Antifungal, Antibacterial, and Antioxidant Activities of Acacia Saligna (Labill.) H. L. Wendl. Flower Extract: HPLC Analysis of Phenolic and Flavonoid Compounds

Abstract

In this study, for the environmental development, the antifungal, antibacterial, and antioxidant activities of a water extract of flowers from Acacia saligna (Labill.) H. L. Wendl. were evaluated. The extract concentrations were prepared by dissolving them in 10% DMSO. Wood samples of Melia azedarach were treated with water extract, and the antifungal activity was examined at concentrations of 0%, 1%, 2%, and 3% against three mold fungi; Fusarium culmorum MH352452, Rhizoctonia solani MH352450, and Penicillium chrysogenum MH352451 that cause root rot, cankers, and green fruit rot, respectively, isolated from infected Citrus sinensis L. Antibacterial evaluation of the extract was assayed against four phytopathogenic bacteria, including Agrobacterium tumefaciens, Enterobacter cloacae, Erwinia amylovora, and Pectobacterium carotovorum subsp. carotovorum, using the micro-dilution method to determine the minimum inhibitory concentrations (MICs). Further, the antioxidant capacity of the water extract was measured via 2,2′-diphenylpicrylhydrazyl (DPPH). Phenolic and flavonoid compounds in the water extract were analyzed using HPLC: benzoic acid, caffeine, and o-coumaric acid were the most abundant phenolic compounds; while the flavonoid compounds naringenin, quercetin, and kaempferol were identified compared with the standard flavonoid compounds. The antioxidant activity of the water extract in terms of IC50 was considered weak (463.71 μg/mL) compared to the standard used, butylated hydroxytoluene (BHT) (6.26 μg/mL). The MIC values were 200, 300, 300, and 100 µg/mL against the growth of A. tumefaciens, E. cloacae, E. amylovora, and P. carotovorum subsp. carotovorum, respectively, which were lower than the positive control used (Tobramycin 10 μg/disc). By increasing the extract concentration, the percentage inhibition of fungal mycelial was significantly increased compared to the control treatment, especially against P. chrysogenum, suggesting that the use of A. saligna flower extract as an environmentally friendly wood bio-preservative inhibited the growth of molds that cause discoloration of wood and wood products.

The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC

“…saccharum with citric acid has shown good inhibition against the growth of T. viride, F. subglutinans, and A. niger [44], which is related to the presence of phenolic compounds such as p-hydroxy benzoic acid, gallic acid, salicylic acid, and caffeine. M. azedarach wood treated with A. saligna flowers has shown antifungal and antibacterial activities with a high content of quercetin, benzoic acid, naringenin, caffeine, o-coumaric acid, and kaempferol [45]. Additionally, M. azedarach wood samples treated with peel extracts of Musa paradisiaca L. in the presence of ellagic acid, gallic acid, rutin, myricetin, and naringenin have shown good antifungal activity against R. solani and F. culmorum, as well as antibacterial activity against A. tumefaciens [39].…”

“…Partial amplification of the 16S rRNA gene using P0 (5 -GAAGAGTTTGATCCTGGCTCAG-3 ) and P6 (5 -CTACGGCTACCTTGTTACGA-3 ) primers was analyzed by a thermal cycler (Techne prime, Cambridge, UK). The partial amplicons were purified and sequenced with a ABI3730XL DNA sequencer at Macrogen Inc. (Seoul, South Korea) [45].…”

“…The HPLC apparatus and conditions used (Table 1), as well as all the standards used, can be found in previous works [39,44,45,52]. The minimum concentration that the detector was able to measure was 0.1 µg/mL.…”

“…On the other hand, and during storage conditions with moist and poor environments, wood, wood containers, and wood-boxes may deteriorate or become stained with the growth of molds [36], which colonize these wood types and use simple sugars and starches for growth [37,38]. Previous works have shown that extracts or essential oils have potential antimicrobial activities against several fungi and bacteria in treated wood of Pinus sylvestris, P. rigida and Fagus sylvatica, Leucaena leucocephala, Melia azedarach, and Acacia saligna [39][40][41][42][43][44][45][46].…”

Inhibition of Fusarium culmorum , Penicillium chrysogenum and Rhizoctonia solani by n‐hexane extracts of three plant species as a wood‐treated oil fungicide

“…Most recently, wood samples treated with Acacia saligna water extract showed inhibition of fungal mycelial growth of F. culmorum , P. chrysogenum and R. solani (Al‐Huqail et al . ).…”