Assessment of selected Yemeni medicinal plants for their in vitro antimicrobial, anticancer, and antioxidant activities

Abstract

Context: The role of natural products as a source for remedies has been recognized since the beginning of mankind. Nevertheless, a minority of folkloricly used medicinal plants have been evaluated for their pharmacological activities.

Objectives: The purpose of this study is to evaluate 33 selected Yemeni plants for their in vitro anticancer, antimicrobial, and antioxidant activities.

Materials and methods: The plants were extracted with methanol and hot water. The obtained 66 extracts were tested for their in vitro cytotoxic activity using the neutral red uptake assay against two cancer cell lines (5637 and MCF-7). The antimicrobial activity was determined using the agar diffusion method and MIC-determination. The DPPH radical method was used for the determination of antioxidant activity.

Results: Interesting cytotoxic activity was observed for Hypoestes forskalei (Vahl) R. Br. (Acanthaceae), Lycium shawii Roem. & Schult. (Solanaceae), Pergularia tomentosa L. (Asclepiadaceae), Psiadia punctulata (DC.) Vatke (Compositae), Pulicaria petiolaris Jaub. & Spach (Compositae) and Rosmarinus officinalis L. (Labiatae) (IC₅₀ values < 50 μg/mL). Antimicrobial activity with MIC values ≤ 125 μg/mL was exhibited against Gram-positive bacteria by Chrozophora oblongifolia (Del.) A.Juss. ex Spreng. (Euphorbiaceae), Myrtus communis L. (Myrtaceae), Phragmanthera regularis (Steud. ex Sprague) M.G. Gilbert (Loranthaceae) and R. officinalis. Antioxidant activity was observed for C. oblongifolia, M. communis, and P. regularis.

Conclusion: The results justified the use of some investigated plants in the Yemeni ethnomedicine. These findings demonstrated that some of the investigated plants could be a source of new cytotoxic and antibiotic compounds; however, further work is needed.

Keywords::

• Antibacterial
• cytotoxic
• folk medicine
• medicinal plants
• radical scavenging
• Yemen

Acknowledgments

Thanks go to Peter Koenig for supporting in the identification of the investigated plants, and to Jutta Fenske for tests with multi-resistant bacteria strains.

Declaration of interest

The first author (Ramzi A. Mothana) would like to extend deep thanks to the Alexander von Humboldt Foundation for a George Foster scholarship enabling the stay at Ernst-Moritz-Arndt University Greifswald. The authors alone are responsible for the content and writing of the paper.