In vitro assessment of cytotoxic, antioxidant and antimicrobial activities of leaves from two grape varieties collected from arid and temperate regions in Palestine

Grape leaves (Vitis vinifera L.) are widely consumed in Palestine, and other Mediterranean countries. Positive health effects of grape products are reported by various studies and pharmaceutical preparations from grape leaves are patented and commercialized as drugs. The aim of this in vitro study is to assess the therapeutic potential of leaf extracts; their cytotoxicity against lung cancerous cells, their antioxidant and antimicrobial activity against several human pathogenic bacterial strains, and according to geographical location, to examine the overall effect of annual rainfall on the aforementioned activities. Leaves from Shami and Baituni grapes, collected from Dahria (an arid region) and Beit Omar (a temperate region) in Palestine were ground to powder using liquid nitrogen and a pestle and mortar. Cytotoxicity was measured against lung cancer cells and muscle cells. Antioxidants potential of leaf extracts and antimicrobial activity against five human pathogenic bacterial strains were assessed. Results showed Shami leaves from Beit Omar inhibited the proliferation of lung cancer cells. Cytotoxicity assessment against lung cancer cells showed leaves from Baituni grapes are ineffective. Antioxidant capacity of the leaf extracts of both genotypes from both locations gave high levels of antioxidants, but no significant differences recorded between treatments. Leaf extracts of both grape genotypes were effective against S. aureus and slightly effective against P. aeruginosa bacteria. However, these extracts were ineffective against L. monocytogenes, S. typimurium and E. coli. Results show the therapeutic potential of leaves of Shami and Baituni might be related to their phytochemical composition. Our findings suggest effective cytotoxic activity of Shami grape leaves against lung cancer cells and provide a preliminary view of the effect of annual rainfall on the grape leaves‘ anticancer and antimicrobial activities.