Screening of Some Local Traditional Plants for their Antitumor and Antibacterial Activities Against the Global Emergence of Multi-Drug Resistant Bacteria

Abstract

Saudi Arabia flora has many medicinal plants which are traditionally used in inhibition of many human pathogens. Echinops macrochaetus (Camel thistle) and Xanthium spinosum (Spiny cocklebur) from the Asteraceae family and Lemongrass (Oymbopogon citrates) from the Gramineae family are one of the local plants which are quite popular but less studied scientfically. Hence in the present work, they were analysed for their medicinal efficacies , for which they were collected and extracted using either hot water or organic solvents (n-butanol, diethyl ether andethyl acetate). The antibacterial activities of the previous plants extracts were detected and the methanolic extract of the three tested plants gave excellent inhibition of the tested bacterial pathogen, Escherichia coli while the aqueous extracts recorded the lowest bacterial inhibition. The susceptibility of the tested bacteria to the three methanolic plant extracts and control antibiotic was tested using agar well diffusion method. The methanolic extract of Echinops recorded excellent antibacterial activity while Xanthium and Oymbopogon recorded moderate activities against the Gram negative Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus mirabilis in addition to the Gram positive Staphylococcus aureus and Enterococcus faecalis. The mean antibacterial activities (bacterial index) was maximum for the methanol extract of Echinops (21.8 mm) followed by Xanthium (13.8 mm) and Oymbopogon (12.5 mm). Moreover, In vitro MTT test and Neutral Red assays were used to detect any antitumor activities of the three tested plant extracts. Echinops extract showed excellent antitumor activity against two cell lines, MCF-7 (breast cancer) and HepG2 (hepatocellular carcinoma) with no toxicity (recorded using Artimia salina for the assay). Also, using fluorescein diacetate microdilution method, minimal inhibitory concentrations (MICs) and the Fractional Inhibitory Concentrations of the methanolic extract of Echinops, ciprofloxacin and their mixture were calculated. FIC index ranged from 0.89-1.15 that means there is an additive effect between Echinops extract and ciprofloxacin. In conclusion, the results show that Echinops methanolic extract single or mixed with the antibiotic ciprofloxacin demonstrated excellent inhibitory activities for all tested urinary tract pathogenic bacteria.