**Chemical Composition and Antioxidant Activity of Steam-Distilled Essential Oil and Glycosidically Bound Volatiles from** *Maclura Tricuspidata* **Fruit**

**Gyung-Rim Yong, Yoseph Asmelash Gebru, Dae-Woon Kim, Da-Ham Kim, Hyun-Ah Han, Young-Hoi Kim and Myung-Kon Kim \***

Department of Food Science and Technology, Chonbuk National University, Jeonju 54896, Jeonbuk, Korea; rudfla1226@naver.com (G.-R.Y.); holden623@naver.com (Y.A.G.); eodns3344@gmail.com (D.-W.K.); dadaham@naver.com (D.-H.K.); hha208@Korea.kr (H.-A.H.); yhoi1307@hanmail.net (Y.-H.K.) **\*** Correspondence: kmyuko@jbnu.ac.kr; Tel.: +82-63-270-25512

Received: 12 November 2019; Accepted: 5 December 2019; Published: 9 December 2019

**Abstract:** Essential oil obtained from *Maclura triscuspidata* fruit has been reported to have functional properties. This study aimed at determining chemical compositions and antioxidant activities of steam-distilled essential oil (SDEO) and glycosidically bound aglycone fraction (GBAF) isolated from fully ripe *M. triscuspidata* fruit. SDEO was isolated by simultaneous steam distillation and extraction (SDE). GBAF was prepared by Amberlite XAD-2 adsorption of methanol extract, followed by methanol elution and enzymatic hydrolysis. Both fractions were analyzed by gas chromatography–mass spectrometry (GC–MS). A total of 76 constituents were identified from both oils. Apart from fatty acids and their esters, the SDEO contained *p*-cresol in the highest concentration (383.5 ± 17.7), followed by δ-cadinene (147.7 ± 7.7), β-caryophyllene (145.7 ± 10.5), β-ionone (141.0 ± 4.5), *n*-nonanal (140.3 ± 20.5), theaspirane A (121.3 ± 4.5) and theaspirane B (99.67 ± 9.05 μg/g). Thirteen carotenoid-derived compounds identified in the SDEO are being isolated from *M. triscuspidata* fruit for the first time. Out of the 22 components identified in GBAF, 14 were present only in the glycosidically bound volatiles. Antioxidant activity of the GBAF was higher than that of SDEO. These results sugges<sup>t</sup> that glycosidically bound volatiles of *M. triscuspidata* fruit have a good potential as natural antioxidants.

**Keywords:** *Maclura triscuspidata fruit; essential oil; glycosidically bound volatiles; gas chromatography-*mass spectroscopy (GC–MS); chemical composition; antioxidant activity
