## 4 Discussion
All the crude polysaccharides contain varying amounts of phenolics (\(p<0.05\)), with significantly high amounts shown in Smet-P and ML-P. Low phenolic content was seen the most, especially in all _Moring_ seed crude polysaccharides extracts and Dan-P. There was a very strong correlation between the phenolic content and antioxidant activities [54]. The crude polysaccharides were obtained after the removal of ethanol-soluble phenolics; therefore, the significant phenolics obtained from Grkgo-P, ML-P, and Snct-P may be regarded as water-soluble phenolics that are not significantly present in other crude polysaccharides. These might also be tightly bound to the polysaccharides as they precipitate together with the polysaccharides. The low phenolic contents in the crude polysaccharide extracts from other plants may be an indication that they are generally poor in phenolics or may be rich in ethanol-soluble phenolics that were removed during the first extraction with chloroform and ethanol. Aside from phenolics, sugars, and proteins that were quantified from these extracts, there may be other bioactive constituents that were not measured; these unmeasured components could also contribute to the overall chemical complexity of the bioactivity of these extracts. We acknowledge this as part of the limitation of this study. Future studies could focus on the complete chemical profiling of the other components. Antioxidants play a prospective role in the prevention of cancer and various other diseases. They are also responsible for the maintenance of homeostasis, hence the need for this study to screen the antioxidative abilities of the polysaccharides obtained from the selected plants. In the present study, the free radical-scavenging abilities of the plant polysaccharide extracts were analyzed by evaluating the DPPH and NO radical-scavenging activities as well as the Ferric-Reducing Antioxidant Power and Cupric-Reducing Antioxidant Capacity. DPPH is a known synthetic free radical for antioxidant assays. It is commonly used for the assessment of natural metabolites' ability to scavenge free radicals, i.e., for estimation of their antioxidant capacities [55]. The results showed that Snct-P, Grkgo-P, and ML-P had significant DPPH-scavenging activities when compared with other crude polysaccharides, while Snct-P had the highest activity among the three; this is evident by its lowest IC\({}_{50}\) among the three. These three crude polysaccharides showed dose-dependent activities, which suggests that they possess radical-reducing capacities [55] with increasing doses and that they can act as hydrogen ion donors and free radical scavengers [56]. Nitric oxide plays a critical role in many physiological and pathological processes; it is essential for cellular signaling, has a short blood half-life of a few seconds, and is a strong vasodilator. Nitric oxide radicals become deleterious when they react with oxygen as they form nitrogen dioxide, which is a very toxic and reactive radical, thereby resulting in oxidative stress [57; 58]. Consequently, the eradication of NO is favorable to living cells [12], and the ability of the plant crude polysaccharide to scavenge NO is measured by the NO-scavenging assay in this study. Snct-P, ML-P, Onion-P, and Grkgo-P displayed significant NO radical-scavenging activity compared to the remaining plant crude polysaccharides. All these crude polysaccharides displayed NO radical-scavenging activities in a dose-dependent manner. This is an indication that these extracts could have the capability to prevent nitrogen dioxide production as their concentration increase, hence protecting against cellular damage [12]. Ferric-Reducing Antioxidant Power (FRAP) quantifies the capacity of a substance to reduce ferric ions (Fe\({}^{3+}\)) to ferrous (Fe\({}^{2+}\)) ions [59]. While ferric ions are not directly harmful, they do contribute to a Fenton reaction with hydrogen peroxide, which produces very reactive free radicals called hydroxide radicals (HO\({}^{-}\)) [25].