## 4 Discussion
However, they also observed significant variations between trees, and in some instances, comparable antioxidant activity was found in both green and yellow leaves. Thus, concerning polyphenolic compounds in ginkgo, our results indicate that the developmental stage plays a significant role. Additionally, we must consider factors such as the age of the tree and variability between individual trees. Fallen leaves and autumn leaves exhibit significantly higher inhibition of acetylcholinesterase increase compared to green leaves, indicating that leaves at later developmental stages contain more bioactive compounds with these activities. The inhibition of acetylcholinesteraseinesterase is associated with neuroprotective potential, and ginkgo is widely recognized for its neuroprotective properties [33]. Compounds contributing to this activity include flavonoids, particularly the dimeric forms such as ginkgetin [34], which are abundant in yellow ginkgo leaves [20] and have been shown to strongly inhibit acetylcholinesteraseinesterase [35]. Another study also supports the finding that yellow ginkgo leaves exhibit stronger cholinesterase inhibition activity compared to green leaves [15]. Different ginkgo extracts have been studied for acetylcholinesterase inhibition [36]; however, our report demonstrates for the first time that infusions also exhibit this activity, although likely at lower levels compared to other extracts. Notably, the highest inhibition recorded in fallen leaves was only 10.4%. Our data showed the high inhibition activity of \(\alpha\)-glucosidase by all three tested infusion types, and we did not record any differences between tested infusions. This inhibition activity is related with potential use of infusions in the treatment of diabetes, since \(\alpha\)-glucosidase inhibitors may inhibit the absorption of carbohydrates from the small intestine [37]. [PERSON] et al. [13] also examined the inhibition activity of \(\alpha\)-glucosidase using ginkgo leaf infusions and ethanolic extracts. The results showed dose-dependent inhibition and variability between trees from which the leaves were collected. Consistent with our findings, the activity of infusions prepared from leaves harvested in both October and June was comparable. A recent docking and in vitro study by [PERSON] et al. [38] examined the \(\alpha\)-glucosidase inhibitory activity of various compounds from ginkgo leaves, identifying quercetin and quercetin as potential inhibitors. These compounds, being water-soluble, are present in ginkgo infusions [7; 39; 40]. Tyrosinases, enzymes responsible for melanin production across all life domains, are targeted by inhibitors used both to prevent certain skin disorders and as active ingredients in skin-whitening products [41]. In our study, significantly higher tyrosinase inhibition was observed in both types of yellow leaf infusions compared to green leaves, suggesting that yellow leaves could also be utilized in such preparations. Ginkgo leaf extracts prepared from leaves collected in September in China with 80% methanol also demonstrated tyrosinase inhibition activity [29]. Additionally, [PERSON] et al. [42] showed that ethanolic extracts from green ginkgo leaves inhibited \(\alpha\)-MSH-induced melanogenesis in murine melanoma (16F10) cells by downregulating melanogenic protein expression. Compounds in ginkgo associated with tyrosinase inhibition include flavonoid aglycones and terpene lactones [43]. However, ginkgo leaves also contain ginkgolic acids, which exhibit tyrosinase inhibition but can cause toxic or allergic reactions when ingested in high amounts; their content is therefore limited to 5 ppm in extracts by the European Pharmacopeia. [PERSON] et al. [27] compared green and yellow ginkgo leaf extracts, reporting significantly higher levels of ginkgolic acids in yellow leaves.