This study aimed to investigate the components, biological activities, and flavor characteristics of Armillaria gallica fermented Gastrodia elata Bl. (FGR) and to explore the changes in bioactive substance contents and biological activities during fermentation stages. Meanwhile, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was applied to identify the composition of flavor substances in FGR. The results showed that the contents of total polyphenols, total flavonoids, gastrodin (GAS), and p-hydroxybenzyl alcohol (HBA) were generally increased during the fermentation process and reached a stable state after 7 days at (57.67 ± 2.72) mg/mL, (52.09 ± 5.03) mg/mL, (4714.62 ± 45.94) μg/mL, and (2064.73 ± 12.82) μg/mL, respectively. However, the total triterpenoid content decreased to (0.12 ± 0.01) mg/mL. The results of antioxidant and cellular assays demonstrated that the antioxidant capacity of FGR was higher than that before fermentation, and exhibited more significant protective activity on PC12 cells. The sensory profile varied at different fermentation time, and the unpleasant odor of G. elata Bl. was significantly reduced after fermentation. The analysis of the relative contents and odor activity values (OAVs) of volatile substances showed that the contents of unpleasant odor substances (p-cresol, isovaleraldehyde, naphthalene, sulfide, and pyrazine) in FGR were decreased, while the contents of volatile components with pleasant aroma (phenylethanol, isovaleraldehyde, 2,3-hexanedione, and 4-N-propylbenzaldehyde) were increased compared to the unfermented control. A. gallica fermentation could alleviate the unpleasant odor of G. elata Bl. and impart more pleasant mushroom-like, floral, and fruity aromas. This study provides data support for FGR development and utilization.

High performance liquid chromatography (HPLC) fingerprints and multi-component determination methods were established to investigate the differences in quality among the dried tubers of wild-simulated Gastrodia elata Bl. (Rhizoma Gastrodiae) from different geographical origins by combining fingerprint similarity evaluation, principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). By comparative analysis of the fingerprints of 15 batches of Rhizoma Gastrodiae samples from major production regions in Guizhou province, a total of 14 shared peaks were identified and assigned to 6 signature components, including gastrodin, p-hydroxybenzyl alcohol, parishin E, parishin B, parishin C and parishin A. PCA showed that the first three principal components cumulatively explained 83.373% of the variance, and gastrodin and parishin A were selected as markers to discriminate between different categories of Rhizoma Gastrodiae. OPLS-DA ascertained that gastrodin, p-hydroxybenzyl alcohol, parishin C, parishin B, and parishin A affected the quality of Rhizoma Gastrodiae. The total content of signature components of Rhizoma Gastrodiae was 12.957–36.738 mg/g, and parishin A accounted for the largest proportion of it. Under the same limiting condition, significant differences in the contents of signature components were observed between wild-simulated and bag-cultivated Rhizoma Gastrodiae. The antioxidant capacity and neuroprotective activity of Rhizoma Gastrodiae were investigated by kits and in vitro cellular experiments, revealing that the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radical and hydroxyl radical scavenging capacity and neuroprotective activities of wild-simulated Rhizoma Gastrodiae on PC12 and HT-22 neurons were superior to those of bag-cultivated Rhizoma Gastrodiae. This study provides data support for the establishment of quality standards for wild-simulated Rhizoma Gastrodiae.