Peptidomic profiling of Kaempferia parviflora and Zingiber officinale and their antioxidant potentials

The study on plant-derived antioxidant peptides is currently receiving increased attention due to their natural origin, safety, and potential applications in nutraceuticals, functional foods, and pharmaceuticals. The Zingiberaceae family widely used traditional medicinal plants; include Kaempferia parviflora (black ginger) and Zingiber officinale (ginger), however, their bioactive peptide composition remains largely unexplored. In this study, proteins were extracted from Z. officinale and K. parviflora using four different pH-based buffers and subsequently filtered through ultrafiltration membranes with 10 kDa and 3 kDa cutoffs. The antioxidant activities of crude extracts, 10 kDa, and 3 kDa filtrates were evaluated using DPPH, FRAP, ABTS, and NOS assays. The highest antioxidant activity was observed in 3 kDa peptides filtrate extracted with Tris HCl pH 8.0 buffer than crude and 10 kDa in all the assays. Using HPLC and MALDI-ToF MS, multiple bioactive sequences were identified common to both species (SVAGRAQGM, MWPFPSDK and MNEYLLPK) alongside unique peptides such as QAKSQGGSN, QNAHHPSPK, PRGSPRTEYE AARR and ADPPHIHASL from Z. officinale and K. parviflora respectively were identified by MALDI-TOF MS. These peptides are associated with numerous biological processes, including metabolic, hydrolytic, antibacterial, and antifungal properties. This finding indicates that Z. officinale and K. parviflora are rich sources of antioxidant peptides, offering promising formulations based on natural products.