High throughput biochemical profiling, and functional potential analysis for valorization of grape peduncles

Area of Science:

• Phytochemistry
• Pharmacology
• Natural Products

Background:

• Vitis vinifera L. (grape) is a globally significant fruit crop, recognized for potential health benefits attributed to its chemical constituents and bioactivities.
• Grape by-products, such as peduncles, are often underutilized, presenting an opportunity to explore their bioactive potential.

Purpose of the Study:

• To evaluate the biochemical composition, antioxidant capacity, and antimicrobial efficacy of ethanolic grape peduncle (EGP) extract.
• To identify key phytochemicals and elemental composition within the EGP extract.
• To assess the cytotoxic and antileishmanial activities of the EGP extract.

Main Methods:

• Phytochemical screening was performed to identify various classes of compounds.
• Total phenolic content (TPC) and total flavonoid content (TFC) were quantified using Gallic Acid Equivalent (GAE) and Quercetin Equivalent (QE) standards, respectively.
• Antioxidant activity was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay.
• Antimicrobial activity was evaluated against selected bacterial and fungal strains via zone of inhibition and percentage inhibition.
• Cytotoxicity was tested against HeLa cell lines, and antileishmanial activity was assessed against Leishmania major promastigotes.
• Elemental analysis was conducted using atomic absorption spectroscopy, and compound identification was performed using Gas Chromatography-Mass Spectrometry (GC-MS).

Main Results:

• The EGP extract contained numerous phytochemicals, including flavonoids, tannins, phenols, and terpenoids.
• Quantified TPC was 7.35 ± 0.25 mg GAE/g and TFC was 29.67 ± 0.13 mg QE/g.
• The DPPH assay yielded an IC50 value of 159.3 μg/mL, indicating moderate antioxidant activity.
• The extract exhibited significant antimicrobial activity, with a maximum zone of inhibition of 27.2 ± 1.60 mm against Salmonella typhi and 74 ± 1.81% inhibition against Epidermophyton floccosum.
• No cytotoxic or antileishmanial activity was observed against HeLa cells or Leishmania major promastigotes.
• Key elements (Fe, Mn, Ni, Pb, Cd) were detected, and approximately 50 compounds were identified via GC-MS.

Conclusions:

• Ethanolic grape peduncle extract is rich in bioactive phytochemicals and possesses notable antioxidant and antimicrobial properties.
• The extract demonstrates significant potential for combating specific bacterial and fungal pathogens.
• Grape peduncles represent a promising and potentially valuable source of natural bioactive compounds for medicinal applications.