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Development of a high-performance thin-layer chromatography method for the rapid quantification of S-equol in biological samples of albino Wistar rats

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Abstract

Equol, an exclusive gut bacteria metabolite, is associated with the incidence of low blood pressure, strokes, and hormone-related cancers due to its estrogen-mimicking structure and antioxidant properties. However, all humans cannot produce S-equol upon consumption of soybean and are thus deprived of the health benefits. Existing methods of equol estimation involve complex instrumentation, which is time-consuming and expensive. Therefore, in this study, we develop a simple, cost-effective, accurate, and rapid high-performance thin-layer chromatography (HPTLC) method for equol estimation. Chromatography was performed on precoated silica gel aluminum 60 F254 HPTLC plates, and it produced a compact spot of equol [retardation factor (RF) value of 0.77 ± 0.04] with a mobile phase ethyl acetate–toluene–formic acid in the ratio 5:4:1 (V/V). Ultraviolet detection was performed densitometrically at λmax 200 nm. The method was validated for precision, recovery, robustness, specificity, limit of detection, and limit of quantification, following the International Council for Harmonisation (ICH) guidelines. It was found that S-equol concentration was higher in rats fed with fermented soybean, and the concentration was higher in feces as compared with urine samples. The highest S-equol content in feces and urine was 16.74 µg g−1 and 6.34 µg mL−1, respectively. Quantification of S-equol by HPTLC enables us to segregate the human population into two groups: equol producers/healthy individuals and nonequol producers/nonhealthy individuals. In this era of personalized medicine, such an insight will prove to be of great value and also reduce the drug load on our body.

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Acknowledgements

The authors are very thankful to the Indian Council Medical Research (ICMR), New Delhi, Ministry of Health and Family Welfare, Government of India for providing financial support to this project under grant sanction no. 3/1/2/89/2018-(Nut).

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Authors and Affiliations

  1. Department of Food Technology, School of Interdisciplinary Sciences & Technology (SIST), Jamia Hamdard, New Delhi, 110062, India

    Megha Gangwar

  2. Microbial and Pharmaceutical Biotechnology Laboratory (MPBL), Department of Pharmacognosy & Phytochemistry, School of Pharmaceutical Education & Research (SPER), Jamia Hamdard, New Delhi, 110062, India

    Megha Gangwar, Jalaluddin Khan & Bibhu Prasad Panda

  3. Department of Chemistry, School of Chemical & Life Sciences (SCLS), Jamia Hamdard, New Delhi, 110062, India

    Mohammad Sarwar Alam

  4. Department of Pharmacognosy & Phytochemistry, School of Pharmaceutical Education & Research (SPER), Jamia Hamdard, New Delhi, 110062, India

    Adil Ahamad

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Correspondence to Bibhu Prasad Panda.

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The authors declare that the animals used in this research work are approved by the Institutional Animal Ethics committee (IAEC), Jamia Hamdard registration number 173/GO/Re/S/2000/CPCSEA project number 1476, and the animals were used per CPCSEA Guidelines for animal experimentation.

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Gangwar, M., Khan, J., Alam, M.S. et al. Development of a high-performance thin-layer chromatography method for the rapid quantification of S-equol in biological samples of albino Wistar rats. JPC-J Planar Chromat 37, 57–67 (2024). https://doi.org/10.1007/s00764-024-00287-y

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