Identification and Potency of Phenolic Compounds in Active Fractions of Unripe Fruit Peel Extract of Kayu Banana (Musa paradisiaca L.Var.Kayu) as an Antidiarrhea Drug In Vitro and In silico

In Indonesia, the unripe fruit of the Kayu banana (M. paradisiaca L. var. Kayu) is a drug that is often used empirically by the people of Senduro village, Lumajang, East Java, Indonesia, to treat diarrhea. This study was conducted to investigate the antibacterial activity of unripe fruit peel, unripe fruit flesh, and unripe fruit. A disc diffusion test was selected to assess the sensitivity of each sample to E. coli.  The disc dilution was used to determine the value of reduction in Optical Density and bacterial growth in E. coli. Total phenolic content to determine phenolic levels in samples that are suspected of providing antibacterial activity. Unripe fruit peel extract shows more optimal antibacterial activity compared to other extracts. The diameter value of the inhibitory zone of the unripe fruit peel extract is 17 mm and the yield of a large ΔOD is -1.3620 at a concentration of 10% w/v. Based on the calculation results from the regression equation, TPC fruit extract was obtained by 86.42 mgGAE/g ekstrak , TPC flesh extracts by 60.75 mgGAE/g ekstrak, and TPC from Unripe fruit Peel extract by 107.80 mgGAE/g ekstrak. These results suggest that the unripe fruit peel extract of banana Kayu has the potential to be antibacterial against E. coli

The ethyl acetate fraction has the most optimal antibacterial activity with an inhibitory zone of 19 mm in E. coli, a ΔOD at Concentration of 1mg/ml of ∆OD (Optical Density) -0.295 in E. coli and no bacterial growth with a total phenol value of 270.88 mg of gallic acid equivalent per gram of fraction. The results of the unripe fruit peel fraction of Kayu banana has different antibacterial activity and can inhibit the growth E. coli. The ethyl acetate fraction has the highest phenol content and a strong antibacterial activity category, so the unripe fruit peel of Kayu bananas can be developed into antibacterial drugs.

Isolation of bioactivity-guided compounds M. paradisiaca L. Var. Kayu has produced three phenolic isolates: irenolon, apigenin, and quercetin. Its structure is determined by interpretation of UV Spectrophotometry, FTIR, UPLC MSMS and 1D and 2D NMR data, and compared with literature. All isolats were evaluated for antibacterial activity in vitro and in silico. Quercetin has the most optimal activity against inhibition of the growth of E. coli bacteria and is able to bind to cell wall formation receptors in bacteria so that bacteria are unable to produce cell walls. This study may provide rational support for the use of unripe banana Kayu in diarrheal infections because the isolates antibacterial compounds are also present in the unripe fruit peel of banana Kayu.

Keywords: E. coli, Kayu banana, phenolic compound, antidiarrhea, apigenin, quercetin.