ABSTRACT
This paper was aimed to study the effect of ethyl acetate extracts of Gentianella acuta on the gene and protein of insulin significant signal IRS-1 and Akt in insulin resistance (IR) HepG2 cells.The CCK-8 method was used to detect the HepG2 cell activity.HepG2 cells of human liver cancer were cultured with high concentration insulin (10-6 mol· L-1)for 36 hours to establish IR cell model.According to the results of CCK-8,the control group,model (IR) group,ethyl acetate extracts of Gentianella acuta IR + 50 μg· mL-1,IR + 500 μg· mL-1 group,and the metformin group were divided.Glucose consumption was measured with a glucose assay kit.The expressions of IRS-1 and Akt gene in IR HepG2 cells were detected by RT-PCR after 6-hour using of ethyl acetate extracts of Gentianella acuta.Western blot was used to detect the expression of IRS-1 and Akt protein after 6-hour using of ethyl acetate extracts of Gentianella acuta.The results showed that when the concentration of ethyl acetate extracts of Gentianella acuta was 500 μg· mL-1,the survival rate reached 95％.When the concentration was higher than 500 μg· mL-1,the survival rate decreased.Compared with the IR group,the IR + 50 μg· mL-1 group and the IR + 500 μg· mL-1 group promoted glucose consumption of IR HepG2 cells,but its effect was less than that of the metformin hydrochloride group.The expression of IRS-1 and Akt in IR HepG2 cells was significantly increased by using RT-PCR in the group of IR + 50 μg· mL-1 and IR + 500 μg·mL-1 compared with the IR group after 6-hour using of ethyl acetate extracts of Gentianella acuta.The expression of IRS-1 and Akt protein in the group of IR + 50 μg· mL-1 and IR + 500 μg· mL-1 was significantly higher than that in the IR group after 6-hour medication detected by western blot.It was concluded that the ethyl acetate extracts of Gentianella acuta can increase the expression of IRS-1,Akt gene,the expression of IRS-1 and Akt protein in HepG2 cells,which may be the mechanism of IR improvement.
ABSTRACT
In the search for novel potent fungi-derived bioactive compounds for bioinsecticide applications, crude ethyl acetate culture filtrate extracts from 110 mangrove fungal endophytes were screened for their toxicity. Toxicity tests of all extracts against brine shrimp (Artemia salina) larvae were performed. The extracts with the highest toxicity were further examined for insecticidal activity against Spodoptera litura larvae and acetylcholinesterase (AChE) inhibition activity. The results showed that the extracts of five isolates exhibited the highest toxicity to brine shrimp at 50% lethal concentration (LC50) values of 7.45 to 10.24 ppm. These five fungal isolates that obtained from Rhizophora mucronata were identified based on sequence data analysis of the internal transcribed spacer region of rDNA as Aspergillus oryzae (strain BPPTCC 6036), Emericella nidulans (strains BPPTCC 6035 and BPPTCC 6038), A. tamarii (strain BPPTCC 6037), and A. versicolor (strain BPPTCC 6039). The mean percentage of S. litura larval mortality following topical application of the five extracts ranged from 16.7% to 43.3%. In the AChE inhibition assay, the inhibition rates of the five extracts ranged from 40.7% to 48.9%, while eserine (positive control) had an inhibition rate of 96.8%, at a concentration of 100 ppm. The extracts used were crude extracts, so their potential as sources of AChE inhibition compounds makes them likely candidates as neurotoxins. The high-performance liquid chromatography profiles of the five extracts differed, indicating variations in their chemical constituents. This study highlights the potential of culture filtrate ethyl acetate extracts of mangrove fungal endophytes as a source of new potential bioactive compounds for bioinsecticide applications.