Related Experiment Video
Updated: Sep 27, 2026

The Terroir Concept Interpreted through Grape Berry Metabolomics and Transcriptomics
Published on: October 5, 2016
Harvest-Time-Dependent variations in phytochemistry and in vitro bioactivities of Vitis vinifera Leaves
Amal M El-Feky1, Noha E Ibrahim2, Wael Mahmoud Aboulthana3
1Pharmacognosy Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, 33 El Bohouth St. (Former El Tahrir St.), P.O. 12622, Dokki, Giza, Egypt. ammelfeky@hotmail.com.
Background:
Vitis vinifera L. leaves are rich in bioactive phytochemicals, but their composition and biological activities may vary considerably with harvest time. This study investigated harvest-dependent changes in the phytochemical profile and in vitro biological activities of grape leaves.
Methods:
Methanolic extracts of V. vinifera leaves collected in March, May, and September were evaluated for photosynthetic pigments, total polyphenols, flavonoids, and tannins. HPLC analysis was used to characterize individual phenolic and flavonoid constituents, while major compounds were isolated and structurally identified. The extracts were further assessed for antioxidant and radical-scavenging, antidiabetic, anti-Alzheimer's, anti-inflammatory, anti-arthritic, and cytotoxic activities.
Results:
Harvest time markedly affected the phytochemical composition and biological activities of the leaves. The May-harvested leaves showed the highest levels of total chlorophyll, polyphenols, flavonoids, and tannins, whereas carotenoids were comparatively higher in the September and March samples. HPLC analysis revealed greater accumulation of phenolic and flavonoid constituents in the May extract, with chlorogenic acid, rosmarinic acid, gallic acid, and naringenin among the predominant compounds. Consistently, the May extract exhibited the strongest antioxidant and radical-scavenging activities and showed superior inhibitory effects in the antidiabetic, anti-Alzheimer's, anti-inflammatory, anti-arthritic, and cytotoxic assays compared with the other harvest periods.
Conclusion:
Harvest time substantially influences the accumulation of bioactive constituents and the in vitro biological potential of V. vinifera leaves. Among the investigated periods, May appeared to be the most favorable harvest time for obtaining grape leaves enriched in bioactive phytochemicals with promising biological activities, supporting their potential valorization as a value-added viticultural by-product.
More Related Videos
05:29Profiling Volatile Compounds in Blackcurrant Fruit using Headspace Solid-Phase Microextraction Coupled to Gas Chromatography-Mass Spectrometry
Published on: June 9, 2021
10:22Improved UPLC-UV Method for the Quantification of Vitamin C in Lettuce Varieties (Lactuca sativa L.) and Crop Wild Relatives (Lactuca spp.)
Published on: June 30, 2020
Related Concept Videos
Biological Clocks and Seasonal Responses
The Calvin Benson Cycle
Light Acquisition