Propolis from the northwest of Argentina as a source of antifungal principles

Abstract

Aims: To determine the antimycotic and cytotoxic activities of partially purified propolis extract on yeasts, xylophagous and phytopathogenic fungi. To compare these activities with pinocembrin and galangin isolated from this propolis and with the synthetic drugs ketoconazole and clortrimazole. Methods and Results: Ethanolic propolis extract was partially purified by cooling at −20°C. Two of its components were isolated by HPLC and identified as pinocembrin and galangin. The antifungal activity was assayed by bioautography, hyphal radial growth, hyphal extent and microdilution in liquid medium. Cytotoxicity was studied with the lethality assay of Artemia salina. The obtained results were compared with the actions of ketoconazole and clortrimazole. The results showed that the antifungal potency of ketoconazole and clortrimazole is higher than pinocembrin, galangin and the partially purified propolis extract in this order. Otherwise, the cytotoxicity of the synthetic drugs is also the highest. Conclusions: Partially purified propolis extract inhibits fungal growth. The comparison of its relative biocide potency and cytotoxicity with synthetic drugs and two components of this propolis (pinocembrin and galangin) showed that the propolis from ‘El Siambón’, Tucumán, Argentina, is a suitable source of antifungal products. Significance and Impact of the Study: The partially purified propolis extract and its isolated compounds, pinocembrin and galangin, have the capacity of being used as antifungals without detriment to the equilibrium of agroecosystems. The impact of this study is that the preparation of agrochemicals with reduced economic costs using a partially purified preparation as the active principle is possible.

Antifungal activity against postharvest fungi by extracts from Colombian propolis

“…creatures that have been killed by bees after an invasion) within the hive by inhibiting microbial growth. 4 Therefore, the presence of propolis may provide an environment not suitable for the growth of fungi and other microorganisms, and consequently to keep the hive environment aseptic. 5 In this way, one of the most frequent applications of bee glue is its antimicrobial activity against many gram-positive and gram-negative bacteria, yeasts and fungi, most of them associated with varying degrees of pathogenicity in humans.…”

“…6,7 However, the action of propolis against phytopathogenic fungi has received little attention. 4 Thus, this natural antifungal agent could be potentially exploited in controlling the growth of phytopathogenic fungi during post-and pre-harvest.…”

In vitro antifungal activity of propolis samples of Czech and Slovak origin

“…as shown by Metzner et al [20], who found substantially lower values of MIC with ethanolic extract of propolis compared with that of pinocembrin (5,7-dihydroxyflavone). On the contrary, Quiroga et al [21] showed that partially purified propolis extract had lower antifungal activity than two isolated compounds pinocembrin and galangin. In the present study, almost all extracts were more effective in inhibiting the fungal strains tested than the raw propolis samples (Table 3).…”

The "in vitro" antifungal activity evaluation of propolis G12 ethanol extract on Cryptococcus neoformans

“…These phenolic compounds are considered as one of the mainly responsible for its antimicrobial activity 1,15 . QUIROGA et al 16 demonstrated that pinocembrin and galangin were partially responsible to the toxic activity against several strains of phytopathogenic fungi. The minimal inhibitory concentration values for pinocembrin and galangin were between 14-40 µg mL -1 .…”