Temperature-Dependent Variations in Antioxidant Activities and Phytochemical Profiles of Passiflora edulis Leaf Extracts

Passiflora edulis leaves contain bioactive compounds and have beneficial and important biological activities. The focus of this research is to pinpoint the optimum water extraction temperature and methods for the greatest antioxidant activity and phytochemical content. Dry powder of P. edulis leaves was extracted using aqueous solvents with temperature variations i.e., maceration (TR), 40 °C (T40), 60 °C (T60), decoction (TD), and ultrasonic-assisted extraction (UAE). All extracts were compared for antioxidant activity (DPPH, FRAP, ABTS), compound content (total polyphenolic and flavonoid content), marker assay (saponin assay using Liebermann-Burchard reagent, and quercetin assay using TLC-densitometry), and determination of the fingerprint pattern of compounds through Fourier Transform Infrared (FTIR) spectra. The antioxidant capacity demonstrated that the extract activity was dose-dependent at all procedure temperatures. Our data showed that decoction (TD) enhanced the antioxidant capacity and also levels of water-soluble flavonoids, polyphenolic, and quercetin compounds. However, the best saponin content was obtained at T60. The FTIR spectra showed the same pattern of all extract functional groups. Therefore, the increasing extraction temperature is directly related to the increase of flavonoid and polyphenol content and their antioxidant activities. HIGHLIGHTS Passiflora edulis leaf has many phytoconstituents that have different bioactivities. The extraction method and temperature will impact the quantity of phytoconstituents extracted. Decoction produced the highest antioxidant activity, while 60 °C gave the best saponin content. FTIR analysis showed similar spectral patterns in all extracts. GRAPHICAL ABSTRACT