Characterization of phenolics and biological activities of different solvent extracts from Withania somnifera fruit

The present work studies the profiling of phenolic bioactive and in vitro biological (anticancer, antioxidant, and antimicrobial) activities of different solvent extracts from Withania somnifera fruit. Anticancer activity was performed using potato-disc assay and Agrobacterium tumefaciens. While antibacterial and antifungal evaluation was done by using disc diffusion method against bacterial (Staphylococcus aureus, S. epidermidis, Escherichia coli, and Klebsiella pneumonia) and fungal (Aspergillus flavus and Fusarium oxysporum) strains. Among different extraction solvents used, n-hexane extract exhibited the highest inhibition of tumour initiation (64%), whereas ethyl acetate (15%) was the lowest by using potato-disc assay. Highest total phenolic and total flavonoid contents were noted for methanolic (69.10 GAE mg/g DW%) and n-hexane (29.45 CE mg/g DW%) extracts, respectively. For antioxidant potential, 2,2,1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC50) and reducing power EC50 were noted to be superior (0.6 and 2.0 mg/mL, respectively) for n-hexane extract. All the tested extracts showed considerable antibacterial and antifungal activity with the highest growth inhibition zones for K. pneumoniae (31.70 mm) and A. flavus (27.09 mm) were shown by n-hexane extract. High Performance Liquid Chromatographic (HPLC) analysis of individual phenolics (gallic acid, 2,288.48 mg/kg) indicated the highest contents of these compounds in n-hexane extract, which might explain the potent biological activities of this extract. Our findings revealed that the bioactive present in the tested fruit had significant potential as anticancer, antibacterial, and antifungal agents. Further studies are needed to elucidate the mechanism of actions of isolated bioactive against specific diseases such as cancer, especially in the case of n-hexane fraction.