## 3 _Nelumbo nucifera_
### Antioxidant Health Promoting Effect of Nelumbo uncifera Bioactives and Extracts
#### 3.2.1 In Vitro Antioxidant Effects of Nelumbo uncifera's Bioactives and Extracts
The extract analyzed in the study contained chlorogenic acid, ferulic acid and coumarin as the primary phytochemicals. Results indicated that the ethyl alcohol (ET) extract derived from lotus petals exhibited superior antioxidant activity compared to the ethyl acetate (EA) extract. This suggests that the bioactive components present in the ET extract possess enhanced antioxidant properties, making it a promising source of antioxidants. Specifically, the antioxidant capacity of the ET extract was found to be 1.5 times higher than that of the EA extract [27]. Finally, [PERSON] et al. assessed the antioxidant potential of various parts of the Sacred Lotus plant, including the seed embryo, flower stalk, stamen, old leaf, petal and leaf stalk, through hot water extraction. By identifying phenolic compounds and flavonoids in the extracts, the researchers sought to understand how these antioxidants contribute to combating oxidative stress using assays such as DPPH, FRAP and ORAC. Oxygen Radical Absorbance Capacity (ORAC) is a method used to measure the antioxidant capacity of a substance against peroxyl radicals. This assay quantifies the ability of antioxidants to scavenge peroxyl radicals and inhibit the oxidative damage caused by these radicals. ORAC values provide information on the overall antioxidant potential of a sample and its capacity to protect against oxidative stress. Results indicated that all parts of the Sacred Lotus exhibited antioxidant activities in all three assays. The old leaf showed the highest DPPH radical scavenging and ORAC activities, while the stamen exhibited the highest FRAP activity. The top three parts with the highest overall antioxidant activities were stamen, old leaf, and petal. Subsequently, mixtures of these parts were analyzed to determine the most effective combination with high antioxidant activities using DPPH, FRAP, and ORAC assays. The study revealed that specific mixtures, such as stamen:old leaf:petal (3:0:0) or only stamen, demonstrated the highest antioxidant activities in both DPPH and FRAP assays, while stamen:old leaf:petal (1:3:3) exhibited the highest ORAC activity [20]. In another study, [PERSON] et al. isolated tryptophan from lotus rhizomes for the first time and identified it as a key active component with antioxidant properties. The evaluation of antioxidant activity included testing erythrocyte hemolysis inhibition by measuring hemolysis percentage after incubating erythrocytes with test samples and assessing lipid peroxidation inhibition by evaluating the malondialdehydedehyde-TBA complex color after incubating kidney homogenates with test samples. The lipid peroxidation assay assesses the ability of antioxidants to inhibit the peroxidation of lipids, which is a key process in oxidative damage to cell membranes. It measures the formation of peroxides as a marker of lipid oxidation. Typtophan from lotus rhizome extract demonstrated potent antioxidant effects in inhibiting erythrocyte hemolysis, with an IC\({}_{50}\) value of 156.3 mg/mL. However, in terms of inhibiting lipid peroxidation, tryptophan from lotus rhizome extract, particularly L2c-3, exhibited limited activity. This study marked the successful isolation of tryptophan from lotus rhizome and highlighted its antioxidant properties [24]. According to one in vitro clinical investigation from [PERSON]. [PERSON] et al., it was observed that lotus rhizome powder in breadsticks can improve consumers' health because of its antioxidant activity. The breadsticks were made with lotus rhizome powder (LRP), and the nutritional composition was analysed. The results showed that all breadsticks containing LRP had significantly higher amounts of total phenolic content, using the coloured reaction of phenolics with Folin-Ciocalteu reagent and total flavonoid content, with the aluminum chloride colorimetric method when compared with the control. The Folin-Ciocalteu assay is used to determine the total phenolic content in samples.