Selective extraction of Cyclopia for enhanced in vitro phytoestrogenicity
Date
2008-03
Authors
Mfenyana, Ciko
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Phytoestrogens are plant compounds whose ability to mimic the action of estrogens has
resulted in their usage for the treatment of menopausal symptoms. Despite uncertainties about the
safety and effectiveness of phytoestrogens in humans, the use of market phytoestrogenic
nutraceuticals and botanicals is on the increase. Positive epidemiological study findings coupled to
an entrenched belief in many societies about the superiority of what they view as “natural”
remedies, as well as the reluctance of women to use the traditional hormone replacement therapy
due to its association with detrimental health effects as reported by studies such as the World Health
Initiative, the Million Women and the Kronos Early Estrogen Prevention studies, are thought to be
instrumental in the growth of the phytoestrogen market.
As the subject of the current thesis, we investigated the candidacy of extracts of the
honeybush plant (genus Cyclopia), which is used for the manufacture of popular tea beverages, for
use in the formulation of a high quality phytoestrogenic nutraceutical with a competitive market
edge. We evaluated four harvestings of Cyclopia (M6-9) available in bulk and selected 2
harvestings (M6 and M7) for further extraction using solvents of differing polarity and also
mimicking the preparation of a cup of tea. Our findings clearly demonstrate that of the resultant 22
extracts the SM6Met and SM6EAc extracts had the highest in vitro potency and efficacy,
respectively. Another exciting finding from our study is the unequivocal demonstration of
phytoestrogenic activity by extracts prepared in the same manner as the traditional cup of
honeybush tea. Additionally, our study has highlighted the importance and the influence of
experimental variables such as the specific harvesting evaluated and the characteristics of the
extraction solvent (e.g. polarity and temperature) on the yield and the estrogenic activity of the
extracts. In addition, the advantage of certain in vitro assays over others for discriminating between
estrogenic substances based on their efficacies and potencies was demonstrated with the alkaline
phosphatase assay being most suitable for discriminating efficacy and the E-screen most suitable for
discriminating potency.
Furthermore, our study has imparted a valuable lesson about the pharmacological behavior
of estrogenic substances by presenting a conundrum in the form of the two desirable
pharmacological parameters (potency and efficacy) occurring in different extracts, an outcome that
complicates the central aim of our study, which is the preparation of an extract that embodies both
parameters. Additionally, the low quantity of known putative phytoestrogens and the presence of
unidentified polyphenols in M6, the source of our choice extracts (SM6Met and SM6EAc), makes
the high estrogenic potency and efficacy of the choice extracts that much more intriguing.
Nonetheless, benchmarking against four market phytoestrogen extracts indicate that the Cyclopia
extracts have comparable estrogenicity suggesting potential as marketable phytoestrogenic
preparations. The combination of the achievement of aims and the birth of new questions from that
very achievement, which are the hallmark of scientific endeavors, have made this study a rewarding
experience and we hope to share the feeling in its entirety with the reader.
Description
Thesis (MSc (Biochemistry))--University of Stellenbosch, 2008.
Keywords
Cyclopia, Phytoestrogens, Nutraceutical, Menopause, Dissertations -- Biochemistry, Theses -- Biochemistry, Herbs -- Therapeutic use