Metabolic Profile of Leaves and Pulp of Passiflora caerulea L. (Bulgaria) and Their Biological Activities.

Abstract

At present, there are no data in the scientific literature on studies aimed at characterizing Passiflora caerulea L. growing in Bulgaria. The present study aimed to investigate the metabolic profile and elemental composition of the leaves and pulp of this Passiflora, as well as to evaluate the antioxidant, antimicrobial and anti-inflammatory activities of its leaf and pulp extracts. The results showed that the pulp predominantly contained the essential amino acid histidine (7.81 mg g-1), while it was absent in the leaves, with the highest concentration being tryptophan (8.30 mg g-1). Of the fatty acids, palmitoleic acid predominated both in the pulp and in the leaves. A major sterol component was β-sitosterol. Fructose (7.50%) was the predominant sugar in the pulp, while for the leaves, it was glucose-1.51%. Seven elements were identified: sodium, potassium, iron, magnesium, manganese, copper and zinc. The highest concentrations of K and Mg were in the pulp (23,946 mg kg-1 and 1890 mg kg-1) and leaves (36,179 mg kg-1 and 5064 mg kg-1). According to the DPPH, FRAP and CUPRAC methods, the highest values for antioxidant activity were found in 70% ethanolic extracts of the leaves, while for the ABTS method, the highest value was found in 50% ethanolic extracts. In the pulp, for all four methods, the highest values were determined at 50% ethanolic extracts. Regarding the antibacterial activity, the 50% ethanolic leaf extracts were more effective against the Gram-positive bacteria. At the same time, the 70% ethanolic leaf extract was more effective against Gram-negative bacteria such as Salmonella enteritidis ATCC 13076. The leaf extracts exhibited higher anti-inflammatory activity than the extracts prepared from the pulp. The obtained results revealed that P. caerulea is a plant that can be successfully applied as an active ingredient in various nutritional supplements or cosmetic products.