Phytochemical Composition, Antioxidant Activity, Spectroscopic (UV-Vis, FT-IR) and GC-MS Analyses of Corn Waste (Corn Cob) Extract from Ethyl Acetate, and Its Wound Healing Evaluation in Wistar Rats

Abstract

Introduction: The exploration of agricultural wastes for bioactive compounds is critical for advancing sustainable biomedical innovations. This study aimed to profile the phytochemical composition, antioxidant, and chemical composition of ethyl acetate extract of corn cob waste and then evaluate its wound healing activity in Wistar rats.

Materials and Methods: Powdered corn cob (1400 g) was extracted with ethyl acetate by maceration and concentrated with rotatory evaporator under reduced pressure. Phytochemicals (flavonoids, alkaloids, terpenoids, tannins, steroids, saponins, cardiac glycosides, anthraquinones and phenols) were examined in the ethyl acetate extract of the corn cob. Antioxidant activity was evaluated through lipid peroxidation inhibition, nitric oxide (NO) radical inhibition, hydrogen peroxide scavenging, DPPH radical scavenging, and ferric reducing antioxidant power (FRAP) assays. UV-Vis spectroscopy was used to identify chromophoric groups, FT-IR analysis elucidated functional groups, and GC-MS profiling determined the detailed chemical constituents of the extract. For in vivo assessment, 21 healthy female Wistar rats (70-130 g) were divided into three groups: povidone-iodine treated (positive control), untreated (negative control), and extract-treated (test group). Standard excision wounds (2 cm diameter) were created under ketamine–xylazine anesthesia, and treatments applied topically once daily for 16 days. Wound contraction was monitored every four days; haematological profiles and histopathological analysis of the blood and organs of control and test rats were also looked into.

Results: Results showed highly abundant (++) flavonoids, saponins, phenols, and alkaloids (Dragendorff’s, Wagner’s), alongside moderate (+) terpenoids, steroids, tannins, cardiac glycosides, and anthraquinones. Concentration-dependent antioxidant analyses across multiple assays suggest notable antioxidant potential, though generally lower values than ascorbic acid. FRAP values indicated moderate ferric ion-reducing capacity (0.6045±0.0075 µg at 100 µg/mL vs. 0.6505±0.0385 µg for ascorbic acid). DPPH radical scavenging reached 75.40±0.20 % at 100 µg/mL, compared to 86.27±0.73% for the standard. Hydrogen peroxide inhibition was 65.06±0.88 % (vs. 79.34±0.22 %), nitric oxide inhibition 67.05±0.49 % (vs. 72.29±0.16 %), and lipid peroxidation inhibition 78.69±0.28 % vs. 83.67±0.22 %. These findings suggest the extract contains electron-rich and radical-quenching phytochemicals with potential for oxidative stress mitigation and wound healing applications, albeit with slightly lower potency than ascorbic acid. UV analysis across 200-800 nm revealed a strong absorption band between 324 nm and 385 nm, with the highest peak (λmax) at 359 nm and a maximum absorbance (Amax) of 3.216. FTIR spectra confirmed the presence of alkanes, alkenes, alcohol, carboxylic acids, aromatics functional groups while GC-MS identified 23 compounds, including 5,8-Dihydroxy-2,7-dimethoxy-1,4-naphthoquinone, piperidine derivatives, pentadecanoic acid, 14-methyl-, methyl ester, and phthalazine-1,4(2H,3H)-dione, 2-(2-methylphenyl), which are well known for their pharmacological and biological activities, such as antimicrobial, anti-inflammatory, and antioxidant effects. Extract-treated rats achieved complete wound closure in 15.10±0.00 days, faster than povidone-iodine (16.00±10.30 days) and untreated controls (18.32±10.50 days). No significant haematological alterations were observed. Histopathological examination revealed complete re-epithelialization, minimal inflammation, and organized collagen deposition in the extract group which is comparable to the standard treatment.

Conclusion: This study showed that ethyl acetate extract of corn cob waste contains bioactive compounds with antioxidant and wound healing properties, demonstrating safety and therapeutic potential for sustainable biomedical applications.