A sirtuin activating biofunctional fights ageing

The dramatic increase in the ageing population and the psychosocial impact of skin ageing has created a demand for new effective interventions. Two related scientific breakthroughs in anti-ageing research were made in the previous decade. First, experiments carried out in yeast led to the proposal that the silent information regulator 2 (Sir2) or sirtuins act as a mediator of life-span extension from dietary restriction.3 Second, resveratrol present in grape skins was identified as an in vitro activator of Sir2 and was reported to increase life span in yeast, worms and flies.4 Since then, sirtuins have gone from a relatively uncharacterised family of proteins to some of the most studied in anti-ageing research. This family of nicotinamide adenine dinucleotide (NAD+)-dependent enzymes are known to deacetylate histones, leading to increased DNA stability and prolonged survival. They are key regulators of cell defence and survival in response to stress involved in diverse biological functions, including cell development, metabolism, gene silencing, DNA repair, cell cycle progression, apoptosis, heterochromatin formation.5 In human skin, SIRT-1 is expressed in the epidermis and dermis. As skin ages, it is subjected to numerous stresses, particularly from UV irradiation. A recent study showed that UVB down-regulates SIRT-1, and Oberdoerffer et al demonstrated that when DNA is damaged by UV light or free radicals, sirtuins act as an emergency choice of response and aid DNA repair mechanism at the site of damage.6 Orsirtine GL, extracted from Oryza sativa, contains SIRT-1-activating compounds, also called “STACS”. Orsitine GL offers a new strategy in photoageing and more generally as a global anti-ageing active ingredient, based on sirtuins, that protects and promotes skin longevity.

Activating SIRT-1 in skin

In fresh ex vivo skin samples, Orsirtine GL (now referred to as ‘the anti-ageing active’) at 1% increases SIRT-1 expression. SIRT-1 exhibited predominant nuclear expression throughout the epidermis. This nuclear localisation of SIRT-1 confirms the essential role of sirtuins in protection and cell survival against stress. Interestingly, SIRT-1 is more strongly expressed with the antiageing active than with resveratrol, a well known SIRT-1 biofunctional ingredient. To further evaluate the expression of SIRT-1, fibroblasts treated with the antiageing active (1%) for 48 hours were analysed by immunostaining (Fig. 1) and western blot analysis. An increase of 29% in SIRT-1 expression, compared to the placebo was observed.