Metabolomic Profiling and Identification of Antioxidant and Antidiabetic Compounds from Leaves of Different Varieties of Morus alba Linn Grown in Kashmir

Abstract

Mulberry (Morus alba L.) is commonly cultivated in Asian countries as a traditional medicine and food supplement. Four Kashmiri Morus alba varieties (Zagtul, Chtattatual, Chattatual Zaingir, and Brentul Kashmir) were evaluated for their proximate composition, mineral content, total phenolic and flavonoid content, antioxidant potential, and antihyperglycemic activity. Furthermore, TLC-MS-bioautography was used for the identification of antioxidant and antidiabetic compounds in the best active extract. Lastly, UPLC-MS was employed for metabolomic profiling of the best variety of M. alba. Among all the varieties, the Zagtul variety was found to have the highest phenolic (71.10 ± 0.44 mg GAE/g DW) and flavonoid (53.22 ± 0.69 mg rutin/g DW) content. The highest antioxidant potential (DPPH) with an IC₅₀ value of 107.88 ± 3.8 μg/mL was recorded for the Zagtul variety. Similarly, α-amylase and α-glucosidase inhibition for antidiabetic potential with IC₅₀ 74.76 ± 6.76 and 109.19 ± 5.78 μg/mL, respectively, was recorded in Zagtul variety. TLC-MS-bioautography for identification of bioactive compounds revealed the presence of chlorogenic acid for antioxidant potential and 1-deoxynojirimycin (DNJ) and syringic acid for antidiabetic potential. Further, bioactive compounds responsible for diverse functions of M. alba were confirmed by UPLC-MS in both negative and positive modes. However, major compounds in the Zagtul variety were identified as chlorogenic acid, moracin N, gallic acid, ferulic acid, morin, 1-deoxynojirimycin, and syringic acid. Hence, based on our findings, it can be concluded that M. alba leaves can be consumed as a promising dietary supplement and can be formulated as phytopharmaceutical for the management of various metabolic disorders.

Figure 1

(A) Proximate analysis of four different Kashmiri varieties of M. alba. (B) Mineral content of different varieties of M. alba.

Figure 2

Total phenolic and flavonoid contents of four different Kashmiri varieties of M. alba.

Figure 3

Free radical scavenging and reducing power capacity of four different Kashmiri varieties of M. alba.

Figure 4

α-Amylase and α-glucosidase inhibitor activity of four different Kashmiri varieties of M. alba.

Figure 5

Developed TLC plate photograph of Zagtul variety of M. alba at (A) 254 nm and (B) 366 nm.

Figure 6

Developed TLC-bioautography plate photograph of Zagtul variety of M. alba and mass spectrometry chromatogram of identified metabolites after being stained with DPPH and α-glucosidase.

Figure 7

Chemical structures of bioactive metabolites identified through UPLC-MS in M. alba leaves.