Phenolic Compounds and Pentacyclic Triterpenes

Decoctions, macerations and fumigations of the stem bark and wood of Terminalia brownii 20 Fresen. are used in traditional medicine for fungal infections and as pesticides on field crops and in 21 traditional granaries in Sudan. In addition, T. brownii is commonly used for protecting wooden 22 houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts 23 of various polarities from the stem wood and bark were screened for their growth inhibitory effects 24 against filamentous fungi commonly causing fruit, vegetable and grain decay, as well as infections 25 in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best 26 antifungal activities, with MIC values of 250 μg/ml against Nattrassia mangiferae and Fusarium 27 verticillioides, and 500 μg/ml against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave 28 almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and 29 were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer 30 chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to 31 identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem 32 bark and wood were found to have a similar qualitative composition of polyphenols and 33 triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis(3) and trans34 (4) resveratrol-3-O-β-galloylglucoside, were identified for the first time in T. brownii. Moreover, 35 methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), 36 naringenin-4`-methoxy-7-pyranoside (7), 5,6-dihydroxy-3`,4`,7-tri-methoxy flavone (12), gallagic acid 37 dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) 38 were characterized. Our results justify the traditional uses of macerations and decoctions of T. brownii 39 stem wood and bark for crop and wood protection and demonstrate that standardized extracts could 40 have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. 41 Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 31 October 2017 doi:10.20944/preprints201710.0194.v1 © 2017 by the author(s). Distributed under a Creative Commons CC BY license. Peer-reviewed version available at Antibiotics 2017, 6, 37; doi:10.3390/antibiotics6040037