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DEFINITION: The idea that certain plant substances can have a longevity-conferring effect on humans.



Why do so many medicines come from plants? There is no doubt that certain plant substances interact with our bodies in a manner which enhances our health. There are many examples of such interaction including bioactives such as salicylates from willows, resveratrol from grapes, EGCG from green tea, and curcumin from tumeric. The xenohormesis hypothesis provides a potential explanation for why such beneficial interactions occur.

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Also check out the short blurb here.

Small molecules that regulate lifespan: evidence for xenohormesis
Laming, Wood, and Sinclair

QUOTE: "The xenohormesis hypothesis. Sirtuin enzymes evolved early in life's history to increase somatic maintenance and survival during times of adversity. The xenohormesis hypothesis of Howitz and Sinclair proposes that primordial species synthesized polyphenolic molecules to stimulate sirtuins during times of stress. Plants have retained this ability. Survival pathways in fungi and animals have retained the ability to respond to plant stress signalling molecules because they provide useful prediction about the state of the environment and/or food supply. This ability would allow organisms to prepare for and survive adversity when they might otherwise perish."


Xenohormesis: Sensing the Chemical Cues of Other Species
Howitz and Sinclair

QUOTE: "Stress-induced plant molecules such as resveratrol, butein, and fisetin can induce defense responses in fungi, nematodes, flies, fish, and mice, leading to an extended life span (Westphal et al., 2007). It has been suggested that such molecules are 'caloric restriction mimetics' (Howitz et al., 2003). As interpreted in the xenohormesis theory, the molecules send a chemical cue analogous to alternate-day fasting. This cue is an early warning gleaned from the environmental stresses felt by the food supply while that food supply is still available."

QUOTE: "Polyphenols are a major group of plant secondary metabolites that encompass a number of chemical classes, including chalcones, stilbenes, flavones, isoflavones, catechins, and anthocyanidins. Interestingly, the majority of these molecules are synthesized by plants in response to stress."


Xenohormesis - What Doesn't Kill Plants May Make Us Stronger

Xenohormesis is a biological principle that explains how environmentally stressed plants produce bioactive compounds that can confer stress resistance and survival benefits to animals that consume them.

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