## 4 Limitations and Future Perspectives  
Despite the proposed benefits, several considerations must be taken into account when proposing the use of naturally grown herbs like rosemary for pharmaceutical and therapeutic uses. And, whilst the evidence suggests that rosemary has undeniable potential in this field, particularly for AD and PD [9; 131], the consistency and validity of the results are the primary factors in need of optimization before establishing its use. A significant gap in the literature on this topic seems to stem from the fact that most of the experimental studies have been performed on animal models or in vitro [10; 79; 129; 130]. So, there is an undeniable need for larger-scale clinical trials that perform a much more thorough investigation of the extracts' results. Another gray area that needs to be addressed is the composition of the extract. Understanding that different cultivating conditions can produce many variables in compounds, it is safe to say that with the aid of biotechnology, further research should be conducted in order to by-pass this drawback [7]. More specifically, the mechanisms of action of other key components of RO, apart from CA and RA, should be fully evaluated in order to determine the correct dose of the extract as well as of each of its components. One solution may be the use of genetically modified rosemary, with a more \"fixed\" and better regulated consistency of compounds, which may also ameliorate sustainability issues and its future widespread use. Lastly, apart from its beneficial synergistic action alongside drugs, a definite area of interest in need of exploration is rosemary's interactions with other treatments in order to minimize the possibilities of adverse reactions or the aggravation of any pre-existing side effects [133]. As far as the future perspective on functional foods and dietary implementations are concerned, it is widely supported by scientists that food antioxidants can diminish the symptoms of AD. This is in agreement with the hypothesis that oxidative stress might be associated with NDs [134]. For instance, a meal with rosemary or its extract as an ingredient contains several bioactive compounds, which can act synergistically and have been investigated for their health benefits. This concept can be intentionally used to improve fortified bio-functional foods or it can be incorporated into supplements or nutraceuticalials [135]. In the cosmetic field, rosemary extracts have displayed more substantial antimicrobial effects on Gram-positive and Gram-negative bacteria and molds. In contrast, their impact on yeasts is weaker. Nevertheless, the antimicrobial properties of rosemary extracts allow for their implementation as ingredients in a series of cosmetic products [136]. Lastly, in terms of pharmaceuticals, a break-through idea still in the making is the conceptualization of RA complexed or encapsulated with nanotechnology-based delivery systems that could improve its solubility, safeguard it from damage, permit its access to tissues that are difficult to enter, and consequently ameliorate its bioavailability. These systems could be of a polymer or lipid-based nature, whose production is optimized to contain a significant but safe amount of RA. Even though this system could face cardinal limitations, nasal delivery could act as a solution concerning the delivery route, providing direct access to the CNS [137]. Moreover, bioinspired compounds are also eligible candidates in the pharmaceutical industry. In the following paradigm, terpenes, to which rosemary attributes many of its beneficial effects, were isolated from microbial metabolites as novel meroterpenoid AChE inhibitors. Solid-state fermentation of Aspergillus terreus allowed for the extraction of terreulactones A and D. Terreulactone A and D belong to meroterpenoids and display AChE inhibition abilities. Isomers of terreulactone A were found to be 10 times weaker AChEIs than terreulactones.