Nutritional, chemical and functional potential of Inga laurina (Fabaceae): A barely used edible species.

Inga laurina is a plant species which produces edible fruits, and until now there is little information available concerning its nutritional, chemical and bioactive composition. In this study, we evaluated for the first time the proximate composition and mineral contents in its fruit (peel, pulp and seed), that is the traditionally consumed part. The seeds obtained the highest protein (19.52 g/100 g), carbohydrate (22.5 g/100 g) and mineral contents, mainly Cu, Cr, P, Mn, Se and Zn. The peel and pulp were excellent sources of fiber (4.5 and 11.05 g/100 g) as well as mineral content, with Cr and Cu standing out in the pulp. This study is notably the first to provide a detailed assessment of the nutritional compositions of traditionally consumed and not consumed parts of this fruit. Sensory analysis of the pulp was also performed, which indicated good acceptance. The antioxidant properties were characterized in the fruit, peels and leaves. The ABTS test showed that leaf supernatant hydroethanolic crude extract (EC50 = 2.70 µg/mL) and its corresponding ethyl acetate (EC50 = 1.68 µg/mL) and butanol (EC50 = 2.48 µg/mL) partitions presented higher antioxidant potential compared to the control Ginkgo biloba (EC50 = 12.17 µg/mL). The most active precipitate extract regarding DPPH was from the peel (EC50 = 13.30 µg /mL) and the most active partition was the ethyl acetate (EC50 = 13.37 µg/mL), both with better activity compared to the control Ginkgo biloba (EC50 = 46.97 µg/mL). The ethyl acetate partition (EC50 = 13.45 µg/mL) and butanol partition (EC50 = 7.97 µg/mL) from the leaves showed the highest antioxidant capacity. Thus, extracts and partitions from the peels and leaves were studied from a phytochemical point of view due to presenting the best results for antioxidant capacity. The presence of phenolic compounds such as myricetin-3-O-rhamnopyranoside, myricetin-3-O-(2″-O-galloyl)-rhamnopyranoside and myricetin-3-O-(2″,4″-di-O-galloyl)-arabinopentoside-methyl ether were observed in the leaf crude extract and polar partitions, being reported for the first time in the Inga genus and Fabaceae family. Moreover, quercetin, quercetin-3-O-galatoctoside, quercetin-3-O-rhamnopyranoside, quercetin-3-O-(2″-O-galloyl)-rhamnoside, and quercetin tri-hexose were identified in the peel crude extract and ethyl acetate partition, in which the galloyl derivative of quercetin was identified for the first time in I. laurina fruit peels. GC-MS enabled separating and identifying substances such as palmitic and stearic acids, and ethyl oleate. It is possible to conclude that I. laurina pulp can be a supplementary food as a source of phenolic compounds, and the other organs of the plant (leaves and peel) are rich in flavonoids with great antioxidant capacity, making this species a promising source of antioxidants.

Design of improved synthetic antifungal peptides with targeted variations in charge, hydrophobicity and chirality based on a correlation study between biological activity and primary structure of plant defensin γ-cores.

Microbial resistance to available drugs is a growing health threat imposing the need for the development of new drugs. The scaffold of plant defensins, including their γ-cores, are particularly good candidates for drug design. This work aimed to improve the antifungal activity of a previous design peptide, named A36,42,44γ32-46VuDef (for short DD) against yeasts by altering its biochemical parameters. We explore the correlation of the biological activity and structure of plant defensins and compared their primary structures by superimposition with VuDef1 and DD which indicated us the favorable position and the amino acid to be changed. Three new peptides with modifications in charge, hydrophobicity (RR and WR) and chirality (D-RR) were designed and tested against pathogenic yeasts. Inhibition was determined by absorbance. Viability of mammalian cells was determined by MTT. The three designed peptides had better inhibitory activity against the yeasts with better potency and spectrum of yeast species inhibition, with low toxicity to mammalian cells. WR, the most hydrophobic and cationic, exhibited better antifungal activity and lower toxicity. Our study provides experimental evidence that targeted changes in the primary structure of peptides based on plant defensins γ-core primary structures prove to be a good tool for the synthesis of new compounds that may be useful as alternative antifungal drugs. The method described did not have the drawback of synthesis of several peptides, because alterations are guided. When compared to other methods, the design process described is efficient and viable to those with scarce resources.