Chemical characterisation and cytotoxicity evaluation of Convolvulus pluricaulis Sieb. ex Spreng. (Convolvulaceae) extracts towards sensitive and multidrug-resistant cancer cells

The modern research on cancer prevention and therapy is looking at the plant kingdom as possible source of molecules or new molecular platforms. Given the large number, variety, and the wide complexity of molecules synthesised by plant cells, researches investigate ethnopharmacology with the aim of enhancing the probability to discover new effective drugs [1]. In relation to these premises, two traditional preparations of Convolvulus pluricaulis Sieb. ex Spreng. (Convolvulaceae) whole plant was investigated: decoction (DEC), derived from the Ayurvedic medicinal system; and hydro-alcoholic extract (HE) closer to the Western phytotherapic tradition. The chemical fingerprinting showed two preparations characterized by the presence of phenolic compounds (es. caffeic acid, p-coumaric acid, isoferulic acid, ferulic acid and vanillin), identified and quantified by gas chromatography following a full validated method [2]. DEC, moreover, showed the presence of stigmasterol and lupeol. Taking into account the biological activity of C. pluricaulis reported in literature, and with the aim of extending its bioactivity panorama, the cytotoxic effect of the preparations, fractions and molecules, against two leukemic cell lines, one drug-sensitive (CCRF-CEM) and one multi-drug-resistant (CEM/ADR5000) was investigated. The best result against the CCRF cells was exhibited by the CHCl₃ DEC extract (IC₅₀= 16,18 ± 0,79 µg/ml), it could be explained by the presence of lupeol (IC₅₀= 9,62 ± 0,21µM), molecule with a well-known anticancer activity. ADR5000, instead, showed cross-resistance towards the every tested phytocomplexes and molecules, even if they exhibited IC₅₀ values lower than the doxorubicin one. The next step of the research will be the ADME evaluation of identified molecules using in silico model (GastroPlus™), and the assessment of the phytocomplexes activity agains cancer stem cells.

Keywords: Convolvulus pluricaulis, chemical characterisation, cytotoxicity, multidrug resistance, leukemia.

References:

[1] Guerrini A, Sacchetti G. From Ethnobotany towards Modern Botanicals as Paradigm of the Medicinal Plants Research: The Case of Ayurveda. Med Aromat Plants 2012; 1

[2] Caligiani A, Malavasi G, Palla G, Angela Marseglia A, Massimiliano Tognolini M, Bruni R. A simple GC-MS method for the screening of betulinic, corosolic, maslinic, oleanolic and ursolic acid contents in commercial botanicals used as food supplement ingredients. Food Chem 2013; 136: 735 – 741