Effects of Potentised Substances on Growth Kinetics of Saccharomyces cerevisiae and Schizosaccharomyces pombe
Claudia Scherra, Stephan Baumgartnera, Jörg Spranger, Meinhard Simond
Key Words
Homeopathic potencies · Yeast · Saccharomyces cerevisiae ·
Schizosaccharomyces pombe · Test system stability
Summary
Background: Homeopathic potencies are used as specific remedies
in complementary medicine. Since the mode of action is
unknown, the presumed specificity is discussed controversially.
Objective: This study investigated the effects of potentised substances
on two yeast species, Saccharomyces cerevisiae and
Schizosaccharomyces pombe, in a stable and reliable test system
with systematic negative controls. Materials and Methods:
Yeast cells were cultivated in either potentised substances or
water controls in microplates and their growth kinetics were
measured photometrically. Water control runs were performed
repeatedly to investigate the stability of the experimental set-up
(systematic negative controls). Results: 4 out of 14 screened
substances seem to have affected the growth curve parameters
slope or yield. Out of these substances, azoxystrobin and phosphorus
were chosen for 8 further replication experiments,
which partly confirmed the results of the screening. On the average
of all experiments, azoxystrobin affected the slope of the
growth curve of Saccharomyces cerevisiae (p < 0.05), and phosphorus
affected the slope of the growth curve of Schizosaccharomyces
pombe (p < 0.05). No effects were seen in the water
control runs. In addition, significant interactions between treatment
with potentised substances and experiment number were
observed in all experiments with potentised substances (p <
0.01), but not in the water control runs. Conclusions: Both yeast
species reacted to certain potentised substances by changing
their growth kinetics. However, the interactions found point to
additional factors of still unknown nature, that modulate the effects
of potentised substances. This stable test system with
yeasts may be suitable for further studies regarding the efficacy
of homeopathic potencies.