Biological Properties And GC-MS Identification of Compounds of Ethanol Extracts and Volatile Oils From Citrus sinensis, Citrus paradisi and Citrus reticulata

The numerous health advantages of citrus fruits are generally well-known. Therefore, this study investigated bioactive properties of ethanol extracts and volatile oils of three citrus fruits (orange, grape and tangerine) wastes. The antioxidant activities of the extracts and volatile oils were assessed using the 2, 2-diphenylpicrylhydrazyl (DPPH) radical scavenging test, while the antimicrobial qualities were determined using agar-well diffusion method. Gas chromatographymass spectrometry (GC-MS) was used to identify the chemicals constituents. The sample peel extracts exhibited effective inhibition against certain bacterial isolates, according to the results of the antibacterial assay. The mycelial inhibitory activity of all the citrus fruit waste extracts against Corynespora sp. was significantly higher (60–84%) than that of any other fungal pathogens under investigation. All the extract exhibited significant (p < 0.05) increases in antioxidant activity in a concentration-dependent manner. Bioactive compounds with known antibacterial properties were identified in the extracts' GC-MS fingerprints. 1,2-benzenedicarboxylic acid and diisooctyl ester were prevalent in grapes, accounting for 22.9% in pomace, 21.64% in seed, 15.07 percent in peel, and 23.15% in volatile oil, respectively. However, in the tangerine samples, n-hexadecanoic acid was the most prevalent compound with peel (25.42%) and seed (23.31%) extracts, and (+)- spathulenol (22.30%) being the most dominant in the volatile oil. In contrast, n-hexadecanoic acid was most dominant in the orange samples with percent composition in pomace (20.94%), seed (21.00%), peel (21.07%), and volatile oil (19.71%). Thus, these findings revealed that the citrus fruits wastes could be alternative sources of bioactive ingredients with antimicrobial and antioxidant potentials.