticancer and antimicrobial drug design. Terminalia chebula has unique phytoconstituents which are employed broadly in the development of medications against different diseases. It has been established that Terminalia chebula fruit could be used as therapeutic agent for cancer treatment. The aim of study was to evaluate the inhibitory effect of T. chebula fruit extract against DHFR enzyme activity and assessment the antioxidant and scavenging activity of T. chebula fruit extract, using DPPH and reducing activity tests Terminalia chebula fruits where extracted. The anti- DHFR enzyme activity was assessed in vitro for the four extracts of Terminalia chebula fruit and MTX. Phytochemical analysis of screening test, gas chromatography-mass spectrometry (GC-MS) analysis and high-performance liquid chromatography (HPLC) was done for the extract with highest biological activity. Antioxidant and radical scavenging activity of the extract with highest biological activity were evaluated via DPPH [1, 1-diphenyl-2-picrylhydrazyl (α, α-diphenyl-β-picrylhydrazyl] and reductive ability test. The percent of DHFR inhibiting activity for the cold methanolic extract was the highest and it was higher than that of MTX (96.0±1.4% vs. 89.0±1.1%, respectively), therefore, it was selected for the proceeding assay. Phytochemical analysis showed that the cold methanolic extract of T. chebula, showed a positive reaction for alkaloids, flavonoids, phenolic compounds, steroids and saponins. Besides, GC-MS analysis showed the presence of pyrogallol compound, while HPLC analysis recorded 3 major peaks with different retention times that were semi-identical to gallic acid, rutin and quercetin standard. The highest radical scavenging activity of T.chebula cold methanolic extract and ascorbic acid according to DPPH were (80.1±2.04% and 85.83±2.1%, respectively) at the maximum studied concentration (200μg/ml), where the activity of ascorbic acid was significantly higher (p≤0.05) than that of T.chebula. Meanwhile, the reductive ability of the cold extract was significantly higher (p ≤ 0.05) than that of vitamin E (0.72±0.15 and 0.41±0.08, respectively) at the maximum studied concentration (250μg/ml). These results suggesting the cold extract of Terminalia chebula has in vitro prominent anti-dihydrofolate reductase activity which is better than that of MTX.