Pythium insidiosum: inhibitory effects of propolis and geopropolis on hyphal growth

Abstract Propolis and geopropolis are resinous products of bees showing antimicrobial effects. There is no data concerning their action against Pythium insidiosum - the causative agent of pythiosis, a pyogranulomatous disease of the subcutaneous tissue that affects mostly horses, dogs and humans. Fragments of 15 isolates of P. insidiodum were incubated with propolis and geopropolis extracts and evaluated for up to seven days to detect the minimal fungicidal concentration (MFC). Propolis inhibited three isolates at 1.0 mg mL-1 after 24 h and all other isolates at 3.4 mg mL-1. Geopropolis led to more variable results, exerting predominantly a fungistatic action than a fungicidal one. Propolis was more efficient than geopropolis in inhibiting P. insidiosum since lower concentrations led to no growth after 24 h. This effect may be due to propolis chemical composition, which has more active compounds than geopropolis. Propolis seemed to be a good candidate for in vivo studies, since treatment with conventional antifungal compounds is difficult in most of the cases, requiring extensive surgical debridement.

Geoprópolis de Melipona fasciculata SMITH: ações citotóxica, imunomoduladora, antibacteriana e antifúngica / Geopropolis of Melipona fasciculata SMITH: cytotoxica actions, immunomodulatory, antibacterial and antifungal

Própolis é composta por substâncias resinosas, coletadas de várias plantas por abelhas africanizadas, adicionando pólen, cera e secreções glandulares, enquanto para a produção de geoprópolis (Geo) as abelhas sem ferrão utilizam materiais resinosos de plantas, cera, e ainda acrescentam terra ou barro. As atividades biológicas da própolis produzida por Apis mellifera têm sido extensivamente estudadas, mas ainda são escassos os trabalhos sobre as propriedades da geoprópolis. Assim, o presente trabalho se propôs a investigar as atividades citotóxica, imunomoduladora, antibacteriana e antifúngica do extrato hidroalcoólico de geoprópolis de Melipona fasciculata Smith. Foi realizada a caracterização química da Geo, verificando que o principal grupo de compostos encontrados foram triterpenos. No tocante às células do carcinoma da laringe humana (HEp-2), Geo apresentou ação inibitória em concentrações mais elevadas; entretanto, esta ação foi somente citostática. Geo apresentou ação imunomoduladora sobre monócitos humanos, estimulando a produção das citocinas estudadas (TNF-α e IL-10). Não foi observada ação antibacteriana contra S. aureus e E. coli, havendo inibição destas linhagens somente com altas concentrações do extrato. Contudo, a associação de Geo com antibióticos favoreceu a ação do cloranfenicol sobre S. aureus. A Geo exerceu ação inibitória sobre Pythium insidiosum, tanto para o isolado obtido de caso humano como de eqüinos. Os resultados sugerem que a Geo apresentou inúmeras propriedades biológicas; contudo, sua ação é menor em comparação à própolis produzida por abelhas africanizadas, talvez devido ao baixo rendimento do extrato e sua difícil solubilidade...

Propolis is composed of resinous substances collected from various plants by Africanized honeybees, adding polen, wax and bee secretions, while for geopropolis (Geo) production stingless bees use resinous materials from plants, wax, but also adding mud or clay. The biological activities of propolis produced by Apis mellifera have been extensively studied, but there are few studies on Geo properties. Thus, the present study investigated the cytotoxic, immunomodulatory, antibacterial and antifungal activities of hydroalcoholic extract of Geo produced by Melipona fasciculata Smith. The chemical characterization of Geo was performed, revealing that the main group of compounds was triterpenes. Geo exerted an inhibitory action on human larynx carcinoma cells (HEp-2) using high concentrations, however, it was only a cytostatic action. Geo exhibited immunomodulatory effects on human monocytes, stimulating cytokines production (TNF-α and IL-10). No antibacterial activity was seen against S. aureus and E. coli. However, the combination of Geo with chloramphenicol favored its effect against S. aureus. Geo exerted an inhibitory action against Pythium insidiosum, both for human or equine isolates. Data suggested that Geo presented several properties; however, its activity is lower compared to propolis produced by honeybees, perhaps due to the low yield of the extract and its difficult solubility...