## 4 Conclusions  
From the obtained data on the radical scavenging activity and total phenolic content in maca root extracts, it can be concluded that for all studied extraction techniques, using water as the solvent was more effective than using ethanol. Presented results indicate that the simple maceration process can be effectively enhanced by different factors: shaking, ultrasounds, and using higher temperatures. In most cases, the prolongation of the extraction time, especially to 60 min, positively influenced the antioxidant activity and amount of extracted phenolic compounds; however, this trend was not observed during reflux extraction, possibly due to some degradation processes at high temperatures. The extract with the highest scavenging activity against the DPPH radical (RSA = 74.8%; TEAC = 229.6 uM TE/L) was obtained in the 60-min maceration with shaking (MSH) using water. The 60-min ultrasound-assisted extraction (UAE) using water was the most effective process for the isolation of phenolic compounds (TPC = 136.9 mg GAE/L). Nevertheless, it should be noted that the effectiveness of phenolics isolation in the 60-min maceration with shaking (MSH) was only slightly lower (TPC = 128.2 mg GAE/L). Because it is easier, more economical, and environmentally friendly in comparison to the UAE method, maceration with shaking can be recommended for the extraction of maca using water to obtain extracts characterized by high antioxidant activity and high content of phenolic compounds. In turn, using ethanol as the solvent, the best results were obtained using the reflux extraction (RE) technique, where even a 15-min process was more effective than other applied techniques, but prolonged to 60 min allowed for obtaining an extract with the highest content of phenolic compounds (TPC = 95.3 mg GAE/L) with the DPPH scavenging activity characterized by RSA = 49.5% and TEAC = 149.5 uM TE/L. Moreover, the comprehensive analysis of data obtained from spectrophotometric and chromatographic analyses led to the conclusion that the antioxidant activity of maca extracts is the result of the presence of various bioactive compounds whose profiles differ in water and alcoholic extracts. Consequently, the specific bioactivity of extracts obtained using water and ethanol will be different, which should be taken into account during the development of some formulations on the basis of maca extracts. It is worth noticing that water extracts, although characterized by better antioxidant properties, do not contain some valuable compounds specific for maca, such as present in ethanolic extracts macamides or fatty acids derivatives, which may be responsible for some characteristic neuroprotective, neuromodulatory, anti-fatigue, or other effects. These studies contribute to expanding the knowledge on the influence of extraction conditions on the composition and radical scavenging activity of maca extracts and can be useful in the elaboration of the appropriate conditions for the effective isolation of the bioactive compounds. The results can be applied in the development and optimization of extraction processes of maca active ingredients in order to obtain dietary supplements characterized by the best antioxidant properties and containing the highest amount of health-promoting compounds. Given the great interest in maca and its compounds, not only as food ingredients but also as therapeutic agents, the research presented in this paper has great potential and should be further developed. One of the directions of research carried out in the future may be the search for more effective extraction methods and appropriate solvents for these methods. In terms of medical applications, maca roots have been mostly described in the literature so far, while the above-ground parts of this plant are mainly used as animal feed. A new direction could also be to investigate the therapeutic potential of the ingredients contained in maca above-ground parts, which could lead to another possible way of utilizing the waste parts of this precious plant.