Delaying the Chronological Aging of the Yeast Saccharomyces cerevisiae by Six Plant Extracts

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Researchers from Concordia University in Montreal, Quebec, Canada, in collaboration with the Quebec-based biotech company Idunn Technologies, published a study in the Journal Oncotarget on 29 March 2016, describing their discovery of six plant extracts that increase yeast chronological lifespan to a significantly greater extent than any of the presently known longevity-extending chemical compounds.  1

For the study, the researchers examined many plant extracts that would increase the chronological lifespan of yeast.  They finally found and used 37 plant extracts for this study.  These plant extracts are listed in the Table 1 below:

Table 1: List of plant extracts that have was used in this study

Abbreviated nameBotanical namePlant part used
PE1Echinacea purpureaWhole plant
PE2Astragalus membranaceousRoot
PE3Rhodiola rosea L.Root
PE4Cimicifuga racemosaRoot and rhizome
PE5Valeriana officinalis L.Root
PE6Passiflora incarnate L.Whole plant
PE7Polygonum cuspidatumRoot and rhizome
PE8Ginkgo bilobaLeaf
PE9Zingiber officinale RoscoeRhizome
PE10Theobroma cacao L.Cacao nibs
PE11Camellia sinensis L. KuntzeLeaf
PE12Apium graveolens L.Seed
PE13Scutellaria baicalensisRoot
PE14Euterpe oleraceaFruit
PE15Withania somniferaRoot and leaf
PE16Phyllanthus emblicaFruit
PE17Camellia sinensisLeaf
PE18Pueraria lobataRoot
PE19Silybum marianumSeed
PE20Eleutherococcus senticosusRoot and stem
PE21Salix albaBark
PE22Glycine max L.Bean
PE24Calendula officinalisFlower
PE25Salvia miltiorrhizaRoot
PE27Panax quinquefoliumRoot
PE28Harpagophytum procumbensRoot
PE29Olea europaea L.Leaf
PE30Gentiana luteaRoot
PE31Piper nigrumFruit
PE32Aesculus hippocastanumSeed
PE33Mallus pumila Mill.Fruit
PE34Fragaria spp.Fruit
PE35Ribes nigrumLeaf
PE36Dioscorea oppositaRoot
PE37Cinnamomum verumBark

Table source:  Discovery of plant extracts that greatly delay yeast chronological aging and have different effects on longevity-defining cellular processes

The means by which these six plant extracts (PEs) delays the onset and decreases the rate of yeast chronological aging is by eliciting a hormetic stress response. The budding yeast Saccharomyces cerevisiae is a beneficial model organism for the discovery of genes, signaling pathways and chemical compounds that slow cellular and organismal aging in eukaryotes across phyla.  Yeast was chosen in this study because aging progresses similarly in both yeast and humans.

The six PEs that were identified include:  2

  • Black Cohosh (Cimicifuga racemosa) (PE4)
  • Valerian  (Valeriana officinalis L.)  (PE5)
  • Passion Flower  (Passiflora incarnata L.)  (PE6)
  • Ginko Biloba  (Ginko biloba)  (PE8)
  • Celery Seed  (Apium graveolens L.)  (PE12)
  • White Willow  (Salix alba)  (PE21)

 

The six identified PEs out of the thirty-seven PEs that were examined showed the highest percentage increase of lifespan, (also known as the chronological lifespan (CLS)), in the yeast,   The researchers determined both the mean (average) CLS and the maximum CLS of the six PEs.

Table 2 below list the six PEs and their mean and max. CLS:

Table 2: Percent increase of lifespan of S. cerevisiae by 6 PEs

Plant Extract (PE)Mean CLSMax CLS
PE4 (Black Cohosh)195%100%
PE5 (Valerian)185%87%
PE6 (Passion Flower)180%80%
PE8 (Ginko Biloba)145%104%
PE12 (Celery Seed)160%107%
PE21 (White Willow)475%369%
CLS - Chronological Lifespan

(Source:  Discovery of plant extracts that greatly delay yeast chronological aging and have different effects on longevity-defining cellular processes)

The researchers noted that PE21 appears to be the most potent longevity-extending pharmacological intervention presently known. It increases the mean and maximum CLS of yeast by 475% and 369%, respectively.  PE21 or White Willow bark represents a much greater effect than rapamycin and metformin, the two best drugs known for their anti-aging effects.

These findings by the researchers imply that these extracts slow aging in the following ways:  3

  • PE4 (Black Cohosh) decreases the efficiency with which the pro-aging TORC1 pathway inhibits the anti-aging SNF1 pathway;
  • PE5 (Valerian) mitigates two different branches of the pro-aging PKA pathway;
  • PE6 (Passion Flower) coordinates processes that are not assimilated into the network of presently known signaling pathways/protein kinases;
  • PE8 (Ginko biloba) diminishes the inhibitory action of PKA on SNF1;
  • PE12 (Celery Seed) intensifies the anti-aging protein kinase Rim15; and
  • PE21 (White Willow) inhibits a form of the pro-aging protein kinase Sch9 that is activated by the pro-aging PKH1/2 pathway.

The researchers showed that each of these six PEs decelerates yeast chronological aging and has different effects on several longevity-defining cellular processes, as illustrated in Figure 1.

An external file that holds a picture, illustration, etc. Object name is oncotarget-07-50845-g009.jpg

Figure 1.  A model for how PE4, PE5, PE6, PE8, PE12 and PE21 delay yeast chronological aging via the longevity-defining network of signaling pathways/protein kinases.  Activation arrows and inhibition bars denote pro-aging processes (displayed in blue color) or anti-aging processes (displayed in red color). Pro-aging or anti-aging signaling pathways and protein kinases are displayed in blue or red color, respectively.  (Source: Discovery of plant extracts that greatly delay yeast chronological aging and have different effects on longevity-defining cellular processes)

Each of the six PEs have different effects on cellular processes that define longevity in organisms across phyla. These effects include the following:

  • increased mitochondrial respiration and membrane potential;
  • augmented or reduced concentrations of reactive oxygen species;
  • decreased oxidative damage to cellular proteins, membrane lipids, and mitochondrial and nuclear genomes;
  • enhanced cell resistance to oxidative and thermal stresses; and
  • accelerated degradation of neutral lipids deposited in lipid droplets.

The researchers also revealed that certain combinations of the six PEs could markedly increase aging-delaying proficiencies of each other.

In conclusion, the study stated that the obvious challenge was to assess whether any of the six PEs can delay the onset and progression of chronic diseases associated with human aging.  Idunn Technologies is collaborating with four other universities for six research programs, to go beyond yeast, and work with an animal model of aging, as well as two cancer models.  4

This study and ongoing research reveals five features of the six PEs as potential interventions for decelerating chronic diseases of old age. These five features include:  5

  • the six PEs are caloric restriction (CR) mimetics that imitate the aging-delaying effects of the CR diet in yeast under non-CR conditions;
  • they are geroprotectors that slow yeast aging by eliciting a hormetic stress response;
  • they extend yeast longevity more efficiently than any lifespan-prolonging chemical compound yet described;
  • they delay aging through signaling pathways and protein kinases implicated in such age-related pathologies as type 2 diabetes, neurodegenerative diseases, cardiac hypertrophy, cardiovascular disease, sarcopenia and cancers; and
  • they extend longevity and delay the onset of age-related diseases in other eukaryotic model organisms.