Abstract
Many phytochemicals demonstrate nonmonotonic dose/concentration-response termed biphasic dose-response and are considered to be hormetic compounds, i.e., they induce biologically opposite effects at different doses. In numerous articles the hormetic nature of phytochemicals is declared, however, no experimental evidence is provided. Our aim was to present the overview of the reports in which phytochemical-induced biphasic dose-response is experimentally proven. Hence, we included in the current review only articles in which the reversal of response between low and high doses/concentrations of phytochemicals for a single endpoint was documented. The majority of data on biphasic dose-response have been found for phytoestrogens; other reports described these types of effects for resveratrol, sulforaphane, and natural compounds from various chemical classes such as isoquinoline alkaloid berberine, polyacetylenes falcarinol and falcarindiol, prenylated pterocarpan glyceollin1, naphthoquinones plumbagin and naphazarin, and panaxatriol saponins. The prevailing part of the studies presented in the current review was performed on cell cultures. The most common endpoint tested was a proliferation of tumor and non-cancerous cells. Very few experiments demonstrating biphasic dose-response induced by phytochemicals were carried out on animal models. Data on the biphasic dose-response of various endpoints to phytochemicals may have a potential therapeutic or preventive implication.
Highlights
Compelling data have shown that the consumption of phytochemicals in the form of concentrated supplements can cause adverse health effects if the doses consumed exceed the toxic threshold
We revealed that the demarked hormetic nature of some phytochemicals has not been experimentally evidenced
The term “hormesis” is often misused and the most common default refers to the identification of hormetic properties exclusively on the basis of low dose effects which is contradictory to the classic definition of hormesis [8]
Summary
Compelling data have shown that the consumption of phytochemicals in the form of concentrated supplements can cause adverse health effects if the doses consumed exceed the toxic threshold. Various phytochemicals demonstrate nonmonotonic dose/concentration-response termed biphasic dose-response and are considered to be hormetic compounds, for example, resveratrol [2,3] curcumin [4], sulforaphane [1]. The term “hormesis” is often misused and the most common default refers to the identification of hormetic properties exclusively on the basis of low dose effects which is contradictory to the classic definition of hormesis [8]. As data on the biphasic concentration/dose-response displayed by resveratrol were extensively reviewed in 2010 [2,3], we presented here reports concerning this subject published from 2010 until 2019. The first one is dedicated to phytoestrogens because the majority of reports on biphasic concentration-response induced by phytochemicals referred to this group of compounds. The literature search was conducted in PubMed, Web of Science and Google Scholar databases from 1990 to 2019; the key search terms were “phytochemicals” or “hormesis” or “biphasic dose-response” or “biphasic concentration-response” or “biphasic effect.”
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
