Effect of Processing and Storage Methods on the Nutritional, Anti-nutritional, and Anti-oxidant Properties of Paeonia emodi, Wall. ex. Royle

Nutritional, anti-nutritional, and anti-mutagenic activities of the fresh and boiled Paeonia emodi leaves were analyzed. Significantly higher vitamin A (64.19 ± 0.18 mg/100 g), C (160.50 ± 1.85 mg/100 g), and E (1.25 ± 0.00 μg/g) contents were recorded in boiled as compared to fresh and dried juvenile leaves. Similarly, significantly higher protein content (329.63 ± 0.33 mg/100 g) was found in boiled budding leaves, carbohydrate content in fresh juvenile (0.353 ± 0.02) and mature leaves (0.353±0.10 mg/g) , methionine content (47.75 ± 0.09 mg/g) in dried budding stage leaves, and proline content (1.23 ± 0.12 μM/g) in dried mature leaves. Anti-nutritional attributes like phytic acid (250.17 ± 0.19 mg/100 g; p < 0.05) and total tannins (48.41 ± 0.09 mg/g) were significantly higher in dried and fresh budding leaves, respectively; however, trypsin inhibition activity (91.90 ± 0.34 %) was observed in dried juvenile leaves. Significantly higher 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (71.13 ± 0.09 mM AAE/100 g) and ferric-reducing antioxidant power (FRAP) activity (3.39 ± 0.01 mM AAE/100 g) were recorded higher in dried budding leaves. On the other hand, 2,2-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging assay (3.55 ± 0.017 mM AAE/100 g) and OH ions (1.69 ± 0.01 mM AAE/100 g) were significantly higher in boiled juvenile leaves and dried mature leaves, respectively. Anti-mutagenic activity of P. emodi extract revealed varying levels of protection against DNA damaging agents. The aqueous extract of P. emodi at budding leaves (500 μg dried) showed comparatively better protective activity as compared to other growth stages. Results of this investigation indicated that the species have nutritional and medicinal value and therefore can be a potential source for nutraceutical and pharmaceutical industries.