Background: The Pakistani Salt Range has a rich floral diversity including Withania coagulans from the Solanaceae family.
Methods: The crude methanolic extracts of the root, leaf, leaf stalk, and fruit of this plant were screened for their cytotoxic activity against human (HeLa, MCF-7, RD) and rat (RG2 and INS-1) cancer cell lines at 20 μg/mL and compared to methotrexate. The IC50 values indicated that leaf stalk and fruit extracts exert an 80% or higher cytotoxic activity against all cell lines at 24 hours.
Results: The leaf stalk extract showed the highest cytotoxic efficacy against all tested cell lines, with IC50 values ranging from 0.96 ± 0.01 μg/mL to 4.73 ± 0.05 μg/mL followed by the fruit extract with IC50 values of 0.69 ± 0.01-6.69 ± 0.06 μg/mL after 48-72 hours incubation. The leaf stalk and seed extracts were analyzed for polyphenols and flavonoids using RP-HPLC. The total flavonoid content (TFC) was calculated for all tested samples, and the highest TFC was recorded for the root extract (394.34 ± 1.26 μg/g). The total phenolic content (TPC) was found in the seed extract (307.86 ± 9.42 μg/g) of W. coagulans. The highest contents of myricetin (358.46 ± 2.91 μg/g) were noted in the leaf extract, and highest quercetin was recorded in the seed extract (21.43 ± 0.13 μg/g). The highest gallic acid concentration (83.62 ± 0.71 μg/g) was recorded in leaf stalk extract and p-hydroxybenzoic acid in the seed extract (157.46 ± 1.43 μg/g).
Conclusion: The present study gives a scientific insight and comparative analysis of various plant parts in this medicinally important plant species from the Salt Range of Pakistan against both human and rat cancer cells.
Keywords: Anticancer; Presto Blue cell metabolic assay; Total flavonoid contents; Total phenolic contents.