In silico approach to safety of botanical dietary supplement ingredients utilizing constituent-level characterization

Abstract

Botanicals used in dietary supplements industry can have toxicology concerns related to endpoint gaps that cannot be fully resolved by a history of use, or existence of conflicting safety data. However, traditional toxicological studies on botanicals are scientifically and pragmatically challenging due to testing of complex mixtures of constituents, cost, time, and animal usage. Alternatively, we developed an in silico decision-tree approach to address data gaps and inform need for further studies by toxicologically evaluating the chemical composition of botanicals. Following advanced multi-detector analytical characterization of a botanical, each chemical constituent is: (a.) quantitatively benchmarked against similar constituents in commonly consumed foods or botanicals with well-established safety profiles, (b.) systematically evaluated for toxicity data utilizing structure-activity relationships, and, (c.) compared to established thresholds of toxicological concern in absence of safety data or structural analogs. Finally, where safety endpoint gaps are identified which cannot be resolved without additional in vitro or in vivo studies, the botanical compositional data are critical to inform on study design. Results with three herbal preparations demonstrate the utility of this novel approach to identify potential hazards and establish safe human use levels for botanicals in a cost efficient and informative manner that minimizes animal use.

Multi-Detector Characterization of Grape Seed Extract to Enable in silico Safety Assessment

“…Thus, 91% of GSE-1 bulk material was accounted for by the CAD detector. Furthermore, the response factor was used to determine which CAD peaks were above the threshold of toxicological concern (Little et al, 2017 ; i.e., at 90 μg per 210 mg dose) for the GSE dietary supplement. Ultimately, there were a total of 39 CAD peaks detected, which were comprised of at least 83 individual components, as determined by HRMS (Figure S6 ).…”

“…There has been no indication of adverse reproductive or developmental effects in humans from dietary exposure to GSE (nor some of the individual components that have been tested), but due to the lack of developmental data, focus was given to constituents with a resulting exposure above Cramer Class III in the TTC approach (European Food Safety and World Health, 2016 ). The application of TTC in an in silico approach to assess safety of botanical dietary supplement ingredients has been discussed previously but in brief is based, in part, on targeting a lower limit of detection for constituent characterization that enables a TTC approach (Little et al, 2017 ). This allows for a worst-case risk assessment to be performed for specific chemical entities.…”

“…Herein, the individual constituents of a GSE, coded GSE-1, above a threshold of toxicological concern (TTC) were quantified and characterized using an ultrahigh performance liquid chromatography–ultraviolet–charged aerosol detector–high resolution mass spectrometry (UHPLC-UV-CAD-HRMS) system, as has been previously reported (Little et al, 2017 ). While there have been no indications of adverse reproductive or developmental effects in humans from dietary exposure to GSE (nor individual components that have been tested), the lack of available developmental toxicity data guided us into taking a conservative approach, using a TTC in accordance with Cramer Class III (90 μg/person/day) (European Food Safety and World Health, 2016 ).…”

“…Similarly, GC-FID and GC-HRMS were used to quantify and identify the volatile constituents, respectively. Using this multi-detector approach, the individual constituents of the GSE were characterized with the very specific goal of using the data for an in silico safety assessment to help guide or obviate the need for classical in vitro and in vivo safety studies (Little et al, 2017 ; VanderMolen et al, 2017 ; Baker and Regg, 2018 ). It should be noted that for the purposes of an in silico safety assessment using the TTC approach, the absolute identification of a constituent is not necessarily required.…”

The role of mass spectrometry and related techniques in the analysis of extractable and leachable chemicals

“…HPLC-CAD-MS is a platform that has been used extensively to quantify and identify small molecule botanicals (Eom et al, 2010;Baker and Regg, 2018;Sica et al, 2018). The botanical safety approach uses the same TTC or SCT thresholds that are converted to an AET to draw the quantitative line for which all chemicals above need to be identified (Little et al, 2017).…”