Alkaloids from Solanum paniculatum L. leaves

Abstract

The roots, stems, leaves and fruits of Solanum paniculatum L. are used in Brazilian folk medicine as well as in culinary [1]. This species was formerly included in Brazilian Pharmacopoeia, but was removed from newer editions, due to the lack of scientific evidence on its medicinal use. Aiming at the expansion of the number of herbal medicines available for basic pharmaceutical care S. paniculatum L. was included by Brazilian Ministry of Health in a list of herbal medicines to guide research on their efficacy and safety. Solanum species are known to synthesize steroidal glycoalkaloids (SGA) in its leaves, roots and fruits. Jurubin, a 3β-amino-5α-furostane alkaloid was isolated from S. paniculatum L. [2]. The present report focus on the results of the phytochemical analysis an alkaloid fraction, obtained from leaves of S. paniculatum L.. Acid hydrolysis of a sample of the alkaloid enriched fraction produced five genins (ESI/HRMS analysis, 2 x C27H44NO2, C27H46NO2, C27H44NO3, C27H46NO3) and only one sugar, identified as glucose (GC/FID of the alditol acetate). These results confirmed that all the alkaloids had genins of the furostane type and were all linked to glucose. HPLC/ESI/HRMS of the alkaloid enriched fraction showed five peaks with formulae: A, C33H58NO8; C33H56NO8 (two peaks, B and C); D, C33H57NO9 and E, C34H59NO8. The spectra of these compounds displayed fragment masses corresponding to the elimination of one hexose plus one water (180 mass units) confirming the results found in the hydrolysis assay. Thus, the data for A, the main peak in HPLC is consistent with O(26)-β-D-glucopyranosyl 3β-amino-5α-furostane-22α,26-diol (jurubin) and the remaining formulae are in accordance with glycosylated 3β-amino-5α-furostanes structures with different degrees of oxygenation and unsaturation.