Milena Bellei Cherene

This study is aimed at isolating and characterizing antimicrobial peptides (AMPs) from the leaves of Capsicum annuum (L.) cv. Carioquinha and investigating their antifungal activity and mechanism of action against phytopathogenic fungi. An initial extract was obtained from leaves through hydromethanolic extraction followed by partitioning with dichloromethane. The extract was resuspended in aqueous acetonitrile and centrifuged to obtain the soluble supernatant fraction (ExS). The ExS fraction was purified by reverse‐phase high‐performance liquid chromatography (RP‐HPLC). Protein bands from the ExS fraction were excised from Tricine‐SDS‐PAGE gels and analyzed by LC–MS/MS. The obtained peptide sequences were compared with protein databases. Antifungal activity of the ExS fraction was evaluated through quantitative fungal growth inhibition assays against the phytopathogenic fungi Fusarium solani , Fusarium oxysporum , Colletotrichum gloeosporioides , and Colletotrichum scovillei , and tests were conducted to investigate the mechanism of action of the peptides present in the ExS fraction. RP‐HPLC analysis of the ExS fraction revealed a single peak (P1) corresponding to a protein band of approximately 6.5 kDa, and all fragments obtained by LC–MS/MS were similar to peptides belonging to the hevein‐like family. The highest inhibition was observed for C. gloeosporioides , with 78.3% growth inhibition at 200 μ g mL ⁻¹ . Mechanistic studies revealed that the ExS fraction caused membrane permeabilization in C. gloeosporioides , induced reactive oxygen species (ROS) production, and reduced cell viability. The ExS fraction also caused vacuolization of hyphae in F. oxysporum . This study highlights the potential of AMPs isolated from C. annuum leaves to inhibit phytopathogenic fungi.

Sorghum (Sorghum bicolor (L.) Moench) is an alternative to the consumption of conventional cereals, with high technological, nutritional and functional potential. The peptides formed during the enzymatic digestion of their proteins have shown a modulating effect on variables related to chronic noncommunicable diseases, including cardiovascular ones. The aim of this study was to identify and characterize the bioactive compounds of sorghum and its hydrolysate in their toxicity, hypocholesterolemic, antiatherogenic, and antioxidant properties in vivo. For the toxicity test, nematodes Caenorhabditis elegans were used. For the experimental study, wild-type C57BL/6 and LDL-cholesterol receptor knockout (LDL-/-) mice were maintained on a normal or atherogenic diet and received whole sorghum flour or its hydrolysate by intragastric oral gavage (800 mg/kg) for 8 weeks. The protein hydrolysate showed the highest concentration of phenolic compounds and high antioxidant activity; the enzymatic hydrolysis reached 42.5% of the proteins, with low molecular weight peptides, in addition to not showing toxicity at the dose used. The in vivo results demonstrated that the flour and hydrolysate reduced the levels of total and LDL-c cholesterol and the lipid deposition in aorta of animals with atherogenic diet, and increased the antioxidant activity in plasma and liver, in addition to plasmatic HDL-c. The hydrolysate also showed an antimutagenic effect by micronucleus test. Therefore, whole sorghum flour and its hydrolysate are a source of antioxidant nutritional compounds that act against the development of hypercholesterolemia and atherogenesis, in addition to an antimutagenic effect and absence of toxicity.