Identification of four entomogenous fungi and the inhibitory effect of their ethanol extracts on Hela cells

Abstract:

[Background] The entomogenous fungi were important resources from the nature, but few of them were found and utilized comparatively. [Objective] To identify four entomogenous fungi collected from the field, and to explore the inhibitory effect of their ethanol extracts on Hela cells. [Methods] Four entomogenous fungi were identified by morphological characteristics, rDNA ITS and β-tubulin sequence analysis. The inhibitory effect of ethanol extracts from mycelium (M-1, M-2, M-3, M-4) and ferment liquid (F-1, F-2, F-3, F-4) on Hela cell proliferation were analyzed by MTT assay. The inhibitory activity of the ethanol extract with the strongest inhibitory effect was detected by cell morphological observation and flow cytometry. [Results] After identification, strains IS and LS are Isaria catenianulata, strains HLS and HLS2 are Isaria farinose. The results of MTT showed that eight kinds of ethanol extracts inhibited the proliferation of Hela cells to some extent, and the order of inhibitory effect of ethanol extracts from mycelium and ferment liquid was Isaria farinosa HLS>Isaria catenianulata LS>Isaria farinosa HLS2>Isaria catenianulata IS, of which F-3 had the strongest inhibitory activity (P<0.001), and its IC50 value was 0.667 8 mg/mL after 24 hours of treatment, while the IC50 value of the other seven ethanol extracts were higher than 1 mg/mL. The cell morphological observation showed that the inhibitory effect of F-3 on Hela cell growth increased with the increase of the concentration when Hela cells were treated with F-3 for 24 h, however. F-3 has only slight toxic effect on BHK-21 cells; flow cytometry showed that F-3 could induce apoptosis of Hela cells, and the total apoptosis rate could reach 32.45% when the treatment concentration was 1.0 mg/mL. [Conclusion] The inhibitory effect of four entomogenous fungi on Hela cell proliferation is significantly different, which may be related to the geographical origin and host of four entomogenous fungi. F-3 ethanol extract from Isaria farinosa has no significant inhibitory effect on the proliferation and growth of BHK-21 cells, but has the strongest inhibitory effect on Hela cells proliferation and growth and has the effect of inducing tumor cells apoptosis, suggesting that it has the further research value.