Anti-Cancer Activity and Phenolic Content of Extracts Derived from Cypriot Carob (Ceratonia siliqua L.) Pods Using Different Solvents.

Gregoria Gregoriou,Marios C Christodoulou,Ioannis J Stavrou,Atalanti Christou,Constantina P Kapnissi-Christodoulou,Andreas I Constantinou,Georgia D Ioannou,Alexandru Vasincu,Christiana M Neophytou,Hermann Stuppner,Eftychia Pinakoulaki,Yiota Gregoriou,Haria Hadjipakkou,Siegfried Aigner,Antonis Kakas

doi:10.3390/molecules26165017

Abstract

Extracts derived from the Ceratonia siliqua L. (carob) tree have been widely studied for their ability to prevent many diseases mainly due to the presence of polyphenolic compounds. In this study, we explored, for the first time, the anti-cancer properties of Cypriot carobs. We produced extracts from ripe and unripe whole carobs, pulp and seeds using solvents with different polarities. We measured the ability of the extracts to inhibit proliferation and induce apoptosis in cancer and normal immortalized breast cells, using the MTT assay, cell cycle analysis and Western Blotting. The extracts’ total polyphenol content and anti-oxidant action was evaluated using the Folin–Ciocalteu method and the DPPH assay. Finally, we used LC-MS analysis to identify and quantify polyphenols in the most effective extracts. Our results demonstrate that the anti-proliferative capacity of carob extracts varied with the stage of carob maturity and the extraction solvent. The Diethyl-ether and Ethyl acetate extracts derived from the ripe whole fruit had high Myricetin content and also displayed specific activity against cancer cells. Their mechanism of action involved caspase-dependent and independent apoptosis. Our results indicate that extracts from Cypriot carobs may have potential uses in the development of nutritional supplements and pharmaceuticals.

Highlights

IntroductionCeratonia siliqua L., known as the Mediterranean carob tree, has been widely studied for the functional chemicals contained in its fruit
Our results indicate that depending on the extraction solvent used and stage of maturity, carob fruit extracts from trees grown in Cyprus have anti-cancer properties that may be attributed to the presence of polyphenols that can induce caspase-dependent and independent apoptosis in breast cancer cells
Our results demonstrated that the Diethyl ether (DE) and Ethyl acetate (EA) whole ripe extracts were highly specific in reducing the viability of MCF-7 cells compared to seeds, pulp, EtOH and Aqueous extracts

Summary

Introduction

Ceratonia siliqua L., known as the Mediterranean carob tree, has been widely studied for the functional chemicals contained in its fruit. The carob fruit contains two major parts (by weight): the pulp (90%) and the seeds (10%). The chemical composition of the carob pulp differs widely depending on cultivar or species, origin, climate, as well as stage of maturity during harvesting [1,2,3]. Recent evidence suggests that extracts derived from peels [6], leaves [7] and seeds [8] of different plant species, edible or not, may induce diverse health-promoting effects, often different from that expected, due to their rich content of bioactive compounds. Carob pulp constituents, including fibers, cyclitols, polyphenols and tannins have been associated with the health-promoting effects of carobs against diabetes, diarrhea and cancer [9,10,11,12,13]

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