Biological activities of plants traditionally used in Egyptian ethnopharmacology

The medicinal use of plants in Egypt is thousands of years old, although the best known record, the “Ebers Papyrus”, dates from approximately 1500 BC [1]. Much of this knowledge survived, especially in rural areas, becoming a valuable contribution to the discovery of compounds which may be the scaffold of new drugs.In the present study, six plants traditionally used in Egypt for medical purposes were chosen: Diospyros lotus, Bauhinia alba, Toona ciliata, Alhagi maurorum, Terminalia muelleri and Pistacia chinensis. Methanol (70%) extracts of aerial parts from these plants were prepared by maceration, evaporated to dryness and tested for bioactivities. The antioxidant activity of the extracts was determined by the DPPH radical scavenging and FeCl₃ reduction assays, the total phenolics by the Folin-Ciocalteau method and the in vitro anticholinesterasic activity by the Ellman method [2]. In vitro cytototoxicity against HeLa, MCF7, A549 and Vero cell lines was carried out according to a previously published method [3]. The strongest antioxidant activities, higher or comparable to quercetin, the standard compound used, were presented by T. muelleri and P. chinensis (EC50 of 4.0 and 4.7 µg/mL for DPPH and 6.95 and 49.3 µg/mL for the FeCl₃ reduction assay, respectively, compared with EC50 of 4.5 and 18.45 µg/mL exhibited by quercetin for the same assays). These results strongly correlated with the polyphenol content of the extracts. T. muelleri actively inhibited acetylcholinesterase (IC₅₀= 222.9 µg/mL, compared with 78.0 µg/mL for galanthamine), while the other extracts were not active in the range of concentrations tested. A. maurorum presented cytotoxicity against all the cell lines tested, particularly against HeLa tumor cell line (EC₅₀= 16.8 µg/mL, compared with 0.12 µg/mL for the standard Taxol). Preliminary phytochemical characterization of the extracts showed the presence of carbohydrates, flavonoids, triterpenes and tannins.

Keywords: Anticholinesterasic, cytotoxicity, antioxidant, ethnopharmacology

References:

[1] Borchardt JK. The beginnings of drug therapy: Ancient mesopotamian medicine, Drug News Perspect 2002; 15: 187 – 192.

[2] Barreto MC, Arruda M, Rego E, Medeiros JS, Rainha N. Cell-free assays. In: Barreto MC, Simões N. Determination of Biological Activities. A Laboratory Manual, N. Universidade dos Açores, Ponta Delgada; 2012: 65 – 81.

[3] Moujir L, Seca AML, Silva AMS & Barreto MC. Cytotoxic activity of diterpenes and extracts of Juniperus brevifolia. Planta Medica 2008; 74: 751 – 753.