本研究采用红曲霉和巨大芽孢杆菌对番石榴叶基质进行混菌固态发酵，探讨发酵过程中番石榴叶精油成分的释放。结果表明，发酵后番石榴叶精油中的20种主要成分种类不变，但精油提取率显著提高，发酵10 d提取率达到未发酵组的6.53倍。组织结构分析结合酶学分析推断，糖苷酶破坏了番石榴叶的细胞壁、腺毛和液泡等结构，并进一步切断糖间链接和糖苷键，促进番石榴叶中芳香化合物的释放。发酵后番石榴叶精油的2,2-二苯基-1-苦基肼DPPH自由基清除能力下降26.15%，但是2,2′-联氮双-3-乙基苯并噻唑啉-6-磺酸阳离子ABTS+自由基清除能力，5-脂氧合酶和酪氨酸酶的抑制能力分别提高 32.66%、18.73%和7.87%，发酵10 d后相应IC50分别达到20.47±2.49 mg/mL、23.21±1.92 μg/mL和107.41±3.48 μg/mL，综合来看发酵能改善该精油的抗氧化和生物活性。本成果可为果树叶精油高效提取提供新方法，为开发新型活性天然保健产品提供途径。

In this work, the release of essential oil from guava leaves during the solid-state fermentation of guava leaf substrate with mixed strains, Monascus anka and Bacillus megaterium, were investigated. The results showed that the 20 main components in the guava leaf essential oil remained unchanged after fermentation, but the rate of essential oil extraction increased significantly and reached 6.53 times that of the unfermented group after 10 days of fermentation. Tissue structure analysis combined with enzymatic analysis inferred that glycosidases destroyed the cell walls, glandular trichomes, and vacuoles of guava leaves, and cleaved the intersugar linkages and glycosidic bonds, to promote the release of aromatic compounds from guava leaves. After fermentation, the DPPH radical scavenging ability of 2,2-diphenyl-1-picrylhydrazyl in guava leaf essential oil decreased by 26.15%, but the ABTS+ radical scavenging ability and 5-lipoxygenase inhibitory capacity and tyrosinase inhibitory capacity of 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) diammonium salt increased by 32.66%, 18.73% and 7.87%, respectively (with the corresponding IC50 values reaching 20.47±2.49 mg/mL, 23.21±1.92 μg/mL and 107.41±3.48 μg/mL, respectively). Overall, fermentation can improve the antioxidant and biological activities of the guava leaf essential oil. The results may provide a new insight into the efficient extraction of fruit leaf essential oils and a pathway for the development of novel natural health products.

广东省科技创新战略专项资金项目（2018JK35202003）；广东省省级科技计划项目（2017B020207003）；广东省科技创新战略专项（大专项+任务清单）项目（2019JK25203010）