Strawberry-Tree Honey Induces Growth Inhibition of Human Colon Cancer Cells and Increases ROS Generation: A Comparison with Manuka Honey.

Sadia Afrin,Stefano Bompadre,Francesca Giampieri,Nadia Spano,José Quiles,Tamara Forbes-Hernandez,Maurizio Battino,Massimiliano Gasparrini,Gavino Sanna

doi:10.3390/ijms18030613

Abstract

Honey is a natural product known to modulate several biological activities including cancer. The aim of the present study was to examine the phytochemical content and the antioxidant activity of Strawberry tree (Arbutus unedo) honey (STH) and its cytotoxic properties against human colon adenocarcinoma (HCT-116) and metastatic (LoVo) cell lines in comparison with Manuka (Leptospermum scoparium) honey (MH). Several unifloral STH and MH were analyzed for their phenolic, flavonoid, amino acid and protein contents, as well as their radical scavenging activities. STH from the Berchidda area showed the highest amount of phenolic, flavonoid, amino acid and protein content, and antioxidant capacity compared to MH. Both STH and MH induced cytotoxicity and cell death in a dose- and time-dependent manner in HCT-116 and LoVo cells, with less toxicity on non-cancer cells. Compared to MH, STH showed more effect at lower concentrations on HCT-116 and LoVo cells. In addition, both honeys increased intracellular reactive oxygen species (ROS) generation. In HCT-116 cells, STH and MH induced similar ROS production but in LoVo cells STH induced a higher percentage of ROS compared to MH. Our results indicate that STH and MH can induce cell growth inhibition and ROS generation in colon adenocarcinoma and metastatic cells, which could be due to the presence of phytochemicals with antioxidant properties. These preliminary results are interesting and suggest a potential chemopreventive action which could be useful for further studies in order to develop chemopreventive agents for colon cancer.

Highlights

In Europe, colorectal cancer is the second most common cancer [1] while over one million new cases are detected each year worldwide [2]
Strawberry tree (Arbutus unedo) honey (STH) from Berchidda area showed the highest content of total polyphenol content (TPC) (1.00 ± 0.02 g gallic acid equivalents (GAE)/kg) followed by the area of Monti (0.86 ± 0.01 g GAE/kg), Luras (0.77 ± 0.02 g GAE/kg), and Sadali (0.76 ± 0.02 g GAE/kg), while the lowest value corresponded to Olbia (0.69 ± 0.01 g GAE/kg)
TPC of STH from Berchidda area was higher compared to previously reported Cuban honey such as amber honey [11], Malaysian honey such as tualang honey [36], Portuguese honey [37] and Algerian honey [38]. These results suggest that STH from Berchidda could have a high antioxidant potential

Summary

Introduction

In Europe, colorectal cancer is the second most common cancer [1] while over one million new cases are detected each year worldwide [2]. Honey is a good source of biological or pharmacological compounds with antioxidant, antibacterial, anti-inflammatory, antihypertensive, hypoglycemic, anti-proliferative, anticancer and anti-metastatic activities [6,7,8,9,10,11,12]. In this case, it has to be taken into consideration that the bioactive compounds of honey are rather variable, and depend on the honey’s floral sources, and on the geographical origins, as well as on seasonal and environmental factors which may be accountable for the detected variations

Objectives

Methods

Results

Conclusion