Phytochemical and pharmacological studies on total alkaloid fraction of Solanum pseudocapsicum species group (Solanaceae).

GUTIÉRREZ, M. A.; ORTEGA, G. ; KONIGHEIM B.; CABRERA J. L; BARBOZA G. E.

Simposio; I Reunión Internacional de Ciencias Farmacéuticas; 2010

Universidad Nacional de Córdoba

Introduction The Solanum pseudocapsicum  species group includes 5 Americans species. It is strongly promising as new potential natural resource. One of its worldwide species, S. pseudocapsicum, has antimicrobial, antiviral, antispasmodic, cytotoxic, antihypertensive, hepatoprotective, anti-tumor and antioxidant properties that have been proved with crude extracts or extracts enriched in alkaloids. From the phytochemical point of view, this species is peculiar by having an alkaloid of unusual structure, the solanocapsine, along with other minor alkaloids. The objectives in this work are: 1) to verify the presence of solanocapsine in the remaining native South American species in order to determine its chemotaxonomical value; 2) to test anticholinesterase and antiviral activities (against non endemic and Argentinean endemic viruses).  Material and methods The alkaloid extraction was made from dry leaves. The identification of solanocapsine was performed by Nuclear Magnetic Resonance Spectroscopy of Carbon (13C NMR), through the presence of the unique and characteristics signal of the 18 carbon of solanocapsine (spectra of 13C RMN, ¦Ä= 96,77 ppm). 13C NMR spectra of extracts enriched in alkaloids were made for S. pseudocapsicum L., S. delicatulum L.B. Smith & Downs, S. argentinum Bitter & Lillo, and S. tucumanense Griseb. The anticholinesterase activity was proved by inhibiting the enzyme acetylcholinesterase, using the Ellman et al. (1) methodology. For the antiviral activity, the Herpes simplex virus type I (VSH-I, strain Kos p31), the virus of the Encephalitis Equina Venezolana (EEV, strain TC83), the virus of the Encephalitis of San Luis (VESL, strain 78V6507) and the virus Jun¨ªn (VJ, strain XJ Cl3) were used. The activity was measured by the method of neutral red uptake. Results The presence of solanocapsine was detected in S. pseudocapsicum, S. argentinum and S. tucumanense. A high inhibition on the acetylcholinesterase was observed in extracts of S. pseudocapsicum while the inhibition was moderate for S. argentinum and S. tucumanense. Solanum delicatulum¡¯s extracts did not show inhibition. Solanum pseudocapsicum showed high antiviral activity against VJ and EEV while S. delicatulum have low activity against EEV and VSH-I. The extracts of S. tucumanense were negative against these viruses. Conclusions Apparently, solanocapsine is a chemotaxonomic marker since it is present in most species of the S. pseudocapsicum species group. The solanocapsine is not responsible for the pharmacological activities tested due to anticholinesterase and antiviral activities were not evidenced in the species with solanocapsine. Solanum pseudocapscium is the species pharmacologically more active. References 1.       Ellman GL, Courtney KD, Andres V Jr, Featherstone RM. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem. Pharmacol. 1961;7: 88-95.