Steroidal glycoalkaloids and molluscicidal activity of Solanum asperum Rich. fruits

Abstract

O fracionamento bio-monitorado do extrato alcaloídico dos frutos verdes de Solanum asperum forneceu um novo alcalóide esteroidal, denominado solanandaina, juntamente com a solasonina e a solamargina. Tanto o extrato alcaloídico como os glicoalcalóides isolados apresentaram potente atividade moluscicida.Bioassay-guided fractionation of the alkaloidal extract of the green fruits of Solanum asperum afforded a new compound, solanandaine along with solasonine and solamargine. The total crude alkaloids as well as the isolated pure alkaloids exhibited significant molluscicidal activity.Keywords: Solanum asperum, glycoalkaloid, solanandaine, solasonine, solamargine, molluscicidal IntroductionSolanum L. (Solanaceae) is distributed mainly throughout the tropical and subtropical regions of the world and is the largest and most complex genus of the family Solanaceae. In Brazil, Solanum is represented by about 350 species. 1 In this region, many species of Solanum are widely used in popular medicine and are commonly known as 'yubeba', the word derived from Tupi Guarani that refers to the prickles found on the stems of several of the species. 1 Some common and wide-spread Solanum species of Brazil had shown 2,3 considerable molluscicidal activity demonstrated by several members of the genus investigated earlier. 4,5 Thus, we have been studying various species of Solanum growing in our country 3,6-10 with the expectation that the extracts of plants of this genus might be useful in the control of Biomphalaria glabrata, the intermediate host of Schistosoma mansoni, the parasite that causes human schistosomiasis in Brazil. In our previous bioassays, the crude MeOH extract of the unripe fruits of S. asperum Rich showed 3,11 activity in studies with Artemia salina (LC 50 = 420.5 g mL -1 ) and Biomphalaria glabrata (LC 50 = 25.5 g mL -1 ). Bioassay-guided fractionation indicated that the activity was concentrated in the alkaloid fraction. Thus, the alkaloid fraction upon CC on Sephadex LH-20 followed by PTLC on Silica gel afforded a new compound, (2) and solamargine (3). In this work, we wish to report the isolation, characterization and the molluscicidal activity of the alkaloids of S. asperum unripe fruits. Results and DiscussionSolanum asperum Rich. is popularly known in Brazil as 'jussara' or 'coça-coça'. It is a neotropical species belonging to the section Brevantherum with wide distribution in South America. Extract of S. asperum unripe fruits demonstrated significant molluscicidal activity. With the aid of biossay-guided fractionation of the crude alkaloid mixture, solanandaine, solasonine and solamargine were isolated from the green fruits of S. asperum. Silva et al. 1049 Vol. 19, No. 5, 2008 Solanandaine (1) (Table 1) are fully compatible with a -D-glucose structure for this hexose unit. The other two anomeric signals are broad singlets at H 5.84 and 6.38, typical of -L-rhamnose unities. The HSQC spectrum shows that the three signals at C 100.6, 102.4 and 103.2 are due to the corresponding anomeric carbons of the three ...

Caavuranamide, a novel steroidal alkaloid from the ripe fruits of Solanum caavurana Vell. (Solanaceae)

“…10 The NOESY spectrum was used to confirm the proposed stereochemistry assignments made for caavuranamide 1 (Figure 2), as the trans junction of A/B ring and cis junction of D/E ring, as well as (25S)-22βN-spirosolane configuration (as observed for tomatidine) 9 and the orientation of 3β-N-formylamino group. A strong NOE (nuclear Overhauser effect) was observed between the signal of CH 3 The crude extracts and fractions obtained from acid-base treatment were evaluated for antimicrobial (Table 2) and in vitro antiproliferative activities (Table 3). According to Table 2, the ethanolic extracts do not show significant activity for neither of tested microorganisms, whereas CH 2 Cl 2 and n-but extracts, as well as those subfractions obtained from acid-base treatment, showed potent activity for E. coli, M. luteus, R. equi, B. subtilis and E. faecium, being similar and even in some cases, stronger than positive control chloramphenicol.…”

“…2 In Brazil, about 350 Solanum species have been identified, many of them endemic. 3 Solanum caavurana Vell. grows as a bush or a small tree with ca.…”

Flavonoids from the GenusSolanum

“…5 No Brasil, cerca de 350 espécies do gênero Solanum foram identificadas, sendo muitas delas endêmicas. 6 Espécies do gênero Solanum tem uma grande importância econômica mundial, já que muitas fazem parte da alimentação humana, como por exemplo: a batata (Solanum tuberosum), a beringela (Solanum melongena), o tomate (Solanum lycopersicum) e o jiló (Solanum gilo) 7 (Figura 1).…”

Derivados citotóxicos de vitanolidos isolados das folhas de Acnistus arborescens

“…15 Outros esteroides que são encontrados na famíla Solanaceae incluem glicosídeos e alcaloides esteroidais, compostos presentes nos gêneros Cestrum e Solanum, sendo este último gênero o que possui o maior número de espécies catalogadas. 16,17 Os primeiros trabalhos sobre a atividade farmacológica de vitanolidos em Acnistus arborescens foram feitos sobre inibidores de tumores; em um deles, utilizando-se do extrato alcoólico das folhas, observou-se significativa atividade biológica in vitro contra células de carcinoma humano da nasofaringe e in vivo contra sarcoma 180 em ratos; a ação farmacológica foi atribuída à vitaferina 1. 3 Acnistus arborescens conhecida popularmente como marianeira ou esporão de galo falso apresenta-se distribuída pelas Américas do Sul e Central; nesta espécie têm sido relatados vários compostos da classe dos vitanolidos incluindo vitacnistinas, 3 vitafisalinas 6,7 e derivados do vitanolido D:…”

“…16,17 Os primeiros trabalhos sobre a atividade farmacológica de vitanolidos em Acnistus arborescens foram feitos sobre inibidores de tumores; em um deles, utilizando-se do extrato alcoólico das folhas, observou-se significativa atividade biológica in vitro contra células de carcinoma humano da nasofaringe e in vivo contra sarcoma 180 em ratos; a ação farmacológica foi atribuída à vitaferina 1.…”