Cytotoxic activity, selectivity, and clonogenicity of fruits and resins of Saudi medicinal plants against human liver adenocarcinoma

Abstract

Background: Edible fruits and resins provide various benefits to mankind including potential medicinal applications. This study aimed to determine the cytotoxicity, selectivity, and clonogenicity of fruits and exudates of certain Saudi medicinal plants (Anethum graveolens (BEP-09), Opuntia ficus-indica (L.) Miller (BEP-10), Boswellia serrata Roxb. ex Colebr. (BEP-11), and Commiphora myrrha (BEP-12)) against human liver adenocarcinoma (HepG2).

Methods: Initial cytotoxicity and cell line selectivity against different cell lines were screened using MTT assay. The most promising extract was subjected to gas chromatography-mass spectrometry (GC-MS) analysis to determine the main phytoconstituents. Clonogenicity was checked for the most active extract.

Results: The selected plants' fruits and resins possess a significant cytotoxic activity estimated as IC₅₀. The fruit of BEP-10 was found to be the most active extract against liver cancer cells (IC₅₀ = 2.82) comparable to both doxorubicin (IC₅₀ = 1.40) and camptothecin (IC₅₀ = 1.11). It showed a selectivity index of 4.47 compared to the normal human foetal lung fibroblast (MRC5) cells. BEP-10 showed a dose-dependent clonogenic effect against HepG2 cells comparable to the effect of doxorubicin. The GC-MS chromatogram of BEP-10 extract revealed the presence of eight small polar molecules, representing 73% of the total identified compounds and the rest three molecules (27%) were non-polar constituents. The furan derivatives represent the chief components in BEP-10 (16.3%), while the aldehyde 5-(hydroxymethyl)-2-furancarboxaldehyde was found to be the main molecule (13.2%).

Conclusion: The fruits of BEP-10 have a potential cytotoxic effect particularly against HepG2. The identified phytoconstituents in the tested plant extract might contribute to the investigated cytotoxic activity.

Keywords: Clonogenicity; Cytotoxicity; MTT assay; Opuntia ficus-indica; Saudi plants; Selectivity index.

FIGURE 1 -

Opuntia ficus-indica (L.) Miller (BEP-10) grows in the Al-Baha area, KSA.

FIGURE 2 -

Yield % of dry extracts obtained after ethanolic extraction and evaporation of four different selected plants. C; control, ***; p ≤ 0.001.

FIGURE 3 -

Structures of chemical constituents identified by gas chromatography-mass spectrometry for the fruits of Opuntia ficus-indica (L.) Miller (BEP-10 extract).

FIGURE 4 -

Peak areas (%) for the major components of Opuntia ficus-indica (L.) Miller (BEP-10 extract).

FIGURE 5 -

Colonies of HepG2 cells treated with A) extract BEP-10 (0, 0.75, 1.5, 2.25 µg/mL; n = 2), and B) doxorubicin (0, 2, 4, and 6 µg/mL; n = 2) for 72 hours in 6-well plates followed by a 14-day period of incubation without extract. Bar graph showing x-axis: extract concentrations (BEP-10) or doxorubicin concentrations; and y-axis: colony number. Results are expressed as cell number ± standard deviation of two independent experiments.